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Sample records for trap gas chromatography-tandem

  1. Determination of volatile organic compounds in exhaled breath of heart failure patients by needle trap micro-extraction coupled with gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Biagini, D; Lomonaco, T; Ghimenti, S; Bellagambi, F G; Onor, M; Scali, M C; Barletta, V; Marzilli, M; Salvo, P; Trivella, M G; Fuoco, R; Di Francesco, F

    2017-11-29

    The analytical performances of needle trap micro-extraction (NTME) coupled with gas chromatography-tandem mass spectrometry were evaluated by analyzing a mixture of twenty-two representative breath volatile organic compounds (VOCs) belonging to different chemical classes (i.e. hydrocarbons, ketones, aldehydes, aromatics and sulfurs). NTME is an emerging technique that guarantees detection limits in the pptv range by pre-concentrating low volumes of sample, and it is particularly suitable for breath analysis. For most VOCs, detection limits between 20 and 500 pptv were obtained by pre-concentrating 25 ml of a humidified standard gas mixture at a flow rate of 15 ml min -1 . For all compounds, inter- and intra-day precisions were always below 15%, confirming the reliability of the method. The procedure was successfully applied to the analysis of exhaled breath samples collected from forty heart failure (HF) patients during their stay in the University Hospital of Pisa. The majority of patients (about 80%) showed a significant decrease of breath acetone levels (a factor of 3 or higher) at discharge compared to admission (acute phase) in correspondence to the improved clinical conditions during hospitalization, thus making this compound eligible as a biomarker of HF exacerbation.

  2. Doping control analysis of anabolic steroids in equine urine by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wong, April S Y; Leung, Gary N W; Leung, David K K; Wan, Terence S M

    2017-09-01

    Anabolic steroids are banned substances in equine sports. Gas chromatography-mass spectrometry (GC-MS) has been the traditional technique for doping control analysis of anabolic steroids in biological samples. Although liquid chromatography-mass spectrometry (LC/MS) has become an important technique in doping control, the detection of saturated hydroxysteroids by LC-MS remains a problem due to their low ionization efficiency under electrospray. The recent development in fast-scanning gas-chromatography-triple-quadrupole mass spectrometry (GC-MS/MS) has provided a better alternative with a significant reduction in chemical noise by means of selective reaction monitoring. Herein, we present a sensitive and selective method for the screening of over 50 anabolic steroids in equine urine using gas chromatography-tandem mass spectrometry (GC-MS/MS). Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Multiresidue determination of pesticides in fruit and vegetables by gas chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Gamón, M; Lleó, C; Ten, A; Mocholí, F

    2001-01-01

    Pesticide residues in fruit and vegetables were determined by gas chromatography/tandem mass spectrometry (GC/MS/MS). Electron impact (EI)/MS/MS and chemical ionization (CI)/MS/MS were developed for 80 compounds, including organochlorine, organophosphorus, organonitrogen, and pyrethroids, providing unambiguous spectral confirmation for these complex matrixes. Residues were extracted from samples with acetone followed by a mixture of dichloromethane-petroleum ether. Two injections per sample were required for analysis of the entire pesticide list by EI/MS/MS and CI/MS/MS. Initial steps involving cleanup and concentration of extracts were eliminated. The excellent selectivity and good linearity allowed quantification and identification of low levels of pesticides in the most difficult matrixes. The method has been used for routine analysis of many vegetables.

  4. Integrated gas and liquid chromatography tandem mass spectrometry for forensic engine lubricating oil identification

    International Nuclear Information System (INIS)

    Shang, D.; McPherson, B.

    2009-01-01

    This paper presented a method for rapid chemical characterization of engine lubricating oils. Motor oils typically contain up to 5 per cent additives, such as detergent, antifoamant, dispersant, emulsifier, antioxidant, friction modifier, colour stabilizer and corrosion inhibitors. Different lube oil products usually have either different additives in various concentrations. As such, the formulation of additives in lube oil products should provide fingerprint information for forensic oil identification. The characterization method used in this study was based on a newly developed fast solvent liquid-liquid sample extraction procedure that combined the use of both liquid chromatography tandem mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) simultaneously together with gas chromatography flame ionization detection (GC-FID). The method was used on a blind sample testing of commercially available engine lubricating products. The sample extraction procedure involved extraction of additives into acidified acetonitrile, two hexane washes of hydrophobic components of lube oil, filtration, and dilution with solvents for GC and LC analysis. The new method proved to be rapid and easy to use. It enabled the identification of unknown additives and hydrocarbons in many different types of fresh lube oils. Further tests will be needed to determine if this method can be used on real-world weathered samples. The method is part of an ongoing effort to deal with mysterious chemical spills, an important aspect of environmental protection and emergency preparedness. 8 refs., 7 figs

  5. Elucidation of urinary metabolites of fluoxymesterone by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Pozo, Oscar J; Van Thuyne, Wim; Deventer, Koen; Van Eenoo, Peter; Delbeke, Frans T

    2008-03-01

    The suitability of liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography mass spectrometry (GC-MS) for the elucidation of fluoxymesterone metabolism has been evaluated. Electrospray ionization (ESI) and collision induced dissociation (CID) fragmentation in LC-MS/MS and electron impact spectra (EI) in GC-MS have been studied for fluoxymesterone and two commercially available metabolites. MS(n) experiments and accurate mass measurements performed by an ion-trap analyser and a QTOF instrument respectively have been used for the elucidation of the fragmentation pathway. The neutral loss scan of 20 Da (loss of HF) in LC-MS/MS has been applied for the selective detection of fluoxymesterone metabolites. In a positive fluoxymesterone doping control sample, 9 different analytes have been detected including the parent compound. Seven of these metabolites were also confirmed by GC-MS including 5 previously unreported metabolites. On the basis of the ionization, the CID fragmentation, the accurate mass of the product ions and the EI spectra of these analytes, a tentative elucidation as well as a proposal for the metabolic pathway of fluoxymesterone has been suggested. The presence of these compounds has also been confirmed by the analysis of five other positive fluoxymesterone urine samples. Copyright (c) 2008 John Wiley & Sons, Ltd.

  6. A gas chromatography-tandem quadrupole mass spectrometric analysis of policosanols in commercial vegetable oils.

    Science.gov (United States)

    Jung, Dong Min; Lee, Mi Jin; Yoon, Suk Hoo; Jung, Mun Yhung

    2011-08-01

    Reportedly policosanols (PCs) have various beneficial functionalities on health. A gas chromatography-tandem mass spectrometry (GC-MS/MS) with a low limit of detection (LOD), and high specificity, recovery, and precision was successfully established for the PC analysis in vegetable oils. The LODs for the PCs were in the range of 0.002 to 0.016 μg/mL. The relative standard deviation (RSD) for the repeated analysis of PCs was less than 3.356%. The mean recoveries for spiked heptacosanol and octacosanol in vegetable oil were 102.3% and 106.3%, respectively. The total PC contents in the vegetable oils varied from 3.01 to 427.83 mg/kg oil. Perilla seed, grape seed, and rice bran oils were found to be highly rich sources of PCs, containing 427.83, 245.15, and 171.17 mg PCs/kg oil, respectively. Corn, sesame, and soybean oils contained only a negligible quantity of PCs. The PC composition in vegetable oils was greatly source dependent. In perilla seed oil, octacosanol was the single most predominant component, representing 55.93% of the total PC. In grape seed oil, however, hexacosanol is the most abundant PC, followed by octacosanol, tetracosanol, and triacontanol in a decreasing order. The major PCs in rice bran oil were triacontanol, octacosanol, hexacosanol, and tetracosanol, which constituted over 87.3% of the total PC. This represents the 1st report on the composition and contents of PC in most vegetable oils analyzed here. The information might be used for the development of vegetable oil products with beneficial functionality. © 2011 Institute of Food Technologists®

  7. Analysis of zearalenone and alpha-zearalenol in urine of ruminants using gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Plasencia, J; Mirocha, C J; Pawlosky, R J; Smith, J F

    1990-01-01

    The present paper describes a sensitive procedure for quantitative analysis of the Fusarium mycotoxins zearalenone and alpha-zearalenol in urine of ruminants. Extraction is done with an octadecyl (C18) column and cleanup with a silica column providing a preparation that is analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The trimethylsilyl ether derivatives of zearalenone and alpha-zearalenol yield molecular ions with m/z 462 and 536, respectively. These ions are selected in the first mass analyzer and then fragmented in a collision cell to give characteristic daughter ions (m/z 151, 333, 318, and 446). The method is known as multiple reaction monitoring (MRM). Elimination of chemical background noise by selecting proper fragment ions produces chromatograms in which identification and quantitation in a biological matrix is possible. The method was tested with sheep urine from an experimental feeding trial and was used to confirm natural mycotoxicosis of cows affected with zearalenone. Zearalenone (1 ppb) and alpha-zearalenol (14 ppb) were found in 2 different cow urine samples. The detection limit for both zearalenone and zearalenol is 1 ppb (1 ng/mL) in urine and is linear between 1 and 20 ppb for the former and 1 and 10 ppb for the latter.

  8. Simultaneous determination of organochlorine and pyrethriod pesticide residues in the Chinese patent medicines by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Mao, Xue J; Zhong, Yao; Yan, Ai P; Wang, Bin; Wang, Yuan X; Wan, Yi Q

    2018-02-01

    A simple, sensitive, reliable method was developed for the simultaneous determination of organochlorine and pyrethriod pesticide residues in Chinese patent medicines Six ingredient rehmannia pills and Xiaoyao pills. These pesticides were extracted by ethyl acetate. The extraction time and volume of ethyl acetate were optimized. Cleanup of extracts was performed with dispersive-solid phase extraction using graphitized carbon black as the sorbent. The determination of pesticides in the final extracts was carried out by gas chromatography-tandem mass spectrometry in multiple reaction monitoring mode (GC-MS/MS, MRM). The linearity of the calibration curves is good in matrix-matched standard and yields the coefficients of determination (R 2 ) ≥0.99 for all of the target analytes. Under optimized conditions, the average recoveries (five replicates) for most pesticides range from 75.5% to 114.6%, and RSDs are less than 10.0%. The LODs of 18 pesticides in Six ingredient rehmannia pill and Xiaoyao pills are in the range of 0.01-8.82 μg kg -1 . The developed method meets the requirements of pesticide residue analysis and could be effectively used for routine analysis of the organochlorine and pyrethriod pesticide residues in Six ingredient rehmannia pills and Xiaoyao pills.

  9. [Determination of propargite, tebuconazole and bromopropylate pesticide residues in Taiwan green jujubes by gas chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Qun; Liu, Chunhua; Wu, Nancun; Wu, Xiaofang; Li, Shuhuai

    2014-08-01

    An analytical method was established for the determination of propargite, tebuconazole and bromopropylate in Taiwan green jujubes (Zizyphus mauritiana Lam) by gas chromatography-tandem mass spectrometry (GC-MS/MS). The sample was extracted with acetonitrile from the Taiwan green jujubes after treated with a homogenizer. The organic phase was then separated from water phase by adding NaCl. The extract was further purified on a carbon/ NH2 cartridge with elution solvents of acetonitrile/toluene (3:1, v/v). Finally, the target analytes were separated by a capillary gas chromatographic column SLB-5MS (30 m x 0. 25 mm x 0. 25 μm). A tandem quadrupole mass spectrometer operated in either full scan mode or in MS/MS mode for multiple reaction monitoring (MRM) was used for the qualitative and quantitative analysis of the constituents, respectively. The results showed that the average recoveries of the three pesticides ranged from 75. 8% to 103. 6% with the RSDs of 1. 7%-9. 3% at the spiking levels from 0.01 mg/kg to 0. 50 mg/kg (n= 5). The calibration curves showed good linearity in the range of 0.01-0.50 mg/kg, with the determination coefficients over 0.99 (R2>0.99). The limits of quantification (LOQs) were 0.01 mg/kg for propargite, tebuconazole and bromopropylate in Taiwan green jujubes. The method is available for the determination of propargite, tebuconazole and bromopropylate pesticide residues in Taiwan green jujubes.

  10. Ring positional differentiation of isomeric N-alkylated fluorocathinones by gas chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Westphal, Folker; Junge, Thomas

    2012-11-30

    In analogy to our previously published procedure for the differentiation of regioisomeric fluoroamphetamines a method was developed, to differentiate ring positional isomeric fluorocathinones by product ion spectrometry of ions generated by chemical ionization (CI) under GC-MS conditions using methane as reagent gas. N-alkylated ortho-, meta- and para-fluorocathinones could be unequivocally differentiated by product ion spectrometry of the hydrogen fluoride loss ions [M+H-HF](+) using a triple quadrupole mass spectrometer with argon as collision gas under normalized collision conditions. This method enables the differentiation of ring positional isomers of fluorocathinones even in complex mixtures and low concentrations. The applicability of the method was shown by the analysis of synthesized N-alkylated ortho-, meta- and para-fluorocathinones and seized designer drug mixtures. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  11. Application of gas chromatography-tandem mass spectrometry for the determination of amphetamine-type stimulants in blood and urine.

    Science.gov (United States)

    Woźniak, Mateusz Kacper; Wiergowski, Marek; Aszyk, Justyna; Kubica, Paweł; Namieśnik, Jacek; Biziuk, Marek

    2018-01-30

    Amphetamine, methamphetamine, phentermine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), and 3,4-methylenedioxy-N-ethylamphetamine (MDEA) are the most popular amphetamine-type stimulants. The use of these substances is a serious societal problem worldwide. In this study, a method based on gas chromatography-tandem mass spectrometry (GC-MS/MS) with simple and rapid liquid-liquid extraction (LLE) and derivatization was developed and validated for the simultaneous determination of the six aforementioned amphetamine derivatives in blood and urine. The detection of all compounds was based on multiple reaction monitoring (MRM) transitions. The most important advantage of the method is the minimal sample volume (as low as 200μL) required for the extraction procedure. The validation parameters, i.e., the recovery (90.5-104%), inter-day accuracy (94.2-109.1%) and precision (0.5-5.8%), showed the repeatability and sensitivity of the method for both matrices and indicated that the proposed procedure fulfils internationally established acceptance criteria for bioanalytical methods The procedure was successfully applied to the analysis of real blood and urine samples examined in 22 forensic toxicological cases. To the best of our knowledge, this is the first work presenting the use of GC-MS/MS for the determination of amphetamine-type stimulants in blood and urine. In view of the low limits of detection (0.09-0.81ng/mL), limits of quantification (0.26-2.4ng/mL), and high selectivity, the procedure can be applied for drug monitoring in both fatal and non-fatal intoxication cases in routine toxicology analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Fast methods for screening of trichothecenes in fungal cultures using gas chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Kristian Fog; Thrane, Ulf

    2001-01-01

    The paper presents a fast method for trichothecene profiling and chemotaxonomic studies in species of Fusarium, Stachybotrys, Trichoderma and Memnoniella. Micro scale extracted crude Fusarium extracts were derivatised using pentafluoropropionic anhydride and analysed by gas chromatography......-acetoxyscirpentriol, nivalenol, fusarenon-X, deoxynivalenol, 15-acetyl- deoxynivalenol and 3-acetyl-deoxynivalenol possible during a 23-min GC run. A slightly modified method could detect trichothecenes produced by Stachybotrys, Memnoniella and Trichoderma, by hydrolysing crude extracts prior to derivatisation...... with heptafluorobuturyl imidazole. All types of derivatised extracts could be reanalysed using negative ion chemical ionisation (NICI) GC-MS for molecular mass determination and verification purposes. A retention time index could be used for correction in retention time drifts between sequences and worked both in EI...

  13. Quantitation of metabolites of the nerve agents sarin, soman, cyclohexylsarin, VX, and Russian VX in human urine using isotope-dilution gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Barr, John R; Driskell, W J; Aston, Linda S; Martinez, Rodolfo A

    2004-01-01

    Organophosphorus nerve agents are among the most toxic organic compounds known and continue to be a threat for both military and terrorist use. We have developed an isotope-dilution gas chromatography-tandem mass spectrometric (GC-MS-MS) method for quantitating the urinary metabolites of the organophosphorus nerve agents sarin (GB), soman (GD), VX, Russian VX (RVX), and cyclohexylsarin (GF). Urine samples were acidified, extracted into ether-acetonitrile, derivatized by methylation with diazomethane, and analyzed by GC-MS-MS. The limits of detection were less than 1 micro g/L for all analytes.

  14. New Methodologies for Qualitative and Semi-Quantitative Determination of Carbon-Centered Free Radicals in Cigarette Smoke Using Liquid ChromatographyTandem Mass Spectrometry and Gas Chromatography-Mass Selective Detection

    Directory of Open Access Journals (Sweden)

    Gerardi AR

    2014-12-01

    Full Text Available Several approaches were explored to develop a high throughput procedure for relative determination of 14 different carbon-centered free radicals, both acyl and alkylaminocarbonyl type, in cigarette smoke. Two trapping procedures using 3-cyano-2,2,5,5-tetramethyl-1-pyrrolidinyloxy, or 3-cyanoproxyl radical (3-CNP were designed for this study: a trapping in solution and b trapping on a solid support which was a Cambridge filter pad. Fresh whole smoke and vapor phase smoke from mainstream cigarette smoke from Kentucky Reference Cigarettes 2R4F, as partitioned via an unadulterated Cambridge filter pad, were transferred into each trapping system in separate experiments. The 3-CNP coated Cambridge filter pad approach was shown to be superior to the impinger procedure as described in this study. Gas chromatography coupled with mass selective detection (GC-MS was employed for the first time as an alternate means of detecting several relatively highly concentrated radical adducts. Liquid chromatography tandem mass spectrometry (LC-MS/MS with precursor ion monitoring and selected ion monitoring (SIM was used for detecting the large array of radicals, including several not previously reported: formyl, crotonyl, acrolein, aminocarbonyl, and anilinocarbonyl radicals. Relative quantitation was achieved using as external calibration standards of 4-(1-pyrrolidinobenzaldehyde and nicotine. It was determined that the yield of carbon-centered free radicals by reference cigarette 2R4F was approximately 265 nmoles/cigarette at 35 mL puff/60 sec interval/2 sec duration smoking conditions.

  15. Inorganic arsenic contents in ready-to-eat rice products and various Korean rice determined by a highly sensitive gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jung, Mun Yhung; Kang, Ju Hee; Jung, Hyun Jeong; Ma, Sang Yong

    2018-02-01

    Rice and rice products have been reported to contain high contents of toxic inorganic arsenic (iAs). The inorganic arsenic contents in microwavable ready-to-eat rice products (n=30) and different types of Korean rice (n=102) were determined by a gas chromatography-tandem mass spectrometry (GC-MS/MS). The method showed low limit of detection (0.015pg), high intra- and inter-day repeatability (eat rice products was 59μgkg -1 (dry weight basis). The mean iAs contents in polished white, brown, black, and waxy rice were 65, 109, 91, and 66μgkg -1 , respectively. The percentages of ready-to-eat rice products, white, brown, black, and waxy rice containing iAs over the maximum level (100μgkg -1 ) set by EU for the infant foods were 17, 4, 70, 36 and 0%, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Phytochemical analyses of Ziziphus jujuba Mill. var. spinosa seed by ultrahigh performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Yang, Bao; Yang, Hongshun; Chen, Feng; Hua, Yanglin; Jiang, Yueming

    2013-11-21

    Ziziphus jujuba Mill. var. spinosa (Z. jujuba) seeds have attracted much attention within the field of medicine due to their significant effects against disturbances of the central nervous system. Secondary metabolites composition is key to the influence of the pharmaceutical and commercial qualities of this plant. In this work, the phytochemical profile of Z. jujuba seeds was analysed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS). The UPLC-MS/MS information identified the main secondary metabolites in Z. jujuba seeds, including flavonoid C-glycosides, triterpene acids and unsaturated fatty acids. The leading chemical identified by UPLC-MS/MS was betulinic acid, and oleic acid was the leading volatile from the GC-MS results. All the samples tested showed similar phytochemical profiles, but levels of the chemical compounds varied. Principal component analysis revealed the principal secondary metabolites that could define the differences in quality. It was confirmed that the combination of UPLC-MS/MS and GC-MS was an effective technique to demonstrate the pharmaceutical quality of Z. jujuba seeds.

  17. Quantification of endocrine disruptors and pesticides in water by gas chromatography-tandem mass spectrometry. Method validation using weighted linear regression schemes.

    Science.gov (United States)

    Mansilha, C; Melo, A; Rebelo, H; Ferreira, I M P L V O; Pinho, O; Domingues, V; Pinho, C; Gameiro, P

    2010-10-22

    A multi-residue methodology based on a solid phase extraction followed by gas chromatography-tandem mass spectrometry was developed for trace analysis of 32 compounds in water matrices, including estrogens and several pesticides from different chemical families, some of them with endocrine disrupting properties. Matrix standard calibration solutions were prepared by adding known amounts of the analytes to a residue-free sample to compensate matrix-induced chromatographic response enhancement observed for certain pesticides. Validation was done mainly according to the International Conference on Harmonisation recommendations, as well as some European and American validation guidelines with specifications for pesticides analysis and/or GC-MS methodology. As the assumption of homoscedasticity was not met for analytical data, weighted least squares linear regression procedure was applied as a simple and effective way to counteract the greater influence of the greater concentrations on the fitted regression line, improving accuracy at the lower end of the calibration curve. The method was considered validated for 31 compounds after consistent evaluation of the key analytical parameters: specificity, linearity, limit of detection and quantification, range, precision, accuracy, extraction efficiency, stability and robustness. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Determination of phthalic acid esters in water samples by hollow fiber liquid-phase microextraction prior to gas chromatography tandem mass spectrometry.

    Science.gov (United States)

    González-Sálamo, Javier; González-Curbelo, Miguel Ángel; Socas-Rodríguez, Bárbara; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel Ángel

    2018-06-01

    A new hollow fiber liquid-phase microextraction (HF-LPME) method has been developed for the extraction of a group of phthalic acid esters (PAEs) of interest from different water samples prior to gas chromatography tandem mass spectrometry analysis. HF-LPME was carried out using 1-octanol as extraction solvent followed by a back extraction step with cyclohexane. The different parameters that affect HF-LPME such as sample pH, ionic strength, extraction time, stirring rate, extraction temperature and back extraction conditions were investigated. The optimized conditions involved the extraction of 10 mL of sample without pH adjustment or addition of salt during 75 min under a stirring of 850 rpm at 60 °C and subsequent desorption with 200 μL of cyclohexane for 10 min in an ultrasonic bath. The method was validated in terms of calibration and recovery studies using dibutyl phthalate-d 4 as internal standard. The developed procedure gave satisfactory recovery (74-120%) and relative standard deviation values (<20%) for the studied PAEs in mineral, tap, pond and waste water samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Analysis of Nitrosamines in Cooked Bacon by QuEChERS Sample Preparation and Gas Chromatography-Tandem Mass Spectrometry with Backflushing.

    Science.gov (United States)

    Lehotay, Steven J; Sapozhnikova, Yelena; Han, Lijun; Johnston, John J

    2015-12-02

    Nitrites are added as a preservative to a variety of cured meats, including bacon, to kill bacteria, extend shelf life, and improve quality. During cooking, nitrites in the meat can be converted to carcinogenic nitrosamines (NAs), the formation of which is mitigated by the addition of antioxidants. In the past, the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) monitored NAs in pan-fried bacon, but FSIS terminated monitoring of NAs in the 1990s due to the very low levels found. FSIS recently chose to conduct a risk assessment of NAs in cooked bacon to determine if current levels warrant routine monitoring of NAs again. To meet FSIS needs, we developed, validated, and implemented a new method of sample preparation and analysis to test cooked bacon for five NAs of most concern, which consist of N-nitroso-dimethylamine, -diethylamine, -dibutylamine, -piperidine, and -pyrrolidine. Sample preparation was based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) approach and analysis by gas chromatography-tandem mass spectrometry. Ruggedness was improved markedly in the analysis of the complex fatty extracts by backflushing the guard column, injection liner, and half of the analytical column after every injection. Validation results were acceptable with recoveries of 70-120% and bacon gave slightly lower concentrations overall compared to pan-frying.

  20. [Determination of pyrethroid pesticides in tea by series two-solid phase extraction-columns cleanup and gas chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Liu, Li; Zhang, Qi; Wang, Haiyan; Feng, Feng; Cao, Hairong; Yang, Zhen; Ke, Zhijun; Chen, Xiyao

    2017-08-08

    A rapid determination method of three pyrethroid pesticides (cyfluthrin, cypermethrin and fenvalerate) in tea was developed by series two-solid phase extraction-column cleanup and external standard method coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) in 30 min. The pesticide residues in tea were extracted with acetonitrile, and cleaned up by Carb/NH 2 and SLH solid-phase extraction columns. After filtration, the target compounds were analyzed by GC-MS and quantified by the external standard method. Under the optimized conditions, good linear ranges of 0.05-2.00 mg/kg were obtained. The limits of detection varied from 0.3 to 1.0 μ g/kg. The linear correlation coefficients were greater than 0.999. At three spiked levels (0.10, 0.50 and 2.00 mg/L), the average recoveries were determined between 80.6% and 116.3% in the four matrices. The inter-day relative standard deviations were between 1.3%-12.6%, and the intra-day relative standard deviations were between 2.7% and 12.1%. This method is simple, fast, and has a good reproducibility, which can meet the requirements of the rapid detection of pyrethroid pesticides in tea.

  1. Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Owens, J; Hok, S; Alcaraz, A; Koester, C

    2008-11-13

    Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

  2. Continental bottled water assessment by stir bar sorptive extraction followed by gas chromatography-tandem mass spectrometry (SBSE-GC-MS/MS).

    Science.gov (United States)

    Guart, Albert; Calabuig, Ignacio; Lacorte, Silvia; Borrell, Antonio

    2014-02-01

    This study was aimed to determine the presence of 69 organic contaminants in 77 representative bottled waters collected from 27 countries all over the world. All water samples were contained in polyethylene terephthalate bottles. Target compounds were (1) environmental contaminants (including 13 polycyclic aromatic hydrocarbons (PAHs), 31 pesticides including organochlorine (OCPs), organophosphorus, and pyrethroids; 7 polychlorinated biphenyls (PCBs); and 7 triazines) and (2) plasticizers (including 6 phthalates and 5 other compounds). Samples were analyzed by stir bar sorptive extraction followed by gas chromatography-tandem mass spectrometry. PAHs, OCPs, PCBs, and triazines, which are indicators of groundwater pollution, were not detected in most of the samples, except for naphthalene (0.005-0.202 μg/L, n = 16). On the other hand, plastic components were detected in 77 % of the samples. Most frequently detected compounds were dimethyl phthalate and benzophenone at concentrations of 0.005-0.125 (n = 41) and 0.014-0.921 (n = 32), respectively. Levels detected are discussed in terms of contamination origin and geographical distribution. Target compounds were detected at low concentrations. Results obtained showed the high quality of bottled water in the different countries around the world.

  3. Quantitation Method for Polyfunctional Thiols in Hops (Humulus lupulus L.) and Beer Using Specific Extraction of Thiols and Gas Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Takazumi, Koji; Takoi, Kiyoshi; Koie, Koichiro; Tuchiya, Youichi

    2017-11-07

    A method for the quantitation of six polyfunctional thiols, 4-methyl-4-sulfanylpentan-2-one (4MSP), 3-sulfanyl-4-methylpentan-1-ol (3S4MP), 3-sulfanyl-4-methylpentyl acetate (3S4MPA), 3-sulfanyl-3-methylbutan-1-ol (3S3MB), 3-sulfanylhexan-1-ol (3SH), and 3-sulfanylhexyl acetate (3SHA), in hops and beer without organic mercury compounds was developed. The method employed specific extraction of thiols using a silver ion solid phase extraction (SPE) cartridge and gas chromatography-tandem mass spectrometry (GC-MS/MS). For all thiols analyzed, good linearity was achieved by adding thioglycerol as an analyte protectant. Recoveries for both hops (74-100%) and beer (79-113%) were acceptable, and the repeatability for both was also good (relative standard deviations of 2.8-8.4%). The limits of detection for the six polyfunctional thiols were below their odor thresholds in beer. The method was applied to quantitation of hops and beer flavored with thiol-containing hop varieties. Due to their detected levels and level variations in different beers, 4MSP and 3S4MP are thought to be important polyfunctional thiols for the characteristic flavor of hop varieties.

  4. Simultaneous in-vial acetylation solid-phase microextraction followed by gas chromatography tandem mass spectrometry for the analysis of multiclass organic UV filters in water.

    Science.gov (United States)

    Vila, Marlene; Celeiro, Maria; Lamas, J Pablo; Garcia-Jares, Carmen; Dagnac, Thierry; Llompart, Maria

    2017-02-05

    UV filters are a class of emerging contaminants that are widely used in personal care products (PCPs) and that can be detected at low concentrations in the aquatic environment (ngL -1 ). Sensitive modern analytical methods are then mandatory to accurately analyze them. A methodology based on solid-phase-microextraction (SPME), considered as a 'Green Chemistry' technique, followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) has been developed for the simultaneous analysis of 14 UV filters of different chemical nature in environmental and recreational waters. In-vial low-cost derivatization was carried out to improve chromatographic performance of phenolic compounds. The extraction parameters (fiber coating, extraction mode, and salt addition) were optimized by means of experimental designs in order to achieve reliable conditions. Finally, the SPME-GC-MS/MS method was validated in terms of linearity, accuracy and precision with LODs in the low ngL -1 level. Its application to the analysis of 28 different samples including sea, river, spa, swimming pool, and aquapark waters, enabled the detection of 11 target UV filters at concentration levels up to 540μgL -1 , highlighting the presence of OCR in all analyzed samples and of 2EHMC (proposed to be considered as priority pollutant) in 79% of them. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Multiresidue analysis of pesticides in olive oil by gel permeation chromatography followed by gas chromatography-tandem mass-spectrometric determination

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Andres Garcia [Department of Physical and Analytical Chemistry, E.P.S. of Linares, University of Jaen, E-23700 Linares, Jaen (Spain); Martos, Natividad Ramos [Department of Physical and Analytical Chemistry, Faculty of Sciences, University of Jaen, E-23071 Jaen (Spain); Ballesteros, Evaristo [Department of Physical and Analytical Chemistry, E.P.S. of Linares, University of Jaen, E-23700 Linares, Jaen (Spain)]. E-mail: eballes@ujaen.es

    2006-02-03

    A method for the multiresidue analysis of olive oil samples for 26 pesticides is proposed. Residual pesticides are extracted from oil using an n-hexane/acetonitrile mixture, extracts being cleaned-up by gel permeation chromatography (GPC) for analysis by gas chromatography-tandem mass spectrometry (GC-MS/MS). Electron ionization and chemical ionization are employed in a single analysis for the determination of pesticides. Pesticide recoveries from virgin and refined olive oil spiked with 10, 100 and 250 {mu}g/kg concentrations of the pesticides ranged from 83.8 to 110.3%. The proposed method features good sensitivity: its limits of quantification are low enough to allow pesticide residues to be determined at concentrations below the maximum residue levels legally accepted. The precision, expressed as relative standard deviation, ranges from 4.93 to 8.11%. Applicability was tested on 40 olive oil samples. Several pesticides were detected in most of the virgin olive oil samples. By contrast, refined olive samples contained few pesticides, and only endosulfan sulphate was detected in all.

  6. Quantitative Analysis of Tetramethylenedisulfotetramine ('Tetramine') Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

    International Nuclear Information System (INIS)

    Owens, J.; Hok, S.; Alcaraz, A.; Koester, C.

    2008-01-01

    Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD 50 = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limit of quantitation was 0.10 (micro)g/mL by LC/MS/MS versus 0.15 (micro)g/mL for GC/MS. Fortifications of the beverages at 2.5 (micro)g/mL and 0.25 (micro)g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.

  7. Determination of nerve agent metabolites in human urine by isotope-dilution gas chromatography-tandem mass spectrometry after solid phase supported derivatization.

    Science.gov (United States)

    Lin, Ying; Chen, Jia; Yan, Long; Guo, Lei; Wu, Bidong; Li, Chunzheng; Feng, Jianlin; Liu, Qin; Xie, Jianwei

    2014-08-01

    A simple and sensitive method has been developed and validated for determining ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA), isobutyl methylphosphonic acid (iBuMPA), and pinacolyl methylphosphonic acid (PMPA) in human urine using gas chromatography-tandem mass spectrometry (GC-MS/MS) coupled with solid phase derivatization (SPD). These four alkyl methylphosphonic acids (AMPAs) are specific hydrolysis products and biomarkers of exposure to classic organophosphorus (OP) nerve agents VX, sarin, RVX, and soman. The AMPAs in urine samples were directly derivatized with pentafluorobenzyl bromide on a solid support and then extracted by liquid-liquid extraction. The analytes were quantified with isotope-dilution by negative chemical ionization (NCI) GC-MS/MS in a selected reaction monitoring (SRM) mode. This method is highly sensitive, with the limits of detection of 0.02 ng/mL for each compound in a 0.2 mL sample of human urine, and an excellent linearity from 0.1 to 50 ng/mL. It is proven to be very suitable for the qualitative and quantitative analyses of degradation markers of OP nerve agents in biomedical samples.

  8. Potential of atmospheric pressure chemical ionization source in gas chromatography tandem mass spectrometry for the screening of urinary exogenous androgenic anabolic steroids.

    Science.gov (United States)

    Raro, M; Portolés, T; Pitarch, E; Sancho, J V; Hernández, F; Garrostas, L; Marcos, J; Ventura, R; Segura, J; Pozo, O J

    2016-02-04

    The atmospheric pressure chemical ionization (APCI) source for gas chromatography-mass spectrometry analysis has been evaluated for the screening of 16 exogenous androgenic anabolic steroids (AAS) in urine. The sample treatment is based on the strategy currently applied in doping control laboratories i.e. enzymatic hydrolysis, liquid-liquid extraction (LLE) and derivatization to form the trimethylsilyl ether-trimethylsilyl enol ether (TMS) derivatives. These TMS derivatives are then analyzed by gas chromatography tandem mass spectrometry using a triple quadrupole instrument (GC-QqQ MS/MS) under selected reaction monitoring (SRM) mode. The APCI promotes soft ionization with very little fragmentation resulting, in most cases, in abundant [M + H](+) or [M + H-2TMSOH](+) ions, which can be chosen as precursor ions for the SRM transitions, improving in this way the selectivity and sensitivity of the method. Specificity of the transitions is also of great relevance, as the presence of endogenous compounds can affect the measurements when using the most abundant ions. The method has been qualitatively validated by spiking six different urine samples at two concentration levels each. Precision was generally satisfactory with RSD values below 25 and 15% at the low and high concentration level, respectively. Most the limits of detection (LOD) were below 0.5 ng mL(-1). Validation results were compared with the commonly used method based on the electron ionization (EI) source. EI analysis was found to be slightly more repeatable whereas lower LODs were found for APCI. In addition, the applicability of the developed method has been tested in samples collected after the administration of 4-chloromethandienone. The highest sensitivity of the APCI method for this compound, allowed to increase the period in which its administration can be detected. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Advantages of Atmospheric Pressure Chemical Ionization in Gas Chromatography Tandem Mass Spectrometry: Pyrethroid Insecticides as a Case Study

    NARCIS (Netherlands)

    Portolés, T.; Mol, J.G.J.; Sancho, J.V.; Hernández, F.

    2012-01-01

    Gas chromatography coupled to mass spectrometry (GC/MS) has been extensively applied for determination of volatile, nonpolar, compounds in many applied fields like food safety, environment, or toxicology. The wide majority of methods reported use electron ionization (EI), which may result in

  10. Determination of cholesterol and four phytosterols in foods without derivatization by gas chromatography-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Yan-Zong Chen

    2015-12-01

    Full Text Available In this study, a method for determination of cholesterol and four phytosterols by gas chromatography coupled with electron impact ionization mode–tandem mass spectrometry without derivatization in general food was developed. The sample was saponified with 7.5% KOH in methanol. After heating on hot plate and reflux for 60 minutes, the saponified portion was extracted with n-hexane/petroleum ether (50:50, v/v. The extracts were evaporated with rotary evaporator and then redissolved with tetrahydrofuran. The tetrahydrofuran layer was transferred into an injection vial and analyzed by gas chromatography on a 30 m VF-5 column. Limit of quantification was 2 mg/kg. Recoveries of cholesterol and four phytosterols from general food were between 91% and 100%.

  11. Simultaneous determination of eighteen nitro-polyaromatic hydrocarbons in PM2.5 by atmospheric pressure gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Yanhao; Li, Ruijin; Fang, Jing; Wang, Chen; Cai, Zongwei

    2018-05-01

    A new atmospheric pressure gas chromatography-tandem mass spectrometry (APGC-MS/MS) was developed to simultaneously separate, identify and quantify 18 nitro-polyaromatic hydrocarbons (NPAHs) in air fine particulate matter (PM 2.5 ). Compared with traditional negative chemical ionization (NCI) or electron impact ionization (EI)-MS/MS methods, APGC-MS/MS equipped with an atmospheric pressure chemical ionization (APCI) source provided better sensitivity and selectivity for NPAHs analysis in PM 2.5 .18 NPAHs were completely separated, and satisfactory linear response (R 2  > 0.99), low instrumental detection limits (0.20-2.18 pg mL -1 ) and method detection limits (0.001-0.015 pg m -3 ) were achieved. Due to the reliable performance of the instrument, only minimal sample pretreatment is needed. It ensured the satisfactory method recovery (70%-120%) and qualified repeatability (RSD: 1.1%-17.2%), which met the requirement of trace analysis of NAPHs in the real environmental PM 2.5 . Using the developed method, the actual PM 2.5 samples collected from Taiyuan, China in both summer and winter were analyzed, and 17 NPAHs but 2-nitrofluorene were detected and quantified. According to the obtained NAPH concentration results, the generation mechanism of NPAHs in PM 2.5 and the effects on NPAHs formation caused by some ambient air pollutants were preliminarily discussed: secondary photochemical reaction might be the dominant source of NPAHs in PM 2.5 collected from Taiyuan in both summer and winter; ambient air pollutants (NO 2 , SO 2 , CO) had more contribution on the NPAHs secondary formation of PM 2.5 in winter. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Simultaneous analysis of Δ(9)-tetrahydrocannabinol and 11-nor-9-carboxy-tetrahydrocannabinol in hair without different sample preparation and derivatization by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Han, Eunyoung; Park, Yonghoon; Kim, Eunmi; In, Sangwhan; Yang, Wonkyung; Lee, Sooyeun; Choi, Hwakyung; Lee, Sangki; Chung, Heesun; Song, Joon Myong

    2011-07-15

    The present study describes a gas chromatography/tandem mass spectrometry-negative ion chemical ionization assay (GC/MS/MS-NCI) for simultaneous analysis of Δ(9)-tetrahydrocannabinol (THC) and 11-nor-9-carboxy-tetrahydrocannabinol (THCCOOH) in hair. Each hair sample, of approximately 20mg, was weighed and the sample was dissolved in 1ml of 1M sodium hydroxide (30min at 85°C) in the presence of THC-d(3) and THCCOOH-d(3). For the analysis of THC, hair samples were extracted with n-hexane:ethyl acetate (9:1) two times; acetic acid and sodium acetate buffer were added for the analysis of THCCOOH, and hair samples were re-extracted with n-hexane:ethyl acetate (9:1) two times. The extracts were then derivatized with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH). This method allowed the analysis of THC and THCCOOH using the GC/MS/MS-NCI assay. This method was also fully validated and applied to hair specimens (n=54) collected from known cannabis users whose urine test results were positive. The concentrations of THC and THCCOOH in hair ranged from 7.52 to 60.41ng/mg and from 0.10 to 11.68pg/mg, respectively. In this paper, we simultaneously measured THC and THCCOOH in human hair using GC/MS/MS-NCI without requiring different sample preparation and derivatization procedures. The analytical sensitivity for THCCOOH in hair was good, while that for THC in hair needs to be improved in further study. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Determination of ∆-9-Tetrahydrocannabinol (THC), 11-hydroxy-THC, 11-nor-9-carboxy-THC and Cannabidiol in Human Plasma using Gas Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Andrenyak, David M; Moody, David E; Slawson, Matthew H; O'Leary, Daniel S; Haney, Margaret

    2017-05-01

    Two marijuana compounds of particular medical interest are delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). A gas chromatography-tandem mass spectrometry (GC-MS-MS) method was developed to test for CBD, THC, hydroxy-THC (OH-THC) and carboxy-THC (COOH-THC) in human plasma. Calibrators (THC and OH-THC, 0.1 to 100; CBD, 0.25 to 100; COOH-THC, 0.5-500 ng/mL) and controls (0.3, 5 and 80 ng/mL, except COOH-THC at 1.5, 25 and 400 ng/mL) were prepared in blank matrix. Deuterated (d3) internal standards were added to 1-mL samples. Preparation involved acetonitrile precipitation, liquid-liquid extraction (hexane:ethyl acetate, 9:1), and MSTFA derivatization. An Agilent 7890 A GC was interfaced with an Agilent 7000 MS Triple Quadrupole. Selected reaction monitoring was employed. Blood samples were provided from a marijuana smoking study (two participants) and a CBD ingestion study (eight participants). Three analytes with the same transitions (THC, OH-THC and COOH-THC) were chromatographically separated. Matrix selectivity studies showed endogenous chromatographic peak area ratios (PAR) at the analyte retention times were THC, OH-THC and COOH-THC were seen; low concentrations of CBD were detected at early time points. In moderate users who had not smoked for at least 9 hours before ingesting an 800 mg oral dose of CBD, the method was sensitive enough to follow residual concentrations of THC and OH-THC; sustained COOH-THC concentrations over 50 ng/mL validated its higher analytical range. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Sensitive determination of THC and main metabolites in human plasma by means of microextraction in packed sorbent and gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rosado, T; Fernandes, L; Barroso, M; Gallardo, E

    2017-02-01

    Cannabis is one of the most available and consumed illicit drug in the world and its identification and quantification in biological specimens can be a challenge given its low concentrations in body fluids. The present work describes a fast and fully validated procedure for the simultaneous detection and quantification of ▵ 9 -tetrahydrocannabinol (▵ 9_ THC) and its two main metabolites 11-hydroxy ▵ 9_ tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-▵ 9 - tetrahydrocannbinol (THC-COOH) in plasma samples using microextraction by packed sorbent (MEPS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). A small plasma volume (0.25mL) pre-diluted (1:20), was extracted with MEPS M1 sorbent as follows: conditioning (4 cycles of 250μL methanol and 4 cycles of 250μL 0.1% formic acid in water); sample load (26 cycles of 250μL); wash (100μL of 3% acetic acid in water followed by 100μL 5% methanol in water); and elution (6 cycles of 100μL of 10% ammonium hydroxide in methanol). The procedure allowed the quantification of all analytes in the range of 0.1-30ng/mL. Recoveries ranged from 53 to 78% (THC), 57 to 66% (11-OH-THC) and 62 to 65% (THC-COOH), allowing the limits of detection and quantification to be set at 0.1ng/mL for all compounds. Intra-day precision and accuracy revealed coefficients of variation (CVs) lower than 10% at the studied concentrations, with a mean relative error within±9%, while inter-day precision and accuracy showed CVs lower than 15% for all analytes at the tested concentrations, with an inaccuracy within±8%. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Simple determination of hydrazine in waste water by headspace solid-phase micro extraction and gas chromatography-tandem mass spectrometry after derivatization with trifluoro pentanedione.

    Science.gov (United States)

    Oh, Jin-Aa; Shin, Ho-Sang

    2017-01-15

    A headspace solid-phase micro extraction (HS-SPME) and gas chromatography-tandem mass spectrometric (GC-MS/MS) method is described to detect hydrazine after derivatization with 1,1,1-trifluoro-2,4-pentanedione (1,1,1-TFPD) to 3-methyl-5-(trifluoromethyl) pyrazole in industrial waste water. The following optimal HS-SPME conditions were used: 85 μm-carboxen-polydimethylsiloxane fibre, 100 mg L -1 TFPD, saturated NaCl, an extraction/derivatization temperature of 80 °C, a heating time of 40 min, and a pH of 9.5. Under the established conditions, the detection and quantification limits were 0.002 μg L -1 and 0.007 μg L -1  by using 5 mL of waste water and the intra- and inter-day relative standard deviations were less than 10.2% at concentrations of 0.02 and 0.1 μg L -1 . The calibration curve showed good linearity, with r 2  = 0.998; the accuracy was in the range of 98.0-103%; and the precision of the assay was less than 10.2% in industrial waste water. Hydrazine was detected over a concentration range of 0.011-0.074 μg L -1 in 5 of 20 waste water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Determination of caffeine, myosmine, and nicotine in chocolate by headspace solid-phase microextraction coupled with gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Müller, Christoph; Vetter, Florian; Richter, Elmar; Bracher, Franz

    2014-02-01

    The occurrence of the bioactive components caffeine (xanthine alkaloid), myosmine and nicotine (pyridine alkaloids) in different edibles and plants is well known, but the content of myosmine and nicotine is still ambiguous in milk/dark chocolate. Therefore, a sensitive method for determination of these components was established, a simple separation of the dissolved analytes from the matrix, followed by headspace solid-phase microextraction coupled with gas chromatography-tandem mass spectrometry (HS-SPME-GC-MS/MS). This is the first approach for simultaneous determination of caffeine, myosmine, and nicotine with a convenient SPME technique. Calibration curves were linear for the xanthine alkaloid (250 to 3000 mg/kg) and the pyridine alkaloids (0.000125 to 0.003000 mg/kg). Residuals of the calibration curves were lower than 15%, hence the limits of detection were set as the lowest points of the calibration curves. The limits of detection calculated from linearity data were for caffeine 216 mg/kg, for myosmine 0.000110 mg/kg, and for nicotine 0.000120 mg/kg. Thirty samples of 5 chocolate brands with varying cocoa contents (30% to 99%) were analyzed in triplicate. Caffeine and nicotine were detected in all samples of chocolate, whereas myosmine was not present in any sample. The caffeine content ranged from 420 to 2780 mg/kg (relative standard deviation 0.1 to 11.5%) and nicotine from 0.000230 to 0.001590 mg/kg (RSD 2.0 to 22.1%). © 2014 Institute of Food Technologists®

  17. Determination of multiple pesticides in fruits and vegetables using a modified quick, easy, cheap, effective, rugged and safe method with magnetic nanoparticles and gas chromatography tandem mass spectrometry.

    Science.gov (United States)

    Li, Yan-Fei; Qiao, Lu-Qin; Li, Fang-Wei; Ding, Yi; Yang, Zi-Jun; Wang, Ming-Lin

    2014-09-26

    Based on a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) sample preparation method with Fe3O4 magnetic nanoparticles (MNPs) as the adsorbing material and gas chromatography-tandem mass spectrometry (GC-MS/MS) determination in multiple reaction monitoring (MRM) mode, we established a new method for the determination of multiple pesticides in vegetables and fruits. It was determined that bare MNPs have excellent function as adsorbent when purified, and it is better to be separated from the extract. The amount of MNPs influenced the clean-up performance and recoveries. To achieve the optimum performance of modified QuEChERS towards the target analytes, several parameters including the amount of the adsorbents and purification time were investigated. Under the optimum conditions, recoveries were evaluated in four representative matrices (tomato, cucumber, orange and apple) with the spiked concentrations of 10 μg kg(-1), 50 μg kg(-1)and 200 μg kg(-1) in all cases. The results showed that the recovery of 101 pesticides ranged between 71.5 and 111.7%, and the relative standard deviation was less than 10.5%. The optimum clean-up system improved the purification efficiency and simultaneously obtained satisfactory recoveries of multiple pesticides, including planar-ring pesticides. In short, the modified QuEChERS method in addition to MNPs used for removing impurities improved the speed of sample pre-treatment and exhibited an enhanced performance and purifying effect. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Determinations of airborne synthetic musks by polyurethane foam coupled with triple quadrupole gas chromatography tandem mass spectrometer.

    Science.gov (United States)

    Wang, I-Ting Ivy; Cheng, Shu-Fang; Tsai, Shih-Wei

    2014-02-21

    Synthetic musk is widely used in various scented consumer products. However, the exposure via inhalation is often ignored due to pleasant smells. In addition, the information regarding the distribution of synthetic musk in air is limited. Hence, this research is aimed to develop a highly sensitive and widely applicable method for the determination of airborne synthetic musk. In this study, polyurethane foam (PUF) and filter were employed for active air sampling. Microwave assisted extraction (MAE) and nitrogen evaporator were performed for sample preparation. A gas chromatography coupled with triple quadrupole tandem mass spectrometer (GC/MS-MS) with specific multiple reaction monitoring (MRM) transition pairs was applied for sample analysis. Compared with using selected ion monitoring (SIM) mode traditionally, the sensitivities were improved in this study about an order at least. In terms of air concentration, as low as 0.48ngm(-3) can be determined when sampling at 3.5Lmin(-1) for 8h. The method established was further applied to the analysis of synthetic musk compounds in air samples collected in a cosmetics plant. The results showed that the airborne concentrations of gaseous polycyclic musk, gaseous nitro-musk, and particle-phase polycyclic musk were 6.4×10(2), 4.0×10(1) and 3.1×10(2)ngm(-3), respectively. Meanwhile, Cashmeran, Celstolide, Galaxolide, and Tonalide were found as the dominant musk compounds in the factory investigated. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Integrated Fourier transform infrared spectroscopy and gas chromatography tandem mass spectrometry for forensic engine lubricating oil and biodiesel analysis

    International Nuclear Information System (INIS)

    Shang, D.

    2009-01-01

    Gas chromatography/mass spectrometry(GC/MS) is commonly used for oil fingerprinting and provides investigators with good forensic data. However, new challenges face oil spill forensic chemistry with the growing use of biodiesel as well as the recycling and reprocessing of used oil, particularly lubricating oils. This paper demonstrated that Fourier transform infrared (FTIR) spectroscopy may be a fast, cost effective and complementary method for forensic analysis of biodiesels (fatty acid methyl esters) and lubricating oils. Attenuated total reflectance (ATR)-FTIR spectroscopy was shown to be an interesting analytic method because of its use in monitoring and quantifying minor chemical compounds in sample matrices and its ability to identify a broad range or organic compounds. Unlike chromatography, FTIR spectroscopy with ATR can provide results without compound separation or lengthy sample preparation steps. This study described the combined use of GC and ATR-FTIR in environmental oil spill identification through the matching of source lube oil samples with artificially weathered samples. Samples recovered from a biodiesel spill incident were also investigated. ATR-FTIR provided detailed spectral information for rapid lube oil differentiation. This study was part of a continuing effort to develop a methodology to deal with chemical spills of unknown origin, which is an important aspect in environmental protection and emergency preparedness. This method was only successfully applied to the short term artificially weathered and fresh lube oil characterization, and to limited cases of biodiesel spills. It was concluded that further validation tests are needed to determine if this method can be applied to real-world weather lube oil samples. 10 refs., 11 figs.

  20. Potential of atmospheric pressure chemical ionization source in gas chromatography tandem mass spectrometry for the screening of urinary exogenous androgenic anabolic steroids

    Energy Technology Data Exchange (ETDEWEB)

    Raro, M.; Portolés, T.; Pitarch, E.; Sancho, J.V.; Hernández, F. [Research Institute for Pesticides and Water, University Jaume I, E-12071 Castellón (Spain); Garrostas, L. [Bioanalysis Research Group, IMIM, Hospital del Mar Medical Research Institute, Doctor Aiguader 88, 08003 Barcelona (Spain); Marcos, J.; Ventura, R.; Segura, J. [Bioanalysis Research Group, IMIM, Hospital del Mar Medical Research Institute, Doctor Aiguader 88, 08003 Barcelona (Spain); Department of Experimental and Health Sciencies, Universitat Pompeu Fabra, Doctor Aiguader 88, 08003 Barcelona (Spain); Pozo, O.J., E-mail: opozo@imim.es [Bioanalysis Research Group, IMIM, Hospital del Mar Medical Research Institute, Doctor Aiguader 88, 08003 Barcelona (Spain)

    2016-02-04

    The atmospheric pressure chemical ionization (APCI) source for gas chromatography-mass spectrometry analysis has been evaluated for the screening of 16 exogenous androgenic anabolic steroids (AAS) in urine. The sample treatment is based on the strategy currently applied in doping control laboratories i.e. enzymatic hydrolysis, liquid–liquid extraction (LLE) and derivatization to form the trimethylsilyl ether-trimethylsilyl enol ether (TMS) derivatives. These TMS derivatives are then analyzed by gas chromatography tandem mass spectrometry using a triple quadrupole instrument (GC-QqQ MS/MS) under selected reaction monitoring (SRM) mode. The APCI promotes soft ionization with very little fragmentation resulting, in most cases, in abundant [M + H]{sup +} or [M + H-2TMSOH]{sup +} ions, which can be chosen as precursor ions for the SRM transitions, improving in this way the selectivity and sensitivity of the method. Specificity of the transitions is also of great relevance, as the presence of endogenous compounds can affect the measurements when using the most abundant ions. The method has been qualitatively validated by spiking six different urine samples at two concentration levels each. Precision was generally satisfactory with RSD values below 25 and 15% at the low and high concentration level, respectively. Most the limits of detection (LOD) were below 0.5 ng mL{sup −1}. Validation results were compared with the commonly used method based on the electron ionization (EI) source. EI analysis was found to be slightly more repeatable whereas lower LODs were found for APCI. In addition, the applicability of the developed method has been tested in samples collected after the administration of 4-chloromethandienone. The highest sensitivity of the APCI method for this compound, allowed to increase the period in which its administration can be detected. - Highlights: • APCI source has been evaluated for the screening of 16 exogenous AAS in urine. • Suitable

  1. Potential of atmospheric pressure chemical ionization source in gas chromatography tandem mass spectrometry for the screening of urinary exogenous androgenic anabolic steroids

    International Nuclear Information System (INIS)

    Raro, M.; Portolés, T.; Pitarch, E.; Sancho, J.V.; Hernández, F.; Garrostas, L.; Marcos, J.; Ventura, R.; Segura, J.; Pozo, O.J.

    2016-01-01

    The atmospheric pressure chemical ionization (APCI) source for gas chromatography-mass spectrometry analysis has been evaluated for the screening of 16 exogenous androgenic anabolic steroids (AAS) in urine. The sample treatment is based on the strategy currently applied in doping control laboratories i.e. enzymatic hydrolysis, liquid–liquid extraction (LLE) and derivatization to form the trimethylsilyl ether-trimethylsilyl enol ether (TMS) derivatives. These TMS derivatives are then analyzed by gas chromatography tandem mass spectrometry using a triple quadrupole instrument (GC-QqQ MS/MS) under selected reaction monitoring (SRM) mode. The APCI promotes soft ionization with very little fragmentation resulting, in most cases, in abundant [M + H] + or [M + H-2TMSOH] + ions, which can be chosen as precursor ions for the SRM transitions, improving in this way the selectivity and sensitivity of the method. Specificity of the transitions is also of great relevance, as the presence of endogenous compounds can affect the measurements when using the most abundant ions. The method has been qualitatively validated by spiking six different urine samples at two concentration levels each. Precision was generally satisfactory with RSD values below 25 and 15% at the low and high concentration level, respectively. Most the limits of detection (LOD) were below 0.5 ng mL −1 . Validation results were compared with the commonly used method based on the electron ionization (EI) source. EI analysis was found to be slightly more repeatable whereas lower LODs were found for APCI. In addition, the applicability of the developed method has been tested in samples collected after the administration of 4-chloromethandienone. The highest sensitivity of the APCI method for this compound, allowed to increase the period in which its administration can be detected. - Highlights: • APCI source has been evaluated for the screening of 16 exogenous AAS in urine. • Suitable precision was

  2. Hollow fiber-based liquid phase microextraction with factorial design optimization and gas chromatography-tandem mass spectrometry for determination of cannabinoids in human hair.

    Science.gov (United States)

    Emídio, Elissandro Soares; de Menezes Prata, Vanessa; de Santana, Fernando José Malagueño; Dórea, Haroldo Silveira

    2010-08-15

    A new method, based on hollow fiber liquid-phase microextraction (HF-LPME) and gas chromatography-tandem mass spectrometry (GC-MSMS), was developed for determination of Delta(9)-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in samples of human hair. Since hair is a solid matrix, the samples were subjected to alkaline digestion using NaOH. The aqueous solutions obtained were extracted using a 6cm polypropylene fiber (600microm i.d., 200microm wall thickness, 0.2microm pore size) for each extraction. A 2(5-1) fractional factorial design for screening, and a central composite design for optimization of significant variables, was applied during development of the extraction method. The variables evaluated were the type of extraction solvent, pH, stirring speed, extraction time, and acceptor phase volume. The optimized conditions for the proposed extraction procedure were 10mg of hair sample; 20microL of butyl acetate; aqueous (pH 14) donor phase containing 6.8% NaCl; 600rpm stirring speed; 20min extraction time. A linear response was obtained in the ranges 1-500pgmg(-1) (CBD and CBN) and 20-500pgmg(-1) (THC), with regression coefficients >0.99. Precision, determined as the relative standard deviation, was 3.3-8.9% (intra-day) and 4.4-13.7% (inter-day). Absolute recoveries varied in the ranges 4.4-4.8% (CBD), 7.6-8.9% (THC) and 7.7-8.2% (CBN). Limits of detection (LOD, S/N=3) and quantification (LOQ, S/N=10) were 0.5-15pgmg(-1) and 1-20pgmg(-1), respectively. The method was successfully used to determine CBD, THC and CBN in hair samples from patients in a drug dependency rehabilitation center. Concentrations varied in the ranges 1-18pgmg(-1) (CBD), 20-232pgmg(-1) (THC) and 9-107pgmg(-1) (CBN), confirming the suitability of the method for monitoring studies. Copyright 2010 Elsevier B.V. All rights reserved.

  3. Application of high-performance liquid chromatography-tandem mass spectrometry with a quadrupole/linear ion trap instrument for the analysis of pesticide residues in olive oil.

    Science.gov (United States)

    Hernando, M D; Ferrer, C; Ulaszewska, M; García-Reyes, J F; Molina-Díaz, A; Fernández-Alba, A R

    2007-11-01

    This article describes the development of an enhanced liquid chromatography-mass spectrometry (LC-MS) method for the analysis of pesticides in olive oil. One hundred pesticides belonging to different classes and that are currently used in agriculture have been included in this method. The LC-MS method was developed using a hybrid quadrupole/linear ion trap (QqQ(LIT)) analyzer. Key features of this technique are the rapid scan acquisition times, high specificity and high sensitivity it enables when the multiple reaction monitoring (MRM) mode or the linear ion-trap operational mode is employed. The application of 5 ms dwell times using a linearly accelerating (LINAC) high-pressure collision cell enabled the analysis of a high number of pesticides, with enough data points acquired for optimal peak definition in MRM operation mode and for satisfactory quantitative determinations to be made. The method quantifies over a linear dynamic range of LOQs (0.03-10 microg kg(-1)) up to 500 microg kg(-1). Matrix effects were evaluated by comparing the slopes of matrix-matched and solvent-based calibration curves. Weak suppression or enhancement of signals was observed (ion (EPI) and MS3 were developed.

  4. The use of multivariate curve resolution methods to improve the analysis of muramic acid as bacterial marker using gas chromatography-mass spectrometry: an alternative method to gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Moazeni-Pourasil, Roudabeh Sadat; Piri, Farhad; Ghassempour, Alireza; Jalali-Heravi, Mehdi

    2014-02-15

    In analysis of muramic acid (MA) as bacterial marker, two dominant disturbing factors lead the researchers to use gas chromatography-tandem mass spectrometry (GC-MS/MS) technique instead of gas chromatography-mass spectrometry (GC-MS). These factors are the trace concentration of MA and fundamental disturbance of base line mass channels in GC-MS technique. This study aimed to utilize multivariate curve resolution (MCR) methods combined with GC-MS to improve the analysis of MA. First, the background and noise in GC-MS analysis were corrected and reduced using MCR methods. In addition, the MA overlapped peaks were resolved to its pure chromatographic and mass spectral profiles. Then the two-way response of each component was reconstructed by the outer product of the pure chromatographic and mass spectral profiles. The overall volume integration (OVI) method was used for quantitative determination. The MA peak area was decreased dramatically after the background correction and noise reduction. The findings severely ratify the appropriateness of using MCR techniques combined with GC-MS analysis as a simple, fast and inexpensive method for the analysis of MA in complex mixtures. The proposed method may be considered as an alternative method to GC-MS/MS for thorough analysis of the bacterial marker. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Comparison of Gas Chromatography-Mass Spectrometry and Gas Chromatography-Tandem Mass Spectrometry with Electron Ionization and Negative-Ion Chemical Ionization for Analyses of Pesticides at Trace Levels in Atmospheric Samples

    Directory of Open Access Journals (Sweden)

    Renata Raina

    2008-01-01

    Full Text Available A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS in selected ion monitoring (SIM with gas chromatography-tandem mass spectrometry (GC-MS/MS in selected reaction monitoring (SRM mode with both electron ionization (EI and negative-ion chemical ionization (NCI are presented for over 50 pesticides ranging from organochlorines (OCs, organophosphorus pesticides (OPs and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin. The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations <100 pg µL−1 (<100 pg m−3 in air. No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5–10 pg µL−1 along with best confirmation (<25% RSD of ion ratio, while GC-NCI/SRM is recommended for use where added selectivity or confirmation is required (such as parathion-ethyl, tokuthion, carbofenothion. GC-EI/SRM at concentration <100 pg µL−1 was not suitable for most pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1–10 pg µL−1 for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT.

  6. Comparison of gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry with electron ionization and negative-ion chemical ionization for analyses of pesticides at trace levels in atmospheric samples.

    Science.gov (United States)

    Raina, Renata; Hall, Patricia

    2008-09-09

    A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) with gas chromatography-tandem mass spectrometry (GC-MS/MS) in selected reaction monitoring (SRM) mode with both electron ionization (EI) and negative-ion chemical ionization (NCI) are presented for over 50 pesticides ranging from organochlorines (OCs), organophosphorus pesticides (OPs) and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin). The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations air). No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5-10 pg microL(-1)) along with best confirmation (pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1-10 pg microL(-1)) for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT).

  7. Development and validation of a multi-residue method for the detection of a wide range of hormonal anabolic compounds in hair using gas chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Rambaud, Lauriane; Monteau, Fabrice; Deceuninck, Yoann; Bichon, Emmanuelle; Andre, Francois; Le Bizec, Bruno

    2007-01-01

    The monitoring of anabolic steroid residues in hair is undoubtedly one of the most efficient strategies to demonstrate the long-term administration of these molecules in meat production animals. A multi-residue sample preparation procedure was developed and validated for 28 steroids. A 100 mg hair sample was grinded into powder and extracted at 50 deg. C with methanol. After acidic hydrolysis and extraction with ethyl acetate, phenolsteroids, such as estrogens, resorcyclic acid lactones and stilbens in one hand, are separated from androgens and progestagens in the other hand. Solid phase extractions were performed before applying a specific derivatisation for each compound sub-group. Detection and identification were achieved using gas chromatography-tandem mass spectrometry with acquisition in the selected reaction monitoring mode after electron ionisation. The method was validated according to the 2002/657/EC guideline. Decision limits (CCα) for main steroids were in the 0.1-10 μg kg -1 range

  8. Urinary screening for methylphenidate (Ritalin) abuse: a comparison of liquid chromatography-tandem mass spectrometry, gas chromatography-mass spectrometry, and immunoassay methods.

    Science.gov (United States)

    Eichhorst, J; Etter, M; Lepage, J; Lehotay, D C

    2004-03-01

    To develop a routine method for detecting methylphenidate (Ritalin) use among drug abusers using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The new methodology was designed to replace less reliable and/or more expensive and time-consuming techniques (GC/MS and ELISA) currently employed in our laboratory, and to provide a combined one-step screening and confirmation LC/MS/MS method. Because methylphenidate abuse is very prevalent in Saskatchewan, there is a demand to provide high volume urine screening both to detect abuse, and to monitor compliance. Random urine samples sent for drugs of abuse testing, standards, and controls were diluted 1:100 in methanol. Diluted specimens were injected directly into an Agilent 1100 liquid chromatograph coupled to a Sciex API 2000 mass spectrometer. The method utilized selected reaction monitoring (SRM) as well as an electrospray ionization source (EIS) to detect both urinary methylphenidate and the more prevalent metabolite, ritalinic acid (RA). There appeared to be little or no sacrifice in sensitivity because the higher dilutions exhibited much less matrix effect. Limit of quantitation (LOQ) for methylphenidate was 100 nM and 500 nM for RA. Linear calibration curves from 100 to 1000 nM for Ritalin and 500 to 5000 nM for RA were acquired. Imprecision of spiked and true specimens did not exceed 10% and at the LOQ, it was less than 20%. A rapid, sensitive, reliable, and highly specific method by LC/MS/MS for detecting methylphenidate and its metabolite, RA, were developed. Both the cost and performance of the LC/MS/MS method were superior to GC/MS or ELISA, and it allows use of a single rapid procedure for both screening and confirmation.

  9. Evaluation and prevention of the negative matrix effect of terpenoids on pesticides in apples quantification by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Giacinti, Géraldine; Raynaud, Christine; Capblancq, Sophie; Simon, Valérie

    2017-02-03

    The sample matrix can enhance the gas chromatography signal of pesticide residues relative to that obtained with the same concentration of pesticide in solvent. This paper is related to negative matrix effects observed in coupled gas chromatography-mass spectrometry ion trap (GC/MS 2 ) quantification of pesticides in concentrated extracts of apple peel prepared by the Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method. It is focused on the pesticides most frequently used on the apple varieties studied, throughout the crop cycle, right up to harvest, to combat pests and diseases and to improve fruit storage properties. Extracts from the fleshy receptacle (flesh), the epiderm (peel) and fruit of three apple varieties were studied by high-performance thin-layer chromatography hyphenated with UV-vis light detection (HPTLC/UV visible). The peel extracts had high concentrations of triterpenic acids (oleanolic and ursolic acids), reaching 25mgkg -1 , whereas these compounds were not detected in the flesh extracts (negative matrix effects in GC/MS 2 . The differences in the behavior of pesticides with respect to matrix effects can be accounted for by the physicochemical characteristics of the molecules (lone pairs, labile hydrogen, conjugation). The HPTLC/UV visible method developed here for the characterization of QuEChERS extracts acts as a complementary clean-up method, aimed to decrease the negative matrix effects of such extracts. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. The performance of atmospheric pressure gas chromatography-tandem mass spectrometry compared to gas chromatography-high resolution mass spectrometry for the analysis of polychlorinated dioxins and polychlorinated biphenyls in food and feed samples.

    Science.gov (United States)

    Ten Dam, Guillaume; Pussente, Igor Cabreira; Scholl, Georges; Eppe, Gauthier; Schaechtele, Alexander; van Leeuwen, Stefan

    2016-12-16

    Recently, gas chromatography tandem mass spectrometry (GC-MS/MS) has been added in European Union (EU) legislation as an alternative to magnetic sector high resolution mass spectrometry (HRMS) for the analysis of dioxins and dioxin like polychlorinated biphenyls (dl-PCB) in food and feed. In this study the performance of APGC-MS/MS compared to GC-HRMS is investigated and compared with EU legislation. The study includes the legislative parameters, relative intermediate precision standard deviation (S Rw ,rel), trueness, sensitivity, linear range and ion ratio tolerance. In addition, over 200 real samples of large variety and spanning several orders of magnitude in concentration were analyzed by both techniques and the selectivity was evaluated by comparing chromatograms. The S Rw ,rel and trueness were evaluated using (in-house) reference samples and fulfill to EU legislation, though the S Rw ,rel was better with GC-HRMS. The sensitivity was considerably better than of GC-HRMS while the linear range was similar. Ion ratios were mostly within the tolerable range of ±15%. A (temporary unresolved) systematic deviation in ion ratio was observed for several congeners, yet this did not lead to exceeding of the maximum ion ratio limits. The APGC-MS/MS results for the non-dioxin-like-PCBs (ndl-PCBs) were negatively biased, particularly for PCB138 and 153 in contaminated samples. The selectivity of APGC-MS/MS was lower for several matrices. Particularly for contaminated samples, interfering peaks were observed in the APGC chromatograms of the native compounds (dioxins) and labeled internal standards (PCBs). These can lead to biased results and ultimately to false positive samples. It was concluded that the determination of dioxins and PCBs using APGC-MS/MS meets the requirements set by the European Commission. However, due to generally better selectivity and S Rw ,rel, GC-HRMS is the preferred method for monitoring purposes. Copyright © 2016 Elsevier B.V. All rights

  11. Automated determination of aliphatic primary amines in wastewater by simultaneous derivatization and headspace solid-phase microextraction followed by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Llop, Anna; Pocurull, Eva; Borrull, Francesc

    2010-01-22

    This paper presents a fully automated method for determining ten primary amines in wastewater at ng/L levels. The method is based on simultaneous derivatization with pentafluorobenzaldehyde (PFBAY) and headspace solid-phase microextraction (HS-SPME) followed by gas chromatography coupled to ion trap tandem mass spectrometry (GC-IT-MS-MS). The influence of main factors on the efficiency of derivatization and of HS-SPME is described in detail and optimized by a central composite design. For all species, the highest enrichment factors were achieved using a 85 microm polyacrylate (PA) fiber exposed in the headspace of stirred water samples (750 rpm) at pH 12, containing 360 g/L of NaCl, at 40 degrees C for 15 min. Under optimized conditions, the proposed method achieved detection limits ranging from 10 to 100 ng/L (except for cyclohexylamine). The optimized method was then used to determine the presence of primary amines in various types of wastewater samples, such as influent and effluent wastewater from municipal and industrial wastewater treatment plants (WWTPs) and a potable water treatment plant. Although the analysis of these samples revealed the presence of up to 1500 microg/L of certain primary amines in influent industrial wastewater, the concentration of these compounds in the effluent and in municipal and potable water was substantially lower, at low microg/L levels. The new derivatization-HS-SPME-GC-IT-MS-MS method is suitable for the fast, reliable and inexpensive determination of primary amines in wastewater in an automated procedure. Copyright 2009 Elsevier B.V. All rights reserved.

  12. Development and validation of a solid-phase extraction and gas chromatography-tandem mass spectrometry method for the determination of isopropyl-9H-thioxanthen-9-one in carton packaged milk.

    Science.gov (United States)

    Allegrone, Gianna; Tamaro, Ilaria; Spinardi, Shara; Grosa, Giorgio

    2008-12-19

    A simple and efficient method for the determination of isopropyl-9H-thioxanten-9-one (ITX) in different fat content milk samples and baby milk samples stored in packaged cartons was developed and validated. Samples were extracted using solid-phase extraction (SPE) and analysed by gas chromatography-tandem mass spectrometry operated in selected reaction monitoring mode (SRM). Validation was carried out in terms of limit of detection (LOD), limit of quantitation (LOQ), linearity, precision and trueness. LOD and LOQ values in the low microg/L were achieved, whereas linearity was established within 0.5-500 microg/L range. Good precision was obtained both in terms of intra-day repeatability and inter-day precision on two concentration levels (RSD% lower than 2%). Good percentage recoveries were obtained (92.0-102.0%) even in the presence of high amount of fat. Finally, the developed method was successfully applied to analyse a number of commercial milk samples with different fat content and baby milk samples.

  13. Development and validation of a multi-residue method for the detection of a wide range of hormonal anabolic compounds in hair using gas chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rambaud, Lauriane [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Monteau, Fabrice [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Deceuninck, Yoann [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Bichon, Emmanuelle [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Andre, Francois [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France); Le Bizec, Bruno [LABERCA, Ecole Nationale Veterinaire de Nantes, Route de Gachet, BP50707, 44307 Nantes Cedex 3 (France)]. E-mail: lebizec@vet-nantes.fr

    2007-03-14

    The monitoring of anabolic steroid residues in hair is undoubtedly one of the most efficient strategies to demonstrate the long-term administration of these molecules in meat production animals. A multi-residue sample preparation procedure was developed and validated for 28 steroids. A 100 mg hair sample was grinded into powder and extracted at 50 deg. C with methanol. After acidic hydrolysis and extraction with ethyl acetate, phenolsteroids, such as estrogens, resorcyclic acid lactones and stilbens in one hand, are separated from androgens and progestagens in the other hand. Solid phase extractions were performed before applying a specific derivatisation for each compound sub-group. Detection and identification were achieved using gas chromatography-tandem mass spectrometry with acquisition in the selected reaction monitoring mode after electron ionisation. The method was validated according to the 2002/657/EC guideline. Decision limits (CC{alpha}) for main steroids were in the 0.1-10 {mu}g kg{sup -1} range.

  14. Simultaneous determination of creatinine and creatine in human serum by double-spike isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS).

    Science.gov (United States)

    Fernández-Fernández, Mario; Rodríguez-González, Pablo; Añón Álvarez, M Elena; Rodríguez, Felix; Menéndez, Francisco V Álvarez; García Alonso, J Ignacio

    2015-04-07

    This work describes the first multiple spiking isotope dilution procedure for organic compounds using (13)C labeling. A double-spiking isotope dilution method capable of correcting and quantifying the creatine-creatinine interconversion occurring during the analytical determination of both compounds in human serum is presented. The determination of serum creatinine may be affected by the interconversion between creatine and creatinine during sample preparation or by inefficient chemical separation of those compounds by solid phase extraction (SPE). The methodology is based on the use differently labeled (13)C analogues ((13)C1-creatinine and (13)C2-creatine), the measurement of the isotopic distribution of creatine and creatinine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the application of multiple linear regression. Five different lyophilized serum-based controls and two certified human serum reference materials (ERM-DA252a and ERM-DA253a) were analyzed to evaluate the accuracy and precision of the proposed double-spike LC-MS/MS method. The methodology was applied to study the creatine-creatinine interconversion during LC-MS/MS and gas chromatography-mass spectrometry (GC-MS) analyses and the separation efficiency of the SPE step required in the traditional gas chromatography-isotope dilution mass spectrometry (GC-IDMS) reference methods employed for the determination of serum creatinine. The analysis of real serum samples by GC-MS showed that creatine-creatinine separation by SPE can be a nonquantitative step that may induce creatinine overestimations up to 28% in samples containing high amounts of creatine. Also, a detectable conversion of creatine into creatinine was observed during sample preparation for LC-MS/MS. The developed double-spike LC-MS/MS improves the current state of the art for the determination of creatinine in human serum by isotope dilution mass spectrometry (IDMS), because corrections are made for all the possible errors

  15. Simultaneous determination of polycyclic aromatic hydrocarbons and tobacco-specific N-nitrosamines in mainstream cigarette smoke using in-pipette-tip solid-phase extraction and on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Luo, Yan-Bo; Chen, Xiao-Jing; Zhang, Hong-Fei; Jiang, Xing-Yi; Li, Xue; Li, Xiang-Yu; Zhu, Feng-Peng; Pang, Yong-Qiang; Hou, Hong-Wei

    2016-08-19

    In this study, a silica/primary secondary amine (SiO2/PSA) was used as an in-pipette-tip solid phase extraction (SPE) sorbent for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific N-nitrosamines (TSNAs) in mainstream cigarette smoke (MSS). We investigated several parameters including an extraction procedure of total particulate matter, type and amount of sorbent and on-line gel permeation chromatography parameters to obtain optimum conditions for a new strategy to target analytes. Under the optimized conditions, we developed a method for the simultaneous determination of PAHs and TSNAs in MSS by coupling in-pipette-tip SPE procedures to an on-line gel permeation chromatography-gas chromatography-tandem mass spectrometry (on-line GPC-GC-MS(2)). Our method had limits of detection for target analytes ranging from 0.01 to 0.23ng/cig. Good linearities were obtained with coefficients of determination (R(2)) greater than 0.9984 for all target analytes. Good reproducibility was obtained as intra- and inter-day precisions, and the relative standard deviations were less than 11.4 and 13.3%, respectively. The recoveries were in the range of 77.1-108.6% at different concentrations for real samples. Compared to previous standard methods for the determination of PAHs and TSNAs in MSS, our method was highly effective, fast, and had low consumption of organic solvent and a high degree of automation. Finally, our method successfully analyzed PAHs and TSNAs in real samples, and no significant deviations were observed when compared to similar analysis using standard methods. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Analysis of twenty phenolic compounds in human urine: hydrochloric acid hydrolysis, solid-phase extraction based on K2CO 3-treated silica, and gas chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lu, Dasheng; Feng, Chao; Wang, Dongli; Lin, Yuanjie; Ip, Ho Sai Simon; She, Jianwen; Xu, Qian; Wu, Chunhua; Wang, Guoquan; Zhou, Zhijun

    2015-05-01

    This study developed a new method for the analysis of 20 phenolic compounds in human urine. The urine samples were prepared by hydrochloric acid (HCl) hydrolysis, liquid-liquid extraction (LLE), and solid-phase extraction (SPE) cleanup. We found that HCl hydrolysis is of similar effectiveness to, and much cheaper than, the traditional enzymatic method. Vanillic acid was co-eluted with butyl paraben and interfered with the determination of butyl paraben in urine. K2CO3-treated-silica-gel SPE was designed to efficiently eliminate interference from the endogenous organic acids (especially vanillic acid) in urine. After derivatization, the samples were analyzed by large-volume-injection gas chromatography-tandem mass spectrometry (LVI-GC-MS-MS). Good linearity (R (2) ≥ 0.996) was established in the range 0.1-100 ng mL(-1) for all analytes. Method detection limits (MDLs) were 0.7-9.8 pg mL(-1). Intraday (n = 5) and interday (n = 5 days) validation was performed, with satisfactory accuracy (recovery: 70-126 % and 73-107 %, respectively) and precision (RSD ≤ 19 %) at two levels (low: 0.1 and 0.5 ng mL(-1); high: 5 and 10 ng mL(-1)). The method was used in a population study and achieved more than 85 % detection for most analytes; mean analyte concentrations were in the range 0.01-185 ng mL(-1). The method is suitable for the analysis of multiple phenolic metabolites in human urine.

  17. Determination of cyflumetofen residue in water, soil, and fruits by modified quick, easy, cheap, effective, rugged, and safe method coupled to gas chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Li, Minmin; Liu, Xingang; Dong, Fengshou; Xu, Jun; Qin, Dongmei; Zheng, Yongquan

    2012-10-01

    A new, highly sensitive, and selective method was developed for the determination of the cyflumetofen residue in water, soil, and fruits by using gas chromatography quadruple mass spectrometry. The target compound was extracted using acetonitrile and then cleaned up using dispersive solid-phase extraction with primary and secondary amine and graphitized carbon black, and optionally by a freezing-out cleanup step. The matrix-matched standards gave satisfactory recoveries and relative standard deviation values in different matrices at three fortified levels (0.05, 0.5, and 1.0 mg kg(-1) ). The overall average recoveries for this method in water, soil, and all fruits matrix at three fortified levels ranged from 76.3 to 101.5% with relative standard deviations in the range of 1.2-11.8% (n = 5). The calculated limits of detection and quantification were typically below 0.005 and 0.015 μg kg(-1), which were much lower than the maximum residue levels established by Japanese Positive List. This study provides a theoretical basis for China to draw up maximum residue level and analytical method for cyflumetofen acaricide in different fruits. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Automated polyvinylidene difluoride hollow fiber liquid-phase microextraction of flunitrazepam in plasma and urine samples for gas chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Cui, Shufen; Tan, Shuo; Ouyang, Gangfeng; Pawliszyn, Janusz

    2009-03-20

    A new polyvinylidene difluoride (PVDF) hollow fiber (200 microm wall thickness, 1.2mm internal diameter, 0.2 microm pore size) was compared with two other polypropylene (PP) hollow fibers (200, 300 microm wall thickness, 1.2mm internal diameter, 0.2 microm pore size) in the automated hollow fiber liquid-phase microextraction (HF-LPME) of flunitrazepam (FLNZ) in biological samples. With higher porosity and better solvent compatibility, the PVDF hollow fiber showed advantages with faster extraction efficiency and operational accuracy. Parameters of the CTC autosampler program for HF-LPME in plasma and urine samples were carefully investigated to ensure accuracy and reproducibility. Several parameters influencing the efficiency of HF-LPME of FLNZ in plasma and urine samples were optimized, including type of porous hollow fiber, organic solvent, agitation rate, extraction time, salt concentration, organic modifier, and pH. Under optimal conditions, extraction recoveries of FLNZ in plasma and urine samples were 6.5% and 83.5%, respectively, corresponding to the enrichment factor of 13 in plasma matrix and 167 in urine matrix. Excellent sample clean-up was observed and good linearities (r(2)=0.9979 for plasma sample and 0.9995 for urine sample) were obtained in the range of 0.1-1000 ng/mL (plasma sample) and 0.01-1000 ng/mL (urine sample). The limits of detection (S/N=3) were 0.025 ng/mL in plasma matrix and 0.001 ng/mL in urine matrix by gas chromatography/mass spectrometry/mass spectrometry.

  19. Method for the quantification of current use and persistent pesticides in cow milk, human milk and baby formula using gas chromatography tandem mass spectrometry.

    Science.gov (United States)

    Chen, Xianyu; Panuwet, Parinya; Hunter, Ronald E; Riederer, Anne M; Bernoudy, Geneva C; Barr, Dana Boyd; Ryan, P Barry

    2014-11-01

    The aim of this study was to develop an analytical method for the quantification of organochlorine (OC), organophosphate (OP), carbamate, and pyrethroid insecticide residues in cow milk, human milk, and baby formula. A total of 25 compounds were included in this method. Sample extraction procedures combined liquid-liquid extraction, freezing-lipid filtration, dispersive primary-secondary amine cleanup, and solid-phase extraction together for effective extraction and elimination of matrix interferences. Target compounds were analyzed using gas chromatography with electron impact ionization-tandem mass spectrometry (GC-EI-MS/MS) in the multiple reaction monitoring (MRM) mode. Average extraction recoveries obtained from cow milk samples fortified at two different concentrations (10 ng/mL and 25 ng/mL), ranged from 34% to 102%, with recoveries for the majority of target compounds falling between 60% and 80%. Similar ranges were found for formula fortified at 25 ng/mL. The estimated limits of detection for most target analytes were in the low pg/mL level (range 3-1600 pg/mL). The accuracies and precisions were within the range of 80-120% and less than 15%, respectively. This method was tested for its viability by analyzing 10 human milk samples collected from anonymous donors, 10 cow milk samples and 10 baby formula samples purchased from local grocery stores in the United States. Hexachlorobenzene, p,p-dicofol, o,p-DDE, p,p-DDE, and chlorpyrifos were found in all samples analyzed. We found detectable levels of permethrin, cyfluthrin, and fenvalerate in some of the cow milk samples but not in human milk or baby formula samples. Some of the pesticides, such as azinphos-methyl, heptachlor epoxide, and the pesticide synergist piperonyl butoxide, were detected in some of the cow milk and human milk samples but not in baby formula samples. Copyright © 2014. Published by Elsevier B.V.

  20. Determination of selected UV filters in indoor dust by matrix solid-phase dispersion and gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Negreira, N; Rodríguez, I; Rubí, E; Cela, R

    2009-07-31

    A simple, inexpensive sample preparation procedure, based on the matrix solid-phase dispersion (MSPD) technique, for the determination of six UV filters: 2-ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (Homosalate, HMS), 3-(4-methylbenzylidene) camphor (4-MBC), isoamyl-p-methoxycinnamate (IAMC), 2-ethylhexyl-p-methoxycinnamate (EHMC) and octocrylene (OCR), in dust from indoor environments is presented and the influence of several operational parameters on the extraction performance discussed. Under the final working conditions, sieved samples (0.5 g) were mixed with the same amount of anhydrous sodium sulphate and dispersed with 2 g of octadecyl bonded silica (C18) in a mortar with a pestle. This blend was transferred to a polypropylene solid-phase extraction cartridge containing 2 g of activated silica, as the clean-up co-sorbent. The cartridge was first rinsed with 5 mL of n-hexane and the analytes were then recovered with 4 mL of acetonitrile. This extract was adjusted to 1 mL, filtered and the compounds were determined by gas chromatography combined with tandem mass spectrometry (GC-MS/MS). Recoveries for samples spiked at two different concentrations ranged between 77% and 99%, and the limits of quantification (LOQs) of the method between 10 and 40 ng g(-1). Analysis of settled dust from different indoor areas, including private flats, public buildings and vehicle cabins, showed that EHMC and OCR were ubiquitous in this matrix, with maximum concentrations of 15 and 41 microg g(-1), respectively. Both UV filters were also quantified in dust reference material SRM 2585 for first time. EHS, 4-MBC and IAMC were detected in some of the analyzed samples, although at lower concentrations than EHMC and OCR.

  1. Simultaneous determination of polycyclic aromatic hydrocarbon quinones by gas chromatography-tandem mass spectrometry, following a one-pot reductive trimethylsilyl derivatization.

    Science.gov (United States)

    Toriba, Akira; Homma, Chiharu; Kita, Masahiro; Uozaki, Waka; Boongla, Yaowatat; Orakij, Walaiporn; Tang, Ning; Kameda, Takayuki; Hayakawa, Kazuichi

    2016-08-12

    We developed a sensitive and selective method to simultaneously analyze 37 polycyclic aromatic hydrocarbon quinones (PAHQs) with GC-MS/MS and applied the method to the analysis of standard atmospheric particulate matter samples. PAHQs were reduced with zinc granules and dithiothreitol (DTT) and the reductants were immediately converted to their silylated derivatives in a test tube. Two trimethylsilyl (TMS) groups were introduced into PAHQs through the one-pot reductive TMS derivatization. The PAHQs were derivatized with a mixed silylation reagent (BSA+TMCS+TMSI; (3:2:3)), which is one of the combinations of TMS-derivatization reagents with the highest reactivity. The derivatives produced different fragmentation between o-PAHQs and p-PAHQs. Therefore, isomers that have the same molecular weight are difficult to separate on a column were separated by the selected reaction monitoring (SRM) mode using the characteristic fragmentations, allowing separation and detection of all PAHQ derivatives in less than 30min. The instrumental detection limit (IDL) of each PAHQ was 1.2-29fg/injection and the method quantification limit (MQL) was 0.8-78μg/kg sample. For quantification, six deuterated PAHQs were used as internal standards to achieve high analytical precision. We applied the developed method to four standard atmospheric particulate matter samples. Results showed that out of 37 PAHQs, 33 compounds were identified and quantified. Moreover, from the 33 PAHQs, 14 were detected for the first time. Similar values were observed for the concentrations of PAHQs that have been quantified in previous reports. This method has the highest practicality in monitoring PAHQs in atmosphere, combustion exhaust gas, and toxicity evaluation. Thus, the method has the potential to become a standard analytical method for such applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. “One-shot” analysis of polybrominated diphenyl ethers and their hydroxylated and methoxylated analogs in human breast milk and serum using gas chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Butryn, Deena M.; Gross, Michael S.; Chi, Lai-Har; Schecter, Arnold; Olson, James R.; Aga, Diana S.

    2015-01-01

    The presence of polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH-BDE) and methoxylated (MeO-BDE) analogs in humans is an area of high interest to scientists and the public due to their neurotoxic and endocrine disrupting effects. Consequently, there is a rise in the investigation of the occurrence of these three classes of compounds together in environmental matrices and in humans in order to understand their bioaccumulation patterns. Analysis of PBDEs, OH-BDEs, and MeO-BDEs using liquid chromatography-mass spectrometry (LC-MS) can be accomplished simultaneously, but detection limits for PBDEs and MeO-BDEs in LC-MS is insufficient for trace level quantification. Therefore, fractionation steps of the phenolic (OH-BDEs) and neutral (PBDEs and MeO-BDEs) compounds during sample preparation are typically performed so that different analytical techniques can be used to achieve the needed sensitivities. However, this approach involves multiple injections, ultimately increasing analysis time. In this study, an analytical method was developed for a “one-shot” analysis of 12 PBDEs, 12 OH-BDEs, and 13 MeO-BDEs using gas chromatography with tandem mass spectrometry (GC-MS/MS). This overall method includes simultaneous extraction of all analytes via pressurized liquid extraction followed by lipid removal steps to reduce matrix interferences. The OH-BDEs were derivatized using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (TBDMS-MTFA), producing OH-TBDMS derivatives that can be analyzed together with PBDEs and MeO-BDEs by GC-MS/MS in “one shot” within a 25-min run time. The overall recoveries were generally higher than 65%, and the limits of detection ranged from 2 to 14 pg in both breast milk and serum matrices. The applicability of the method was successfully validated on four paired human breast milk and serum samples. The mean concentrations of total PBDEs, OH-BDEs, and MeO-BDEs in breast milk were 59, 2.2, and 0.57 ng g −1 lipid

  3. “One-shot” analysis of polybrominated diphenyl ethers and their hydroxylated and methoxylated analogs in human breast milk and serum using gas chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Butryn, Deena M.; Gross, Michael S. [Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States); Chi, Lai-Har [Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Schecter, Arnold [Department of Pharmacology and Toxicology, University of Louisville College of Medicine, Louisville, KY 40202 (United States); Olson, James R. [Department of Pharmacology and Toxicology, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Department of Epidemiology and Environmental Health, University at Buffalo, The State University of New York, Buffalo, NY 14214 (United States); Aga, Diana S., E-mail: dianaaga@buffalo.edu [Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, NY 14260 (United States)

    2015-09-10

    The presence of polybrominated diphenyl ethers (PBDEs) and their hydroxylated (OH-BDE) and methoxylated (MeO-BDE) analogs in humans is an area of high interest to scientists and the public due to their neurotoxic and endocrine disrupting effects. Consequently, there is a rise in the investigation of the occurrence of these three classes of compounds together in environmental matrices and in humans in order to understand their bioaccumulation patterns. Analysis of PBDEs, OH-BDEs, and MeO-BDEs using liquid chromatography-mass spectrometry (LC-MS) can be accomplished simultaneously, but detection limits for PBDEs and MeO-BDEs in LC-MS is insufficient for trace level quantification. Therefore, fractionation steps of the phenolic (OH-BDEs) and neutral (PBDEs and MeO-BDEs) compounds during sample preparation are typically performed so that different analytical techniques can be used to achieve the needed sensitivities. However, this approach involves multiple injections, ultimately increasing analysis time. In this study, an analytical method was developed for a “one-shot” analysis of 12 PBDEs, 12 OH-BDEs, and 13 MeO-BDEs using gas chromatography with tandem mass spectrometry (GC-MS/MS). This overall method includes simultaneous extraction of all analytes via pressurized liquid extraction followed by lipid removal steps to reduce matrix interferences. The OH-BDEs were derivatized using N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (TBDMS-MTFA), producing OH-TBDMS derivatives that can be analyzed together with PBDEs and MeO-BDEs by GC-MS/MS in “one shot” within a 25-min run time. The overall recoveries were generally higher than 65%, and the limits of detection ranged from 2 to 14 pg in both breast milk and serum matrices. The applicability of the method was successfully validated on four paired human breast milk and serum samples. The mean concentrations of total PBDEs, OH-BDEs, and MeO-BDEs in breast milk were 59, 2.2, and 0.57 ng g{sup −1} lipid

  4. Online trapping and enrichment ultra performance liquid chromatography-tandem mass spectrometry method for sensitive measurement of 'arginine-asymmetric dimethylarginine cycle' biomarkers in human exhaled breath condensate

    Energy Technology Data Exchange (ETDEWEB)

    Di Gangi, Iole Maria, E-mail: giordano@pediatria.unipd.it [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy); Pirillo, Paola [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy); Carraro, Silvia [Unit of Allergy and Respiratory Diseases, Department of Women' s and Children' s Health, University of Padova (Italy); Gucciardi, Antonina; Naturale, Mauro [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy); Baraldi, Eugenio [Unit of Allergy and Respiratory Diseases, Department of Women' s and Children' s Health, University of Padova (Italy); Giordano, Giuseppe [Chromatography and Mass Spectrometry Laboratory, Department of Women' s and Children' s Health, University of Padova (Italy)

    2012-11-19

    Highlights: Black-Right-Pointing-Pointer Simultaneous quantification of 'arginine-ADMA cycle' metabolites developed in EBC. Black-Right-Pointing-Pointer EBC is a non-invasive matrix highly useful in patients with respiratory diseases. Black-Right-Pointing-Pointer Method, fast, precise and accurate, is suitable in the pediatric clinical studies. Black-Right-Pointing-Pointer Sensitivity is increased using on-line trapping and enrichment-UPLC-MS/MS method. Black-Right-Pointing-Pointer EBC measurements in asthmatic adolescents confirm that ADMA is increased in asthma. - Abstract: Background: Exhaled breath condensate (EBC) is a biofluid collected non invasively that, enabling the measurement of several biomarkers, has proven useful in the study of airway inflammatory diseases, including asthma, COPD and cystic fibrosis. To the best of our knowledge, there is no previous report of any analytical method to detect ADMA in EBC. Objectives: Aim of this work was to develop an online sample trapping and enrichment system, coupled with an UPLC-MS/MS method, for simultaneous quantification of seven metabolites related to 'Arginine-ADMA cycle', using the isotopic dilution. Methods: Butylated EBC samples were trapped in an online cartridge, washed before and after each injection with cleanup solution to remove matrix components and switched inline into the high pressure analytical column. Multiple reaction monitoring in positive mode was used for analyte quantification by tandem mass spectrometry. Results: Validation studies were performed in EBC to examine accuracy, precision and robustness of the method. For each compound, the calibration curves showed a coefficient of correlation (r{sup 2}) greater than 0.992. Accuracy (%Bias) was <3% except for NMMA and H-Arg (<20%), intra- and inter-assay precision (expressed as CV%) were within {+-}20% and recovery ranged from 97.1 to 102.8% for all analytes. Inter-day variability analysis on 20 EBC of adult subjects did

  5. Approach to the study of flavone di-C-glycosides by high performance liquid chromatography-tandem ion trap mass spectrometry and its application to characterization of flavonoid composition in Viola yedoensis.

    Science.gov (United States)

    Cao, Jie; Yin, Chengle; Qin, Yan; Cheng, Zhihong; Chen, Daofeng

    2014-10-01

    The mass spectrometric (MS) analysis of flavone di-C-glycosides has been a difficult task due to pure standards being unavailable commercially and to that the reported relative intensities of some diagnostic ions varied with MS instruments. In this study, five flavone di-C-glycoside standards from Viola yedoensis have been systematically studied by high performance liquid chromatography-electrospray ionization-tandem ion trap mass spectrometry (HPLC-ESI-IT-MS(n)) in the negative ion mode to analyze their fragmentation patterns. A new MS(2) and MS(3) hierarchical fragmentation for the identification of the sugar nature (hexoses or pentoses) at C-6 and C-8 is presented based on previously established rules of fragmentation. Here, for the first time, we report that the MS(2) and MS(3) structure-diagnostic fragments about the glycosylation types and positions are highly dependent on the configuration of the sugars at C-6 and C-8. The base peak ((0,2) X1 (0,2) X(2)(-) ion) in MS(3) spectra of di-C-glycosides could be used as a diagnostic ion for flavone aglycones. These newly proposed fragmentation behaviors have been successfully applied to the characterization of flavone di-C-glycosides found in V. yedoensis. A total of 35 flavonoid glycosides, including 1 flavone mono-C-hexoside, 2 flavone 6,8-di-C-hexosides, 11 flavone 6,8-di-C-pentosides, 13 flavone 6,8-C-hexosyl-C-pentosides, 5 acetylated flavone C-glycosides and 3 flavonol O-glycosides, were identified or tentatively identified on the base of their UV profiles, MS and MS(n) (n = 5) data, or by comparing with reference substances. Among these, the acetylated flavone C-glycosides were reported from V. yedoensis for the first time. Copyright © 2014 John Wiley & Sons, Ltd.

  6. Enantioselective determination of triazole fungicide simeconazole in vegetables, fruits, and cereals using modified QuEChERS (quick, easy, cheap, effective, rugged and safe) coupled to gas chromatography/tandem mass spectrometry

    International Nuclear Information System (INIS)

    Li Jing; Dong Fengshou; Xu Jun; Liu Xingang; Li Yuanbo; Shan Weili; Zheng Yongquan

    2011-01-01

    Highlights: · Simeconazole enantiomers were baseline separated by gas chromatography. · Optical pure enantiomer was prepared and their elution order was distinguished. · Clean-up/enrichment procedure was based on the modification of QuEChERS method. · Cleanup step was further improved by solid phase extraction (SPE) technology. · Analysis of samples was accomplished by GC-MS/MS. - Abstract: A rapid and effective method for enantioselective determination of simeconazole enantiomers in food products (cucumber, tomato, apple, pear, wheat and rice) has been developed. The enantiomers were resolved by capillary gas chromatography (GC) using a commercial chiral column (BGB-172) and a temperature program from 150 deg. C (held for 1 min) and then raised at 10 deg. C min -1 to 240 deg. C (held for 10 min). This enantioselective gas chromatographic separation was combined with a clean-up/enrichment procedure based on the modification of QuEChERS (quick, easy, cheap, effective, rugged and safe) method. Co-extractives were removed with graphitized carbon black/primary secondary amine (GCB/PSA) solid-phase extraction (SPE) cartridges using acetonitrile:toluene (3:1, v/v) as eluent. Gas chromatography/ion trap mass spectrometry (GC-ITMS) with electron ionization (EI) was then used for qualitative and quantitative determination of the simeconazole enantiomers. Two precursor-to-product ion transitions (m/z 121-101 and 195-153) with the best signal intensity were chosen to build the multiple-reaction monitoring (MRM) acquisition method. The limits of detection for each enantiomer of simeconazole in six food products ranged between 0.4 and 0.9 μg kg -1 , which were much lower than maximum residue levels (MRLs) established by Japan. The methodology was successfully applied for the enantioselective analysis of simeconazole enantiomers in real samples, indicating its efficacy in investigating the environmental stereochemistry of simeconazole in food matrix.

  7. Enantioselective determination of triazole fungicide simeconazole in vegetables, fruits, and cereals using modified QuEChERS (quick, easy, cheap, effective, rugged and safe) coupled to gas chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Li, Jing; Dong, Fengshou; Xu, Jun; Liu, Xingang; Li, Yuanbo; Shan, Weili; Zheng, Yongquan

    2011-09-19

    A rapid and effective method for enantioselective determination of simeconazole enantiomers in food products (cucumber, tomato, apple, pear, wheat and rice) has been developed. The enantiomers were resolved by capillary gas chromatography (GC) using a commercial chiral column (BGB-172) and a temperature program from 150°C (held for 1 min) and then raised at 10°C min(-1) to 240°C (held for 10 min). This enantioselective gas chromatographic separation was combined with a clean-up/enrichment procedure based on the modification of QuEChERS (quick, easy, cheap, effective, rugged and safe) method. Co-extractives were removed with graphitized carbon black/primary secondary amine (GCB/PSA) solid-phase extraction (SPE) cartridges using acetonitrile:toluene (3:1, v/v) as eluent. Gas chromatography/ion trap mass spectrometry (GC-ITMS) with electron ionization (EI) was then used for qualitative and quantitative determination of the simeconazole enantiomers. Two precursor-to-product ion transitions (m/z 121-101 and 195-153) with the best signal intensity were chosen to build the multiple-reaction monitoring (MRM) acquisition method. The limits of detection for each enantiomer of simeconazole in six food products ranged between 0.4 and 0.9 μg kg(-1), which were much lower than maximum residue levels (MRLs) established by Japan. The methodology was successfully applied for the enantioselective analysis of simeconazole enantiomers in real samples, indicating its efficacy in investigating the environmental stereochemistry of simeconazole in food matrix. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Enantioselective determination of triazole fungicide simeconazole in vegetables, fruits, and cereals using modified QuEChERS (quick, easy, cheap, effective, rugged and safe) coupled to gas chromatography/tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Li Jing, E-mail: lijing2011@gmail.com [Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Key Laboratory of Pesticide Chemistry and Application, Ministry of Agriculture, Beijing, 100193 (China); Dong Fengshou; Xu Jun; Liu Xingang; Li Yuanbo [Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Key Laboratory of Pesticide Chemistry and Application, Ministry of Agriculture, Beijing, 100193 (China); Shan Weili [Institute for the Control of Agrochemicals, Ministry of Agriculture, Beijing 100125 (China); Zheng Yongquan, E-mail: yongquan_zheng@yahoo.com.cn [Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Key Laboratory of Pesticide Chemistry and Application, Ministry of Agriculture, Beijing, 100193 (China)

    2011-09-19

    Highlights: {center_dot} Simeconazole enantiomers were baseline separated by gas chromatography. {center_dot} Optical pure enantiomer was prepared and their elution order was distinguished. {center_dot} Clean-up/enrichment procedure was based on the modification of QuEChERS method. {center_dot} Cleanup step was further improved by solid phase extraction (SPE) technology. {center_dot} Analysis of samples was accomplished by GC-MS/MS. - Abstract: A rapid and effective method for enantioselective determination of simeconazole enantiomers in food products (cucumber, tomato, apple, pear, wheat and rice) has been developed. The enantiomers were resolved by capillary gas chromatography (GC) using a commercial chiral column (BGB-172) and a temperature program from 150 deg. C (held for 1 min) and then raised at 10 deg. C min{sup -1} to 240 deg. C (held for 10 min). This enantioselective gas chromatographic separation was combined with a clean-up/enrichment procedure based on the modification of QuEChERS (quick, easy, cheap, effective, rugged and safe) method. Co-extractives were removed with graphitized carbon black/primary secondary amine (GCB/PSA) solid-phase extraction (SPE) cartridges using acetonitrile:toluene (3:1, v/v) as eluent. Gas chromatography/ion trap mass spectrometry (GC-ITMS) with electron ionization (EI) was then used for qualitative and quantitative determination of the simeconazole enantiomers. Two precursor-to-product ion transitions (m/z 121-101 and 195-153) with the best signal intensity were chosen to build the multiple-reaction monitoring (MRM) acquisition method. The limits of detection for each enantiomer of simeconazole in six food products ranged between 0.4 and 0.9 {mu}g kg{sup -1}, which were much lower than maximum residue levels (MRLs) established by Japan. The methodology was successfully applied for the enantioselective analysis of simeconazole enantiomers in real samples, indicating its efficacy in investigating the environmental

  9. Argon gas atoms trapping by carbon dendrites

    Science.gov (United States)

    Danilaev, M. P.; Bogoslov, E. A.; Polskii, Y. E.

    2017-11-01

    The conditions of argon gas atoms trapping by carbon dendrites, which growing in atmospheric pressure gas-discharge plasma, are considered in that paper. It’s showing that the argons atoms trapping by the carbon diamond-like cell can occur in arc gas discharge with current density more than j 0 ∼ 45 mA/sm2 and provided that the eximer molecules of noble gas and carbon atoms (e.g., ArC) can be formed.

  10. Detection of lysergic acid diethylamide (LSD) in urine by gas chromatography-ion trap tandem mass spectrometry.

    Science.gov (United States)

    Sklerov, J H; Kalasinsky, K S; Ehorn, C A

    1999-10-01

    A confirmatory method for the detection and quantitation of lysergic acid diethylamide (LSD) is presented. The method employs gas chromatography-tandem mass spectrometry (GC-MS-MS) using an internal ionization ion trap detector for sensitive MS-MS-in-time measurements of LSD extracted from urine. Following a single-step solid-phase extraction of 5 mL of urine, underivatized LSD can be measured with limits of quantitation and detection of 80 and 20 pg/mL, respectively. Temperature-programmed on-column injections of urine extracts were linear over the concentration range 20-2000 pg/mL (r2 = 0.999). Intraday and interday coefficients of variation were LSD-positive samples in this laboratory. Comparisons with alternate GC-MS methods and extraction procedures are discussed.

  11. Screening the Hanford tanks for trapped gas

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, P.

    1995-10-01

    The Hanford Site is home to 177 large, underground nuclear waste storage tanks. Hydrogen gas is generated within the waste in these tanks. This document presents the results of a screening of Hanford`s nuclear waste storage tanks for the presence of gas trapped in the waste. The method used for the screening is to look for an inverse correlation between waste level measurements and ambient atmospheric pressure. If the waste level in a tank decreases with an increase in ambient atmospheric pressure, then the compressibility may be attributed to gas trapped within the waste. In this report, this methodology is not used to estimate the volume of gas trapped in the waste. The waste level measurements used in this study were made primarily to monitor the tanks for leaks and intrusions. Four measurement devices are widely used in these tanks. Three of these measure the level of the waste surface. The remaining device measures from within a well embedded in the waste, thereby monitoring the liquid level even if the liquid level is below a dry waste crust. In the past, a steady rise in waste level has been taken as an indicator of trapped gas. This indicator is not part of the screening calculation described in this report; however, a possible explanation for the rise is given by the mathematical relation between atmospheric pressure and waste level used to support the screening calculation. The screening was applied to data from each measurement device in each tank. If any of these data for a single tank indicated trapped gas, that tank was flagged by this screening process. A total of 58 of the 177 Hanford tanks were flagged as containing trapped gas, including 21 of the 25 tanks currently on the flammable gas watch list.

  12. Liquid Chromatography-Tandem Mass Spectrometry: An Emerging Technology in the Toxicology Laboratory.

    Science.gov (United States)

    Zhang, Yan Victoria; Wei, Bin; Zhu, Yu; Zhang, Yanhua; Bluth, Martin H

    2016-12-01

    In the last decade, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has seen enormous growth in routine toxicology laboratories. LC-MS/MS offers significant advantages over other traditional testing, such as immunoassay and gas chromatography-mass spectrometry methodologies. Major strengths of LC-MS/MS include improvement in specificity, flexibility, and sample throughput when compared with other technologies. Here, the basic principles of LC-MS/MS technology are reviewed, followed by advantages and disadvantages of this technology compared with other traditional techniques. In addition, toxicology applications of LC-MS/MS for simultaneous detection of large panels of analytes are presented. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Quantification of five compounds with heterogeneous physicochemical properties (morphine, 6-monoacetylmorphine, cyamemazine, meprobamate and caffeine) in 11 fluids and tissues, using automated solid-phase extraction and gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Bévalot, Fabien; Bottinelli, Charline; Cartiser, Nathalie; Fanton, Laurent; Guitton, Jérôme

    2014-06-01

    An automated solid-phase extraction (SPE) protocol followed by gas chromatography coupled with tandem mass spectrometry was developed for quantification of caffeine, cyamemazine, meprobamate, morphine and 6-monoacetylmorphine (6-MAM) in 11 biological matrices [blood, urine, bile, vitreous humor, liver, kidney, lung and skeletal muscle, brain, adipose tissue and bone marrow (BM)]. The assay was validated for linearity, within- and between-day precision and accuracy, limits of quantification, selectivity, extraction recovery (ER), sample dilution and autosampler stability on BM. For the other matrices, partial validation was performed (limits of quantification, linearity, within-day precision, accuracy, selectivity and ER). The lower limits of quantification were 12.5 ng/mL(ng/g) for 6-MAM, morphine and cyamemazine, 100 ng/mL(ng/g) for meprobamate and 50 ng/mL(ng/g) for caffeine. Analysis of real-case samples demonstrated the performance of the assay in forensic toxicology to investigate challenging cases in which, for example, blood is not available or in which analysis in alternative matrices could be relevant. The SPE protocol was also assessed as an extraction procedure that could target other relevant analytes of interest. The extraction procedure was applied to 12 molecules of forensic interest with various physicochemical properties (alimemazine, alprazolam, amitriptyline, citalopram, cocaine, diazepam, levomepromazine, nordazepam, tramadol, venlafaxine, pentobarbital and phenobarbital). All drugs were able to be detected at therapeutic concentrations in blood and in the alternate matrices.

  14. Headspace solid-phase microextraction coupled to gas chromatography-tandem mass spectrometry for the determination of haloanisoles in sparkling (cava and cider) and non-sparkling (wine) alcoholic beverages.

    Science.gov (United States)

    Ruiz-Delgado, Ana; Arrebola-Liébanas, Francisco Javier; Romero-González, Roberto; López-Ruiz, Rosalía; Garrido Frenich, Antonia

    2016-10-01

    A highly sensitive analytical method was developed to determine 2,4,6-trichloroanisole (TCA), 2,3,4,6-tetrachloroanisole (TeCA), 2,4,6-tribromoanisole (TBA) and 2,3,4,5,6-pentachloroanisole (PCA) in sparkling alcoholic beverages. The method was based on the use of headspace solid-phase microextraction (HS-SPME) using a polydimethylsiloxane (PDMS) fibre. It was coupled to gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS) for the detection and quantification of the target haloanisoles. The method was fully automated and no sample preparation was needed. The method was validated for alcoholic beverages. The influence of CO 2 on the extraction efficiency was also evaluated for the studied sparkling drinks (cava and cider). All the calibration curves showed good linearity (R 2  > 0.98) within the tested range (1-50 ng l -1 ). Recoveries were evaluated at three different levels (1, 5 and 50 ng l -1 ) and were always between 71% and 119%. Precision was expressed as relative standard deviation (RSD), and was evaluated as intra- and inter-day precisions, with values ≤ 22% in both cases. Limits of quantitation (LOQs) were ≤ 0.91 ng l -1 , which are below the sensory threshold levels for such compounds in humans. The validated method was applied to commercial samples, 10 cavas and 10 ciders, but it was also used for the analysis of nine red wines and four white wines, demonstrating the further applicability of the proposed method to non-sparkling beverages. TCA was detected in most samples at up to 0.45 ng l -1 .

  15. Development of a multi-residue method for the determination of pesticides in cereals and dry animal feed using gas chromatography-tandem quadrupole mass spectrometry II. Improvement and extension to new analytes.

    Science.gov (United States)

    Walorczyk, Stanisław

    2008-10-24

    This paper describes the extension and re-validation of a previously published multi-residue method to currently 140 pesticides and 4 pesticide degradation products in cereals and feedingstuffs. The pesticides were extracted using buffered QuEChERS ("quick, easy, cheap, rugged, effective and safe") method and then cleaned up using dispersive solid-phase extraction with Bondesil PSA and C18 sorbents, and optionally by a freezing-out clean-up step. The final extracts were analyzed in a single injection gas chromatographic-tandem quadrupole mass spectrometric (GC-MS/MS) acquisition method. A high degree of confidence was achieved by entering two multiple reaction monitoring transitions per compound. In this way, quantification of analytical results and unequivocal identification of pesticide residues in compliance with the recent European Union criteria could be done in a single analysis. Thorough optimization of the GC-MS/MS acquisition conditions and application of an effective clean-up procedure has resulted in a remarkable enhancement of the validation parameters. The linearity of the calibration curves was excellent in matrix-matched standards, and yielded the coefficients of determination (R(2))> or =0.99 for approximately 96% of the target analytes. Average recoveries of the pesticides spiked at 0.01mgkg(-1) into a feed mixture and wheat grain were in the range 70-120% with associated RSD values feed mixtures and other samples such as malt, starch and dry vegetables have been analyzed. A total of 15 different pesticides have been detected, among which pirimiphos methyl (19 cases), deltamethrin (14 cases), tolylfluanid (5 cases), dichlofluanid (5 cases), and tebuconazole (4 cases) were the most frequently encountered ones.

  16. Multi-class, multi-residue analysis of pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers and novel flame retardants in fish using fast, low-pressure gas chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Sapozhnikova, Yelena, E-mail: yelena.sapozhnikova@ars.usda.gov [US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 193038 (United States); Lehotay, Steven J. [US Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 193038 (United States)

    2013-01-03

    Highlights: Black-Right-Pointing-Pointer A method for analysis of POPs and novel flame retardants in catfish was developed. Black-Right-Pointing-Pointer The method is based on a QuEChERS extraction, d-SPE clean-up and low pressure GC/MS-MS. Black-Right-Pointing-Pointer The method validation demonstrated good recoveries and low detection limits. Black-Right-Pointing-Pointer The method was successfully applied for analysis of catfish samples from the market. - Abstract: A multi-class, multi-residue method for the analysis of 13 novel flame retardants, 18 representative pesticides, 14 polychlorinated biphenyl (PCB) congeners, 16 polycyclic aromatic hydrocarbons (PAHs), and 7 polybrominated diphenyl ether (PBDE) congeners in catfish muscle was developed and evaluated using fast low pressure gas chromatography triple quadrupole tandem mass spectrometry (LP-GC/MS-MS). The method was based on a QuEChERS (quick, easy, cheap, effective, rugged, safe) extraction with acetonitrile and dispersive solid-phase extraction (d-SPE) clean-up with zirconium-based sorbent prior to LP-GC/MS-MS analysis. The developed method was evaluated at 4 spiking levels and further validated by analysis of NIST Standard Reference Materials (SRMs) 1974B and 1947. Sample preparation for a batch of 10 homogenized samples took about 1 h/analyst, and LP-GC/MS-MS analysis provided fast separation of multiple analytes within 9 min achieving high throughput. With the use of isotopically labeled internal standards, recoveries of all but one analyte were between 70 and 120% with relative standard deviations less than 20% (n = 5). The measured values for both SRMs agreed with certified/reference values (72-119% accuracy) for the majority of analytes. The detection limits were 0.1-0.5 ng g{sup -1} for PCBs, 0.5-10 ng g{sup -1} for PBDEs, 0.5-5 ng g{sup -1} for select pesticides and PAHs and 1-10 ng g{sup -1} for flame retardants. The developed method was successfully applied for analysis of catfish samples

  17. Collisionless modes of a trapped Bose gas

    NARCIS (Netherlands)

    Bijlsma, M.J.; Stoof, H.T.C.

    1999-01-01

    We calculate the excitation frequencies of low-lying modes of a trapped Bose-condensed gas at nonzero temperatures. In our calculation we include the dynamics of the noncondensed cloud, and find agreement with experimental results if we assume that in the experiment both the in-phase and

  18. Collisionless modes of a trapped Bose gas

    NARCIS (Netherlands)

    Bijlsma, M.J.; Stoof, H.T.C.

    1999-01-01

    We calculate the excitation frequencies of the low-lying modes of a trapped Bose-condensed gas at nonzero temperatures. We include in our calculation the dynamics of the noncondensed cloud, and find agreement with experimental results if we assume that in the experiment both the in-phase and

  19. Iodine Gas Trapping using Granular Porous Bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yim, Mansung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    {sup 129}I is a radionuclide with a very long half-life of 1.57 Χ 10{sup 7} years and has negative health effects to the human body. Therefore, the emission of {sup 129}I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous {sup 129}I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing {sup 129}I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping {sup 129}I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling.

  20. Micro-pulverized extraction pretreatment for highly sensitive analysis of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol in hair by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Kuwayama, Kenji; Miyaguchi, Hajime; Yamamuro, Tadashi; Tsujikawa, Kenji; Kanamori, Tatsuyuki; Iwata, Yuko T; Inoue, Hiroyuki

    2015-11-30

    A primary metabolite of Δ(9) -tetrahydrocannabinol, 11-nor-9-carboxytetrahydrocannabinol (THC-COOH), serves as an effective indicator for cannabis intake. According to the recommendations of the Society of Hair Testing, at least 0.2 pg/mg of THC-COOH (cut-off level) must be present in a hair sample to constitute a positive result in a drug test. Typically, hair is digested with an alkaline solution and is subjected to gas chromatography/tandem mass spectrometry (GC/MS/MS) with negative ion chemical ionization (NICI). It is difficult to quantify THC-COOH at the cut-off level using liquid chromatography/tandem mass spectrometry (LC/MS/MS) without acquisition of second-generation product ions in triple quadrupole-ion trap mass spectrometers, because large amounts of matrix components in the low-mass range produced by digestion interfere with the THC-COOH peak. Using the typical pretreatment method (alkaline dissolution) and micro-pulverized extraction (MPE) with a stainless bullet, we compared the quantification of THC-COOH using GC/MS/MS and LC/MS/MS. MPE reduced the amount of matrix components in the low-mass range and enabled the quantification of THC-COOH at 0.2 pg/mg using a conventional triple quadrupole liquid chromatograph coupled to a mass spectrometer. On the other hand, the MPE pretreatment was unsuitable for GC/MS/MS, probably due to matrix components in the high-mass range. The proper combination of pretreatments and instrumental analyses was shown to be important for detecting trace amounts of THC-COOH in hair. In MPE, samples can be prepared rapidly, and LC/MS/MS is readily available, unlike GC/MS/MS with NICI. The combination of MPE and LC/MS/MS might therefore be used in the initial screening for THC-COOH in hair prior to confirmatory analysis using GC/MS/MS with NICI. Copyright © 2015 John Wiley & Sons, Ltd.

  1. Quantification and validation of ertapenem using a liquid chromatography-tandem mass spectrometry method

    NARCIS (Netherlands)

    van Rijn, S.P.; Wessels, A.M.A.; Greijdanus, B.; Touw, D.J.; Alffenaar, J.W.C.

    Ertapenem, a carbapenem, relies on time-dependent killing. Therapeutic drug monitoring (TDM) should be considered, when ertapenem is used in specific populations, to achieve optimal bactericidal activity and optimize drug-dosing regimens. No validated liquid chromatography-tandem mass spectrometry

  2. Determination of Bedaquiline in Human Serum Using Liquid Chromatography-Tandem Mass Spectrometry

    NARCIS (Netherlands)

    Alffenaar, Jan-Willem C.; Bolhuis, Mathieu; van Hateren, Kai; Sturkenboom, Marieke; Akkerman, Onno; de Lange, Wiel; Greijdanus, Ben; van der Werf, Tjip; Touw, Daan

    Bedaquiline, a diarylquinoline for the treatment of multidrug-resistant tuberculosis (TB), relies on exposure-dependent killing. As data on drug exposure in specific populations are scarce, pharmacokinetic studies may be of interest. No simple and robust validated liquid chromatography-tandem mass

  3. Confirmatory analysis of acetylgestagens in plasma using liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Mortensen, Sarah Kelly; Pedersen, Mikael

    2007-01-01

    -assisted liquid-liquid extraction (LLE) on Extrelut NT columns followed by C18 solid-phase extraction (SPE). Analytes were analysed using liquid chromatography-tandem mass spectrometry (I-C-MS/MS), and quantification was performed using matrix-matched calibration standards in combination with deuterated internal...

  4. Thermodynamic Properties of a Trapped Interacting Bose Gas

    OpenAIRE

    Shi, Hualin; Zheng, Wei-Mou

    1996-01-01

    A Bose gas in an external potential is studied by means of the local density approximation. Analytical results are derived for the thermodynamic properties of an ideal Bose gas in a generic power-law trapping potential, and their dependence on the mutual interaction of atoms in the case of a non-ideal Bose gas.

  5. Quantification of citalopram or escitalopram and their demethylated metabolites in neonatal hair samples by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Frison, Giampietro; Favretto, Donata; Vogliardi, Susanna; Terranova, Claudio; Ferrara, Santo Davide

    2008-08-01

    Citalopram and escitalopram are highly selective serotonin reuptake inhibitors widely used in the treatment of depression. They exhibit adverse drug reactions and side effects, however, and the development of specific methods for their determination is of great interest in clinical and forensic toxicology. A liquid chromatography-tandem mass spectrometry method has been developed and validated for the assay of citalopram, escitalopram, and their demethylated metabolites in 10-mg hair samples. The analytes were extracted by incubation in methanol and liquid/liquid extraction with diethyl ether/dichloromethane. Gradient elution on a narrow bore C18 column was realized using clomipramine-d3 as an internal standard. Positive ion electrospray ionization and tandem mass spectrometry determination by collision-induced dissociation were performed in an ion trap mass spectrometer. The method exhibited a linear range of 25 to 2000 pg/mg, a quantification limit of 25 pg/mg for all analytes, relative standard deviations in the range of 12.10 to 9.80 (intraassay), and 13.80 to 11.78 (interassay), and accuracies (as percent recovery of the spiked standards) in the range of 90% to 110%; it was applied to the determination of citalopram and escitalopram and their metabolites in hair samples of two newborns to document their in utero exposure to the drugs. The method proved suitable for neonatal hair analysis of citalopram or escitalopram and was applied to two real cases of gestational exposure.

  6. Density excitations of a harmonically trapped ideal gas

    Indian Academy of Sciences (India)

    (a) Static structure factor; (b) characteristic frequency for trapped gas (full line) and free gas (dashed line) and ω=Ω (dash–dotted line). 4. Dynamic correlations. It is straightforward to show that the density-fluctuation correlation functions of the non-interacting gas take the simple form. Fqq' (t) = C(s) qq' (t) − e1. 2 (q2+q'2)u2.

  7. Simultaneous determination of Δ9-tetrahydrocannabinol, cannabidiol, cannabinol and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid in hair using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Dulaurent, S; Gaulier, J M; Imbert, L; Morla, A; Lachâtre, G

    2014-03-01

    For several years, hair analyses have become a powerful tool to investigate past exposure towards xenobiotics. In the case of illicit drugs and more precisely of cannabis exposure, four compounds are usually investigated: Δ(9)-tetrahydrocannabinol (THC), the main active compound of cannabis, one of its metabolites [11-nor-Δ(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH)] and two cannabinoids (cannabinol and cannabidiol). Up until now, the hair determination of the carboxylic metabolite of THC, which has been described as the only marker allowing distinguishing consumption and passive exposure, has been performed using a gas chromatography-tandem mass spectrometry method. The aim of this study was to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantitative determination of the four markers. The sample preparation was based on an alkaline hydrolysis of hair samples followed by a liquid-liquid extraction of compounds in acidic conditions using a hexane/ethyl acetate mixture. The method was validated and the results were satisfactory: intra- and inter-assay accuracies below 9% and relative standard deviation below 15% for the four compounds. Moreover, the limit of quantification for THC-COOH, the most challenging compound, was validated at 0.2 pg/mg. This concentration is in accordance with the recommendations made by a scientific society which specializes in hair testing. It makes it possible to distinguish the kind of exposure to cannabis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. Simultaneous analysis of nine aromatic amines in mainstream cigarette smoke using online solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Jie; Bai, Ruoshi; Zhou, Zhaojuan; Liu, Xingyu; Zhou, Jun

    2017-04-01

    A fully automated analytical method was developed and validated by this present study. The method was based on two-dimensional (2D) online solid-phase extraction liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) to determine nine aromatic amines (AAs) in mainstream smoke (MSS) simultaneously. As a part of validation process, AAs yields for 16 top-selling commercial cigarettes from China market were evaluated by the developed method under both Health Canada Intensive (HCI) and ISO machine smoking regimes. The gas phase of MSS was trapped by 25 mL 0.6 M hydrochloric acid solution, while the particulate phase was collected on a glass fiber filter. Then, the glass fiber pad was extracted with hydrochloric acid solution in an ultrasonic bath. The extract was analyzed with 2D online SPE-LC-MS/MS. In order to minimize the matrix effects of sample on each analyte, two cartridges with different extraction mechanisms were utilized to cleanup disturbances of different polarity, which were performed by the 2D SPE. A phenyl-hexyl analytical column was used to achieve a chromatographic separation. Under the optimized conditions, the isomers of p-toluidine, m-toluidine and o-toluidine, 3-aminobiphenyl and 4-aminobiphenyl, and 1-naphthylamine and 2-naphthylamine were baseline separated with good peak shapes for the first time. The limits of detection for nine AAs ranged from 0.03 to 0.24 ng cig -1 . The recovery of the measurement of nine AAs was from 84.82 to 118.47%. The intra-day and inter-day precisions of nine AAs were less than 10 and 16%, respectively. Compared with ISO machine smoking regime, the AAs yields in MSS were 1.17 to 3.41 times higher under HCI machine smoking regime. Graphical abstract New method using online SPE-LC/MS/MS for analysis of aromatic amines in mainstream cigarette smoke.

  9. Gas-partitioning tracer test to qualify trapped gas during recharge

    Science.gov (United States)

    Heilweil, Victor M.; Kip, Solomon D.; Perkins, Kim S.; Ellett, Kevin M.

    2004-01-01

    Dissolved helium and bromide tracers were used to evaluate trapped gas during an infiltration pond experiment. Dissolved helium preferentially partitioned into trapped gas bubbles, or other pore air, because of its low solubility in water. This produced observed helium retardation factors of as much as 12 relative to bromide. Numerical simulations of helium breakthrough with both equilibrium and kinetically limited advection/dispersion/retardation did not match observed helium concentrations. However, better fits were obtained by including a decay term representing the diffusive loss of helium through interconnected, gas-filled pores. Calculations indicate that 7% to more than 26% of the porosity beneath the pond was filled with gas. Measurements of laboratory hydraulic properties indicate that a 10% decrease in saturation would reduce the hydraulic conductivity by at least one order of magnitude in the well-sorted sandstone, but less in the overlying soils. This is consistent with in situ measurements during the experiment, which show steeper hydraulic gradients in sandstone than in soil. Intrinsic permeability of the soil doubled during the first six months of the experiment, likely caused by a combination of dissolution and thermal contraction of trapped gas. Managers of artificial recharge basins may consider minimizing the amount of trapped gas by using wet, rather than dry, tilling to optimize infiltration rates, particularly in well-sorted porous media in which reintroduced trapped gas may cause substantial reductions in permeability. Trapped gas may also inhibit the amount of focused infiltration that occurs naturally during ephemeral flood events along washes and playas.

  10. Determination of parabens in serum by liquid chromatography-tandem mass spectrometry: Correlation with lipstick use.

    Science.gov (United States)

    Tahan, Gabriella Padovani; Santos, Nayara de Kássia Souza; Albuquerque, Ana Carolina; Martins, Isarita

    2016-08-01

    Parabens are the most widely used preservative and are considered to be relatively safe compounds. However, studies have demonstrated that they may have estrogenic activity, and there is ongoing debate regarding the safety and potential cancer risk of using products containing these compounds. In the present work, liquid chromatography-tandem mass spectrometry was applied to determine methylparaben and propylparaben concentrations in serum, and the results were correlated with lipstick application. Samples were analyzed using liquid-liquid extraction, followed by liquid chromatography-tandem mass spectrometry. The validation results demonstrated the linearity of the method over a range of 1-20 ng/mL, in addition to the method's precision and accuracy. A statistically significant difference was demonstrated between serum parabens in women who used lipstick containing these substances compared with those not using this cosmetic (p = 0.0005 and 0.0016, respectively), and a strong association was observed between serum parabens and lipstick use (Spearman correlation = 0.7202). Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Liquid chromatography-tandem mass spectrometry direct injection analysis of organophosphorus flame retardants in Ontario surface water and wastewater effluent.

    Science.gov (United States)

    Hao, Chunyan; Helm, Paul A; Morse, David; Reiner, Eric J

    2018-01-01

    Organophosphorus flame retardants (OPFRs) started to be used in plastics, electronics and furnishings back in the 1960s and became popular again last decade. They are now widely present in the environment and regarded as "new" emerging organic pollutants. An effective liquid chromatography-tandem mass spectrometry (LC-MS/MS) direct injection analysis (DIA) method was developed to monitor OPFR levels in aquatic environment. The removal of sample extraction and concentration steps not only improved operation efficiency, but also reduced the potential contamination commonly observed during the sample preparation process before. Positive background signals from the analytical instrument were eliminated by employing a "trap" column in front of the sample injector while an ACE C18 and an ACE C18-PFP column were compared for the separation of OPFRs. Nineteen OPFR related compounds were evaluated and rapid signal drops were observed for seven of them including TOTP, TMTP, TPTP, TEHP, T35DMPP, T2iPPP and EHDP, due to their low water solubility. The other twelve compounds, TMP, TEP, TPrP, TiPP, TBP, TCEP, TCPP, TDCPP, TPP, TBEP, BDCP and BEHP, were included for the measurement of OPFRs in drinking water, surface water, ground water and wastewater effluent samples. The instrumental detection limits of these twelve OPFRs at signal-to-noise ≥3 were in the 1.5-30 ng/L range. The method was applied for the determination of OPFRs in surface water and wastewater samples in Ontario, Canada, and BEHP, TBEP, TBP, TCEP, TCPP, TDCPP, and TEP were commonly detected. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  12. Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Bornø, Andreas; Foged, Lene; van Hall, Gerrit

    2014-01-01

    The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments...... in connection to in vivo metabolic studies investigating glucose turnover and lipolytic rate. Moreover, in order to keep up with this new fast analysis, simple derivatization procedures have been developed. Prior to analysis, glucose and glycerol were derivatized using benzoyl chloride in order to form...... benzoylated derivatives via new simplified fast procedures. For glucose, two internal standards were evaluated, [U-(13) C(6)]glucose and [U-(13) C(6), D(7)]glucose, and for glycerol, [U-(13) C(3), D(8)]glycerol was used. The method was validated by means of calibration curves, quality control samples...

  13. Analysis of bromate in drinking water using liquid chromatography-tandem mass spectrometry without sample pretreatment.

    Science.gov (United States)

    Kosaka, Koji; Asami, Mari; Takei, Kanako; Akiba, Michihiro

    2011-01-01

    An analytical method for determining bromate in drinking water was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The (18)O-enriched bromate was used as an internal standard. The limit of quantification (LOQ) of bromate was 0.2 µg/L. The peak of bromate was separated from those of coexisting ions (i.e., chloride, nitrate and sulfate). The relative and absolute recoveries of bromate in two drinking water samples and in a synthesized ion solution (100 mg/L chloride, 10 mg N/L nitrate, and 100 mg/L sulfate) were 99-105 and 94-105%, respectively. Bromate concentrations in 11 drinking water samples determined by LC-MS/MS were water without sample pretreatment.

  14. Determination of dapsone in meat and milk by liquid chromatography tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadjigeorgiou, M. [State General Laboratory of Cyprus, Veterinary Drug Residues Lab, Kimonos 44, 1451 Nicosia (Cyprus)], E-mail: mhadjigeorgiou@sgl.moh.gov.cy; Papachrysostomou, Ch.; Theodorou, Z.; Kanari, P.; Constantinou, S. [State General Laboratory of Cyprus, Veterinary Drug Residues Lab, Kimonos 44, 1451 Nicosia (Cyprus)

    2009-04-01

    Within the EU the use of dapsone (4,4-diaminodiphenylsulfone) is prohibited in food-producing animals and consequently it's included in the Annex IV of the Directive 90/2377/EC. A quantitative confirmatory method has been developed and validated according to the criteria defined in the Commission Decision 2002/657/EC, for the determination of dapsone in meat and milk. Samples, after homogenization in alkaline conditions and organic solvent extraction, were purified on silica gel solid phase extraction cartridges. The eluate was evaporated and redissolved in mobile phase and was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive electrospray ionisation (ESI) using deuterium labelled Sulphadimidine-d7 as internal standard. The calculated value for, decision limit, CC{alpha} is 0.12 {mu}g kg{sup -1}, and the detection capability; CC{beta} value is 0.16 {mu}g kg{sup -1}.

  15. Determination of dapsone in meat and milk by liquid chromatography tandem mass spectrometry

    International Nuclear Information System (INIS)

    Hadjigeorgiou, M.; Papachrysostomou, Ch.; Theodorou, Z.; Kanari, P.; Constantinou, S.

    2009-01-01

    Within the EU the use of dapsone (4,4-diaminodiphenylsulfone) is prohibited in food-producing animals and consequently it's included in the Annex IV of the Directive 90/2377/EC. A quantitative confirmatory method has been developed and validated according to the criteria defined in the Commission Decision 2002/657/EC, for the determination of dapsone in meat and milk. Samples, after homogenization in alkaline conditions and organic solvent extraction, were purified on silica gel solid phase extraction cartridges. The eluate was evaporated and redissolved in mobile phase and was analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS) in positive electrospray ionisation (ESI) using deuterium labelled Sulphadimidine-d7 as internal standard. The calculated value for, decision limit, CCα is 0.12 μg kg -1 , and the detection capability; CCβ value is 0.16 μg kg -1

  16. Determination of olanzapine in whole blood using simple protein precipitation and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2009-01-01

    A simple, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of the antipsychotic drug olanzapine in whole blood using dibenzepine as internal standard (IS). After acidic methanol-induced protein precipitation...

  17. Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

  18. Liquid chromatography-tandem mass spectrometric assay for the nucleoside reverse transcriptase inhibitor emtricitabine in human plasma

    NARCIS (Netherlands)

    Sparidans, Rolf W.; Prins, Jan M.; Schellens, Jan H. M.; Beijnen, Jos H.

    2007-01-01

    A liquid chromatography-tandem mass spectrometric assay for the determination of the antiretroviral nucleoside emtricitabine in human plasma was developed and validated using a simple sample pre-treatment procedure. After addition of 5'-deoxy-5-fluorocytidine as the internal standard and protein

  19. Concentration determination of urinary metabolites of N,N-dimethylacetamide by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yamamoto, Shinobu; Matsumoto, Akiko; Yui, Yuko; Miyazaki, Shota; Kumagai, Shinji; Hori, Hajime; Ichiba, Masayoshi

    2018-03-27

    N,N-Dimethylacetamide (DMAC) is widely used in industry as a solvent. It can be absorbed through human skin. Therefore, it is necessary to determine exposure to DMAC via biological monitoring. However, the precision of traditional gas chromatography (GC) is low due to the thermal decomposition of metabolites in the high-temperature GC injection port. To overcome this problem, we have developed a new method for the simultaneous separation and quantification of urinary DMAC metabolites using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Urine samples were diluted 10-fold in formic acid, and 1-μl aliquots were injected into the LC-MS/MS equipment. A C18 reverse-phase Octa Decyl Silyl (ODS) column was used as the analytical column, and the mobile phase consisted of a mixture of methanol and aqueous formic acid solution. Urinary concentrations of DMAC and its known metabolites (N-hydroxymethyl-N-methylacetamide (DMAC-OH), N-methylacetamide (NMAC), and S- (acetamidomethyl) mercapturic acid (AMMA) ) were determined in a single run. The dynamic ranges of the calibration curves were 0.05-5 mg/l (r≥0.999) for all four compounds. The limits of detection for DMAC, DMAC-OH, NMAC, and AMMA in urine were 0.04, 0.02, 0.05, and 0.02 mg/l, respectively. Within-run accuracies were 96.5%-109.6% with relative standard deviations of precision being 3.43%-10.31%. The results demonstrated that the proposed method could successfully quantify low concentrations of DMAC and its metabolites with high precision. Hence, this method is useful for evaluating DMAC exposure. In addition, this method can be used to examine metabolite behaviors in human bodies after exposure and to select appropriate biomarkers.

  20. Thermodynamic properties of a rotating Bose gas in harmonic trap

    Science.gov (United States)

    Hassan, A. S.; El-Badry, A. M.; Soliman, S. S. M.

    2011-10-01

    In this paper, the thermodynamic properties of a rotating Bose gas in harmonic trap are investigated. In particularly, the condensate fraction, critical temperature and heat capacity are analytically calculated. A simple semiclassical approximation, which is the density of state approach, is suggested. This approach is able to include the effects, such as the finite size and the chemical potential when becomes equal to the energy of the lowest energy state, that altered the rotating ideal Bose gas simultaneously. The calculated results show that the thermodynamic properties depend strongly on the rotation rate. The rapid rotation leads to a highly anisotropic confinement potential. The possibility for dimensionality cross-over to lower dimensions for this system is discussed. We compare the outcome results with the experimental measured data of Coddington et al. [Phys. Rev. A 70, 063607 (2004)].

  1. Linear spin waves in a trapped Bose gas

    International Nuclear Information System (INIS)

    Nikuni, T.; Williams, J.E.; Clark, C.W.

    2002-01-01

    An ultracold Bose gas of two-level atoms can be thought of as a spin-1/2 Bose gas. It supports spin-wave collective modes due to the exchange mean field. Such collective spin oscillations have been observed in recent experiments at JILA with 87 Rb atoms confined in a harmonic trap. We present a theory of the spin-wave collective modes based on the moment method for trapped gases. In the collisionless and hydrodynamic limits, we derive analytic expressions for the frequencies and damping rates of modes with dipole and quadrupole symmetry. We find that the frequency for a given mode is given by a temperature-independent function of the peak density n, and falls off as 1/n. We also find that, to a very good approximation, excitations in the radial and axial directions are decoupled. We compare our model to the numerical integration of a one-dimensional version of the kinetic equation and find very good qualitative agreement. The damping rates, however, show the largest deviation for intermediate densities, where one expects Landau damping--which is unaccounted for in our moment approach--to play a significant role

  2. Monitoring salivary melatonin concentrations in children with sleep disorders using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Khan, Sohil A; George, Rani; Charles, Bruce G; Taylor, Paul J; Heussler, Helen S; Cooper, David M; McGuire, Treasure M; Pache, David; Norris, Ross L G

    2013-06-01

    Melatonin is synthesized in the pineal gland and is an important circadian phase marker, especially in the determination of sleep patterns. Both temporary and permanent abnormal sleep patterns occur in children; therefore, it is desirable to have methods for monitoring melatonin in biological fluids in the diagnosis and treatment of such disorders. The objective of the study is to develop a liquid chromatography-tandem mass spectrometry method for the determination of melatonin in saliva and to apply it to monitoring salivary concentrations in children with sleep disorders. A deuterated internal standard (d7-melatonin) was added to a diluted saliva sample (20 µL) in an autosampler vial insert, and 50 µL were injected. Plasticware was strictly avoided, and all glassware was scrupulously cleaned and then baked at 120°C for at least 48 hours to obtain satisfactory performance. Reverse-phase chromatography was performed on a C8 column using a linear gradient elution profile comprising mobile phases A (0.1% aqueous formic acid) and B (15% methanol in acetonitrile containing 0.1% formic acid), pumped at a total flow rate of 0.8 mL/min. The run time was 8 minutes. After atmospheric pressure chemical ionization, mass spectrometric detection was in positive ion mode. Mass detection was by selected reaction monitoring mode with the following mass transitions used for quantification: melatonin, m/z 233.0 → 173.8 and d7-melatonin, m/z 240.0 → 178.3. Linearity (r > 0.999) was established from 3.9 to 1000 pg/mL. Imprecision (coefficient of variation percent) was less than 11%, and accuracy was 100-105% (7.0-900 pg/mL). The method was selective, and the mean (range) ratio of the slopes of calibrations in water to those in daytime saliva samples collected from 10 healthy adult subjects was 0.989 (0.982-0.997), indicating negligible matrix effects. The application of the assay was demonstrated in healthy adults and in children being clinically investigated for sleep

  3. Sensitive liquid chromatography-tandem mass spectrometry method for quantification of hydrochlorothiazide in human plasma.

    Science.gov (United States)

    Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Wishu, S; Varma, D P

    2005-12-01

    A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of hydrochlorothiazide (I), a common diuretic and anti-hypertensive agent. The analyte and internal standard, tamsulosin (II) were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reversed-phase column (Waters symmetry C18) with a mobile phase of 10 mm ammonium acetate-methanol (15:85, v/v). The protonated analyte was quantitated in negative ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 296.1 solidus in circle 205.0 and m/z 407.2 solidus in circle 184.9 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.5-200 ng/mL for hydrochlorothiazide in human plasma. The lower limit of quantitation was 500 pg/mL, with a relative standard deviation of less than 9%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.5 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. (c) 2005 John Wiley & Sons, Ltd.

  4. [Rapid determination of 8 urinary carbamate pesticides by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Liu, Hualiang; Wang, Yuan; Zhu, Baoli

    2015-11-01

    To establish a method for simultaneously determining the urinary concentrations of 8 carbamate pesticides. After being purified by acetonitrile precipitation, urine samples were transferred to a liquid chromatography-tandem mass spectrometry system, and the concentrations of 8 carbamate pesticides were determined by external standard method. A C18 column was used for ultra-high-performance liquid chromatography; methanol/ammonium acetate solution was used as the mobile phase for gradient elution; the mass spectrometer was operated in a multi-reaction monitoring mode. The calibration curves were linear when the urinary concentrations of these carbamate pesticides were 20~800 µg/L, and the recovery rates were 61.0%~121% at spiked levels of 20, 200 and 800 µg/L, with a relative standard deviation of 1.7%~5.5%. This determination method meets the Guide for establishing occupational health standards-part 5: Determination methods of chemicals in biological materials, and can be used for simultaneous determination of 8 carbamate pesticides in the urine of poisoning patients.

  5. Microfluidic platform for liquid chromatography-tandem mass spectrometry analyses of complex peptide mixtures.

    Science.gov (United States)

    Xie, Jun; Miao, Yunan; Shih, Jason; Tai, Yu-Chong; Lee, Terry D

    2005-11-01

    A microfluidic chip that integrates all the fluidic components of a gradient liquid chromatography (LC) system is described. These chips were batch-fabricated on a silicon wafer using photolithographic processes and with Parylene as the main structural material. The fabricated chip includes three electrolysis-based electrochemical pumps, one for loading the sample and the other two for delivering the solvent gradient; platinum electrodes for delivering current to the pumps and establishing the electrospray potential; a low-volume static mixer; a column packed with silica-based reversed-phase support; integrated frits for bead capture; and an electrospray nozzle. The fabricated structures were able to withstand pressures in excess of 250 psi. The device was used to perform a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of a mixture of peptides from the trypsin digestion of bovine serum albumen (BSA). Gradient elution through the 1.2-cm column was performed at a flow rate of 80 nL/min. Compared to the analysis of the same sample using a commercial nanoflow LC system, the chromatographic resolution was nearly as good, and the total cycle time was significantly reduced because of the minimal volume between the pumps and the column. Results demonstrate the potential of mass-produced, low-cost microfluidic systems capable of performing LC separations for proteomics applications.

  6. Targeted liquid chromatography tandem mass spectrometry to quantitate wheat gluten using well-defined reference proteins.

    Directory of Open Access Journals (Sweden)

    Kathrin Schalk

    Full Text Available Celiac disease (CD is an inflammatory disorder of the upper small intestine caused by the ingestion of storage proteins (prolamins and glutelins from wheat, barley, rye, and, in rare cases, oats. CD patients need to follow a gluten-free diet by consuming gluten-free products with gluten contents of less than 20 mg/kg. Currently, the recommended method for the quantitative determination of gluten is an enzyme-linked immunosorbent assay (ELISA based on the R5 monoclonal antibody. Because the R5 ELISA mostly detects the prolamin fraction of gluten, a new independent method is required to detect prolamins as well as glutelins. This paper presents the development of a method to quantitate 16 wheat marker peptides derived from all wheat gluten protein types by liquid chromatography tandem mass spectrometry (LC-MS/MS in the multiple reaction monitoring mode. The quantitation of each marker peptide in the chymotryptic digest of a defined amount of the respective reference wheat protein type resulted in peptide-specific yields. This enabled the conversion of peptide into protein type concentrations. Gluten contents were expressed as sum of all determined protein type concentrations. This new method was applied to quantitate gluten in wheat starches and compared to R5 ELISA and gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD, which resulted in a strong correlation between LC-MS/MS and the other two methods.

  7. Simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gupta, V K; Jain, Rajeev; Lukram, Ojitkumar; Agarwal, Shilpi; Dwivedi, Ashish

    2011-01-15

    A rapid and sensitive liquid chromatography tandem mass spectrometry method has been developed and validated for the simultaneous determination of ramipril, ramiprilat and telmisartan in human plasma. The solid-phase extraction technique was used for the extraction of ramipril, ramiprilat and telmisartan from human plasma. Trandolaprilat and hydrochlorothiazide were used as the internal standards (ISs). Chromatography was performed on a Hypurity C18, 5 μm, 50 mm × 4.6mm column, with the mobile phase consisting of ammonium acetate and acetonitrile (in a 20:80 ratio), followed by detection using mass spectrometry. The method involves a simple reversed isocratic chromatography condition and mass spectrometry detection, which enables detection at sub-nanogram levels. The method was validated and the lower limit of quantification for ramipril, ramiprilat and telmisartan was found to be 0.1 ng mL(-1), 0.1 ng mL(-1) and 2 ng mL(-1), respectively. The mean recovery for ramipril, ramiprilat and telmisartan ranged from 90.1 to 104.1%. This method increased the sensitivity and selectivity; resulting in high-throughput analysis of ramipril, ramiprilat and telmisartan using two different ISs in a single experiment for bioequivalence studies, with a chromatographic run time of 1.5 min only. Copyright © 2010 Elsevier B.V. All rights reserved.

  8. Analysis of nerve agent metabolites from nail clippings by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Appel, Amanda S; Logue, Brian A

    2016-09-15

    While several methods for the bioanalysis of nerve agents or their metabolites have been developed for the verification of nerve agent exposure, these methods are generally limited in the amount of time after an exposure that markers of exposure can be detected (due to rapid metabolism from biological matrices). In this study, a method for the analysis of nerve agent hydrolysis products from nail clippings was developed to allow evaluation of nails as a long-term repository of these markers. Pinacolyl methylphosphonic acid (PMPA) and isopropyl methylphosphonic acid (IMPA) were extracted from nail samples with N,N-dimethylformamide and subsequently analyzed by liquid chromatography-tandem mass spectrometry. Limits of detection for PMPA and IMPA were 0.3μg/kg and 7.5μg/kg and linear ranges were 0.75-300μg/kg and 30-1500μg/kg, respectively. Precision was within 10% and 8% for PMPA and IMPA, respectively, and accuracy was 100±12% for both analytes. The approach presented here is complementary to current methods for nerve agent exposure verification, and should allow for long-term determination of nerve agent poisoning. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Detection of various freshwater cyanobacterial toxins using ultra-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Oehrle, Stuart A; Southwell, Ben; Westrick, Judy

    2010-05-01

    Several freshwater cyanobacteria species have the capability to produce toxic compounds, frequently referred to as cyanotoxins. The most prevalent of these cyanotoxins is microcystin LR. Recognizing the potential health risk, France, Italy, Poland, Australia, Canada, and Brazil have set either standards or guidelines for the amount of microcystin LR permissible in drinking water based on the World Health Organization guideline of one microg/L of microcystin LR. Recently, the United States Environmental Protection Agency has begun to evaluate the occurrence and health effects of cyanotoxins and their susceptibility to water treatment under the Safe Drinking Water Act through the Contaminant Candidate List (CCL). A recent update of the Contaminant Candidate List focuses research and data collection on the cyanotoxins microcystin LR, anatoxin-a, and cylindrospermopsin. Liquid Chromatography/Tandem-Mass Spectrometry (LC/MS/MS) is a powerful tool for the analysis of various analytes in a wide variety of matrices because of its sensitivity and selectivity. The use of smaller column media (sub 2 microm particles) was investigated to both improve the speed, sensitivity and resolution, and to quantify the CCL cyanotoxins, in a single analysis, using Ultra-Performance Liquid Chromatography (UPLC) combined with tandem mass spectrometry. Natural waters and spiked samples were analyzed to show proof-of-performance. The presented method was able to clearly resolve each of the cyanotoxins in less than eight minutes with specificity and high spike recoveries. Copyright 2009 Elsevier Ltd. All rights reserved.

  10. [Determination of amitrole in agricultural products by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Li, Li; Fu, Jian; Gao, Hongliang; Ren, Haitao; Lou, Xishan; Guan, Lihui

    2010-03-01

    A high performance liquid chromatography-tandem mass spectrometry method (HPLC-MS/MS) was developed for the analysis of amitrole residues in agricultural products. The samples were extracted by 25% acetone for wheat, fish, pork and liver samples, 1% acetic acid-25% acetone for maize and peanut samples, 1% acetic acid solution for honeysuckle, the powder of ginger, the powder of bunge prickly ash and tea leaves samples, 1% acetic acid solution-dichloromethane for apple, pineapple, spinach, carrot, perilla leaves samples, respectively, followed by liquid-liquid extraction with dichloromethane. The samples were then cleaned up by PCX or Envi-Carb solid-phase extraction cartridge. The amitrole was determined and confirmed by HPLC-MS/MS. The results showed a linear relationship in the range of 0.005 -0.1 mg/kg for amitrole. The correlation coefficient was 0.999 7. The average recoveries of amitrole in wheat, maize, peanut, pineapple, apple, carrot, spinach, pork, the powder of ginger, the powder of bunge prickly ash, perilla, liver, fish, honeysuckle and tea were 67.5% - 98.1%. The relative standard deviations (RSDs) were 1.0% - 9.8%. The limits of quantitation were 10 microg/kg for wheat, maize, peanut, pineapple, apple, carrot, spinach, pork, perilla, liver, fish, honeysuckle and 20 microg/kg for the powder of bunge prickly ash, the powder of ginger and tea, respectively. The method is simple, sensitive and accurate.

  11. Liquid chromatography-tandem mass spectrometry for analysis of intestinal permeability of loperamide in physiological buffer.

    Directory of Open Access Journals (Sweden)

    Miriam S Rubelt

    Full Text Available Analysis of in vitro samples with high salt concentrations represents a major challenge for fast and specific quantification with liquid chromatography-tandem mass spectrometry (LC-MS/MS. To investigate the intestinal permeability of opioids in vitro employing the Ussing chamber technique, we developed and validated a fast, sensitive and selective method based on LC-MS/MS for the determination of loperamide in HEPES-buffered Ringer's solution. Chromatographic separation was achieved with an Atlantis dC18 column, 2.1 mm×20 mm, 3 µm particle size and a gradient consisting of methanol/0.1% formic acid and ammonium acetate. The flow rate was 0.7 ml/min, and the total run time was 3 min. For quantification, two mass transitions for loperamide and a deuterated internal standard (methadone-d(3 were used. The lower limit of loperamide quantification was 0.2 ng/ml. This new LC-MS/MS method can be used for the detection of loperamide in any experimental setup using HEPES-buffered Ringer's solution as a matrix compound.

  12. Optimization of a liquid chromatography-tandem mass spectrometry method for quantification of the plant lignans secoisolariciresinol, matairesinol, lariciresinol and pinoresinol in foods

    NARCIS (Netherlands)

    Milder, I.E.J.; Arts, I.C.W.; Venema, D.P.; Lasaroms, J.J.P.; Wähälä, K.; Hollman, P.C.H.

    2004-01-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of the four major enterolignan precursors [secoisolariciresinol, matairesinol, lariciresinol, and pinoresinol] in foods. The method consists of alkaline methanolic extraction, followed by

  13. Detection and quantitation of trace phenolphthalein (in pharmaceutical preparations and in forensic exhibits) by liquid chromatography-tandem mass spectrometry, a sensitive and accurate method.

    Science.gov (United States)

    Sharma, Kakali; Sharma, Shiba P; Lahiri, Sujit C

    2013-01-01

    Phenolphthalein, an acid-base indicator and laxative, is important as a constituent of widely used weight-reducing multicomponent food formulations. Phenolphthalein is an useful reagent in forensic science for the identification of blood stains of suspected victims and for apprehending erring officials accepting bribes in graft or trap cases. The pink-colored alkaline hand washes originating from the phenolphthalein-smeared notes can easily be determined spectrophotometrically. But in many cases, colored solution turns colorless with time, which renders the genuineness of bribe cases doubtful to the judiciary. No method is known till now for the detection and identification of phenolphthalein in colorless forensic exhibits with positive proof. Liquid chromatography-tandem mass spectrometry had been found to be most sensitive, accurate method capable of detection and quantitation of trace phenolphthalein in commercial formulations and colorless forensic exhibits with positive proof. The detection limit of phenolphthalein was found to be 1.66 pg/L or ng/mL, and the calibration curve shows good linearity (r(2) = 0.9974). © 2012 American Academy of Forensic Sciences.

  14. Chemotaxonomic studies of nine Paris species from China based on ultra-high performance liquid chromatography tandem mass spectrometry and Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Wang, Yuanzhong; Liu, Ehu; Li, Ping

    2017-06-05

    Paris species, which contain steroid saponins, have been used as herb folk medicines in Asia. In the present study, a comprehensive strategy based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and Fourier transform infrared (FT-IR) spectroscopy was firstly proposed to evaluate the chemotaxonomic relationships of nine Paris species sampled from different geographical regions in China. Principle component analysis (PCA) based on FT-IR data revealed chemical similarities in term of the nine species and geographical regions, indicating the accumulation of metabolites affected by the combination of geographical factors and species. The chemotaxonomic relationships of four species supported the morphological taxonomy and implied ancestry from P. polyphylla. After high-efficiency chromatographic separation, ions trap/time-of-flight mass spectrometry (IT-TOFMS) and triple quadrupole mass spectrometry (QQQ-MS) were used to identify unknown metabolites and simultaneously determine six key compounds (polyphyllin I, II, V, VI, VII and gracillin) in Paris species, respectively. The tentative identification of 22 steroid saponins was indicative of a common biosynthetic pathway in Paris species. Phytoecdysones, gracillin and open-chain steroid saponins were considered as key precursors. According to Pearson's correlation analysis, an insignificant correlation was found between diosgenin-type and pennogenin-type saponins belonging to the same biosynthetic pathways in the current stage. Our results could provide a reasonable foundation for chemotaxonomy or further studies of Paris species. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Magnetic trapping and thermal isolation of nitrogen hydride molecules using the buffer gas techniques

    Science.gov (United States)

    Tsikata, Edem

    Thermal isolation of trapped NH molecules is accomplished. We cool NH molecules to 500 mK using helium vapor buffer gas and magnetically trap them in the 4 Tesla field of an anti-Helmholtz superconducting magnet. The helium is introduced using a fast-acting cryogenic valve, allowing us to abruptly switch off the flow. The buffer gas rapidly exits the trapping region through a large diameter orifice. We trap 105 molecules with lifetimes exceeding 20 s. The prospect of extending the loading and trapping techniques to observe atom-molecule collisions is investigated.

  16. Quantification of acrylamide in foods selected by using gas chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Delević Veselin M.

    2016-01-01

    Full Text Available Acrylamide is toxic and probably carcinogenic compound, made as a result of high-temperature thermal treatment of carbohydrate-rich foodstuffs. In this article a method is improved for the extraction and quantitation of acrylamide in foods produced based on corn flour that are represented in our traditional diet. Acrylamide extraction was carried out using reduced volume of saturated solution of bromine water and the GC - MS method for the quantification was shown. Quantification of acrylamide was preceded by: sample homogenization, acrylamide extraction using water, extract purification using solid phase extraction, bromination, using a reduced volume of bromine water solution, dehydrobromination with sodium thiosulfate and transformation of dibromopropenamide in 2,3- 2- bromopropenamide using triethylamine. Regression and correlation analysis were applied for the probability level of 0.05. Calibration is performed in the concentration range 5-80 ug/kg with a detection limit 6.86 mg / kg and the limits of quantification 10.78 ug/kg and the coefficient of determination R2 > 0.999. Calibration curve was obtained: y = 0,069x + 0,038. Recovery values were an average from 97 to 110%. Proposed GC-MS method is simple, precise and reliable for the determination of acrylamide in the samples of thermal treated foods. Our results show that the tested foods quantify the presence of acrylamide in concentrations of 18 to 77 mg/kg acrylamide depending on whether the food was prepared by cooking or baking.

  17. Determination of ractopamine and salbutamol in pig hair by liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Kai-Chun Chang

    2018-04-01

    Full Text Available A liquid chromatography tandem mass spectrometric method was developed for the determination of two β-agonists (ractopamine and salbutamol in pig hair samples. An isotope of ractopamine-d5 or salbutamol-d6 as an internal standard was used to carry out quantitative analysis. Concentrated sodium hydroxide was used to pretreat hair samples and then purified by the solid phase extraction (SPE procedure. The extracted solution was evaporated and reconstituted for injection in the instrument with electrospray ionization (ESI operating in a positive multiple-reaction-monitoring (MRM mode. Ractopamine and salbutamol separation were performed on C18 analytical column under gradient condition. The internal standard calibration curve was linear in the range of concentration from 0.5 to 100 ng mL−1 (R2 > 0.995. Recoveries of this method estimated at three spiked concentrations of 100, 250 and 500 ng mL−1 in pig hair samples, were 79–82% for ractopamine and 77–96% for salbutamol. The corresponding inter-day and intra-day precisions expressed as relative standard deviation (RSD % were 3.8–6.4% and 3.8–8.6%, respectively. The analytical time for one sample was 8 min. The detection limit of this method was 0.6 and 8.3 ng mL−1 for ractopamine and salbutamol, respectively. This developed method can be applied for monitoring the use of the β-agonists salbutamol and ractopamine in swine feed incurred pig hair. Keywords: Salbutamol, Ractopamine, Hair, Tandem mass

  18. Determination of ractopamine and salbutamol in pig hair by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Chang, Kai-Chun; Chang, Yu-Ting; Tsai, Chin-En

    2018-04-01

    A liquid chromatography tandem mass spectrometric method was developed for the determination of two β-agonists (ractopamine and salbutamol) in pig hair samples. An isotope of ractopamine-d5 or salbutamol-d6 as an internal standard was used to carry out quantitative analysis. Concentrated sodium hydroxide was used to pretreat hair samples and then purified by the solid phase extraction (SPE) procedure. The extracted solution was evaporated and reconstituted for injection in the instrument with electrospray ionization (ESI) operating in a positive multiple-reaction-monitoring (MRM) mode. Ractopamine and salbutamol separation were performed on C18 analytical column under gradient condition. The internal standard calibration curve was linear in the range of concentration from 0.5 to 100 ng mL -1  (R 2  > 0.995). Recoveries of this method estimated at three spiked concentrations of 100, 250 and 500 ng mL -1 in pig hair samples, were 79-82% for ractopamine and 77-96% for salbutamol. The corresponding inter-day and intra-day precisions expressed as relative standard deviation (RSD %) were 3.8-6.4% and 3.8-8.6%, respectively. The analytical time for one sample was 8 min. The detection limit of this method was 0.6 and 8.3 ng mL -1 for ractopamine and salbutamol, respectively. This developed method can be applied for monitoring the use of the β-agonists salbutamol and ractopamine in swine feed incurred pig hair. Copyright © 2017. Published by Elsevier B.V.

  19. On-line high speed lipid extraction for nanoflow liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lee, Ju Yong; Yang, Joon Seon; Park, Se Mi; Byeon, Seul Kee; Moon, Myeong Hee

    2016-09-16

    An on-line lipid extraction method is introduced by utilizing a short capillary extraction column using HILIC and C4 particles prior to nanoflow liquid chromatography-tandem mass spectrometry (nLC-MS/MS). The on-line extraction using a urine sample spiked with PL standards showed similar or slightly higher recovery values (86%-96%) of phospholipids (PLs) compared to those obtained by the conventional off-line extraction based on the Folch method with or without using the air-exposed drying process. In this study, we demonstrated that PL oxidation can occur during the air-exposed drying process of lipid extracts in standard liquid-liquid extraction procedures, which was confirmed by the oxidized PL (OxPL) molecules that were generated from an off-line extraction using a few PL standards. Quantitative comparison of these OxPL species between on- and off-line extraction followed by nLC-MS/MS with multiple reaction monitoring (MRM) analysis showed a significant decrease (2-10 fold) in unwanted OxPL species when on-line extraction was employed. While the number of identified PLs from a urine sample was somewhat lower than those by off-line extraction, the number of OxPLs was significantly reduced (from 70 to 22) with on-line extraction. The new method offers high speed (∼5min) automated extraction of PLs with nLC-MS/MS analysis and presents the possibility of handling a biological sample with a very limited amount of lipids. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Simultaneous quantification of Pacific ciguatoxins in fish blood using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Mak, Yim Ling; Wu, Jia Jun; Chan, Wing Hei; Murphy, Margaret B; Lam, James C W; Chan, Leo L; Lam, Paul K S

    2013-04-01

    Ciguatera fish poisoning (CFP) is a food intoxication caused by exposure to ciguatoxins (CTXs) in coral reef fish. Rapid analytical methods have been developed recently to quantify Pacific-CTX-1 (P-CTX-1) in fish muscle, but it is destructive and can cause harm to valuable live coral reef fish. Also fish muscle extract was complex making CTX quantification challenging. Not only P-CTX-1, but also P-CTX-2 and P-CTX-3 could be present in fish, contributing to ciguatoxicity. Therefore, an analytical method for simultaneous quantification of P-CTX-1, P-CTX-2, and P-CTX-3 in whole blood of marketed coral reef fish using sonication, solid-phase extraction (SPE), and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. The optimized method gave acceptable recoveries of P-CTXs (74-103 %) in fish blood. Matrix effects (6-26 %) in blood extracts were found to be significantly reduced compared with those in muscle extracts (suppressed by 34-75 % as reported in other studies), thereby minimizing potential for false negative results. The target P-CTXs were detectable in whole blood from four coral reef fish species collected in a CFP-endemic region. Similar trends in total P-CTX levels and patterns of P-CTX composition profiles in blood and muscle of these fish were observed, suggesting a relationship between blood and muscle levels of P-CTXs. This optimized method provides an essential tool for studies of P-CTX pharmacokinetics and pharmacodynamics in fish, which are needed for establishing the use of fish blood as a reliable sample for the assessment and control of CFP.

  1. Applying liquid chromatography-tandem mass spectrometry to assess endodontic sealer microleakage

    Directory of Open Access Journals (Sweden)

    André Luiz da Costa MICHELOTTO

    2015-01-01

    Full Text Available The objective of this study was to describe a new method for the quantitative analysis of a microleakage of endodontic filling materials. Forty extracted single-rooted teeth were randomly divided into three experimental groups. After root canal shaping, the experimental groups were filled using the lateral condensation technique with the Epiphany system (G1, with gutta-percha + Sealapex (G2, and with gutta-percha + AH Plus (G3. Each root was mounted on a modified leakage testing device, and caffeine solution was used as a tracer (2000 ng mL-1, pH 6.0, applied in the coronal direction towards the tooth apex, creating a hydrostatic pressure of 2.55 kPa. Presence of caffeine in the receiving solution was measured after 10, 30, and 60 days, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS. None of the groups presented microleakage at 10 days. At 30 days, G2 and G3 showed similar infiltration patterns (means: 16.0 and 13.9 ng mL-1, respectively, whereas G1 showed significantly higher values (mean: 105.2 ng mL-1. At 60 days, leakage values were 182.6 ng mL-1for G1, 139.0 ng mL-1 for G2, and 53.5 ng mL-1 for G3. AH Plus showed the best sealing ability and HPLC-MS/MS showed high sensitivity and specificity for tracer quantification.

  2. Validated method for determination of mazindol in human plasma by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Kim, Sung-Su; Lee, Heon-Woo; Lee, Kyung-Tae

    2009-04-01

    A simple liquid chromatography/tandem mass spectrometry (LC/MS/MS) method with electrospray ionization in positive ion multiple reaction monitoring mode was developed for the quantification of mazindol (an anorectic agent) in human plasma. Fluoxetine was adopted as an internal standard (IS), and sample preparation involved one-step liquid/liquid extraction using ethyl acetate. The transition monitored were m/z 285>44 for mazindol and m/z 310>44 for IS. Chromatographic separation was achieved on a Capcell Pak MGII C(18) column using an isocratic mobile phase, consisting of acetonitrile-20mM ammonium formate in water (50:50, v/v, adjusted to pH 3.5 with formic acid) at a flow-rate of 0.2mL/min. The retention times of mazindol and fluoxetine were 1.03min and 1.45min, respectively. The lower limit of quantitation (LLOQ) was 0.1ng/mL using 200microL of plasma, and no interferences were detected in chromatograms. The bench top stability of mazindol was evaluated in buffered and non-buffered plasma. The selectivity, linearity, precision, accuracy, recovery, and stability of the devised method were fully validated and absolute and relative matrix effects were evaluated. The described method provides a fast and sensitive analytical tool for determining mazindol levels in plasma, and was successfully applied to a pharmacokinetic study in 24 healthy human subjects after oral administration of 2mg tablet formulation of mazindol under fasting conditions.

  3. Chiral chromatography-tandem mass spectrometry applied to the determination of pro-resolving lipid mediators.

    Science.gov (United States)

    Homann, Julia; Lehmann, Christoph; Kahnt, Astrid S; Steinhilber, Dieter; Parnham, Michael J; Geisslinger, Gerd; Ferreirós, Nerea

    2014-09-19

    Pro-resolving lipid mediators are a class of endogenously synthesized molecules derived from different fatty acids, such as arachidonic, docosahexaenoic or eicosapentaenoic acid, which are derived into four different product families: lipoxins, resolvins, maresins and protectins. For quantitation of these compounds, a sensitive, selective and robust liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantitation of lipoxin A4, 6-epi-lipoxin A4, lipoxin B4 and lipoxin A5, the D-series resolvins D1 and D2 as well as aspirin-triggered lipoxin A4 and resolvin D1, maresin and protectin and the pathway markers 17(S)-hydroxy-docosahexaenoic acid and 17(R)-hydroxy-docosahexaenoic acid in cell culture supernatants. For this purpose, a chiral column was connected in series with a reversed-phase column to achieve efficient analyte separation and high sensitivity. Sample pre-treatment included a fast and simple liquid-liquid extraction procedure. Limits of quantitation in the range of 0.1-0.5ng/mL cell culture media, absolute recoveries between 90 and 115%, intra- and interday precision of less than 13% and an accuracy of less than 11% were obtained. Stability of the samples after 60 days storage at -80°C, three freeze/thaw cycles and 4h at room temperature has been demonstrated for all analytes. Sample extracts can be stored at 7°C for 24h without degradation of the analytes. Deviations of less than 13% in the accuracy, evaluated in terms of relative error, were obtained. The suitability of the method has been demonstrated in cell culture supernatants of human polymorphonuclear leukocytes, stimulated with 15R-hydroxy-eicosatetraenoic acid and in cell culture media of human polymorphonuclear leukocytes co-incubated with human platelets. From all studied analytes, lipoxin A4 and 6-epi-lipoxin A4 were found in cell culture media under both incubation conditions, while 15-epi-lipoxin A4 was additionally detected in cell

  4. Detection of 10 sweeteners in various foods by liquid chromatography/tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Chui-Shiang Chang

    2014-09-01

    Full Text Available The analytical method for sweeteners in various food matrixes is very important for food quality control and regulation enforcement. A simple and rapid method for the simultaneous determination of 10 sweeteners [acesulfame potassium (ACS-K, aspartame (ASP, cyclamate (CYC, dulcin (DUL, glycyrrhizic acid (GA, neotame (NEO, neohesperidin dihydrochalcone (NHDC, saccharin (SAC, sucralose (SCL, and stevioside (STV] in various foods by liquid chromatography/tandem mass chromatography (LC–MS/MS was developed. The chromatographic separation was performed on a Phenomenex Luna Phenyl-Hexyl (5 μm, 4.6 mm × 150 mm column with gradient elution of 10 mM ammonium acetate in water and 10 mM ammonium acetate in methanol. The recoveries of the 10 sweeteners were between 75% and 120%, and the coefficients of variation were less than 20%. The limits of quantification were 0.5 μg/kg for NHDC and SCL. For the other sweeteners, the limits of quantification were 0.1 μg/kg. Compared to the traditional high-performance liquid chromatography method, the LC–MS/MS method could provide better sensitivity, higher throughput, enhanced specificity, and more sweeteners analyzed in a single run. The samples included 27 beverages (16 alcoholic and 11 nonalcoholic beverages and 15 pickled foods (1 pickled pepper, 3 candies, and 11 candied fruits. Two remanufactured wines were found to contain 7.2, 8.5 μg/g SAC and 126.5, 123 μg/g CYC, respectively. ACS-K, ASP, SCL, and NEO were detected in five beverages and drinks. The pickled peppers and candied fruits were found to contain SAC, GA, CYC, ASP, STV, NEO, and ACS-K. The wine with sweeteners detected was remanufactured wine, not naturally fermented wine. Therefore, the ingredient label for the sweeteners of remanufactured wine should be regulated by the proper authority for inspection of sweeteners.

  5. Quantification of galactose-1-phosphate uridyltransferase enzyme activity by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Li, Yijun; Ptolemy, Adam S; Harmonay, Lauren; Kellogg, Mark; Berry, Gerard T

    2010-05-01

    The diagnosis of galactosemia usually involves the measurement of galactose-1-phosphate uridyltransferase (GALT) activity. Traditional radioactive and fluorescent GALT assays are nonspecific, laborious, and/or lack sufficient analytical sensitivity. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based assay for GALT enzyme activity measurement. Our assay used stable isotope-labeled alpha- galactose-1-phosphate ([(13)C(6)]-Gal-1-P) as an enzyme substrate. Sample cleanup and separation were achieved by reversed-phase ion-pair chromatography, and the enzymatic product, isotope-labeled uridine diphosphate galactose ([(13)C(6)]-UDPGal), was detected by MS/MS at mass transition (571 > 323) and quantified by use of [(13)C(6)]-Glu-1-P (265 > 79) as an internal standard. The method yielded a mean (SD) GALT enzyme activity of 23.8 (3.8) mumol x (g Hgb)(-1) x h(-1) in erythrocyte extracts from 71 controls. The limit of quantification was 0.04 micromol x (g Hgb)(-1) x h(-1) (0.2% of normal control value). Intraassay imprecision was determined at 4 different levels (100%, 25%, 5%, and 0.2% of the normal control values), and the CVs were calculated to be 2.1%, 2.5%, 4.6%, and 9.7%, respectively (n = 3). Interassay imprecision CVs were 4.5%, 6.7%, 8.2%, and 13.2% (n = 5), respectively. The assay recoveries at the 4 levels were higher than 90%. The apparent K(m) of the 2 substrates, Gal-1-P and UDPGlc, were determined to be 0.38 mmol/L and 0.071 mmol/L, respectively. The assay in erythrocytes of 33 patients with classical galactosemia revealed no detectable activity. This LC-MS/MS-based assay for GALT enzyme activity will be useful for the diagnosis and study of biochemically heterogeneous patients with galactosemia, especially those with uncommon genotypes and detectable but low residual activities.

  6. Detection and identification of drugs and toxicants in human body fluids by liquid chromatography-tandem mass spectrometry under data-dependent acquisition control and automated database search.

    Science.gov (United States)

    Oberacher, Herbert; Schubert, Birthe; Libiseller, Kathrin; Schweissgut, Anna

    2013-04-03

    Systematic toxicological analysis (STA) is aimed at detecting and identifying all substances of toxicological relevance (i.e. drugs, drugs of abuse, poisons and/or their metabolites) in biological material. Particularly, gas chromatography-mass spectrometry (GC/MS) represents a competent and commonly applied screening and confirmation tool. Herein, we present an untargeted liquid chromatography-tandem mass spectrometry (LC/MS/MS) assay aimed to complement existing GC/MS screening for the detection and identification of drugs in blood, plasma and urine samples. Solid-phase extraction was accomplished on mixed-mode cartridges. LC was based on gradient elution in a miniaturized C18 column. High resolution electrospray ionization-MS/MS in positive ion mode with data-dependent acquisition control was used to generate tandem mass spectral information that enabled compound identification via automated library search in the "Wiley Registry of Tandem Mass Spectral Data, MSforID". Fitness of the developed LC/MS/MS method for application in STA in terms of selectivity, detection capability and reliability of identification (sensitivity/specificity) was demonstrated with blank samples, certified reference materials, proficiency test samples, and authentic casework samples. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Determination of olanzapine in whole blood using simple protein precipitation and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2009-01-01

    A simple, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of the antipsychotic drug olanzapine in whole blood using dibenzepine as internal standard (IS). After acidic methanol-induced protein precipitation......, and stability. The absolute recovery obtained was 103% for olanzapine and 68% for IS. An LOQ of 0.005 mg/kg olanzapine in whole blood was achieved. Inter- and intraday precision were less than 11% within concentrations from 0.01 to 0.50 mg/kg, and the accuracy ranged from 85 to 115%. The method was subsequently...

  8. Simultaneous Determination of 25 Common Pharmaceuticals in Whole Blood Using Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2012-01-01

    An ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of 25 common pharmaceuticals in whole blood. The selected pharmaceuticals represent the most frequently detected drugs in our forensic laboratory with basic properties...... elution using a Waters ACQUITY Ultra-Performance Liquid Chromatography system. Quantification was performed on a Waters tandem quadrupole ACQUITY TQD using multiple reaction monitoring in positive mode. The analytes were eluted within 11 min. The limit of quantification (LOQ) ranged from 0.002 to 0.01 mg...

  9. Determination of anabolic steroids with gas chromatography-ion trap mass spectrometry using hydrogen as carrier gas.

    Science.gov (United States)

    Impens, S; De Wasch, K; De Brabander, H

    2001-01-01

    Helium is considered to be the ideal carrier gas for gas chromatography/mass spectrometry (GC/MS) in general, and for use with an ion trap in particular. Helium is an inert gas, can be used without special precautions for security and, moreover, it is needed as a damping gas in the trap. A disadvantage of helium is the high viscosity resulting in long GC run times. In this work hydrogen was tested as an alternative carrier gas for GC in performing GC/MS analyses. A hydrogen generator was used as a safe source of hydrogen gas. It is demonstrated that hydrogen can be used as a carrier gas for the gas chromatograph in combination with helium as make-up gas for the trap. The analysis time was thus shortened and the chromatographic performance was optimized. Although hydrogen has proven useful as a carrier gas in gas chromatography coupled to standard detectors such as ECD or FID, its use is not mentioned extensively in the literature concerning gas chromatography-ion trap mass spectrometry. However, it is worth considering as a possibility because of its chromatographic advantages and its advantageous price when using a hydrogen generator. Copyright 2001 John Wiley & Sons, Ltd.

  10. [Determination of congo red in beef by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    Science.gov (United States)

    Lin, Hui; Xu, Chunxiang; Yan, Chunrong; Zhang, Zheng; Wang, Suilou

    2013-09-01

    A method was developed for the determination of congo red in beef. The analyte was identified by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry (LC-QTOF MS) and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the congo red in the beef sample was separated on an Agilent ZORBAX Eclipse Plus C18 Rapid Resolution HD UPLC column (50 mm x 2.1 mm, 1.8 microm) HPLC , using 95% (volume percentage) methanol as the mobile phase at 0.2 mL/min. The detection was performed on an AB 4000 + triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The results showed that the linear range of congo red mass concentration was 0.03 - 1 mg/L with the correlation coefficient of 0.999 8. The method had a good precision with the RSDs lower than 5% and the recoveries ranging from 88% to 91%. The limit of detection (LOD) of congo red was 0.01 mg/L. With good reproducibility, the method is simple, fast and effective for the determination of the illegally added congo red in beef and other meat products.

  11. [Simultaneous analysis the residues of 20 hormones in foods of animal origin by liquid chromatography tandem mass spectrometry].

    Science.gov (United States)

    Liu, Guihua; Qin, Wei; Liu, Honghe; Zhu, Zhou

    2013-01-01

    To develop a quick and accurate method for simultaneous determining the multi-residues of hormones in foods of animal origin by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and to investigate these residues in swine, bovine, egg and milk collected from local markets in Shenzhen. The sample was firstly extracted with acetonitrile, and then subjected to solid-phase extraction clean-up using HLB-NH2 cartridges after defatted with hexane, lastly detected by high performance liquid chromatography-tandem mass spectrometry. Identification was achieved by electrospray ionization (ESI) in both positive and negative mode using multiple reaction monitoring. Quantification was performed by internal standard calibration. The study showed that there was a certain amount of endogenous hormones in collected samples. The limits of quantification were 0.5 - 1.0 microg/kg for 20 hormones in swine, bovine, egg and milk. Average recoveries were 60.4% -118.2%, and the relative standard deviations were 2.5% - 16.2%. This method was quick and accurate which could be used for determination of hormones in foods of animal origin (such as swine, bovine, egg and milk).

  12. The injection of inert gas ions into solids: their trapping and escape

    International Nuclear Information System (INIS)

    Carter, G.; Armour, D.G.; Donnelly, S.E.; Ingram, D.C.; Webb, R.P.

    1980-01-01

    The first part of this contribution will review experimental studies of the trapping probabilities of ions injected into solids as a function of ion energy and indicate how the data can be modelled theoretically. It will be demonstrated that trapping is a two stage process, the first involving penetration into the solid and the second requiring atom dissolution and experimental evidence will be cited to show how the latter process may be dominant for light ions which create little radiation damage. For low ion fluences, injected atoms are generally trapped in isolation but as fluence increases gas-defect complexes are formed and it will be shown how post bombardment thermal evaluation studies can provide evidence for the growth of these complexes. Concomitant with trapping however, dissolved gas may be evolved from the solid by some form of sputtering process, sometimes by mechanisms much more efficient than congruent sputtering of the solid together with the trapped species. Measurements of the trapped atom concentration-ion fluence behaviour and of the evolution of one initially trapped species by bombardment with a second species provide information on the physical processes involved in trapped atom sputtering and upon the mechanism of gas incorporation saturation and experimental studies in this area, together with some first approximation theoretical investigations will be discussed. It will be shown that an important mechanism in dictating incorporation saturation, in addition to sputtering, is the atomic saturation of the solid by the implant. (author)

  13. Sudden expansion of a one-dimensional bose gas from power-law traps.

    Science.gov (United States)

    Campbell, A S; Gangardt, D M; Kheruntsyan, K V

    2015-03-27

    We analyze free expansion of a trapped one-dimensional Bose gas after a sudden release from the confining trap potential. By using the stationary phase and local density approximations, we show that the long-time asymptotic density profile and the momentum distribution of the gas are determined by the initial distribution of Bethe rapidities (quasimomenta) and hence can be obtained from the solutions to the Lieb-Liniger equations in the thermodynamic limit. For expansion from a harmonic trap, and in the limits of very weak and very strong interactions, we recover the self-similar scaling solutions known from the hydrodynamic approach. For all other power-law traps and arbitrary interaction strengths, the expansion is not self-similar and shows strong dependence of the density profile evolution on the trap anharmonicity. We also characterize dynamical fermionization of the expanding cloud in terms of correlation functions describing phase and density fluctuations.

  14. Nonequilibrium Spin Dynamics in a Trapped Fermi Gas with Effective Spin-Orbit Interactions

    International Nuclear Information System (INIS)

    Stanescu, Tudor D.; Zhang Chuanwei; Galitski, Victor

    2007-01-01

    We consider a trapped atomic system in the presence of spatially varying laser fields. The laser-atom interaction generates a pseudospin degree of freedom (referred to simply as spin) and leads to an effective spin-orbit coupling for the fermions in the trap. Reflections of the fermions from the trap boundaries provide a physical mechanism for effective momentum relaxation and nontrivial spin dynamics due to the emergent spin-orbit coupling. We explicitly consider evolution of an initially spin-polarized Fermi gas in a two-dimensional harmonic trap and derive nonequilibrium behavior of the spin polarization. It shows periodic echoes with a frequency equal to the harmonic trapping frequency. Perturbations, such as an asymmetry of the trap, lead to the suppression of the spin echo amplitudes. We discuss a possible experimental setup to observe spin dynamics and provide numerical estimates of relevant parameters

  15. Quality by Design–Applied Liquid Chromatography-Tandem Mass Spectrometry Determination of Enzalutamide Anti-Prostate Cancer Therapy Drug in Spiked Plasma Samples

    Directory of Open Access Journals (Sweden)

    ASK Sankar

    2017-08-01

    Full Text Available This research article presents the Quality by Design (QbD–finalised conditions for a method that uses liquid chromatography-tandem mass spectrometry for the determination of concentration of enzalutamide (ENZ, an atypical anticancer drug, in a drug formulation and in spiked plasma samples. Critical process attributes (CPA considered to be the influential parameters in separation, identification, and quantification processes by ultrahigh-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry (UHPLC-ESI-MS/MS were organic content, buffer strength, pH modifier, flow rate, spray voltage, sheath gas, and auxiliary gas that alter critical analytical attributes, such as retention time (R1 and area (R2. These factors were evaluated first in a factorial design (Taguchi orthogonal array design and then extensively in a central composite design (CCD to zero-in on the mobile phase for the quantification of ENZ standard drug and along with its internal standard (ENZIS in spiked plasma samples and in formulation. Pareto chart from initial factorial design (Taguchi orthogonal array design model suggested which of the CPA factors should be given the weightage, that is, to be exhaustively analysed in the CCD and response surface analysis. The elaborated parameters proposed by World Health Organization were studied by method validation, ie, selectivity, linearity, accuracy, precision repeatability system-suitability tests, method robustness/ruggedness, sensitivity, and stability. The strategy followed gives an insight on the development of a robust QbD-compliant quantitative UHPLC-ESI-MS/MS method for ENZ drug containing plasma samples (spiked.

  16. Quantum Impurity in a One-dimensional Trapped Bose Gas

    DEFF Research Database (Denmark)

    Salami Dehkharghani, Amin; Volosniev, A. G.; Zinner, N. T.

    2015-01-01

    We present a new theoretical framework for describing an impurity in a trapped Bose system in one spatial dimension. The theory handles any external confinement, arbitrary mass ratios, and a weak interaction may be included between the Bose particles. To demonstrate our technique, we calculate...

  17. Analysis of 10 systemic pesticide residues in various baby foods using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yang, Angel; Abd El-Aty, A M; Park, Jong-Hyouk; Goudah, Ayman; Rahman, Md Musfiqur; Do, Jung-Ah; Choi, Ok-Ja; Shim, Jae-Han

    2014-06-01

    Ten systemic pesticides, comprising methomyl, thiamethoxam, acetamiprid, carbofuran, fosthiazate, metalaxyl, azoxystrobin, diethofencarb, propiconazole, and difenoconazole, were detected in 13 baby foods (cereals, boiled potatoes, fruit and milk) using QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) for sample preparation and liquid chromatography tandem mass spectrometry for analysis. The matrix-matched calibration curves showed good linearity with determination coefficients (R(2) ) >0.992. The limits of detection and quantitation were 0.0015-0.003 and 0.005-0.01 mg/kg, respectively. The mean recoveries of three different concentrations ranged from 69.2 to 127.1% with relative standard deviations market, and none of the samples were found to contain pesticide residues. This method is suitable for the identification and quantification of systemic pesticides with matrix-matched standards in various baby foods. Copyright © 2013 John Wiley & Sons, Ltd.

  18. Matrix effect on the determination of synthetic corticosteroids and diuretics by liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Dikunets, M. A.; Appolonova, S. A.; Rodchenkov, G. M.

    2009-04-01

    This work presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) procedure for selective and reliable screening of corticosteroids and diuretics in human urine. Sample preparation included the extraction, evaporation of the organic extract under nitrogen, and solution of the dry residue. The extract was analyzed by HPLC combined with tandem mass spectrometry using electro-spraying ionization at atmospheric pressure with negative ion recording. The mass spectra of all compounds were recorded, and the characteristic ions, retention times, and detection limits were determined. The procedure was validated by evaluating the degree of the matrix suppression of ionization, extraction of analytes from human biological liquid, and the selectivity and specificity of determination.

  19. Liquid chromatography tandem mass spectrometry method for simultaneous determination of metoprolol tartrate and ramipril in human plasma.

    Science.gov (United States)

    Gowda, K Veeran; Mandal, Uttam; Senthamil Selvan, P; Sam Solomon, W D; Ghosh, Animesh; Sarkar, Amlan Kanti; Agarwal, Sangita; Nageswar Rao, T; Pal, Tapan Kumar

    2007-10-15

    A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of metoprolol tartrate (MT) and ramipril, in human plasma. Both the drugs were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v). The chromatographic separation was performed on a reversed-phase C8 column with a mobile phase of 10 mM ammonium formate-methanol (3:97, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The method was validated over the concentration range of 5-500 ng/ml for metoprolol and ramipril in human plasma. The precursor to product ion transitions of m/z 268.0-103.10 and m/z 417.20-117.20 were used to measure metoprolol and ramipril, respectively.

  20. A graphene tip coupled with liquid chromatography tandem mass spectrometry for the determination of four synthetic adulterants in slimming supplements.

    Science.gov (United States)

    Jin, Renyao; Li, Linqiu; Guo, Lianxian; Li, Weiqiao; Shen, Qing

    2017-06-01

    Slimming supplements were popularly sold online driven by the increasement of obesity and the development of social networking platform. However, events of drug abuse in slimming supplements were also frequently reported. In this study, a graphene tip solid-phase extraction (Gtip SPE) and ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established for determining fenfluramine, phenolphthalein, bumetanide, and sibutramine in slimming supplements. It was validated in terms of linearity (0.9985-0.9995), LOD (1.8ngmL -1 ), LOQ (5.6ngmL -1 ), intra-day precision (Phenolphthalein was also found with content lower than 5.2mgg -1 . The successful application of Gtip SPE and UPLC-MS/MS method indicated its advantage in analyzing low level of contaminates resulted from violation of regulation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Determination of olanzapine in whole blood using simple protein precipitation and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2009-01-01

    A simple, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of the antipsychotic drug olanzapine in whole blood using dibenzepine as internal standard (IS). After acidic methanol-induced protein precipitation...... of the whole blood samples, olanzapine and IS were chromatographed on a reversed-phase Zorbax Extend-C(18)-column at pH 9.0. Quantification was performed on a triple-quadrupole mass spectrometer employing electrospray ionization technique operating in multiple reaction monitoring and positive ion mode. Total...... chromatographic run time was 15 min, and calibration curve was linear over the concentration range of 0.005 to 0.50 mg/kg olanzapine in whole blood. The method was validated for selectivity, matrix interference, recovery, linearity, limit of detection, limit of quantitation (LOQ), accuracy, precision...

  2. Ultra-high-performance liquid chromatography-tandem mass spectrometry measurement of climbazole deposition from hair care products onto artificial skin and human scalp

    NARCIS (Netherlands)

    Chen, G.; Hoptroff, M.; Fei, X.; Su, Y.; Janssen, H.-G.

    2013-01-01

    A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal

  3. Ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) for determination of GHB, precursors and metabolites in different specimens

    DEFF Research Database (Denmark)

    Busardò, Francesco Paolo; Kyriakou, Chrystalla; Marchei, Emilia

    2017-01-01

    -butyrolactone (GBL), are illegal recreational drugs of abuse. A procedure based on ultra-high-performance liquid chromatography tandem mass spectrometry has been developed and validated in plasma, urine, cerebrospinal fluid and hair for acute and chronic exposure to GHB and in seized preparations coming from black...

  4. METHOD 544. DETERMINATION OF MICROCYSTINS AND NODULARIN IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY (LC/MS/MS)

    Science.gov (United States)

    Method 544 is an accurate and precise analytical method to determine six microcystins (including MC-LR) and nodularin in drinking water using solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS). The advantage of this SPE-LC/MS/MS is its sensi...

  5. Simultaneous identification of multiple β-lactamases in Acinetobacter baumannii in relation to carbapenem and ceftazidime resistance, using liquid chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Trip, H.; Mende, K.; Majchrzykiewicz-Koehorst, J.A.; Sedee, N.J.A.; Hulst, A.G.; Jansen, H.J.; Murray, C.K.; Paauw, A.

    2015-01-01

    Shotgun proteomics using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied to detect β-lactamases in clinical Acinetobacter baumannii isolates. The correlation of the detection of β-lactamase proteins (rather than PCR detection of the corresponding genes) with the resistance

  6. Enantioselective determination of methylphenidate and ritalinic acid in whole blood from forensic cases using automated solid-phase extraction and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Thomsen, Ragnar; B. Rasmussen, Henrik; Linnet, Kristian

    2012-01-01

    A chiral liquid chromatography tandem mass spectrometry (LC–MS-MS) method was developed and validated for quantifying methylphenidate and its major metabolite ritalinic acid in blood from forensic cases. Blood samples were prepared in a fully automated system by protein precipitation followed...

  7. Liquid chromatography-tandem mass spectrometric assay for the T790M mutant EGFR inhibitor osimertinib (AZD9291) in human plasma

    NARCIS (Netherlands)

    Rood, Johannes J M; van Bussel, Mark T J; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2016-01-01

    A method for the quantitative analysis by ultra-performance liquid chromatography-tandem mass spectrometry of the highly selective irreversible covalent inhibitor of EGFR-TK, osimertinib in human plasma was developed and validated, using pazopanib as an internal standard. The validation was

  8. Quantification of urinary mono-hydroxylated metabolites of polycyclic aromatic hydrocarbons by on-line solid phase extraction-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Yuesong; Meng, Lei; Pittman, Erin N; Etheredge, Alisha; Hubbard, Kendra; Trinidad, Debra A; Kato, Kayoko; Ye, Xiaoyun; Calafat, Antonia M

    2017-02-01

    Human exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed through monitoring of urinary mono-hydroxylated PAHs (OH-PAHs). Gas chromatography (GC) has been widely used to separate OH-PAHs before quantification by mass spectrometry in biomonitoring studies. However, because GC requires derivatization, it can be time consuming. We developed an on-line solid phase extraction coupled to isotope dilution-high performance liquid chromatography-tandem mass spectrometry (on-line-SPE-HPLC-MS/MS) method for the quantification in urine of 1-OH-naphthalene, 2-OH-naphthalene, 2-OH-fluorene, 3-OH-fluorene, 1-OH-phenanthrene, the sum of 2-OH and 3-OH-phenanthrene, 4-OH-phenanthrene, and 1-OH-pyrene. The method, which employed a 96-well plate platform and on-line SPE, showed good sensitivity (i.e., limits of detection ranged from 0.007 to 0.09 ng/mL) and used only 100 μL of urine. Accuracy, calculated from the recovery percentage at three spiking levels, varied from 94 to 113 %, depending on the analyte. The inter- and intra-day precision, calculated from 20 repeated measurements of two quality control materials, varied from 5.2 to 16.7 %. Adequate method performance was also confirmed by acceptable recovery (83-102 %) of two NIST standard reference materials (3672 and 3673). This high-throughput on-line-SPE-HPLC-MS/MS method can be applied in large-scale epidemiological studies. Graphical abstract Example LC-MS chromatogram of urinary mono-hydroxylated PAH metabolites.

  9. Graphene based solid phase extraction combined with ultra high performance liquid chromatography-tandem mass spectrometry for carbamate pesticides analysis in environmental water samples.

    Science.gov (United States)

    Shi, Zhihong; Hu, Junda; Li, Qi; Zhang, Shulan; Liang, Yuhuan; Zhang, Hongyi

    2014-08-15

    In this paper, graphene, a new sorbent material, was synthesized and used for solid-phase extraction (SPE) of the six carbamate pesticides (pirimicarb, baygon, carbaryl, isoprocarb, baycarb and diethofencarb) in environmental water samples. The target analytes can be extracted on the graphene-packed SPE cartridge, and then eluted with acetone. The eluate was collected and dried by high purity nitrogen gas at room temperature. 1mL of 20% (v/v) acetonitrile aqueous solution was used to redissolve the residue. The final sample solution was analyzed by ultra performance liquid chromatography-tandem quadrupole mass spectrometry (UPLC-MS/MS) system. Under optimum conditions, good linearity was obtained for the carbamates with correlation coefficient in the range of 0.9992-0.9998. The limits of detection (S/N=3) for the six carbamate pesticides were in the range of 0.5-6.9ngL(-1). Relative standard deviations (RSD) for five replicate determinations were below 5.54%. RSD values for cartridge-to-cartridge precision (n=7) were in the range of 1.27-8.13%. After proper regeneration, the graphene-packed SPE cartridge could be re-used over 100 times for standard solution without significant loss of performance. The enrichment factors for the target analytes were in the range of 34.2-51.7. The established method has been successfully applied to the determination of carbamate pesticide residues in environmental water samples such as river water, well water and lake water. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Liquid chromatography-tandem mass spectrometry method for the determination of thiosulfate in human blood and urine as an indicator of hydrogen sulfide poisoning.

    Science.gov (United States)

    Maseda, Chikatoshi; Hayakawa, Akira; Okuda, Katsuhiro; Asari, Masaru; Tanaka, Hiroki; Yamada, Hiromi; Jin, Shigeki; Horioka, Kie; Matoba, Kotaro; Shiono, Hiroshi; Matsubara, Kazuo; Shimizu, Keiko

    2017-01-01

    Being a stable metabolite of hydrogen sulfide, thiosulfate has been utilized as an index for hydrogen sulfide poisoning (HSP). Thiosulfate analysis is mainly performed using gas chromatography/mass spectrometry (GC-MS) due to its high sensitivity and specificity. The GC-MS analysis requires two-step derivatizations of thiosulfate, and the derivative is not stable in solution as it has a disulfide moiety. To resolve this stability issue, we developed a novel analytical method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for monitoring the pentafluorobenzyl derivative of thiosulfate (the first reaction product of the GC-MS method) in this study. The established method exhibited high reproducibility despite being a more simplified and rapid procedure compare to the GC-MS method. Phenyl 4-hydroxybenzoate was used as an internal standard because 1,3,5-tribromobenzene which had been used in the GC-MS method was not suitable compound for LC-MS/MS with Electrospray ionization (ESI) negative detection. The linear regression of the peak area ratios versus concentrations was fitted over the concentration ranges of 0.5-250μM and 0.25-250μM in blood and urine, respectively. The validation results satisfied the acceptance criteria for intra- and inter-day accuracy and precision. Blood and urine samples from 12 suspected HSP cases were tested using this method. The thiosulfate concentration detected in the sample coincided well with that determined at the scene of each HSP accident. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  11. On the isobaric space of 25-hydroxyvitamin D in human serum: potential for interferences in liquid chromatography/tandem mass spectrometry, systematic errors and accuracy issues.

    Science.gov (United States)

    Qi, Yulin; Geib, Timon; Schorr, Pascal; Meier, Florian; Volmer, Dietrich A

    2015-01-15

    Isobaric interferences in human serum can potentially influence the measured concentration levels of 25-hydroxyvitamin D [25(OH)D], when low resolving power liquid chromatography/tandem mass spectrometry (LC/MS/MS) instruments and non-specific MS/MS product ions are employed for analysis. In this study, we provide a detailed characterization of these interferences and a technical solution to reduce the associated systematic errors. Detailed electrospray ionization Fourier transform ion cyclotron resonance (FTICR) high-resolution mass spectrometry (HRMS) experiments were used to characterize co-extracted isobaric components of 25(OH)D from human serum. Differential ion mobility spectrometry (DMS), as a gas-phase ion filter, was implemented on a triple quadrupole mass spectrometer for separation of the isobars. HRMS revealed the presence of multiple isobaric compounds in extracts of human serum for different sample preparation methods. Several of these isobars had the potential to increase the peak areas measured for 25(OH)D on low-resolution MS instruments. A major isobaric component was identified as pentaerythritol oleate, a technical lubricant, which was probably an artifact from the analytical instrumentation. DMS was able to remove several of these isobars prior to MS/MS, when implemented on the low-resolution triple quadrupole mass spectrometer. It was shown in this proof-of-concept study that DMS-MS has the potential to significantly decrease systematic errors, and thus improve accuracy of vitamin D measurements using LC/MS/MS. Copyright © 2014 John Wiley & Sons, Ltd.

  12. Development of the Next Generation Gas Trap for the Space Station Internal Thermal Control System

    Science.gov (United States)

    Leimkuehler, Thomas O.; Spelbring, Chris; Reeves, Daniel R.; Holt, James M.

    2003-01-01

    The current dual-membrane gas trap is designed to remove non-condensed gases (NCG) from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Design goals are to meet or exceed the current requirements to (1) include greater operating ranges and conditions, (2) eliminate reliance on the current hydrophilic tube fabrication process, and (3) increase operational life and tolerance to particulate and microbial growth fouling. In addition, the next generation gas trap will essentially be a 'dropin" design such that no modifications to the ITCS pump package assembly (PPA) will be required, and the implementation of the new design will not affect changes to the ITCS operational conditions, interfaces, or software. This paper will present the initial membrane module design and development work which has included (1) a trade study among several conceptual designs, (2) performance modeling of a hydrophobic-only design, and (3) small-scale development test data for the hydrophobic-only design. Testing has shown that the hydrophobic-only design is capable of performing even better than the current dual-membrane design for both steady-state gas removal and gas slug removal.

  13. A catalytic reactor for the trapping of free radicals from gas phase oxidation reactions

    Science.gov (United States)

    Conte, Marco; Wilson, Karen; Chechik, Victor

    2010-10-01

    A catalytic reactor for the trapping of free radicals originating from gas phase catalytic reactions is described and discussed. Radical trapping and identification were initially carried out using a known radical generator such as dicumyl peroxide. The trapping of radicals was further demonstrated by investigating genuine radical oxidation processes, e.g., benzaldehyde oxidation over manganese and cobalt salts. The efficiency of the reactor was finally proven by the partial oxidation of cyclohexane over MoO3, Cr2O3, and WO3, which allowed the identification of all the radical intermediates responsible for the formation of the products cyclohexanol and cyclohexanone. Assignment of the trapped radicals was carried out using spin trapping technique and X-band electron paramagnetic resonance spectroscopy.

  14. Demonstration of fly-ash filter for trapping volatile radioactive cesium in off-gas stream

    International Nuclear Information System (INIS)

    Chun, K. S.; Park, J. J.; Shon, J. S.; Shin, J. M.; Choi, K. W.

    2000-02-01

    The object of this study is to design and operate the fly ash filter unit for trapping cesium in the vitrification pilot process of radioactive waste in the low and medium level. It is necessary to reuse fly ash, which is a kind of waste from coal fired power plant, in trapping cesium generated from vitrification process and improving safety and removal efficiency of off gas treatment system. According to the XRD analysis on the trapping cesium compounds by the fly ash filter, the thermally stable pollucite phase was formed when the SO x or NO x was used as the carrier gas. The trapping efficiency of volatile cesium by the fly ash filter was decreased with the increase of face velocity, whereas the efficiency was increased with the increase of the reaction temperature. And also, by increasing the reaction time, the efficiency was decreased. The trapping efficiency of volatile cesium by the fly ash filter was higher than 99.5 percent under the air or NO x /air as a carrier gas, however, the efficiency was decreased to 99.0 percent under the NO x /N 2 as a carrier gas. By the way, the effect of NO x in the vitrification pilot process might be negligible due to the supply of the significant amount of oxygen. However, because using the SO x as the carrier gas the efficiency was slightly decreased to 93.5 percent, the influence of the SO x on the trapping cesium by the fly ash filter seems to be concerned in that pilot process. The fly ash filter unit was performed in the vitrification pilot process, but the trapping efficiency of cesium by that filter could not measured because analytical instruments can not detect the cesium. However, it is confirmed that the the stainless steel 310 can be used for the material of filter frame and housing and shows the corrosion resistance at high temperature (1000 deg C). (author)

  15. Continuous chemical cold traps for reprocessing off-gas purification

    International Nuclear Information System (INIS)

    Henrich, E.; Bauder, U.; Steinhardt, H.J.; Bumiller, W.

    1985-01-01

    Absorption of nitrogen oxides and iodine from simulated reprocessing plant off-gas streams has been studied using nitric acid and nitric acid/hydrogen peroxide mixtures at low temperatures. The experiments were carried out at the laboratory and on the engineering scale. The pilot plant scale column has 0.8 m diameter and 16 absorption plates at 0.2 m spacing. Cooling coils on the plates allow operating temperatures down to -60 0 C. The NO concentration in the feed gas usually has been 1% by volume and the flow rate 4-32 m 3 (STP) per hour. The iodine behavior has been studied using I-123 tracer. Results of the study are presented. The chemistry of the processes and the advantages and disadvantages in correlation to the various applications for an off-gas purification in a reprocessing plant are compared and discussed. The processes are compatible with the PUREX process and do not produce additional waste

  16. Liquid chromatography tandem mass spectrometry method for the estimation of lamotrigine in human plasma: Application to a pharmacokinetic study

    Directory of Open Access Journals (Sweden)

    Santosh Ghatol

    2013-04-01

    Full Text Available A reliable, selective and sensitive liquid chromatography tandem mass spectrometry method was developed and validated for the quantification of lamotrigine in human plasma using lamotrigine-13C3, d3 as an internal standard. Analyte and internal standard were extracted from human plasma by solid-phase extraction and detected in positive ion mode by tandem mass spectrometry with electrospray ionization (ESI interface. Chromatographic separation was performed on a Chromolith® SpeedROD; RP-18e column (50−4.6 mm i.d. using acetonitrile: 5±0.1 mM ammonium formate solution (90:10, v/v as the mobile phase at a flow rate of 0.500 mL/min. The calibration curves were linear over the range of 5.02–1226.47 ng/mL with the lower limit of quantitation validated at 5.02 ng/mL. The analytes were found stable in human plasma through three freeze (−20 °C-thaw (ice-cold water bath cycles and under storage on bench-top in ice-cold water bath for at least 6.8 h, and also in the mobile phase at 10 °C for at least 57 h. The method has shown good reproducibility, as the intra- and inter-day precisions were within 3.0%, while the accuracies were within ±6.0% of nominal values. The validated LC–MS/MS method was applied for the evaluation of pharmacokinetic and bioequivalence parameters of lamotrigine after an oral administration of 50 mg lamotrigine tablet to thirty-two healthy adult male volunteers. Keywords: Lamotrigine, Liquid chromatography/tandem mass spectrometry, Solid phase extraction, Pharmacokinetic study

  17. Power-law distributions for a trapped ion interacting with a classical buffer gas.

    Science.gov (United States)

    DeVoe, Ralph G

    2009-02-13

    Classical collisions with an ideal gas generate non-Maxwellian distribution functions for a single ion in a radio frequency ion trap. The distributions have power-law tails whose exponent depends on the ratio of buffer gas to ion mass. This provides a statistical explanation for the previously observed transition from cooling to heating. Monte Carlo results approximate a Tsallis distribution over a wide range of parameters and have ab initio agreement with experiment.

  18. Evaluation of nandrolone and ractopamine in the urine of veal calves: liquid chromatography-tandem mass spectrometry approach.

    Science.gov (United States)

    Chiesa, L; Panseri, S; Cannizzo, F T; Biolatti, B; Divari, S; Benevelli, R; Arioli, F; Pavlovic, R

    2017-04-01

    Under European legislation, the use of growth promoters is forbidden in food-producing livestock. The application of unofficial protocols with diverse combinations of veterinary drugs, administered in very low concentrations, hinders reliable detection and subsequent operative prevention. It was observed that nandrolone (anabolic steroid) and ractopamine (β-adrenergic agonist) are occasionally administered to animals, but little is known about their synergic action when they are administered together. Two specific analytical methods based on liquid chromatography-tandem mass spectrometry have been developed, both of which include hydrolysis of the corresponding conjugates. For the nandrolone method, solid-phase extraction was necessary for the complete elimination of the interferences, while employment of the Quantitation Enhanced Data-Dependent scan mode during MS acquisition of ractopamine enabled the utilization of simple liquid-liquid extraction. The nandrolone method was linear in the range of 0.5-25 ng/mL, while the ractopamine calibration curve was constructed from 0.5 to 1000 ng/mL. The corresponding coefficients of correlations were >0.9907. The lower limit of quantification for both methods was 0.5 ng/mL, followed by overall recoveries >81%. Precisions expressed as relative standard deviations were ractopamine-enriched diet were analysed. Those methods might be useful for studying the elimination patterns of the administered compounds along with characterization of the main metabolic pathways. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Identification and measurement of illicit drugs and their metabolites in urban wastewater by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Castiglioni, Sara; Zuccato, Ettore; Crisci, Elisabetta; Chiabrando, Chiara; Fanelli, Roberto; Bagnati, Renzo

    2006-12-15

    Residues of illicit drugs and their metabolites that are excreted by humans may flow into and through wastewater treatment plants. The aim of this study was to develop a method for the determination of cocaine, amphetamines, morphine, cannabinoids, methadone, and some of their metabolites in wastewater. Composite 24-h samples from urban treatment plants were enriched with deuterated internal standards before solid-phase extraction. High-pressure liquid chromatography tandem mass spectrometry with multiple reaction monitoring was used for quantitation. Recoveries were generally higher than 80%, and limits of quantifications were in the low nanograms-per-liter range for untreated and treated wastewater. The overall variability of the method was lower than 10% for untreated and 5% for treated wastewater. The method was applied to wastewater samples coming from two treatment plants in Italy and Switzerland. Quantification ranges were found to be 0.2-1 microg/L for cocaine and its metabolite benzoylecgonine, 80-200 ng/L for morphine, 10 ng/L for 6-acetylmorphine, 60-90 ng/L for 11-nor-9-carboxy-Delta9-tetrahydrocannabinol, 10-90 ng/L for methadone and its main metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, and lower than 20 ng/L for amphetamines. As previously reported for cocaine, this method could be useful to estimate and monitor drug consumption in the population in real time, helping social scientists and authorities to combat drug abuse.

  20. A novel method for analysing key corticosteroids in polar bear (Ursus maritimus) hair using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Weisser, Johan J; Hansen, Martin; Björklund, Erland; Sonne, Christian; Dietz, Rune; Styrishave, Bjarne

    2016-04-01

    This paper presents the development and evaluation of a methodology for extraction, clean-up and analysis of three key corticosteroids (aldosterone, cortisol and corticosterone) in polar bear hair. Such a methodology can be used to monitor stress biomarkers in polar bears and may provide as a useful tool for long-term and retrospective information. We developed a combined pressurized liquid extraction (PLE)-solid phase extraction (SPE) procedure for corticosteroid extraction and clean-up followed by high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis. This procedure allows for the simultaneous determination of multiple steroids, which is in contrast to previous polar bear studies based on ELISA techniques. Absolute method recoveries were 81%, 75% and 60% for cortisol, corticosterone and aldosterone, respectively. We applied the developed method on a hair sample pooled from four East Greenland polar bears. Herein cortisol and corticosterone were successfully determined in levels of 0.32±0.02ng/g hair and 0.13±0.02ng/g hair, respectively. Aldosterone was below limit of detection (LOD<0.17ng/g). The cortisol hair concentration found in these East Greenland polar bears was consistent with cortisol levels previously determined in the Southern Hudson Bay and James Bay in Canada using ELISA kits. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Validation of a Multiresidue Analysis Method for 379 Pesticides in Human Serum Using Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Shin, Yongho; Lee, Jonghwa; Lee, Jiho; Lee, Junghak; Kim, Eunhye; Liu, Kwang-Hyeon; Lee, Hye Suk; Kim, Jeong-Han

    2018-04-04

    A screening method for simultaneous analysis of 379 pesticides in human serum was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Electrospray ionization with positive/negative switching mode of LC-MS/MS was adopted, and scheduled multiple reaction monitoring for each target compound was established. The limit of quantitation was 10 ng/mL for 94.5% of the total pesticides, and the correlation coefficients of calibration were ≥0.990 for 93.9% of the pesticides. For the sample preparation, scaled-down QuEChERS were used. Serum (100 μL) was extracted with acetonitrile (400 μL), partitioned with magnesium sulfate (40 mg) and sodium chloride (10 mg), and the upper layer was used for analysis without further cleanup steps. For the accuracy and precision tests, most of the pesticides showed excellent results in intra- and interday conditions. In the recovery tests at 10, 50, and 250 ng/mL, 85.8-91.8% of all target compounds satisfied the recovery range of 70-120% (relative standard deviation ≤20%).

  2. Determination of pesticides and pesticide degradates in filtered water by direct aqueous-injection liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Sandstrom, Mark W.; Kanagy, Leslie K.; Anderson, Cyrissa A.; Kanagy, Christopher J.

    2016-01-11

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for determination of 229 pesticides compounds (113 pesticides and 116 pesticide degradates) in filtered water samples from stream and groundwater sites. The pesticides represent a broad range of chemical classes and were selected based on criteria such as current-use intensity, probability of occurrence in streams and groundwater, and toxicity to humans or aquatic organisms. More than half of the analytes are pesticide degradates. The method involves direct injection of a 100-microliter (μL) sample onto the LC-MS/MS without any sample preparation other than filtration. Samples are analyzed with two injections, one in electrospray ionization (ESI) positive mode and one in ESI negative mode, using dynamic multiple reaction monitoring (MRM) conditions, with two MRM transitions for each analyte. The LC-MS/MS instrument parameters were optimized for highest sensitivity for the most analytes. This report describes the analytical method and presents characteristics of the method validation including bias and variability, detection levels, and holding-time studies.

  3. Extraction and Liquid Chromatography-Tandem Mass Spectrometry Detection of 3-Monochloropropanediol Esters and Glycidyl Esters in Infant Formula.

    Science.gov (United States)

    Leigh, Jessica K; MacMahon, Shaun

    2016-12-14

    A method was developed for the extraction of fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD) and glycidol from infant formula, followed by quantitative analysis of the extracts using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These process-induced chemical contaminants are found in refined vegetable oils, and studies have shown that they are potentially carcinogenic and/or genotoxic, making their presence in edible oils (and processed foods containing these oils) a potential health risk. The extraction procedure involves a liquid-liquid extraction, where powdered infant formula is dissolved in water and extracted with ethyl acetate. Following shaking, centrifugation, and drying of the organic phase, the resulting fat extract is cleaned-up using solid-phase extraction and analyzed by LC-MS/MS. Method performance was confirmed by verifying the percent recovery of each 3-MCPD and glycidyl ester in a homemade powdered infant formula reference material. Average ester recoveries in the reference material ranged from 84.9 to 109.0% (0.6-9.5% RSD). The method was also validated by fortifying three varieties of commercial infant formulas with a 3-MCPD and glycidyl ester solution. Average recoveries of the esters across all concentrations and varieties of infant formula ranged from 88.7 to 107.5% (1.0-9.5% RSD). Based on the validation results, this method is suitable for producing 3-MCPD and glycidyl ester occurrence data in all commercially available varieties of infant formula.

  4. A Liquid Chromatography - Tandem Mass Spectrometry Approach for the Identification of Mebendazole Residue in Pork, Chicken, and Horse.

    Directory of Open Access Journals (Sweden)

    Ji Sun Lee

    Full Text Available A confirmatory and quantitative method of liquid chromatography-tandem mass spectrometry (LC-MS/MS for the determination of mebendazole and its hydrolyzed and reduced metabolites in pork, chicken, and horse muscles was developed and validated in this study. Anthelmintic compounds were extracted with ethyl acetate after sample mixture was made alkaline followed by liquid chromatographic separation using a reversed phase C18 column. Gradient elution was performed with a mobile phase consisting of water containing 10 mM ammonium formate and methanol. This confirmatory method was validated according to EU requirements. Evaluated validation parameters included specificity, accuracy, precision (repeatability and within-laboratory reproducibility, analytical limits (decision limit and detection limit, and applicability. Most parameters were proved to be conforming to the EU requirements. The decision limit (CCα and detection capability (CCβ for all analytes ranged from 15.84 to 17.96 μgkg-1. The limit of detection (LOD and the limit of quantification (LOQ for all analytes were 0.07 μgkg-1 and 0.2 μgkg-1, respectively. The developed method was successfully applied to monitoring samples collected from the markets in major cities and proven great potential to be used as a regulatory tool to determine mebendazole residues in animal based foods.

  5. Determination of valnemulin in swine and bovine tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Li, Hui; Wang, Yingyu; Li, Xiaowei; Fu, Qin; Shan, Yawen; Liu, Tianhe; Xia, Xi

    2016-03-01

    A sensitive and reliable method has been developed and validated for the determination of valnemulin in swine and bovine muscle, liver, and kidney using solid-phase extraction (SPE) and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The tissue samples were extracted with mixture solution of acetonitrile and 0.01mol/L hydrochloric acid, defatted by n-hexane, and further cleaned up using SPE cartridges with polymeric sorbent. Gradient UHPLC separation was performed using an Acquity BEH C18 column with water and acetonitrile as the mobile phase. Multiple reaction monitoring mode of two precursor-product ion transitions for valnemulin was used. Mean recoveries from fortified samples ranged from 93.4 to 104.3% with 3.3-10.7% relative standard deviation. The limit of detection and quantification was 0.2 and 1μg/kg for the analyte, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Ultra-performance liquid chromatography-tandem mass spectrometric method for the determination of strychnine and brucine in mice plasma.

    Science.gov (United States)

    Liu, Yanwen; Zhu, Ronghua; Li, Huande; Yan, Miao; Lei, Yanqing

    2011-09-15

    A selective, simple and efficient method-ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for determination of two toxic alkaloids, namely strychnine and brucine in mice plasma. The UPLC separation was carried out using a 1.7 μm BEH C(18) column (50 mm × 2.1 mm) with a mobile phase consisting of methanol:0.1% formic acid (25:75, v/v), hence providing high efficiency, high resolution and excellent peak shape for the analytes and internal standard. The method was validated over the range of 2.48-496.4 ng/ml for strychnine and 2.64-528 ng/ml for brucine, respectively. Intra- and inter-day accuracy ranged from 95.0% to 107.9% for strychnine, 93.4% to 103.3% for brucine, and the precisions were within 13.8%. The extraction recoveries of both the two alkaloids exceed 81.9%. With a simple and minor sample preparation procedure and short run-time (strychnine and brucine in vivo. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Determination of 20 synthetic dyes in chili powders and syrup-preserved fruits by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Tsai, Chia-Fen; Kuo, Ching-Hao; Shih, Daniel Yang-Chih

    2015-09-01

    A liquid chromatography/tandem mass spectrometry (LC-MS/MS) method is developed to simultaneously determine 20 synthetic dyes (New Coccine, Indigo Carmine, Erythrosine, Tartrazine, Sunset Yellow FCF, Fast Green FCF, Brilliant Blue FCF, Allura Red AC, Amaranth, Dimethyl Yellow, Fast Garnet GBC, Para Red, Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Orange G, Sudan Red 7B, Sudan Red B, and Sudan Red G) in food samples. This method offers high sensitivity and selectivity through the selection of two fragment ion transitions under multiple reaction monitoring mode to satisfy the requirements of both quantitation and qualitation. Using LC-MS/MS, the newly developed extraction protocol used in this study is rapid and simple and does not require the use of solid-phase extraction cartridges. The linearities and recoveries of the method are observed at the concentration range of 0.10-200 μg/kg and more than 90% for all dyes, respectively. The method has been successfully applied to screen 18 commercial chili powders and six commercial syrup-preserved fruits purchased from retail establishments in Taipei City. The results show that three legal food dyes, Tartrazine, and/or Sunset Yellow FCF, and/or New Coccine, are present in some syrup-preserved fruits. Amaranth, an illegal food dye in certain countries but declared illegal in Taiwan, is found in an imported syrup-preserved fruit. Copyright © 2014. Published by Elsevier B.V.

  8. Determination of metoserpate, buquinolate, and diclofenac in pork, eggs, and milk using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Park, Jin-A; Abd El-Aty, A M; Zheng, Weijia; Kim, Seong-Kwan; Choi, Jeong-Min; Hacımüftüoğlu, Ahmet; Shim, Jae-Han; Shin, Ho-Chul

    2018-02-23

    In this work, a method was developed for the simultaneous determination of residual metoserpate, buquinolate and diclofenac in pork, milk, and eggs. Samples were extracted with 0.1% formic acid in acetonitrile, defatted with n-hexane, and filtered prior to analysis using liquid chromatography-tandem mass spectrometry. The analytes were separated on a C 18 column using 0.1% acetic acid and methanol as the mobile phase. The matrix-matched calibration curves showed good linearity over a concentration range of 5-50 ng/g with coefficients of determination (R 2 ) ≥0.991. The intra- and inter-day accuracies (expressed as recovery percentage values) calculated using three spiking levels (5, 10, and 20 μg/kg) were 80-108.65 and 74.06-107.15%, respectively, and the precisions (expressed as relative standard deviation) were 2.86-13.67 and 0.05-11.74%, respectively, for the tested drugs determined in various matrices. The limits of quantification (1 and 2 μg/kg) were below the uniform residual level (0.01 mg/kg) set for compounds that have no specific maximum residue limit (MRL). The developed method was tested using market samples and none of the target analytes was detected in any of the samples. The validated method proved to be practicable for detection of the tested analytes in pork, milk, and eggs. Copyright © 2018 John Wiley & Sons, Ltd.

  9. Investigation of the immunogenicity of a protein drug using equilibrium dialysis and liquid chromatography tandem mass spectrometry detection.

    Science.gov (United States)

    Ji, Qin C; Rodila, Ramona; Morgan, Sherry J; Humerickhouse, Rod A; El-Shourbagy, Tawakol A

    2005-09-01

    Biotherapeutics such as protein and peptide drugs have attracted significant attention in the medical community and pharmaceutical industry in recent years. Immunogenicity is one of the major concerns in the development and application of biotherapeutics. Although great efforts have been put forth in reducing immunogenicity, monitoring the free ("active") drug concentration and the antibody formation is critical for preclinical and clinical studies. Currently, it is still a challenging task to have a standardized test method monitoring immunogenicity when biotherapeutic compounds such as proteins and peptides are administrated. Combined with liquid chromatography/tandem mass spectrometry detection, the equilibrium dialysis technique that is conventionally used for measuring the free and bound concentration of small organic molecules was extended to the application of measuring the free and bound concentrations of a protein drug with a relative molecular mass over 10,000 from plasma samples containing antibody. This novel approach could also be used for accurately measuring the antibody concentration when a reference standard of the antibody is available.

  10. Determination of artificial sweeteners in sewage sludge samples using pressurised liquid extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ordoñez, Edgar Y; Quintana, José Benito; Rodil, Rosario; Cela, Rafael

    2013-12-13

    An analytical method for the determination of six artificial sweeteners in sewage sludge has been developed. The procedure is based on pressurised liquid extraction (PLE) with water followed by solid-phase extraction (SPE) and subsequent liquid chromatography-tandem mass spectrometry analysis. After optimisation of the different PLE parameters, extraction with aqueous 500mM formate buffer (pH 3.5) at 80°C during a single static cycle of 21min proved to be best conditions. After a subsequent SPE, quantification limits, referred to dry weight (dw) of sewage sludge, ranged from 0.3ng/g for acesulfame (ACE) to 16ng/g for saccharin (SAC) and neohespiridine dihydrochalcone. The trueness, expressed as recovery, ranged between 72% and 105% and the precision, expressed as relative standard deviation, was lower than 16%. Moreover, the method proved its linearity up to the 2μg/g range. Finally, the described method was applied to the determination of the artificial sweeteners in primary and secondary sewage sludge from urban wastewater treatment plants. Four of the six studied artificial sweeteners (ACE, cyclamate, SAC and sucralose) were found in the samples at concentrations ranging from 17 to 628ng/g dw. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Determination of artificial sweeteners in water samples by solid-phase extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ordóñez, Edgar Y; Quintana, José Benito; Rodil, Rosario; Cela, Rafael

    2012-09-21

    The development and performance evaluation of an analytical method for the determination of six artificial sweeteners in environmental waters using solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry are presented. To this end, different SPE alternatives have been evaluated: polymeric reversed-phase (Oasis HLB, Env+, Plexa and Strata X), and mixed-mode with either weak (Oasis WAX) or strong anionic-exchange (Oasis MAX and Plexa PAX) sorbents. Among them, reversed-phase sorbents, particularly Oasis HLB and Strata X, showed the best performance. Oasis HLB provided good trueness (recoveries: 73-112%), precision (RSD<10%) and limits of quantification (LOQ: 0.01-0.5 μg/L). Moreover, two LC separation mechanisms were evaluated: reversed-phase (RPLC) and hydrophilic interaction (HILIC), with RPLC providing better performance than HILIC. The final application of the method showed the presence of acesulfame, cyclamate, saccharin and sucralose in the wastewater and surface water samples analyzed at concentrations up to 54 μg/L. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Determination of artificial sweeteners in beverages with green mobile phases and high temperature liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ordoñez, Edgar Y; Rodil, Rosario; Quintana, José Benito; Cela, Rafael

    2015-02-15

    A new analytical procedure involving the use of water and a low percentage of ethanol combined to high temperature liquid chromatography-tandem mass spectrometry has been developed for the determination of nine high-intensity sweeteners in a variety of drink samples. The method permitted the analysis in 23min (including column reequilibration) and consuming only 0.85mL of a green organic solvent (ethanol). This methodology provided limits of detection (after 50-fold dilution) in the 0.05-10mg/L range, with recoveries (obtained from five different types of beverages) being in the 86-110% range and relative standard deviation values lower than 12%. Finally, the method was applied to 25 different samples purchased in Spain, where acesulfame and sucralose were the most frequently detected analytes (>50% of the samples) and cyclamate was found over the legislation limit set by the European Union in a sample and at the regulation boundary in three others. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Liquid Chromatography-Tandem Mass Spectrometry Analysis of Perfluorooctane Sulfonate and Perfluorooctanoic Acid in Fish Fillet Samples

    Directory of Open Access Journals (Sweden)

    Viviana Paiano

    2012-01-01

    Full Text Available Perfluorooctane sulfonate (PFOS and perfluorooctanoic (PFOA acid are persistent contaminants which can be found in environmental and biological samples. A new and fast analytical method is described here for the analysis of these compounds in the edible part of fish samples. The method uses a simple liquid extraction by sonication, followed by a direct determination using liquid chromatography-tandem mass spectrometry (LC-MS/MS. The linearity of the instrumental response was good, with average regression coefficients of 0.9971 and 0.9979 for PFOS and PFOA, respectively, and the coefficients of variation (CV of the method ranged from 8% to 20%. Limits of detection (LOD were 0.04 ng/g for both the analytes and recoveries were 90% for PFOS and 76% for PFOA. The method was applied to samples of homogenized fillets of wild and farmed fish from the Mediterranean Sea. Most of the samples showed little or no contamination by perfluorooctane sulfonate and perfluorooctanoic acid, and the highest concentrations detected among the fish species analyzed were, respectively, 5.96 ng/g and 1.89 ng/g. The developed analytical methodology can be used as a tool to monitor and to assess human exposure to perfluorinated compounds through sea food consumption.

  14. Determination of Platycodin D and Platycodin D3 in Rat Plasma Using Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Tae-Hyun Kim

    2014-01-01

    Full Text Available Platycodon grandiflorum has long been used as a traditional oriental medicine for respiratory disorder. Platycodin D (PD is known as the main component isolated from the root of PG. A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS method has been developed and validated for the quantitation of PD in rat plasma. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization and multiple reaction monitoring in positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of PD were linear over the concentration range of 50–10,000 ng/mL in rat plasma. The coefficient of variation and relative error at five QC levels were 1.0 to 8.8% and 0.7 to 8.7%, respectively. After a single oral administration of 500 mg/kg and a single intravenous administration of 25 mg/kg of 3% PD extract (a PG extract including 3% of PD, platycodin D and platycodin D3 were detected and pharmacokinetic parameters were estimated. The oral bioavailability of platycodin D and platycodin D3 was 0.29% and 1.35% in rats at 500 mg/kg of 3% PD extract of PG, respectively. The present method can be applied to pharmacokinetic analysis of platycodins and platycosides of the PG.

  15. Development of Extraction Methods for the Analysis of Perfluorinated Compounds in Leather with High Performance Liquid Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Zhang, Yan; Wang, Youchao; Tang, Chuanjiang; Nie, Jingmei; Xu, Chengtao

    2018-01-01

    Perfluorinated compounds (PFCs), used to provide water, oil, grease, heat and stain repellency to a range of textile and other products, have been found to be persistent in the environment and are associated with adverse effects on humans and wildlife. This study presents the development and validation of an analytical method to determine the simultaneous presence of eleven PFCs in leather using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The perfluorinated compounds were primarily extracted from the samples by a liquid extraction procedure by ultrasonic, in which the parameters were optimized. Then the solid-phase extraction (SPE) is the most important advantages of the developed methodology. The sample volume and elution conditions were optimized by means of an experimental design. The proposed method was applied to determine the PFCs in leather, where the detection limits of the eleven compounds were 0.09-0.96 ng/L, and the recoveries of all compounds spiked at 5 ng/L concentration level were in the range of 65-96%, with a better RSD lower than 19% (n = 7).

  16. Determination of caprolactam and 6-aminocaproic acid in human urine using hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wu, Ya-Hsueh; Wu, Ming-Ling; Lin, Chun-Chi; Chu, Wei-Lan; Yang, Chen-Chang; Lin, Robert Tate; Deng, Jou-Fang

    2012-02-15

    A simple and rapid assay based on hydrophilic interaction liquid chromatography with tandem mass spectrometry has been first developed and validated for simultaneous determination of caprolactam (CA) and 6-aminocaproic acid (6-ANCA) in human urine using 8-aminocaprylic acid as internal standard. A 20μL aliquot of urine was injected directly into the liquid chromatography tandem mass spectrometry (LC-MS-MS) system. The analytes were separated on a Phenomenex Luna HILIC column with gradient elution. Detection was performed on Triple Quadrupole LC-MS in positive ions multiple reaction monitoring mode using electrospray ionization. The calibration curves were linear (r(2)≥0.995) over the concentration range from 62.5 to 1250ng/mL for CA and 31.25 to 1000ng/mL for 6-ANCA. The detection limits of CA and 6-ANCA were 62.5 and 15.6ng/mL, respectively. The intra-day and inter-day precisions were within 8.7% and 9.9%, respectively. The intra-day and inter-day accuracy were between 5.3% and 3.5%, and between 6.1% and 6.6%, respectively. The method proved to be simple and time efficient, and was successfully applied to evaluate the kinetics of caprolactam in one unusual case of caprolactam poisoning. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. A simple and selective liquid chromatography- tandem mass spectrometry method for determination of ε-aminocaproic acid in human plasma

    Directory of Open Access Journals (Sweden)

    Ganesh S. Moorthy

    2015-07-01

    Full Text Available Understanding the clinical pharmacology of the antifibrinolytic drug epsilon-aminocaproic acid (EACA is critical for rational drug administration in children. The aim of this study is to develop a reliable assay for the determination of EACA in human plasma. We describe a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS assay for EACA in human plasma. Sample preparation involved plasma dilution (1:2040, followed by reversed-phase chromatographic separation and selective detection using tandem mass spectrometry. EACA had a linear range of 1 - 250 μg/mL. The intraday precision based on the standard deviation of replicates of quality control samples ranged from 4.7 to 10.4% and the accuracy ranged from 92-106%. The interday precision ranged from 4.6 to 9.8% and the accuracy ranged from 95-103%. Stability studies showed that EACA was stable during the conditions for sample preparation and storage. The described method is robust and successfully employed for clinical studies of EACA in children

  18. Simultaneous identification of abused drugs, benzodiazepines, and new psychoactive substances in urine by liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Hei-Hwa Lee

    2016-03-01

    Full Text Available A literature search reveals no studies concerning simultaneous identification of commonly abused drugs, benzodiazepines, and new psychoactive substances in urine by liquid chromatography tandem mass spectrometry (LC–MS/MS. We developed and validated an LC–MS/MS method for simultaneous identification of multiple abused drugs, benzodiazepines, and new psychoactive substances in urine from suspected drug abusers. The instrument was operated in multiple-reaction monitoring using an electrospray ionization mode. Chromatograms were separated using an ACE5 C18 column on a gradient of acetonitrile. After liquid–liquid extraction, samples were passed through a 0.22-μm polyvinylidene difluoride filter before injection into the LC–MS/MS. The limits of quantitation ranged from 0.5 ng/mL to 31.3 ng/mL. The linearity ranged from 0.5 ng/mL to 200 ng/mL. The precision results were below 15.4% (intraday and 18.7% (interday. The intraday accuracy ranged from 85.9% to 121.0%; interday accuracy ranged from 66.1% to 128.7%. The proposed method was applied to 769 urine samples. The most common three drugs identified were ketamine, amphetamine, and opiates. The drug positive rate for one or more drugs was 79.6%. Our results demonstrate the suitability of the LC–MS/MS method for simultaneous identification of multiple abused drugs, benzodiazepines, and new psychoactive substances in urine.

  19. Stereoselective pharmacokinetic study of rhynchophylline and isorhynchophylline epimers in rat plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Xin; Zheng, Mei; Liu, Jia; Qiao, Zhou; Liu, Wenyuan; Feng, Feng

    2017-06-01

    1. In this study, the stereoselective pharmacokinetics of rhynchophylline (RIN) and isorhynchophylline (IRN) in rat plasma were investigated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). 2. A rapid, robust and sensitive LC-MS/MS method for simultaneous quantification of RIN and IRN in rat plasma was established and validated. Chromatographic separation was performed on a Poroshell 120 EC-C 18 column under a gradient elution with methanol and water containing 0.01% ammonia as mobile phase. Calibration curve was linear over a concentration range of 1-2000 ng/mL for both epimers. 3. After intravenous administration, there was no apparent difference in pharmacokinetic parameters between two epimers. However, after oral administration, RIN showed remarkable higher plasma exposure than IRN. The bioavailability, C max and AUC 0- t of RIN were about 9.2-fold, 6.4-fold and 9.1-fold higher than those of IRN at 10 mg/kg, and 7.8-fold, 4.3-fold and 7.7-fold at 20 mg/kg, respectively. Additionally, with dosage enhanced from 10 mg/kg to 20 mg/kg, the plasma concentrations of RIN or IRN increased significantly and the bioavailability enhanced about three times. 4. In conclusion, the results of this work demonstrated for the first time that the pharmacokinetics of RIN and IRN have stereoselectivity.

  20. Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry Analysis of Fosetyl-Aluminum in Airborne Particulate Matter

    Directory of Open Access Journals (Sweden)

    Francesca Buiarelli

    2018-01-01

    Full Text Available Fosetyl-aluminum is a synthetic fungicide administered to plants especially to prevent diseases caused by the members of the Peronosporales and several Phytophthora species. Herein, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS method to analyze residues of fosetyl-A1 in air particulate matter. This study was performed in perspective of an exposure assessment of this substance of health concern in environments where high levels of fosetly-Al, relatively to airborne particulate matter, can be found after spraying it. The cleanup procedure of the analyte, from sampled filters of atmospheric particulate matter, was optimized using a Strata X solid-phase extraction cartridge, after accelerated extraction by using water. The chromatographic separation was achieved using a polymeric column based on hydrophilic interaction in step elution with water/acetonitrile, whereas the mass spectrometric detection was performed in negative electrospray ionization. The proposed method resulted to be a simple, fast, and suitable method for confirmation purposes.

  1. Determination of cyclovirobuxine D in human plasma by liquid chromatography tandem mass spectrometry and application in a pharmacokinetic study

    Directory of Open Access Journals (Sweden)

    Ling-li Mu

    2011-10-01

    Full Text Available A sensitive and reliable method based on liquid chromatography tandem mass spectrometry (LC–MS/MS for the quantitation of cyclovirobuxine D in human plasma has been developed and validated. Sample preparation by solid phase extraction was followed by separation on a CN column with a mobile phase of methanol–water (95:5, v/v containing 0.2% formic acid. Mass spectrometric detection in the positive ion mode was carried out by selected reaction monitoring (SRM of the transitions at m/z 403.0→372.0 for cyclovirobuxine D and m/z 325.0→234.0 for citalopram (internal standard. The method was linear in the range 10–200 ng/L with LLOQ of 10 ng/L, recovery >85%, and no significant matrix effects. Intra- and inter-day precisions were all <9% with accuracies of 94.0–104.8%. The method was successfully applied to a pharmacokinetic study involving a single oral administration of a 2 mg cyclovirobuxine D tablet to twenty-two healthy Chinese volunteers.

  2. Ultra-performance liquid chromatography-tandem mass spectrometry method for the analysis of amphetamines in plasma.

    Science.gov (United States)

    Fernández, María del Mar Ramírez; Samyn, Nele

    2011-10-01

    A fast and selective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for the determination of amphetamines (amphetamine, methamphetamine, methylenedioxymethamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, ephedrine, and p-methoxyamphetamine) in plasma has been developed and validated. Sample preparation was performed by liquid-liquid extraction using ethyl acetate. For optimized chromatographic performance with repeatable retention times, narrow and symmetrical peaks, and focusing all analytes at the column inlet, a gradient start, with acid mobile phase consisting of 0.1% formic acid and methanol was chosen. Positive electrospray ionization MS-MS detection was performed with two multiple reaction monitoring transitions for each analyte. Deuteriumlabeled internal standards were used for five of the analytes. The limit of detection was in the range 0.25-1.25 ng/mL, and the limit of quantification was fixed at the lowest calibrator of 2.5 ng/mL for all of the compounds. The RSD values of the intra- and interassay precision and accuracy were lower than 11% at four concentration levels, including two external quality controls. No or only minor matrix effects were observed, and the extraction method presented recoveries higher than 93% for all the compounds. Total run time, including equilibration, was 12 min. The method is routinely used at the National Institute of Criminalistics and Criminology for quantitative determination of the main amphetamines in plasma from forensic and driving under the influence cases.

  3. [Determination of avermectin, diclazuril, toltrazuril and metabolite residues in pork by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Gong, Xiaoming; Sun, Jun; Dong, Jing; Yu, Jinling; Wang, Hongtao

    2011-03-01

    A method for the determination of avermectin, ivermectin, doramectin, moxidectin, eprinomectin, diclazuril, toltrazuril and its two metabolite residues in pork was developed using QuEChERS method with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with acetonitrile and purified through QuEChERS method using ODS as the sorbent. The target compounds were separated on a Venusil ASB C18 column (150 mm x 2.1 mm, 3.0 microm) and detected by HPLC-MS/MS. The linear ranges were 0.005 - 0.2 mg/L and the correlation coefficients were all above 0.990. The average recoveries and the relative standard deviations ranged from 73.2% to 91.5% and from 12% to 17% at the spiked levels of 0.005, 0.01 and 0.02 mg/kg for the 9 analytes in pork matrix. This method is reliable, and suitable for the determination of the residues of avermectin and related compounds in pork.

  4. Multi-residue determination of plant growth regulators in apples and tomatoes by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Xue, Jiaying; Wang, Suli; You, Xiangwei; Dong, Jiannan; Han, Lijun; Liu, Fengmao

    2011-11-15

    A sensitive and rapid multi-residue analytical method for plant growth regulators (PGRs) (i.e., chlormequat, mepiquat, paclobutrazol, uniconazole, ethephon and flumetralin) in apples and tomatoes was developed using high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). A homogenised sample was extracted with a mixture of methanol/water (90:10, v/v) and adjusted to pH <3 with formic acid. Primary secondary amine (PSA) adsorbent was used to clean up the sample. The determination was performed using electrospray ionisation (ESI) and a triple quadrupole (QqQ) analyser. Under the optimised method, the results showed that, except for ethephon, the recoveries were 81.8-98.1% in apples and tomatoes at the spiked concentrations of 0.005 to 2 mg/kg, with relative standard deviations (RSDs) of less than 11.7%. The limits of quantification (LOQs) were lower than their maximum residue limits (MRLs). The procedure was concluded as a practical method to determine the PGR residues in fruit and vegetables and is also suitable for the simultaneous analysis of the amounts of samples for routine monitoring. The analytical method described herein demonstrates a strong potential for its application in the field of PGR multi-residue analysis to help assure food safety. Copyright © 2011 John Wiley & Sons, Ltd.

  5. [Determination of 11 ultraviolet absorbents in sun-screening cosmetics by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lin, Weixuan; Sun, Xingquan; Ma, Jie

    2013-05-01

    A method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been established for the simultaneous determination of eleven ultraviolet absorbents in sunscreening cosmetics. The cosmetic sample was extracted by methanol-ethanol-water (80: 10: 10, v/v/v). The extract was separated by reversed-phase high performance liquid chromatography on an Eclipse XDB-C18 chromatographic column (150 mm x 4.6 mm, 5 microm) with a gradient elution of acetonitrile and water containing 0.1% formic acid. The analyte was detected by MS/ MS with the multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention time and the relative abundance ratio of the characteristic ions, and quantitative analysis on calibration curve method. The research results showed that the limits of quantification (LOQ, S/N = 10) of the eleven ultraviolet absorbents ranged from 200 to 500 mg/kg and the average recoveries ranged from 77. 17% to 98.32% with the relative standard deviations from 2.40% to 11.11%. The method is suitable to detect the eleven ultraviolet absorbents in cream and milky sun-screening cosmetics.

  6. Pesticide residue determination in surface waters by stir bar sorptive extraction and liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Giordano, A; Fernández-Franzón, M; Ruiz, M J; Font, G; Picó, Y

    2009-03-01

    In this stir bar sorptive extraction (SBSE) method, 16 pesticides were extracted from surface water samples by sorption onto 1 mm polydimethylsiloxane layer coated on a 10-mm-length stir bar magnet. After liquid desorption of the analytes with 1 ml of methanol, the detection was performed on a liquid chromatography-tandem mass spectrometry with a triple quadrupole (QqQ) analyzer using selected reaction monitoring mode via electrospray ionization. Parameters affecting SBSE operation, including sample volume, salt addition, extraction time, stirring rate, and desorption conditions, have been evaluated. The optimized SBSE method required two 50 ml aliquots of surface water samples, one aliquot was added of 30% NaCl and stirred at 900 rpm during 1 h for testing five pesticides with log K(o/w) 3. The method was validated in spiked surface water samples at limits of quantifications (LOQs) and ten times the LOQs showing recoveries Albufera Lake and surrounding channels, showing that SBSE is a powerful tool for routine control analysis of pesticide residues in surface water.

  7. [Determination of thyreostats in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lech, Rodziewicz; Jolanta, MasŁOwiecka; Anna, Sadowska; Halina, Car

    2017-10-08

    Five thyreostats (TSs), namely tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil, were determined in bovine urine using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in positive electrospray ionization mode. Extraction and clean-up were achieved using a ChemElut cartridge with tert -butyl methyl ether, without a derivatization step. Separation was achieved on an Acquity UPLC SS T3 column. The mobile phase was acetonitrile and water containing 0.2% (v/v) formic acid. The mass spectrometer was operated in multiple reaction monitoring mode. Urine samples were spiked with TS solution at levels corresponding to 5, 10, 15, and 20 μg/L. The accuracy (internal standard corrected) ranged from 92% to 107%, with a repeatability precision (relative standard deviation, RSD) less than 15% for all five analytes. The RSDs within-laboratory reproducibility was less than 26%. The decision limits (CCα) and detection capabilities (CCβ) were obtained from a calibration curve and were in the ranges of 3.1-6.1 μg/L and 4.0-7.4 μg/L, respectively. The CCα and CCβ values were below the recommended concentration, which was set at 10 μg/L. The results show that the described method is suitable for the direct detection of TSs in bovine urine. This method can also be used to determine TSs in porcine urine.

  8. Determination of 20 synthetic dyes in chili powders and syrup-preserved fruits by liquid chromatography/tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Chia-Fen Tsai

    2015-09-01

    Full Text Available A liquid chromatography/tandem mass spectrometry (LC-MS/MS method is developed to simultaneously determine 20 synthetic dyes (New Coccine, Indigo Carmine, Erythrosine, Tartrazine, Sunset Yellow FCF, Fast Green FCF, Brilliant Blue FCF, Allura Red AC, Amaranth, Dimethyl Yellow, Fast Garnet GBC, Para Red, Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Orange G, Sudan Red 7B, Sudan Red B, and Sudan Red G in food samples. This method offers high sensitivity and selectivity through the selection of two fragment ion transitions under multiple reaction monitoring mode to satisfy the requirements of both quantitation and qualitation. Using LC-MS/MS, the newly developed extraction protocol used in this study is rapid and simple and does not require the use of solid-phase extraction cartridges. The linearities and recoveries of the method are observed at the concentration range of 0.10–200 μg/kg and more than 90% for all dyes, respectively. The method has been successfully applied to screen 18 commercial chili powders and six commercial syrup-preserved fruits purchased from retail establishments in Taipei City. The results show that three legal food dyes, Tartrazine, and/or Sunset Yellow FCF, and/or New Coccine, are present in some syrup-preserved fruits. Amaranth, an illegal food dye in certain countries but declared illegal in Taiwan, is found in an imported syrup-preserved fruit.

  9. Simultaneous Determination of Hormonal Residues in Treated Waters Using Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Rayco Guedes-Alonso

    2013-01-01

    Full Text Available In the last years, hormone consumption has increased exponentially. Because of that, hormone compounds are considered emerging pollutants since several studies have determinted their presence in water influents and effluents of wastewater treatment plants (WWTPs. In this study, a quantitative method for the simultaneous determination of oestrogens (estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, and diethylstilbestrol, androgens (testosterone, and progestogens (norgestrel and megestrol acetate has been developed to determine these compounds in wastewater samples. Due to the very low concentrations of target compounds in the environment, a solid phase extraction procedure has been optimized and developed to extract and preconcentrate the analytes. Determination and quantification were performed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS. The method developed presents satisfactory limits of detection (between 0.15 and 9.35 ng·L−1, good recoveries (between 73 and 90% for the most of compounds, and low relative standard deviations (under 8.4%. Samples from influents and effluents of two wastewater treatment plants of Gran Canaria (Spain were analyzed using the proposed method, finding several hormones with concentrations ranged from 5 to 300 ng·L−1.

  10. [Determination of paraquat residue in plant-derived foodstuffs by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Bo, Haibo

    2011-02-01

    A sensitive and selective method is presented for the determination of paraquat residue in fruits, vegetables, beans and grain by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Paraquat in samples was extracted with water and cleaned-up with a weak cation exchange (WCX) column to obtain an extract suitable for analysis using HPLC-MS/MS. The paraquat was separated by a CAPCELL PAK ST column (150 mm x 2.0 mm) and with acetonitrile-10 mmol/L ammonium acetate solution (adjusted to pH 4.0 by formic acid) as the mobile phase, and multiple reaction monitoring (MRM) was used with electrospray ionization in the positive ion mode. The calibration curve was linear between the peak area and the mass concentration of paraquat from 0.01 to 0.1 mg/L with the correlation coefficient of 0.993. Recoveries of paraquat spiked in samples at three levels ranged from 84.0% to 106.0% with the relative standard deviations of 7.8% - 18.8%. The limits of detection (LODs) of paraquat were 0.01 mg/kg in fruits and vegetables and 0.05 mg/kg in beans and grain. The LODs can meet the requirements of international maximum residue limit.

  11. Rapid Determination of Imatinib in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jeong Soo; Cho, Eun Gi; Huh, Wooseong; Ko, Jaewook; Jung, Jin Ah; Lee, Sooyoun [Samsung Medical Center, Seoul (Korea, Republic of)

    2013-08-15

    A simple, fast and robust analytical method was developed to determine imatinib in human plasma using liquid chromatography-tandem mass spectrometry with electrospray ionization in the positive ion mode. Imatinib and labeled internal standard were extracted from plasma with a simple protein precipitation. The chromatographic separation was performed using an isocratic elution of mobile phase involving 5.0 mM ammonium formate in water -5.0 mM ammonium formate in methanol (30:70, v/v) over 3.0 min on reversed-stationary phase. The detection was performed using a triple-quadrupole tandem mass spectrometer in multiple-reaction monitoring mode. The developed method was validated with lower limit of quantification of 10 ng/mL. The calibration curve was linear over 10-2000 ng/mL (R{sup 2} > 0.99). The method validation parameters met the acceptance criteria. The spiked samples and standard solutions were stable under conditions for storage and handling. The reliable method was successfully applied to real sample analyses and thus a pharmacokinetic study in 27 healthy Korean male volunteers.

  12. Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ma, Li; Ashworth, Daniel; Yates, Scott R

    2016-11-30

    This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The hormones were preconcentrated by solid phase extraction. Pretreatment variables were optimized for a better compatibility with electrospray ionization interfaced mass spectrometry. The analytes were analyzed in multiple-reaction monitoring mode with two pairs of precursor product ion transitions. The proposed method was validated with method detection limits of 0.01-0.33ng/g and good linearities (r 2 >0.9901) throughout the studied concentration range. The recoveries of analytes at the spiking levels (5ng/g and 25ng/g) ranged from 71.2% to 99.7%, with relative standard deviations below 20%. The method was used to determine the target compounds in honey samples (orange blossom, clover and multiflower) obtained from supermarkets. Two samples of honey were found to contain trace amounts of estrone (MQL) or progesterone (0.2±0.1ng/g), respectively. Published by Elsevier B.V.

  13. Rapid and Precise Measurement of Serum Branched-Chain and Aromatic Amino Acids by Isotope Dilution Liquid Chromatography Tandem Mass Spectrometry

    OpenAIRE

    Yang, Ruiyue; Dong, Jun; Guo, Hanbang; Li, Hongxia; Wang, Shu; Zhao, Haijian; Zhou, Weiyan; Yu, Songlin; Wang, Mo; Chen, Wenxiang

    2013-01-01

    BACKGROUND: Serum branched-chain and aromatic amino acids (BCAAs and AAAs) have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. METHODS: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standar...

  14. Assesment of endocrinal and biochemical entities through liquid chromatography?tandem mass spectrometry/mass spectrometer: Inter-relative investigation of the interaction based cardiovascular formulation

    OpenAIRE

    Das, Rakesh; Pal, Tapan Kumar

    2015-01-01

    Background: Combinatory oral dosage treatment of atorvastatin (ATVS) and olmesartan (OLM) drugs to cardiovascular patients reflects unpredicted results instead of its individual therapy, which was accessed on quantification of endocrinal and biochemicals of plasma through liquid chromatography-tandem mass spectrometry/mass spectrometer (LCMS/MS). Objective: Mission was to track the remarkable biochemical variation in the plasma after induction of the combined formulation, to evaluate the phar...

  15. Screening and quantitative determination of twelve acidic and neutral pharmaceuticals in whole blood by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Simonsen, Kirsten Wiese; Steentoft, Anni; Buck, Maike

    2010-01-01

    . The method was fully validated for salicylic acid, paracetamol, phenobarbital, carisoprodol, meprobamate, topiramate, etodolac, chlorzoxazone, furosemide, ibuprofen, warfarin, and salicylamide. The method also tentatively includes thiopental, theophylline, piroxicam, naproxen, diclophenac, and modafinil......We describe a multi-method for simultaneous identification and quantification of 12 acidic and neutral compounds in whole blood. The method involves a simple liquid-liquid extraction, and the identification and quantification are performed using liquid chromatography-tandem mass spectrometry...

  16. On-line solid phase extraction-liquid chromatography-tandem mass spectrometry for insect repellent residue analysis in surface waters using atmospheric pressure photoionization.

    Science.gov (United States)

    Molins-Delgado, Daniel; García-Sillero, Daniel; Díaz-Cruz, M Silvia; Barceló, Damià

    2018-04-06

    Insect repellents (IRs) are a group of organic chemicals whose function is to prevent the ability of insects of landing in a surface. These compounds have been found in the environment and may pose a risk to non-target organisms. In this study, an on-line solid phase extraction - high performance liquid chromatography-tandem mass spectrometry multiresidue method was developed using an atmospheric photoionization source (SPE-HPLC-(APPI)-MS/MS). The use of the APPI as an alternative ionization technique to electrospray (ESI) and atmospheric pressure chemical ionization (APCI) allowed expanding the range of analytical techniques suitable for the analysis of IRs, so far relied in gas chromatography. High sensitivity and precision was reached with method limits of quantification between 0.2 and 4.6 ng l -1 and interday and intraday precision equal or below 15%. The validated method was applied to the study of surface water samples from three European river basins with different flow regime (Adige River in Italy, Sava River in the Balkans, and Evrotas River in Greece). The results showed that two IRs (DEET and Bayrepel) were ubiquitous in the Sava and Evrotas basins, reaching concentrations as high as 105 μg l -1 of Bayrepel in the Sava River, and 5 μg l -1 of DEET in the Evrotas River. Densely populated areas and effluent waste waters are pointed out as the responsible for this pollution. In the alpine river Adige, only three samples showed low levels of IRs (6.01-37.8 ng l -1 ). The concentrations measured were used to perform an environmental risk assessment based on the hazard quotients (HQs) estimation approach by using the chronic and acute eco-toxicity data available. The results revealed that despite the high frequency and eventually high concentrations of these IRs determined in the three basins, only few sites were at risk, with 1 < HQs < 3.3. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  17. Effects of Surfactant Contamination on the Next Generation Gas Trap for the ISS Internal Thermal Control System

    Science.gov (United States)

    Leimkuehler, Thomas O.; Lukens, Clark; Reeves, Daniel R.; Holt, James M.

    2004-01-01

    The current dual-membrane gas trap is designed to remove non-condensed gas bubbles from the Internal Thermal Control System (ITCS) coolant on board the International Space Station (ISS). To date it has successfully served its purpose of preventing gas bubbles from causing depriming, overspeed, and shutdown of the ITCS pump. However, contamination in the ITCS coolant has adversely affected the gas venting rate and lifetime of the gas trap, warranting a development effort for a next-generation gas trap. Previous testing has shown that a hydrophobic-only design is capable of performing even better than the current dual-membrane design for both steady-state gas removal and gas slug removal in clean deionized water. This paper presents results of testing to evaluate the effects of surfactant contamination on the steady-state performance of the hydrophobic-only design.

  18. Validation and application of a high-performance liquid chromatography--tandem mass spectrometry assay for mosapride in human plasma.

    Science.gov (United States)

    Ramakrishna, N V S; Vishwottam, K N; Manoj, S; Koteshwara, M; Chidambara, J; Varma, D P

    2005-09-01

    A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of mosapride (I), a novel and potent gastroprokinetic agent that enhances the upper gastrointestinal motility by stimulating 5-HT(4) receptor. The analyte and internal standard, tamsulosin (II), were extracted by liquid-liquid extraction with diethyl ether-dichloromethane (70:30, v/v) using a Glas-Col Multi-Pulse Vortexer. The chromatographic separation was performed on a reversed-phase Waters symmetry C(18) column with a mobile phase of 0.03% formic acid-acetonitrile (10:90, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The mass transitions m/z 422.3 -->198.3 and m/z 409.1 -->228.1 were used to measure I and II, respectively. The assay exhibited a linear dynamic range of 0.5-100.0 ng/mL for mosapride in human plasma. The lower limit of quantitation was 500 pg/mL with a relative standard deviation of less than 15%. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. A run time of 2.0 min for each sample made it possible to analyze a throughput of more than 400 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. Copyright (c) 2005 John Wiley & Sons, Ltd.

  19. [Simultaneous determination of clevidipine butyrate and its metabolite clevidipine acid in dog blood by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Wei, Hui-hui; Gu, Yuan; Liu, Yan-ping; Wei, Guang-li; Chen, Yong; Liu, Chang-xiao; Si, Duan-yun

    2015-10-01

    A rapid, sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of clevidipine butyrate and its primary metabolite clevidipine acid in dog blood. After one-step protein precipitation with methanol, the chromatographic separation was carried out on an Ecosil C18 column (150 mm x 4.6 mm, 5 µm) with a gradient mobile phase consisting of methanol and 5 mmol · L(-1) ammonium formate. A chromatographic total run time of 13.0 min was achieved. The quantitation analysis was performed using multiple reaction monitoring (MRM) at the specific ion transitions of m/z 454.1 [M-H]- --> m/z 234.1 for clevidipine butyrate, m/z 354.0 [M-H]- --> m/z 208.0 for clevidipine acid and m/z 256.1 [M-H]- --> m/z 227.1 for elofesalamide (internal standard, IS) in the negative ion mode with electrospray ionization (ESI) source. The linear calibration curves for clevidipine butyrate and clevidipine acid were obtained in the concentration ranges of 0.5-100 ng · mL and 1-200 ng · mL(-1), separately. The lower limit of quantification of clevidipine butyrate and clevidipine acid were 0.5 ng · mL(-1) and 1 ng · mL(-1). The intra and inter-assay precisions were all below 12.9%, the accuracies were all in standard ranges. Stability testing indicated that clevidipine butyrate and clevidipine acid in dog blood with the addition of denaturant methanol was stable under various processing and/or handling conditions. The validated method has been successfully applied to a pharmacokinetic study of clevidipine butyrate injection to 8 healthy Beagle dogs following intravenous infusion at a flow rate of 5 mg · h(-1) for 0.5 h.

  20. Rapid quantification of metabolic intermediates in blood by liquid chromatography-tandem mass spectrometry to investigate congenital lactic acidosis.

    Science.gov (United States)

    Peng, Minzhi; Cai, Yanna; Fang, Xiefan; Liu, Li

    2016-10-26

    A novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been established to quantify metabolic intermediates, including lactate (Lac), pyruvate (Pyr), acetoacetate (ACAC) and 3-hydroxybutyrate (3-HB) in blood. Samples were deproteinized with methanol-acetonitrile solution, and analytes were separated on an adamantyl group-bonded reverse phase column and detected in multiple reaction monitoring mode. Total analysis time was 4 min per sample. Method validation results displayed that limits of quantification were 10.0 μmol L -1 for Lac and Pyr, and 5.0 μmol L -1 for ACAC and 3-HB. The within- and between-run coefficients of variation were in the range of 1.2-6.4% for all analytes. The recoveries were ranged from 95.6 to 111.5%. The reference values of analytes were determined for the pediatric population. Duo to instability of Lac, Pyr and ACAC in vitro, a comprehensive stability assay was performed to determine optimal conditions for sample collection, pretreatment and storage. Results showed that precipitation of protein in blood at bedside combined with low storage temperature could effectively preserve the integrity of Lac, Pyr and 3-HB, but the precipitated protein accelerated degradation of ACAC. Isolation of supernatant fluid slowed degradation of ACAC. Supernatant samples could store at -20 °C for 10 days. The use of plasma or serum to determine these intermediates was not recommended. In this study, 450 samples from patients were analyzed, and 7 patients were diagnosed as congenital lactic acidosis. With the advantages of rapid, accurate and reliable, this method is very suitable for congenital lactic acidosis screening and researches related to energy metabolism. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. New ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of irbesartan in human plasma

    Directory of Open Access Journals (Sweden)

    Tanveer A. Wani

    2015-09-01

    Full Text Available With the objective of reducing analysis time and maintaining good efficiency, there has been substantial focus on high-speed chromatographic separations and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS is a preeminent analytical tool for rapid biomedical analysis. In this study a simple, rapid, sensitive, and specific ultra-performance liquid chromatography-MS/MS method was developed and validated for quantification of the angiotensin II receptor antagonist, irbesartan (IRB, in human plasma. After a simple protein precipitation using methanol and acetonitrile, IRB and internal standard (IS telmisartan were separated on Acquity UPLC BEH C18 column (50 mm × 2.1 mm, i.d. 1.7 μm, Waters, Milford, MA, USA using a mobile phase consisted of acetonitrile: methanol: 10 mM ammonium acetate (70: 15: 15 v/v/v with a flow rate of 0.4 mL/min and detected MS/MS in negative ion mode. The ion transitions recorded in multiple reaction monitoring mode were m/z 427.2→193.08 for IRB and m/z 513.2→469.3 for IS. The assay exhibited a linear dynamic range of 2–500 ng/mL for IRB in human plasma with good correlation coefficient of (0.995 and with a lower limit of quantitation of 2 ng/mL. The intra- and interassay precisions were satisfactory; the relative standard deviations did not exceed 9.91%. The proposed UPLC-MS/MS method is simple, rapid, and highly sensitive, and hence it could be reliable for pharmacokinetic and toxicokinetic study in both animals and humans.

  2. Simultaneous quantification of batrachotoxin and epibatidine in plasma by ultra-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Shiraishi, Yosuke; Ogawa, Tadashi; Suzuki, Takayoshi; Iwai, Masae; Kusano, Maiko; Zaitsu, Kei; Kondo, Fumio; Ishii, Akira; Seno, Hiroshi

    2017-03-01

    An ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous quantification of batrachotoxin and epibatidine in plasma. Plasma samples were pretreated by liquid-liquid extraction with acetonitrile and methanol. The toxins were separated on a reversed phase C18-column (2.1mm×50mm, 1.7μm) using a formic acid/acetonitrile gradient elution. Quantification was carried out by mass chromatography with each product ion referenced against midazolam-d 4 as an internal standard (IS). The two toxins and the IS were separated within 2min. The calibration curves for the two toxins spiked into human plasma showed good linearities in the range from 2.5 to 250ng/mL. The detection limits were estimated to be 0.5ng/mL for batrachotoxin and 1ng/mL for epibatidine with a signal-to-noise ratio of 3:1. Overall recoveries ranged from 69.6% to 98.2%, and no significant matrix effects were observed. The intra- and interday accuracies were 94.7-102.3%, and the precisions were 1.0-10.3%. This method was successfully applied for the quantification of batrachotoxin and epibatidine in rat plasma samples taken after intraperitoneal administration of the toxins. This is the first report to use UPLC-MS/MS to simultaneously quantify batrachotoxin and epibatidine in plasma samples. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Ultra performance liquid chromatography-tandem mass spectrometry for the determination of amicarthiazol residues in soil and water samples.

    Science.gov (United States)

    Gui, Wen-jun; Tian, Jie; Tian, Chun-xia; Li, Shu-ying; Ma, You-ning; Zhu, Guo-nian

    2014-12-01

    A reliable and rapid method has been optimized to determine the residue of amicarthiazol in soil and environmental water samples. After extraction and evaporation, the extraction was carried out with solid phase extraction (SPE) cleanup using HLB cartridge (only soil samples) and for the quantitative determination by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The resulting residues of amicarthiazol were analyzed by a gradient separation performed on a UPLC system with a C18 column, methanol and water containing 0.1% (v v(-1)) formic acid as the mobile phase in the mode of electrospray positive ionization (ESI(+)) and multiple reaction monitoring (MRM). Results showed that the recoveries for spiked samples were 74.4-97.1% and 72.1-109.9% for soil and water, respectively, with the relative standard deviation (RSD) less than 10.2% when fortified at 10, 100 and 1000μgL(-1). The limits of detection (LODs) and the limits of quantification (LOQs) for matrix matched standards ranged from 0.073-0.425μgL(-1) and 0.243-1.42μgL(-1). The intra-day precision (n=5) and the inter-day precision over 10 days (n=10) for the amicarthiazol in soils and water samples spiked at 100μgL(-1) was 7.9% and 15.9%, respectively. Results indicated that the developed method could be a helpful tool for the controlling and monitoring of the risks posed by amicarthiazol to human health and environment safety. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Toxin Profile of Gymnodinium catenatum (Dinophyceae) from the Portuguese Coast, as Determined by Liquid Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Costa, Pedro R.; Robertson, Alison; Quilliam, Michael A.

    2015-01-01

    The marine dinoflagellate Gymnodinium catenatum has been associated with paralytic shellfish poisoning (PSP) outbreaks in Portuguese waters for many years. PSP syndrome is caused by consumption of seafood contaminated with paralytic shellfish toxins (PSTs), a suite of potent neurotoxins. Gymnodinium catenatum was frequently reported along the Portuguese coast throughout the late 1980s and early 1990s, but was absent between 1995 and 2005. Since this time, G. catenatum blooms have been recurrent, causing contamination of fishery resources along the Atlantic coast of Portugal. The aim of this study was to evaluate the toxin profile of G. catenatum isolated from the Portuguese coast before and after the 10-year hiatus to determine changes and potential impacts for the region. Hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS) was utilized to determine the presence of any known and emerging PSTs in sample extracts. Several PST derivatives were identified, including the N-sulfocarbamoyl analogues (C1–4), gonyautoxin 5 (GTX5), gonyautoxin 6 (GTX6), and decarbamoyl derivatives, decarbamoyl saxitoxin (dcSTX), decarbamoyl neosaxitoxin (dcNeo) and decarbamoyl gonyautoxin 3 (dcGTX3). In addition, three known hydroxy benzoate derivatives, G. catenatum toxin 1 (GC1), GC2 and GC3, were confirmed in cultured and wild strains of G. catenatum. Moreover, two presumed N-hydroxylated analogues of GC2 and GC3, designated GC5 and GC6, are reported. This work contributes to our understanding of the toxigenicity of G. catenatum in the coastal waters of Portugal and provides valuable information on emerging PST classes that may be relevant for routine monitoring programs tasked with the prevention and control of marine toxins in fish and shellfish. PMID:25871287

  5. Direct Determination of Six Cytokinin Nucleotide Monophosphates in Coconut Flesh by Reversed-Phase Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Cao, Zhao-Yun; Ma, You-Ning; Sun, Li-Hua; Mou, Ren-Xiang; Zhu, Zhi-Wei; Chen, Ming-Xue

    2017-11-15

    Coconut contains many uncharacterized cytokinins that have important physiological effects in plants and humans. In this work, a method based on liquid chromatography-tandem mass spectrometry was developed for identification and quantification of six cytokinin nucleotide monophosphates in coconut flesh. Excellent separation was achieved using a low-coverage C18 bonded-phase column with an acidic mobile phase, which greatly improved the retention of target compounds. To enable high-throughput analysis, a single-step solid-phase extraction using mixed-mode anion-exchange cartridges was employed for sample preparation. This proved to be an effective method to minimize matrix effects and ensure high selectivity. The limits of detection varied from 0.06 to 0.3 ng/mL, and the limits of quantification ranged from 0.2 to 1.0 ng/mL. The linearity was statistically verified over 2 orders of magnitude, giving a coefficient of determination (R 2 ) greater than 0.9981. The mean recoveries were from 81 to 108%; the intraday precision (n = 6) was less than 11%; and the interday precision (n = 11) was within 14%. The developed method was applied to the determination of cytokinin nucleotide monophosphates in coconut flesh samples, and four of them were successfully identified and quantified. The results showed that trans-zeatin riboside-5'-monophosphate was the dominant cytokinin, with a concentration of 2.7-34.2 ng/g, followed by N 6 -isopentenyladenosine-5'-monophosphate (≤12.9 ng/g), while the concentrations of cis-zeatin riboside-5'-monophosphate and dihydrozeatin riboside-5'-monophosphate were less than 2.2 and 4.9 ng/g, respectively.

  6. Toxin Profile of Gymnodinium catenatum (Dinophyceae from the Portuguese Coast, as Determined by Liquid Chromatography Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Pedro R. Costa

    2015-04-01

    Full Text Available The marine dinoflagellate Gymnodinium catenatum has been associated with paralytic shellfish poisoning (PSP outbreaks in Portuguese waters for many years. PSP syndrome is caused by consumption of seafood contaminated with paralytic shellfish toxins (PSTs, a suite of potent neurotoxins. Gymnodinium catenatum was frequently reported along the Portuguese coast throughout the late 1980s and early 1990s, but was absent between 1995 and 2005. Since this time, G. catenatum blooms have been recurrent, causing contamination of fishery resources along the Atlantic coast of Portugal. The aim of this study was to evaluate the toxin profile of G. catenatum isolated from the Portuguese coast before and after the 10-year hiatus to determine changes and potential impacts for the region. Hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS was utilized to determine the presence of any known and emerging PSTs in sample extracts. Several PST derivatives were identified, including the N-sulfocarbamoyl analogues (C1–4, gonyautoxin 5 (GTX5, gonyautoxin 6 (GTX6, and decarbamoyl derivatives, decarbamoyl saxitoxin (dcSTX, decarbamoyl neosaxitoxin (dcNeo and decarbamoyl gonyautoxin 3 (dcGTX3. In addition, three known hydroxy benzoate derivatives, G. catenatum toxin 1 (GC1, GC2 and GC3, were confirmed in cultured and wild strains of G. catenatum. Moreover, two presumed N-hydroxylated analogues of GC2 and GC3, designated GC5 and GC6, are reported. This work contributes to our understanding of the toxigenicity of G. catenatum in the coastal waters of Portugal and provides valuable information on emerging PST classes that may be relevant for routine monitoring programs tasked with the prevention and control of marine toxins in fish and shellfish.

  7. Toxin profile of Gymnodinium catenatum (Dinophyceae) from the Portuguese coast, as determined by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Costa, Pedro R; Robertson, Alison; Quilliam, Michael A

    2015-04-13

    The marine dinoflagellate Gymnodinium catenatum has been associated with paralytic shellfish poisoning (PSP) outbreaks in Portuguese waters for many years. PSP syndrome is caused by consumption of seafood contaminated with paralytic shellfish toxins (PSTs), a suite of potent neurotoxins. Gymnodinium catenatum was frequently reported along the Portuguese coast throughout the late 1980s and early 1990s, but was absent between 1995 and 2005. Since this time, G. catenatum blooms have been recurrent, causing contamination of fishery resources along the Atlantic coast of Portugal. The aim of this study was to evaluate the toxin profile of G. catenatum isolated from the Portuguese coast before and after the 10-year hiatus to determine changes and potential impacts for the region. Hydrophilic interaction liquid chromatography tandem mass spectrometry (HILIC-MS/MS) was utilized to determine the presence of any known and emerging PSTs in sample extracts. Several PST derivatives were identified, including the N-sulfocarbamoyl analogues (C1-4), gonyautoxin 5 (GTX5), gonyautoxin 6 (GTX6), and decarbamoyl derivatives, decarbamoyl saxitoxin (dcSTX), decarbamoyl neosaxitoxin (dcNeo) and decarbamoyl gonyautoxin 3 (dcGTX3). In addition, three known hydroxy benzoate derivatives, G. catenatum toxin 1 (GC1), GC2 and GC3, were confirmed in cultured and wild strains of G. catenatum. Moreover, two presumed N-hydroxylated analogues of GC2 and GC3, designated GC5 and GC6, are reported. This work contributes to our understanding of the toxigenicity of G. catenatum in the coastal waters of Portugal and provides valuable information on emerging PST classes that may be relevant for routine monitoring programs tasked with the prevention and control of marine toxins in fish and shellfish.

  8. Evaluation of commercial ginkgo and echinacea dietary supplements for colchicine using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Li, Wenkui; Sun, Yongkai; Fitzloff, John F; van Breemen, Richard B

    2002-09-01

    In response to concerns that commercial dietary supplements containing Ginkgo biloba (ginkgo) and Echinacea purpurea, Echinacea angustifolia, or Echinacea pallida (echinacea) might be contaminated with colchicine, a highly selective and sensitive assay was developed for colchicine that is based on high-performance liquid chromatography-tandem mass spectrometry (LC-MS-MS). The method utilizes reversed-phase HPLC separation of compounds in a methanolic extract of the dietary supplement or botanical sample followed by positive ion electrospray ionization with collision-induced dissociation and multiple reaction monitoring of three characteristic fragmentation pathways of the protonated molecule of colchicine, m/z 400 --> 358, 400 --> 326, and 400 --> 310. The minimal detectable concentration of colchicine using this assay was 10 pg on-column, which is equivalent to 20 ppb colchicine in a 0.5 g ginkgo leaf sample. The method was validated by analyzing 0.5 g samples spiked with colchicine and determining the recovery. A total of 26 commercial ginkgo and echinacea dietary supplements were purchased from pharmacies in Chicago, IL, and analyzed for colchicine. In contrast to a recent report, no colchicine was detected in any of the samples. In addition, authenticated ginkgo leaves were collected, assayed, and found to contain no colchicine, which is consistent with the botanical literature. On the basis of the results obtained using this new LC-MS-MS assay, which is more sensitive and more selective than previously published methods for colchicine, we find no cause for concern regarding colchicine contamination of ginkgo or echinacea dietary supplements.

  9. Detection of singly- and doubly-charged quaternary ammonium drugs in equine urine by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Ho, Emmie N M; Kwok, W H; Wong, April S Y; Wan, Terence S M

    2012-01-13

    Quaternary ammonium drugs (QADs) are anticholinergic agents some of which are known to have been abused or misused in equine sports. A recent review of literature shows that the screening methods reported thus far for QADs mainly cover singly-charged QADs. Doubly-charged QADs are extremely polar substances which are difficult to be extracted and poorly retained on reversed-phase columns. It would be ideal if a comprehensive method can be developed which can detect both singly- and doubly-charged QADs. This paper describes an efficient liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the simultaneous detection and confirmation of 38 singly- and doubly-charged QADs at sub-parts-per-billion (ppb) to low-ppb levels in equine urine after solid-phase extraction. Quaternary ammonium drugs were extracted from equine urine by solid-phase extraction (SPE) using an ISOLUTE(®) CBA SPE column and analysed by LC/MS/MS in the positive electrospray ionisation mode. Separation of the 38 QADs was achieved on a polar group embedded C18 LC column with a mixture of aqueous ammonium formate (pH 3.0, 10 mM) and acetonitrile as the mobile phase. Detection and confirmation of the 38 QADs at sub-ppb to low-ppb levels in equine urine could be achieved within 16 min using selected reaction monitoring (SRM). Matrix interference of the target transitions at the expected retention times was not observed. Other method validation data, including precision and recovery, were acceptable. The method was successfully applied to the analyses of drug-administration samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Development of liquid chromatography-tandem mass spectrometry methods for the quantitation of Anisakis simplex proteins in fish.

    Science.gov (United States)

    Fæste, Christiane Kruse; Moen, Anders; Schniedewind, Björn; Haug Anonsen, Jan; Klawitter, Jelena; Christians, Uwe

    2016-02-05

    The parasite Anisakis simplex is present in many marine fish species that are directly used as food or in processed products. The anisakid larvae infect mostly the gut and inner organs of fish but have also been shown to penetrate into the fillet. Thus, human health can be at risk, either by contracting anisakiasis through the consumption of raw or under-cooked fish, or by sensitisation to anisakid proteins in processed food. A number of different methods for the detection of A. simplex in fish and products thereof have been developed, including visual techniques and PCR for larvae tracing, and immunological assays for the determination of proteins. The recent identification of a number of anisakid proteins by mass spectrometry-based proteomics has laid the groundwork for the development of two quantitative liquid chromatography-tandem mass spectrometry methods for the detection of A. simplex in fish that are described in the present study. Both, the label-free semi-quantitative nLC-nESI-Orbitrap-MS/MS (MS1) and the heavy peptide-applying absolute-quantitative (AQUA) LC-TripleQ-MS/MS (MS2) use unique reporter peptides derived from anisakid hemoglobin and SXP/RAL-2 protein as analytes. Standard curves in buffer and in salmon matrix showed limits of detection at 1μg/mL and 10μg/mL for MS1 and 0.1μg/mL and 2μg/mL for MS2. Preliminary method validation included the assessment of sensitivity, repeatability, reproducibility, and applicability to incurred and naturally-contaminated samples for both assays. By further optimization and full validation in accordance with current recommendations the LC-MS/MS methods could be standardized and used generally as confirmative techniques for the detection of A. simplex protein in fish. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Photodegradation of multiclass fungicides in the aquatic environment and determination by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Celeiro, Maria; Facorro, Rocio; Dagnac, Thierry; Vilar, Vítor J P; Llompart, Maria

    2017-08-01

    The photodegradation behaviour for nine widespread fungicides (benalaxyl, cyprodinil, dimethomorph, fenhexamide, iprovalicarb, kresoxim-methyl, metalaxyl, myclobutanil and tebuconazole) was evaluated in different types of water. Two different systems, direct UV photolysis and UVC/H 2 O 2 advanced oxidation process (AOP), were applied for the photodegradation tests. For the monitoring of the target compound degradation, a method based on direct injection liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. Several fungicide photodegradation by-products were tentatively identified by high-resolution mass spectrometry (HRMS) as well. For the photolysis studies, the efficiency of different types of radiation, UVC (λ = 254 nm) and UVA (λ = 365 nm), was compared. UVC photolysis provided the highest removal with a complete degradation for fenhexamide and kresoxim-methyl, and percentages between 48 and 78% for the other compounds, excluding iprovalicarb and myclobutanil with removals <35%, after 30 min of irradiation. Besides, the photodegradation tests were performed with different initial concentrations of fungicides, and the efficiency of two photoreactor systems was compared. In all cases, the kinetics followed pseudo-first order, and the half-life times could also be calculated. The addition of H 2 O 2 under UVC light allowed an improvement of the reaction kinetics, especially for the most recalcitrant fungicides, obtaining in all cases removals higher than 82% in less than 6 min. Finally, in order to evaluate the suitability of the proposed systems, both UVC photolysis and UVC/H 2 O 2 system were tested in different real water matrices (wastewater, tap water, swimming pool water and river water), showing that the UVC/H 2 O 2 system had the highest removal efficiency in less than 6 min, for all water samples.

  12. Determination of sulfonamides in animal tissues by modified QuEChERS and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Wen, Ching-Hsuan; Lin, Shu-Ling; Fuh, Ming-Ren

    2017-03-01

    In this study, the salting-out solvent extraction and dispersive solid-phase extraction (dSPE) clean-up steps in QuEChERS (quick, easy, cheap, effective, rugged, and safe) method were optimized to reduce matrix effect and efficiently extract target sulfonamides from a variety of edible animal tissues. The extracted sulfonamides were then analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS). Good extraction recoveries (74.0-100.3% in five different sources of animal tissues; n=3) with acceptable matrix effect (<10%, except for liver samples) were obtained using the proposed method. For the first time, a commercial ND-lipids cartridge was used to remove hydrophobic matrix components from fat-rich animal tissues in the clean-up step of QuEChERS. In addition, good linearity (0.125-12.5ngg -1 ) was observed using matrix-matched calibration (in beef). Limits of detection (LODs) were estimated at 0.01-0.03ngg -1 in beef, pork, and chicken samples. For beef tripe and pig liver samples, the LODs were in the range of 0.02-0.04ngg -1 . Good intra-day/inter-day precision (1.0-10.5%/0.4-8.0%) and accuracy (95.2-107.2%/97.8-102.1%) were also achieved using the modified QuEChERS for sample pretreatment. The applicability of the modified QuEChERS-LC-MS/MS method was demonstrated by determining the occurrence of target sulfonamides in various edible animal tissues for potential food safety analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Quantification of a male sea lamprey pheromone in tributaries of Laurentian Great Lakes by liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Xi, X.; Johnson, N.S.; Brant, C.O.; Yun, S.-S.; Chambers, K.L.; Jones, A.D.; Li, W.

    2011-01-01

    We developed an assay for measuring 7α,12α,24-trihydroxy-5a-cholan-3-one-24-sulfate (3kPZS), a mating pheromone released by male sea lampreys (Petromyzon marinus), at low picomolar concentrations in natural waters to assess the presence of invasive populations. 3kPZS was extracted from streamwater at a rate of recovery up to 90% using a single cation-exchange and reversed-phase mixed-mode cartridge, along with [2H5]3kPZS as an internal standard, and quantified using ultrahigh performance liquid chromatography-tandem mass spectrometry. The limit of detection was below 0.1 ng L–1 (210 fM), which was the lowest concentration tested. Intra- and interday coefficients of variation were between 0.3–11.6% and 4.8–9.8%, respectively, at 1 ng 3kPZS L–1 and 5 ng 3kPZS L–1. This assay was validated by repeat measurements of water samples from a stream spiked with synthesized 3kPZS to reach 4.74 ng L–1 or 0.24 ng L–1. We further verified the utility of this assay to detect spawning populations of lampreys; in the seven tributaries to the Laurentian Great Lakes sampled, 3kPZS concentrations were found to range between 0.15 and 2.85 ng L–1 during the spawning season in known sea lamprey infested segments and were not detectable in uninfested segments. The 3kPZS assay may be useful for the integrated management of sea lamprey, an invasive species in the Great Lakes where pheromone-based control and assessment techniques are desired.

  14. Determination of fluoroquinolones in aquaculture products by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

    Science.gov (United States)

    Pearce, J N; Burns, B G; van de Riet, J M; Casey, M D; Potter, R A

    2009-01-01

    An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of fluoroquinolones-ciprofloxacin (CIPRO), danofloxacin (DANO), enrofloxacin (ENRO) and sarafloxacin (SARA)-in aquaculture products, specifically salmon, shrimp and tilapia. After initial sample extraction with an acidic acetonitrile solution, the extract was diluted with dichloromethane and centrifuged, then an aliquot was concentrated and applied to a C18 solid-phase extraction cartridge and concentrated for a second time. The resultant residue was dissolved in acetonitrile, diluted with water, and then further defatted with hexane. The fluoroquinolone residues were determined by UPLC with an HSS T3 C18 reverse-phase column using an ammonium hydroxide-formic acid buffer in an acetonitrile gradient with MS/MS detection using multiple reaction monitoring. Average recoveries for salmon tissue ranged from 73% for DANO to 95% for SARA, for shrimp from 71% for DANO to 109% for SARA, and from 62% for DANO to 111% for SARA in tilapia, fortified at the 1.0 ng g(-1) level. Standard curves were linear between 0.002 and 0.5 ng injected for all compounds. Detection limits of 0.2 ng g(-1) for CIPRO, DANO, ENRO, and SARA were easily obtainable. The operational errors, interferences, and recoveries for fortified samples demonstrate that this described method is suitable for routine use in a regulatory programme. The recommended method is simple, rapid, specific and reliable for the routine monitoring of fluoroquinolone residues in aquatic species such as salmon, tilapia and shrimp.

  15. Quantification of anthocyanins and flavonols in milk-based food products by ultra performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nagy, Kornél; Redeuil, Karine; Bertholet, Raymond; Steiling, Heike; Kussmann, Martin

    2009-08-01

    The present article describes the development and validation of an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the comprehensive quantification of anthocyanin and flavonol constituents of milk-based food products. Protein precipitation by acidified methanol and ultrafiltration was utilized as sample preparation to preserve overall polyphenol composition but to eliminate milk proteins in order to comply with UPLC. Reversed-phase chromatography was optimized to achieve separation of 27 analytes in 10 min in order to reduce suppression effects, achieve a wide dynamic range, and most importantly, to resolve isomeric compounds. Positive-ion electrospray mass spectrometric detection and fragmentation of analytes was optimized, final transitions were selected for maximized selectivity, reliable quantification, and reduction of false positives. The quantitative performance of the method was validated, the main features include (1) range of lower limits of detection 0.3-30 ng/mL for glycosylated analytes, 10-300 ng/mL for aglycones, (2) lower limits of quantification 1-100 ng/mL for glycosylated analytes, 30-1,000 ng/mL for aglycones, (3) averaged intraday precision 9%, (4) calibrated range 2-180,000 ng/mL for glycosylated analytes, 60-600,000 ng/mL for aglycones, and (5) averaged accuracy 101%. Applications for yogurt and ice cream products are given. The presented data suggest that this method will help to better characterize the polyphenol composition of milk-based food products for quality control, for assessment of dietary intake, and for polyphenol bioavailability/bioefficacy studies.

  16. Air and Surface Sampling Method for Assessing Exposures to Quaternary Ammonium Compounds Using Liquid Chromatography Tandem Mass Spectrometry.

    Science.gov (United States)

    LeBouf, Ryan F; Virji, Mohammed Abbas; Ranpara, Anand; Stefaniak, Aleksandr B

    2017-07-01

    This method was designed for sampling select quaternary ammonium (quat) compounds in air or on surfaces followed by analysis using ultraperformance liquid chromatography tandem mass spectrometry. Target quats were benzethonium chloride, didecyldimethylammonium bromide, benzyldimethyldodecylammonium chloride, benzyldimethyltetradecylammonium chloride, and benzyldimethylhexadecylammonium chloride. For air sampling, polytetrafluoroethylene (PTFE) filters are recommended for 15-min to 24-hour sampling. For surface sampling, Pro-wipe® 880 (PW) media was chosen. Samples were extracted in 60:40 acetonitrile:0.1% formic acid for 1 hour on an orbital shaker. Method detection limits range from 0.3 to 2 ng/ml depending on media and analyte. Matrix effects of media are minimized through the use of multiple reaction monitoring versus selected ion recording. Upper confidence limits on accuracy meet the National Institute for Occupational Safety and Health 25% criterion for PTFE and PW media for all analytes. Using PTFE and PW analyzed with multiple reaction monitoring, the method quantifies levels among the different quats compounds with high precision (<10% relative standard deviation) and low bias (<11%). The method is sensitive enough with very low method detection limits to capture quats on air sampling filters with only a 15-min sample duration with a maximum assessed storage time of 103 days before sample extraction. This method will support future exposure assessment and quantitative epidemiologic studies to explore exposure-response relationships and establish levels of quats exposures associated with adverse health effects. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  17. Analysis of volatile organic compounds by cryogenic oven trapping gas chromatography

    OpenAIRE

    渡部, 加奈子; 石井, 晃; 李, 暁鵬; 鈴木, 修; 鈴木, 加奈子

    2000-01-01

    Recently, a microcomputer-controlled device for lowering oven temperature below 0℃ has become available for new types of gas chromatography (GC) instruments. This device was originally designed for rapid cooling of an oven to reduce the time for analysis. In our laboratories, we are using it for trapping volatile organic compounds (VOCs) inside a capillary column at cryogenic oven temperatures; as much as 5 ml of headspace vapor can be injected into a medium-bore capillary column without any ...

  18. Determination of interfering triazine degradation products by gas chromatography-ion trap mass spectrometry.

    Science.gov (United States)

    Magnuson, M L; Speth, T F; Kelty, C A

    2000-01-28

    Deethylatrazine (DEA), an atrazine degradation product, has been added to the US Environmental Protection Agency's Drinking Water Contaminant Candidate List (CCL). In its gas chromatographic analysis, DEA can coelute with deisopropylatrazine (DIA), another degradation product. The present work demonstrates that the coelution of DEA and DIA can induce a significant (up to approximately 50%) positive bias in the DEA determination, when using an ion-trap mass spectrometer as the detector. The DIA determination is unaffected by the coelution within experimental error. This may be explained in terms of gas-phase ion fragment populations. A correction factor to the observed DEA concentration may be developed based on the measured DIA concentration.

  19. Gas chromatography-tandem mass spectrometry with atmospheric pressure chemical ionization for fluorotelomer alcohols and perfluorinated sulfonamides determination.

    Science.gov (United States)

    Portolés, Tania; Rosales, Luis E; Sancho, Juan V; Santos, F Javier; Moyano, Encarnación

    2015-09-25

    Ionization and in source-fragmentation behavior of four fluorotelomer alcohols (FTOH) (4:2 FTOH, 6:2 FTOH, 8:2 FTOH and 10:2 FTOH) and four N-alkyl fluorooctane sulfonamides/-ethanols (N-MeFOSA, N-EtFOSA, N-MeFOSE and N-EtFOSE) by APCI has been studied and compared with the traditionally used EI and CI. Protonated molecule was the base peak of the APCI spectrum in all cases giving the possibility of selecting it as a precursor ion for MS/MS experiments. Following, CID fragmentation showed common product ions for all FOSAs/FOSEs (C4F7 and C3F5). Nevertheless, the different functionality gave characteristic pattern fragmentations. For instance, FTOHs mainly loss H2O+HF, FOSAs showed the losses of SO2 and HF while FOSEs showed the losses of H2O and SO2. Linearity, repeatability and LODs have been studied obtaining instrumental LODs between 1 and 5fg. Finally, application to river water and influent and effluent waste water samples has been carried out in order to investigate the improvements in detection capabilities of this new source in comparison with the traditionally used EI/CI sources. Matrix effects in APCI have been evaluated in terms of signal enhancement/suppression when comparing standards in solvent and matrix. No matrix effects were observed and concentrations found in samples were in the range of 1-100pgL(-1) far below the LODs achieved with methods previously reported. Unknown related perfluoroalkyl substances, as methyl-sulfone and methyl-sulfoxide analogues for FTOHs, were also discovered and tentatively identified. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. The ultimate veal calf reference experiment: Hormone residue analysis data obtained by gas and liquid chromatography tandem mass spectrometry

    NARCIS (Netherlands)

    Nielen, M.W.F.; Lasaroms, J.J.P.; Essers, M.L.; Sanders, M.B.; Heskamp, H.H.; Bovee, T.F.H.; Rhijn, van J.A.; Groot, M.J.

    2007-01-01

    A lifetime controlled reference experiment has been performed using 42 veal calves, 21 males and 21 females which were fed and housed according to European regulations and common veterinary practice. During the experiment feed, water, urine and hair were sampled and feed intake and growth were

  1. Quantum quench in a harmonically trapped one-dimensional Bose gas

    Science.gov (United States)

    Collura, Mario; Kormos, Márton; Calabrese, Pasquale

    2018-03-01

    We study the nonequilibrium dynamics of a one-dimensional Bose gas trapped by a harmonic potential for a quench from zero to infinite interaction. The different thermodynamic limits required for the equilibrium pre- and post-quench Hamiltonians are the origin of a few unexpected phenomena that have no counterparts in the translational-invariant setting. We find that the dynamics is perfectly periodic with breathing time related to the strength of the trapping potential. For very short times, we observe a sudden expansion leading to an extreme dilution of the gas and to the emergence of slowly decaying tails in the density profile. The haste of the expansion induces an undertow-like effect with a pronounced local minimum of the density at the center of the trap. At half period there is a refocusing phenomenon characterized by a sharp central peak of the density, juxtaposed to algebraically decaying tails. We finally show that the time-averaged density is correctly captured by a generalized Gibbs ensemble built with the conserved mode occupations.

  2. Quantification of vitamin B6 vitamers in human cerebrospinal fluid by ultra performance liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ham, M. van der, E-mail: M.vanderHam-3@umcutrecht.nl [Department of Metabolic Diseases and Netherlands Metabolomics Center, University Medical Center (UMC) Utrecht, Huispost KC02.069.1, Lundlaan 6, 3584 EA Utrecht (Netherlands); Albersen, M., E-mail: M.Albersen@umcutrecht.nl [Department of Metabolic Diseases and Netherlands Metabolomics Center, University Medical Center (UMC) Utrecht, Huispost KC02.069.1, Lundlaan 6, 3584 EA Utrecht (Netherlands); Koning, T.J. de, E-mail: T.deKoning@umcutrecht.nl [Department of Pediatric Metabolic Diseases, Wilhelmina Children' s Hospital, University Medical Center (UMC) Utrecht, Huispost KC03.063.0, Lundlaan 6, 3584 EA Utrecht (Netherlands); Visser, G., E-mail: G.Visser-4@umcutrecht.nl [Department of Pediatric Metabolic Diseases, Wilhelmina Children' s Hospital, University Medical Center (UMC) Utrecht, Huispost KC03.063.0, Lundlaan 6, 3584 EA Utrecht (Netherlands); Middendorp, A., E-mail: Alfred_Middendorp@waters.com [Waters Chromatography B.V., Florijnstraat 19, Postbus 379, 4870 AJ Etten-Leur (Netherlands); Bosma, M., E-mail: M.Bosma@umcutrecht.nl [Department of Metabolic Diseases and Netherlands Metabolomics Center, University Medical Center (UMC) Utrecht, Huispost KC02.069.1, Lundlaan 6, 3584 EA Utrecht (Netherlands); Verhoeven-Duif, N.M., E-mail: N.Verhoeven@umcutrecht.nl [Department of Metabolic Diseases and Netherlands Metabolomics Center, University Medical Center (UMC) Utrecht, Huispost KC02.069.1, Lundlaan 6, 3584 EA Utrecht (Netherlands); Sain-van der Velden, M.G.M. de, E-mail: M.G.deSain@umcutrecht.nl [Department of Metabolic Diseases and Netherlands Metabolomics Center, University Medical Center (UMC) Utrecht, Huispost KC02.069.1, Lundlaan 6, 3584 EA Utrecht (Netherlands)

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer We present a sensitive UPLC-MS/MS method for quantification of B6 vitamers in human CSF. Black-Right-Pointing-Pointer Our method is very accurate since stable isotope labeled internal standards are used. Black-Right-Pointing-Pointer We present data on light sensitivity, temperature dependence and rostrocaudal gradient. Black-Right-Pointing-Pointer With PN supplementation, concentrations of PL, PM, PN and PA in CSF are increased. Black-Right-Pointing-Pointer Our fully validated method is suitable for implementation in a diagnostic setting. - Abstract: Since vitamin B6 is essential for normal functioning of the central nervous system, there is growing need for sensitive analysis of B6 vitamers in cerebrospinal fluid (CSF). This manuscript describes the development and validation of a rapid, sensitive and accurate method for quantification of the vitamin B6 vitamers pyridoxal (PL), pyridoxamine (PM), pyridoxine (PN), pyridoxic acid (PA), pyridoxal 5 Prime -phosphate (PLP), pyridoxamine 5 Prime -phosphate (PMP) and pyridoxine 5 Prime -phosphate (PNP) in human CSF. The method is based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with a simple sample preparation procedure of protein precipitation using 50 g L{sup -1} trichloroacetic acid containing stable isotope labeled internal standards: PL-D{sub 3} for PL and PM, PN-{sup 13}C{sub 4} for PN, PA-D{sub 2} for PA and PLP-D{sub 3} for the phosphorylated vitamers. B6 vitamers were separated (Acquity HSS-T3 UPLC column) with a buffer containing acetic acid, heptafluorobutyric acid and acetonitrile. Positive electrospray ionization was used to monitor transitions m/z 168.1 {yields} 150.1 (PL), 169.1 {yields} 134.1 (PM), 170.1 {yields} 134.1 (PN), 184.1 {yields} 148.1 (PA), 248.1 {yields} 150.1 (PLP), 249.1 {yields} 232.1 (PMP) and 250.1 {yields} 134.1 (PNP). The method was validated at three concentration levels for each B6 vitamer in CSF

  3. A simple solid-phase extraction method for the analysis of red cell phospholipids by liquid chromatography- tandem mass spectrometry.

    Science.gov (United States)

    Nguyen, Van Long

    2018-02-25

    There has been increasing interest in the analysis of phospholipids in red blood cells as potential long-term biomarkers of different disease states. Here, we describe a simple method for the analysis of two phospholipids: 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanol (PE 16:0/18:1) and 1-Palmitoyl-2-linoleoyl-sn-glycero-3-phosphoethanol (PE 16:/0/18:2) in erythrocytes by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Whole blood samples were removed free of plasma and washed in isotonic saline. Red cells were lysed with ultrapure water. Lysate samples were processed using a hybrid solid-phase extraction (SPE) phospholipid cartridge (1 mL, 30 mg). Both PE 16:0/18:1 and PE 16:0/18:2 and their deuterated internal standards were separated on an ACE C4 (150 mm × 2.1 mm, 2.7 μm particle size) by gradient elution at a flow rate of 0.5 mL per minute using mobile phases consisting of 0.01 mol/L ammonium acetate in: water (A), methanol (B), and isopropanol (C). The phospholipid species were quantified by the following transitions: PE 16:0/18:1: 701.5→281.3 and PE 16:0/18:2: 699.5→279.3. Both PE species displayed linearity ranging from 10 to 500 μg/L. The coefficient of variation (CV%) of PE 16:0/18:1 concerning intraday and interday precision was between 1.9%-2.6% and 3.0%-4.3%, respectively. For PE 16:0/18:2, this was between 1.8%-3.4% and 3.7%-4.1%, respectively. Both phospholipid species had accuracy (PE 16:0/18:1: 91%-98% and PE 16:0/18:2: 94%-103%) and extraction recovery (PE 16:0/18:1: 95%-106% and PE 16:0/18:2: 92%-102%) exceeding 90% over the analytical range. The limit of detection was 5 μg/L. Here we propose a simple SPE LC-MS/MS method for analyzing phospholipids in erythrocytes, which can be easily adopted. © 2018 Wiley Periodicals, Inc.

  4. Determination of cyanuric acid residues in catfish, trout, tilapia, salmon and shrimp by liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Karbiwnyk, Christine M. [Animal Drugs Research Center, U.S. Food and Drug Administration, P.O. Box 25087, Denver, CO 80225-0087 (United States)], E-mail: christine.karbiwnyk@fda.hhs.gov; Andersen, Wendy C.; Turnipseed, Sherri B. [Animal Drugs Research Center, U.S. Food and Drug Administration, P.O. Box 25087, Denver, CO 80225-0087 (United States); Storey, Joseph M.; Madson, Mark R. [Denver District Laboratory, U.S. Food and Drug Administration, P.O. Box 25087, Denver, CO 80225-0087 (United States); Miller, Keith E. [Center for Veterinary Medicine, U.S. Food and Drug Administration, 8401 Muirkirk Road, Laurel, MD 20708 (United States); Gieseker, Charles M.; Miller, Ron A.; Rummel, Nathan G.; Reimschuessel, Renate [University of Denver, Department of Chemistry and Biochemistry, Denver, CO 80208 (United States)

    2009-04-01

    In May 2007, investigators discovered that waste material from the pet food manufacturing process contaminated with melamine (MEL) and/or cyanuric acid (CYA) had been added to hog and chicken feeds. At this time, investigators also learned that adulterated wheat gluten had been used in the manufacture of aquaculture feeds. Concern that the contaminated feed had been used in aquaculture and could enter the human food supply prompted the development of a method for the determination of CYA residues in the edible tissues of fish and shrimp. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was employed as a sensitive technique for the analysis of CYA in catfish, tilapia, salmon, trout and shrimp tissue. CYA was extracted from ground fish or shrimp with an acetic acid solution, defatted with hexane, and isolated with a graphitic carbon black solid-phase extraction column. Residues were separated from matrix components using a porous graphitic carbon LC column, and then analyzed with electrospray ionization in negative ion mode on a triple quadrupole mass spectrometer. Selective reaction monitoring was performed on the [M-H]{sup -}m/z 128 ion resulting in the product ions m/z 85 and 42. Recoveries from catfish, tilapia and trout fortified with 10-100 {mu}g kg{sup -1} of CYA averaged 67% with a relative standard deviation (R.S.D.) of 18% (n = 107). The average method detection limit (MDL) for catfish, tilapia and trout is 3.5 {mu}g kg{sup -1}. An internal standard, {sup 13}C{sub 3}-labeled CYA, was used in the salmon and shrimp extractions. Average recovery of CYA from salmon was 91% (R.S.D. = 15%, n = 18) with an MDL of 7.4 {mu}g kg{sup -1}. Average recovery of CYA from shrimp was 85% (R.S.D. = 10%, n = 13) with an MDL of 3.5 {mu}g kg{sup -1}.

  5. Measurement of total and free docetaxel concentration in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rigo-Bonnin, Raül; Cobo-Sacristán, Sara; Gonzalo-Diego, Núria; Colom, Helena; Muñoz-Sánchez, Carmen; Urruticoechea, Ander; Falo, Catalina; Alía, Pedro

    2016-01-05

    Docetaxel is a semi-synthetic taxane with cytotoxic anti-neoplastic activity and, currently used as anticancer agent in several types of cancer. Docetaxel is highly bound to plasma proteins, and this significantly determines its clearance and activity. Therefore, measurement of free docetaxel in plasma is pharmacologically important when pharmacokinetics is investigated. We developed and validated chromatographic methods by ultra-performance liquid chromatography-tandem mass spectrometry to measure total and free docetaxel concentration in human plasma. The final validated methods involved liquid-liquid extraction followed by dryness under nitrogen evaporation. To measure free docetaxel concentration, sample preparation was preceded by ultrafiltration. Chromatographic separation was achieved using an Acquity(®) UPLC(®) BEH™ (2.1×100 mm id, 1.7 μm) reverse-phase C18 column at a flow rate of 0.4 mL/min, using isocratic elution mode containing ammonium acetate/formic acid in water/methanol (30:70 v/v) as mobile phase. Docetaxel and its internal standard (paclitaxel) were detected by electrospray ionization mass spectrometry in positive ion multiple reaction monitoring mode using mass-to-charge (m/z) transitions of 808.3→527.0 (quantifier) and 808.3→509.0 (qualifier); and 854.3→569.0 (quantifier) and 854,3→509,0 (qualifier), respectively. The run time per sample was 3.5 min. The limits of quantification were 1,95 and 0.42 μg/L and linearity was observed between 1.95 and 1000 and 0.42-100 μg/L for total and free docetaxel, respectively. Coefficients of variation and absolute relative biases were less than 13.8% and 10.0%. Recovery values were greater than 79.4%. Evaluation of the matrix effect showed ion suppression and no carry-over was observed. The validated methods could be useful for both therapeutic drug monitoring and pharmacokinetic studies. They could be applied to daily clinical laboratory practice to measure the concentration of total and free

  6. Multi-residue determination of 10 selected new psychoactive substances in wastewater samples by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Borova, Viola L; Gago-Ferrero, Pablo; Pistos, Constantinos; Thomaidis, Nikolaos S

    2015-11-01

    New psychoactive substances (NPSs) have become increasingly popular in recent years. The analysis of these substances in influent wastewater (IWW) can be used to track their use in communities. In addition, an evaluation of the amount of NPSs released to the aquatic environment can be performed through the analysis of effluent wastewater (EWW). This study presents the development, validation and application of an analytical methodology, based on solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), for the determination of 10 NPSs in IWW and EWW. Synthetic cannabinoids, cathinones, piperazines and pyrrolidophenones are included among the target analytes. To the authors' knowledge, it is the first time that eight out of these substances (4'-methylpyrrolidinobutyrophenone (MPPP), a-pyrrolidinopentiophenone (a-PVP), 2-[(1S,3R)-3-hydroxycyclohexyl]-5-(2-methyl-2-octanyl) phenol (CP47,497), (1-naphthyl(1-pentyl-1H-indol-3-yl) methanone (JWH-018), (1-butyl-1H-indol-3-yl)(1-naphthyl) methanone (JWH-073), (4-ethyl-1-naphthyl)(1-pentyl-1H-indol-3-yl) methanone (JWH-210), (4-methyl-1-naphthyl) (1-pentyl-1H-indol-3-yl) methanone (JWH-122) and 2-(2-methoxyphenyl)-1-(1-pentyl-1H-indol-3-yl) ethanone (JWH-250)) are investigated in wastewater. The optimized conditions for the analysis of this set of compounds included a SPE clean-up step using a polymeric sorbent and the use of a pentafluorophenyl (PFP) chromatographic column. Despite the broad range of physicochemical properties of the analytes the method allowed acceptable absolute recoveries (40-109%) for all the studied compounds at different levels of concentration. Low method limits of detection (MLODs) were achieved, ranging between 0.3 and 10 ng/L except for BZP and CP47,497 (20 and 23 ng/L, respectively), allowing a reliable and accurate quantification of the analytes. The method was successfully applied to the analysis of IWW and EWW samples from five wastewater treatment plants

  7. Determination of Albendazole and Metabolites in Silkworm Bombyx mori Hemolymph by Ultrafast Liquid Chromatography Tandem Triple Quadrupole Mass Spectrometry

    Science.gov (United States)

    Li, Li; Xing, Dong-Xu; Li, Qing-Rong; Xiao, Yang; Ye, Ming-Qiang; Yang, Qiong

    2014-01-01

    Albendazole is a broad-spectrum parasiticide with high effectiveness and low host toxicity. No method is currently available for measuring albendazole and its metabolites in silkworm hemolymph. This study describes a rapid, selective, sensitive, synchronous and reliable detection method for albendazole and its metabolites in silkworm hemolymph using ultrafast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-MS/MS). The method is liquid-liquid extraction followed by UFLC separation and quantification in an MS/MS system with positive electrospray ionization in multiple reaction monitoring mode. Precursor-to-product ion transitions were monitored at 266.100 to 234.100 for albendazole (ABZ), 282.200 to 208.100 for albendazole sulfoxide (ABZSO), 298.200 to 159.100 for albendazole sulfone (ABZSO2) and 240.200 to 133.100 for albendazole amino sulfone (ABZSO2-NH2). Calibration curves had good linearities with R2 of 0.9905–0.9972. Limits of quantitation (LOQs) were 1.32 ng/mL for ABZ, 16.67 ng/mL for ABZSO, 0.76 ng/mL for ABZSO2 and 5.94 ng/mL for ABZSO2-NH2. Recoveries were 93.12%–103.83% for ABZ, 66.51%–108.51% for ABZSO, 96.85%–105.6% for ABZSO2 and 96.46%–106.14% for ABZSO2-NH2, (RSDs <8%). Accuracy, precision and stability tests showed acceptable variation in quality control (QC) samples. This analytical method successfully determined albendazole and its metabolites in silkworm hemolymph in a pharmacokinetic study. The results of single-dose treatment suggested that the concentrations of ABZ, ABZSO and ABZSO2 increased and then fell, while ABZSO2-NH2 level was low without obvious change. Different trends were observed for multi-dose treatment, with concentrations of ABZSO and ABZSO2 rising over time. PMID:25255321

  8. Targeted Multiresidue Analysis of Veterinary Drugs in Milk-Based Powders Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

    Science.gov (United States)

    Wittenberg, James B; Simon, Kelli A; Wong, Jon W

    2017-08-30

    An analytical method was developed and validated for the determination of 40 veterinary drugs in various milk-based powders. The method involves acetonitrile/water extraction, solid-phase filtration for lipid removal in fat-containing matrices, and analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The limits of quantitation (LOQ) ranged from 0.02 to 82 ng/g. Acceptable recoveries (70-120%, RSD powder. Similar results were obtained for whole milk powder, milk protein concentrate, whey protein concentrate, and whey protein isolate. This new method will allow for better monitoring of a wide range of veterinary drugs in milk-based powders.

  9. Sensitive analysis of blonanserin, a novel antipsychotic agent, in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ogawa, Tadashi; Hattori, Hideki; Kaneko, Rina; Ito, Kenjiro; Iwai, Masayo; Mizutani, Yoko; Arinobu, Tetsuya; Ishii, Akira; Suzuki, Osamu; Seno, Hiroshi

    2010-01-01

    A rapid and sensitive method for analysis of blonanserin in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry is presented. After pretreatment of a plasma sample by solid-phase extraction, blonanserin was analyzed by the system with a C(18) column. This method gave satisfactory recovery rates, reproducibility, and good linearity of calibration curve in the range of 0.01-10.0 ng/mL for quality control samples spiked with blonanserin. The detection limit was as low as 1 pg/mL. This method seems very useful in forensic and clinical toxicology and pharmacokinetic studies.

  10. Simple and Sensitive Analysis of Blonanserin and Blonanserin C in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry and Its Application

    OpenAIRE

    Zheng, Yunliang; Hu, Xingjiang; Liu, Jian; Wu, Guolan; Zhou, Huili; Zhu, Meixiang; Zhai, You; Wu, Lihua; ShenTu, Jianzhong

    2014-01-01

    A highly sensitive, simple, and rapid liquid chromatography tandem mass spectrometry method to simultaneously determine blonanserin and blonanserin C in human plasma with AD-5332 as internal standard (IS) was established. A simple direct protein precipitation method was used for the sample pretreatment, and chromatographic separation was performed on a Waters XBridge C8 (4.6 × 150 mm, 3.5  μ m) column. The mobile phase consists of a mixture of 10 mM ammonium formate and 0.1% formic acid in wa...

  11. Identificationof potential lung cancer biomarkers by liquid chromatography tandem mass spectrometry-based proteomics analysis of secretomes of two lung cancer cell lines.

    Science.gov (United States)

    Shevchenko, Valeriy E; Kovalev, Sergey V; Arnotskaya, Natalia E; Kudryavtsev, Igor A

    2013-01-01

    A label-free nano-liquid chromatography tandem mass spectrometry proteomics analysis on the conditioned media (CM) of two lung cancer cell lines of different histological backgrounds to identify secreted or membrane-bound proteins as novel lung cancer biomarkers was performed. Five hundred and seventy seven proteins were identified and 38% of them were classified as extracellular or membrane-bound. For the search of potential biomarkers of lung cancer a series of selection criteria were proposed. We detected known or putative lung cancer markers. In addition, 40 novel proteins were identified, whose role as biomarkers of lung cancer should be explored further.

  12. Simultaneous determination of ethanol's four types of non-oxidative metabolites in human whole blood by liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Zhang, Xinyu; Zheng, Feng; Lin, Zebin

    2017-01-01

    , but it was difficult to achieve because of their wide range of polarity. This work describes development and validation of a simple liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for 4 types of ethanol non-oxidative metabolites (ethyl glucuronide, ethyl sulfate, fatty acid ethyl esters......The importance of ethanol non-oxidative metabolites as the specific biomarkers of alcohol consumption in clinical and forensic settings is increasingly acknowledged. Simultaneous determination of these metabolites can provide a wealth of information like drinking habit and history...

  13. Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry Measurement of Caffeine in Caffeine-Laced Pants and in Urine and Skin of a Pants User

    OpenAIRE

    Pellegrini, Manuela; Orsi, Daniela De; Guarino, Carmine; Rotolo, Maria; Giovannandrea, Rita di; Pacifici, Roberta; Pichini, Simona

    2014-01-01

    A fast and sensitive ultra-performance liquid chromatography tandem mass spectrometry method was developed for the measurement of caffeine in caffeine-laced pants and in urine and skin of a pants user. The substance and its internal standard (N-ethylnorcotinine) were separated by reversed phase chromatography with 5 mM ammonium formate pH 3.0 and 0.3% formic acid in acetonitrile mobile phase (83:17 v/v) by isocratic elution and detected by tandem mass spectrometry operated in multiple reacti...

  14. The Laser Ion Source Trap (LIST) coupled to a gas cell catcher

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, T. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)], E-mail: tetsu@riken.jp; Cocolios, T.E.; Gentens, J.; Huyse, M.; Ivanov, O.; Kudryavtsev, Yu.; Pauwels, D.; Van den Bergh, P.; Van Duppen, P. [Instituut voor Kern- en Stralingsfysica, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)

    2009-09-01

    The proof of principle of the Laser Ion Source Trap (LIST) coupled to a gas cell catcher system has been demonstrated at the Leuven Isotope Separator On Line (LISOL). The experiments were carried out by using the modified gas cell-based laser ion source and the SextuPole Ion Guide (SPIG). Element-selective resonance laser ionization of neutral atoms was taking place inside the cold jet expanding out of the gas cell catcher. The laser path was oriented in longitudinal as well as transverse geometries with respect to the atoms flow. The enhancement of beam purity and the feasibility for in-source laser spectroscopy were investigated in off-line and on-line conditions.

  15. First and second sound of a unitary Fermi gas in highly oblate harmonic traps

    International Nuclear Information System (INIS)

    Hu, Hui; Dyke, Paul; Vale, Chris J; Liu, Xia-Ji

    2014-01-01

    We theoretically investigate first and second sound modes of a unitary Fermi gas trapped in a highly oblate harmonic trap at finite temperatures. Following the idea by Stringari and co-workers (2010 Phys. Rev. Lett. 105 150402), we argue that these modes can be described by the simplified two-dimensional two-fluid hydrodynamic equations. Two possible schemes—sound wave propagation and breathing mode excitation—are considered. We calculate the sound wave velocities and discretized sound mode frequencies, as a function of temperature. We find that in both schemes, the coupling between first and second sound modes is large enough to induce significant density fluctuations, suggesting that second sound can be directly observed by measuring in situ density profiles. The frequency of the second sound breathing mode is found to be highly sensitive to the superfluid density. (paper)

  16. Coalbed gas desorption in canisters: Consumption of trapped atmospheric oxygen and implications for measured gas quality

    International Nuclear Information System (INIS)

    Jin, Hui; Schimmelmann, Arndt; Mastalerz, Maria; Pope, James; Moore, Tim A.

    2010-01-01

    Desorption canisters are routinely employed to quantify coalbed gas contents in coals. If purging with inert gas or water flooding is not used, entrapment of air with ∝ 78.08 vol.% nitrogen (N 2 ) in canisters during the loading of coal results in contamination by air and subsequent overestimates of N 2 in desorbed coalbed gas. Pure coalbed gas does not contain any elemental oxygen (O 2 ), whereas air contamination originally includes ∝ 20.95 vol.% O 2 and has a N 2 /O 2 volume ratio of ∝ 3.73. A correction for atmospheric N 2 is often attempted by quantifying O 2 in headspace gas and then proportionally subtracting atmospheric N 2 . However, this study shows that O 2 is not a conservative proxy for air contamination in desorption canisters. Time-series of gas chromatographic (GC) compositional data from several desorption experiments using high volatile bituminous coals from the Illinois Basin and a New Zealand subbituminous coal document that atmospheric O 2 was rapidly consumed, especially during the first 24 h. After about 2 weeks of desorption, the concentration of O 2 declined to near or below GC detection limits. Irreversible loss of O 2 in desorption canisters is caused by biological, chemical, and physical mechanisms. The use of O 2 as a proxy for air contamination is justified only immediately after loading of desorption canisters, but such rapid measurements preclude meaningful assessment of coalbed gas concentrations. With increasing time and progressive loss of O 2 , the use of O 2 content as a proxy for atmospheric N 2 results in overestimates of N 2 in desorbed coalbed gas. The indicated errors for nitrogen often range in hundreds of %. Such large analytical errors have a profound influence on market choices for CBM gas. An erroneously calculated N 2 content in CBM would not meet specifications for most pipeline-quality gas. (author)

  17. Temperature Dependence of the Thermal Conductivity of a Trapped Dipolar Bose-Condensed Gas

    Science.gov (United States)

    Yavari, H.

    2018-02-01

    The thermal conductivity of a trapped dipolar Bose condensed gas is calculated as a function of temperature in the framework of linear response theory. The contributions of the interactions between condensed and noncondensed atoms and between noncondensed atoms in the presence of both contact and dipole-dipole interactions are taken into account to the thermal relaxation time, by evaluating the self-energies of the system in the Beliaev approximation. We will show that above the Bose-Einstein condensation temperature ( T > T BEC ) in the absence of dipole-dipole interaction, the temperature dependence of the thermal conductivity reduces to that of an ideal Bose gas. In a trapped Bose-condensed gas for temperature interval k B T > k B T, since the relaxation rate {τ}_{c12}^{-1} is independent of temperature and the relaxation rate due to dipolar interaction goes to zero exponentially, the T 2 temperature behavior for the thermal conductivity comes from the thermal mean velocity of the particles. We will also show that in the high-temperature limit ( k B T > n 0 g B ) and low momenta, the relaxation rates {τ}_{c12}^{-1} and {τ}_{dd12}^{-1} change linearly with temperature for both dipolar and contact interactions and the thermal conductivity scales linearly with temperature.

  18. Optimisation of the neutron source based on gas dynamic trap for transmutation of radioactive wastes

    Science.gov (United States)

    Anikeev, Andrey V.

    2012-06-01

    The Budker Institute of Nuclear Physics in collaboration with the Russian and foreign organizations develop the project of 14 MeV neutron source, which can be used for fusion material studies and for other application. The projected neutron source of plasma type is based on the plasma Gas Dynamic Trap (GDT), which is a special magnetic mirror system for plasma confinement. Presented work continues the subject of development the GDT-based neutron source (GDT-NS) for hybrid fusion-fission reactors. The paper presents the results of recent numerical optimization of such neutron source for transmutation of the long-lives radioactive wastes in spent nuclear fuel.

  19. Gas Pulsation Control by a Shunt Pulsation Trap with Perforated Tubes and an Optional Absorptive Silencer

    OpenAIRE

    Huang, Paul Xiubao; Yonkers, Sean; Hokey, David

    2016-01-01

    This paper is a continuing work from the same authors on the same topic of gas pulsation control using a shunt pulsation trap method by Huang (2012a, 2014). Traditionally, a serial pulsation dampener/muffler, often a reactive type, is connected AFTER the discharge of a positive displacement compressor or engine. It is capable of reducing pressure pulsation level up to 10-20 folds or 20-40 dB but is bulky and suffers sizable back pressure losses. It has been demonstrated in the previous theore...

  20. Ultrapressure liquid chromatography-tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for quantification of 4-methoxydiphenylmethane in pharmacokinetic evaluation.

    Science.gov (United States)

    Farhan, Nashid; Fitzpatrick, Sean; Shim, Yun M; Paige, Mikell; Chow, Diana Shu-Lian

    2016-09-05

    4-Methoxydiphenylmethane (4-MDM), a selective augmenter of Leukotriene A4 Hydrolase (LTA4H), is a new anti-inflammatory compound for potential treatment of chronic obstructive pulmonary disease (COPD). Currently, there is no liquid chromatography tandem mass spectrometric (LC-MS/MS) method for the quantification of 4-MDM. A major barrier for developing the LC-MS/MS method is the inability of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) to ionize 4-MDM due to its hydrophobicity and lack of any functional group for ionization. With the advent of atmospheric pressure photoionization (APPI) technique, many hydrophobic compounds have been demonstrated to ionize by charge transfer reactions. In this study, a highly sensitive ultrapressure liquid chromatography tandem mass spectrometry assay using atmospheric pressure photoionization (UPLC-APPI-MS/MS) for the quantifications of 4-MDM in rat plasma has been developed and validated. 4-MDM was extracted from the plasma by solid phase extraction (SPE) and separated chromatographically using a reverse phase C8 column. The photoionization (PI) was achieved by introducing anisole as a dopant to promote the reaction of charge transfer. The assay with a linear range of 5 (LLOQ)-400ngmL(-1) met the regulatory requirements for accuracy, precision and stability. The validated assay was employed to quantify the plasma concentrations of 4-MDM after an oral dosing in Sprague Dawley (SD) rats. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. [Determination of 35 antibiotic residues of tetracyclines, sulfonamides, penicillins, macrolides and amphenicols in milk by liquid chromatography-tandem mass spectromtery].

    Science.gov (United States)

    Wang, Hao; Zhao, Li; Yang, Hongmei; Pan, Hongyan; Shi, Hailiang; Qian, Cong; Zhang, Shan

    2015-09-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the simultaneous determination of 35 antibiotic residues of tetracyclines, sulfonamides, penicillins, macrolides and amphenicols in milk. The samples were extracted with alkaline acetonitrile and McIlvaine buffer solution under ultrasonication. The separation of target compounds was performed on an Eclipse XDB-C, column (150 mm x 2.1 mm, 3.5 µm) with gradient elution at a flow rate of 0.25 mL/min, and with an injection volume of 10 µL. The identification and quantification of the compounds were completed by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring ( MRM) mode. The limits of detection were all below 10.0 µg/kg. The average spiked recoveries of the method ranged from 70. 1% to 109. 9% with relative standard deviations (RSDs) of 2.89%-9.99%. After validation, the method was applied to the analysis of antibiotic residues in milk products in China. Fifty samples were screened under the well defined methodology, and the results showed that chloramphenicol, only in one sample, was monitored with the content of 0.48 µg/kg. A risk of contamination of milk with chloramphenicol has been determined to exist. Therefore this method is convenient, rapid, sensitive and reliable, and can be successfully applied to the simultaneous detection of the 35 antibiotic residues of tetracyclines, sulfonamides, penicillins, macrolides and amphenicols in milk.

  2. Dynamics of a trapped 1D Bose gas for finite interaction strength

    Science.gov (United States)

    Muth, Dominik; Mering, Alexander; Fleischhauer, Michael

    2008-05-01

    We investigate the dynamics of a 1D Bose gas in a harmonic trap with point like interactions, recently studied experimentally in [1]. Starting from a discretisation of this model we calculate the groundstate properties and time evolution in the resulting Bose-Hubbard model using the time-evolving block decimation algorithm, TEBD. Both the case of vanishing interaction strength corresponding to the trivial case of free bosons, and the quasi integrable hard core case are well understood [2]. Furthermore recently exact solutions have been found in the absence of a trap potential and few particles [3]. We are focusing on the dynamics in the region with finite repulsive interaction and in a trap. Forall cases, using TEBD, we are able to calculate the propagation in both momentum and real space. [1] T. Kinoshita, T. Wenger, D. Weiss, Nature 440, 900 (2006) [2] M. Rigol, V. Dunjko, V. Yurovsky, M. Olshanii, Phys. Rev. Lett. 98, 050405 (2007) [3] H. Buljan, R. Pezer and T. Gasenzer, arXiv:0709.1444 (2007)

  3. Simultaneous determination of bisphenol A, tetrabromobisphenol A, and perfluorooctanoic acid in small household electronics appliances of "Prohibition on Certain Hazardous Substances in Consumer Products" instruction using ultra-performance liquid chromatography-tandem mass spectrometry with accelerated solvent extraction.

    Science.gov (United States)

    Guo, Qiaozhen; Du, Zhenxia; Zhang, Yun; Lu, Xiaoyu; Wang, Jinhua; Yu, Wenlian

    2013-02-01

    Simultaneous determination of bisphenol A, tetrabromobisphenol A, and perfluorooctanoic acid in small household electronics appliances by accelerated solvent extraction-ultra-performance liquid chromatography-tandem mass spectrometry was established. Samples, heated for 5 min, were extracted by toluene/methanol (10:1, v/v) under the pressure 1500 psi at 100°C, and were extracted 3 static cycles with 20 min per cycle. And then 15 mL extractant solvent was used to wash the samples, and at last the sample was purged by nitrogen for 100 s. The partial extractant (10 mL) was concentrated by nitrogen and re-dissolved with 1 mL methanol/water (1:1, v/v). The three compounds were separated by BEH C18 column effectively in 3 min and detected by electrospray ionization mode mass spectrometry. The linear ranges for bisphenol A, perfluorooctanoic acid, and tetrabromobisphenol A were 1-100, 10-1000 ng/mL, and 0.1-10 μg/mL, respectively. The correlation coefficient was greater than 0.996. The LOD and limit of quantitation for three compounds were 0.1, 10, 1 ng/mL, and 0.5, 50, 5 ng/mL, respectively. And the recoveries were 84-92, 76-82, and 72-74%, respectively, with RSD < 5%. The method was successfully used in determining the real samples. The method and the result were confirmed by liquid chromatography-ion trap-time of flight mass spectrometry. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Chiral analysis of amphetamines in hair by liquid chromatography-tandem mass spectrometry: compliance-monitoring of attention deficit hyperactivity disorder (ADHD) patients under Elvanse® therapy and identification after controlled low-dose application.

    Science.gov (United States)

    Binz, Tina M; Williner, Elena; Strajhar, Petra; Dolder, Patrick C; Liechti, Matthias E; Baumgartner, Markus R; Kraemer, Thomas; Steuer, Andrea E

    2018-02-01

    Amphetamine (AMP) is used as an illicit drug and also for the treatment of attention deficit hyperactivity disorder (ADHD). Respective drugs most often contain the enantiomer (S)-AMP as active compound or (S)-AMP is formed from the prodrug lisdexamfetamine (Elvanse®) whereas the illicit drug is usually traded as racemate ((R/S)-AMP). A differentiation between the use of the medically prescribed drug and the abuse of illicit street amphetamine is of great importance, for example in retrospective consumption monitoring by hair analysis. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the chiral separation and quantitation of (S)- and (R)-AMP in hair was developed. For this purpose, 20 mg hair was extracted and derivatized with N-(2,4-dinitro-5-fluorophenyl)-L(S)-valinamide L(S)-(DNPV) to yield amphetamine diastereomers. Baseline separation of the resulting diastereomers was achieved on a high-pressure liquid-chromatography system (HPLC) coupled to a Sciex QTRAP® 5500 linear ion trap quadrupole mass spectrometer. The method was successfully validated. Analysis of hair samples from nine Elvanse® patients revealed only (S)-AMP in eight cases; one subject showed both enantiomers indicating a (side-) consumption of street amphetamine. The analysis of the 16 amphetamine users' samples showed only racemic amphetamine. Furthermore, it could be shown in a controlled study that (S)-AMP can be detected after administration of even very low doses of lisdexamfetamine and dexamphetamine, which can be of interest in forensic toxicology and especially in drug-facilitated crime (DFC). The method now enables the retrospective compliance-monitoring of ADHD patients and the differentiation between medically prescribed intake of (S)-amphetamine and abuse of illicit street amphetamine. Copyright © 2017 John Wiley & Sons, Ltd.

  5. Full validation of a method for the determination of drugs of abuse in non-mineralized dental biofilm using liquid chromatography-tandem mass spectrometry and application to postmortem samples.

    Science.gov (United States)

    Henkel, Kerstin; Altenburger, Markus J; Auwärter, Volker; Neukamm, Merja A

    2018-01-01

    Alternative matrices play a major role in postmortem forensic toxicology, especially if common matrices (like body fluids or hair) are not available. Incorporation of illicit and medicinal drugs into non-mineralized dental biofilm (plaque) seems likely but has not been investigated so far. Analysis of plaque could therefore extend the spectrum of potentially used matrices in postmortem toxicology. For this reason, a rapid, simple and sensitive method for the extraction, determination and quantification of ten drugs of abuse from plaque using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and fully validated. Amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), 3,4-methylenedioxyamphetamine (MDA), cocaine, benzoylecgonine, morphine, codeine and 6-acetylmorphine were extracted from 2mg of dried and powdered plaque via ultrasonication with acetonitrile. The extracts were analyzed on a triple-quadrupole linear ion trap mass spectrometer in scheduled multiple reaction monitoring mode (sMRM). The method was fully validated and proved accurate, precise, selective and specific with satisfactory linearity within the calibrated ranges. The lower limit of quantification was 10-15pgmg -1 for all compounds except for MDA (100pgmg -1 ) and amphetamine (200pgmg -1 ). The method has been successfully applied to three authentic postmortem samples with known drug history. Amphetamine, MDMA, cocaine, benzoylecgonine, morphine and codeine could be detected in these cases in concentrations ranging from 18pgmg -1 for cocaine to 1400pgmg -1 for amphetamine. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Determination of stanozolol and 3′-hydroxystanozolol in rat hair, urine and serum using liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Deshmukh Nawed IK

    2012-12-01

    Full Text Available Abstract Background Anabolic androgenic steroids, such as stanozolol, are typically misused by athletes during preparation for competition. Out-of-competition testing presents a unique challenge in the current anti-doping detection system owing to logistic reasons. Analysing hair for the presence of a prohibited drug offers a feasible solution for covering the wider window in out-of-competition testing. To assist in vivo studies aiming to establish a relationship between drug levels detected in hair, urine and blood, sensitive methods for the determination of stanozolol and its major metabolite 3′-hydroxystanozolol were developed in pigmented hair, urine and serum, using brown Norway rats as a model system and liquid chromatography tandem mass spectrometry (LC-MS/MS. Results For method development, spiked drug free rat hair, blood and urine samples were used. The newly developed method was then applied to hair, urine and serum samples from five brown Norway rats after treatment (intraperitoneal with stanozolol for six consecutive days at 5.0 mg/kg/day. The assay for each matrix was linear within the quantification range with determination coefficient (r2 values above 0.995. The respective assay was capable of detecting 0.125 pg/mg stanozolol and 0.25 pg/mg 3′-hydroxystanozolol with 50 mg hair; 0.063 ng/mL stanozolol and 0.125 ng/mL 3′-hydroxystanozolol with 100 μL of urine or serum. The accuracy, precision and extraction recoveries of the assays were satisfactory for the detection of both compounds in all three matrices. The average concentrations of stanozolol and 3′-hydroxystanozolol, were as follows: hair = 70.18 ± 22.32 pg/mg and 13.01 ± 3.43 pg/mg; urine = 4.34 ± 6.54 ng/mL and 9.39 ± 7.42 ng/mL; serum = 7.75 ± 3.58 ng/mL and 7.16 ± 1.97 ng/mL, respectively. Conclusions The developed methods are sensitive, specific and reproducible for the determination of stanozolol

  7. Experiments in support of the Gas Dynamic Trap based facility for plasma–material interaction testing

    Energy Technology Data Exchange (ETDEWEB)

    Soldatkina, E.I., E-mail: E.I.Soldatkina@inp.nsk.su [Budker Institute of Nuclear Physics SB RAS, Lavrentieva Prospect 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090 (Russian Federation); Arakcheev, A.S.; Bagryansky, P.A. [Budker Institute of Nuclear Physics SB RAS, Lavrentieva Prospect 11, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090 (Russian Federation)

    2013-11-15

    Highlights: • Measurement of plasma heat flux in the mirror of a GDT device had been conducted. • The power density up to 0.25 GW m{sup −2} was experimentally obtained. • Steady state operation has not been achieved due to short NBI pulse. • The possibility of creating the PMI setup based on GDT had been discussed. -- Abstract: The power density along the field lines in the scrape-off layer plasma in machines of the class of ITER, Wendelstein 7-X, NSTX-U is in the range of few hundreds megawatt per square meter. It is crucial for the future of tokamaks and stellarators to develop the plasma science and component technology to handle such high plasma heat fluxes. It would be valuable to produce parallel plasma heat fluxes at these power densities, impinging on test components at very shallow angles, as planned in tokamaks. The primary objective of this work is the direct measurement of plasma heat fluxes in the mirror throat of a Gas Dynamic Trap device. Options to develop a facility for plasma–material interaction testing based on the Gas Dynamic Trap are discussed.

  8. Formation of Gas Traps in the Martian Soil and Implications for Methane Variability on Mars.

    Science.gov (United States)

    Pavlov, A.; Davis, J.; Redwing, E.; Trainer, M. G.; Johnson, C.

    2017-12-01

    Several independent groups have reported on the detection of methane in the Martian atmosphere. Mars Science Laboratory (MSL) methane observations display rapid increase of the atmospheric methane abundance from 1 ppb to 7 ppb levels followed by an abrupt disappearance suggest the possibility of small, local, near-surface sources of methane. Such sources may take the form of shallow subsurface cemented soil caps which can trap gases and are readily activated by either motion of the MSL rover itself, by impacts of small meteorites, or even annual climate oscillations. We have simulated the formation of such soil caps in the shallow subsurface Martian-like condition. We show that the initially uniform sample of icy soil (JSC-Mars-1A) with Mg perchlorate exhibit quick stratification on the scale of several cm under Martian pressures over the period of several days. Briny water migrates towards the top of the sample resulting in the enhanced abundance of perchlorates in the top few cm. As water evaporates and ice sublimates from the top of the sample, perchlorate remains in the top layer of soil causing soil cementation and formation of the cap. The observed caps were solid, ice-free and effectively shut off sublimation of ice from underneath the cap. We tested whether similar soil caps can trap various gases (including methane) in the shallow subsurface of Mars. We injected neon gas at the bottom of the soil sample and monitored neon gas permeability through the soil sample by measuring gas pressure differential above and below the soil sample. We found that a mixture of JSC-Mars-1A and 5% of Mg perchlorate produce gas impermeable soil cap capable of withstanding an excess of 5 mbars of neon under the cap at the soil temperatures +0.5 C - +9 C. The cap remained gas impermeable after subsequent cooling of the sample soil sample to the subzero temperatures. Gas permeability of the soil caps under various temperatures and atmospheric pressures will be reported. Our

  9. Experimental investigation of the trapping and energy loss mechanisms of intense relativistic electron rings in hydrogen gas and plasma

    International Nuclear Information System (INIS)

    Smith, A.C. Jr.

    1977-01-01

    The results of an experimental study on the trapping and energy loss mechanisms of intense, relativistic electron rings confined in Astron-like magnetic field geometries are presented. The work is subdivided into four sections: gas trapping; average ring electron energetics; plasma trapping, and hollow-beam cusp-injection into gas and plasma. The mechanisms by which the injected beam coalesces into a current ring in the existing Cornell RECE-Berta facility are considered. To investigate the nature of ring electron energy loss mechanisms following completion of the trapping process, a diagnostic was developed utilizing multi-foil X-ray absorption spectroscopy to analyze the Bremsstrahlung generated by the electrons as they impinge upon a thin tungsten wire target suspended in the circulating current. Finally, a set of preliminary experimental results is presented in which an annular electron beam was passed through a coaxial, non-adiabatic magnetic cusp located at one end of a magnetic mirror well

  10. Development of a buffer gas trap for the confinement of positrons and study of positronium production in the GBAR experiment

    CERN Document Server

    AUTHOR|(CDS)2101248; van der Werf, Dirk

    The GBAR experiment relies on the production of antihydrogen positive ions to achieve its goal of measuring the gravitational acceleration of antimatter at rest. The ANTION project, included in the GBAR enterprise, is responsible for the production of these antimatter ions. Moreover, it also aims to measure the cross section of antihydrogen production throughout the collision of antiprotons and positronium atoms, as well as the matter cross sections of hydrogen and the hydrogen negative ion. These experiments imply the formation of a very dense positronium cloud, thus a large amount of positrons will be implanted on a positron/positronium converter material. This thesis reports the construction of a three stage buffer gas trap with the goal of trapping and accumulating positrons for the ANTION project. The combination of the Penning-type trap with a LINAC source constitutes a unique experimental setup. The trap was commissioned and optimized and is now fully operational. Trapping protocols were studied and...

  11. COLD TRAPS

    Science.gov (United States)

    Thompson, W.I.

    1958-09-30

    A cold trap is presented for removing a condensable component from a gas mixture by cooling. It consists of a shell, the exterior surface of which is chilled by a refrigerant, and conductive fins welded inside the shell to condense the gas, and distribute the condensate evenly throughout the length of the trap, so that the trap may function until it becomes completely filled with the condensed solid. The contents may then be removed as either a gas or as a liquid by heating the trap. This device has particuinr use as a means for removing uranium hexafluoride from the gaseous diffusion separation process during equipment breakdown and repair periods.

  12. Selective Trapping of Volatile Fission Products with an Off-Gas Treatment System

    Energy Technology Data Exchange (ETDEWEB)

    B.R. Westphal; J.J. Park; J.M. Shin; G.I. Park; K.J. Bateman; D.L. Wahlquist

    2008-07-01

    A head-end processing step, termed DEOX for its emphasis on decladding via oxidation, is being developed for the treatment of spent oxide fuel by pyroprocessing techniques. The head-end step employs high temperatures to oxidize UO2 to U3O8 resulting in the separation of fuel from cladding and the removal of volatile fission products. Development of the head-end step is being performed in collaboration with the Korean Atomic Energy Research Institute (KAERI) through an International Nuclear Energy Research Initiative. Following the initial experimentation for the removal of volatile fission products, an off-gas treatment system was designed in conjunction with KAERI to collect specific fission gases. The primary volatile species targeted for trapping were iodine, technetium, and cesium. Each species is intended to be collected in distinct zones of the off-gas system and within those zones, on individual filters. Separation of the volatile off-gases is achieved thermally as well as chemically given the composition of the filter media. A description of the filter media and a basis for its selection will be given along with the collection mechanisms and design considerations. In addition, results from testing with the off-gas treatment system will be presented.

  13. Performance characterization of a quantitative liquid chromatography-tandem mass spectrometric method for 12 macrolide and lincosamide antibiotics in salmon, shrimp and tilapia.

    Science.gov (United States)

    Dickson, Leslie C

    2014-09-15

    This paper describes an extension and performance characterization of a quantitative confirmatory multi-residue liquid chromatography-tandem mass spectrometric method for residues of macrolide and lincosamide antibiotics, originally validated for application to bovine kidney tissues, to tissues of salmon, shrimp and tilapia. The 12 analytes include clindamycin, erythromycin A, gamithromycin, josamycin, lincomycin, neospiramycin 1, oleandomycin, pirlimycin, spiramycin 1, tildipirosin, tilmicosin and tylosin A. The limit of detection was 0.5 μg/kg. Within-laboratory precision evaluated over the analytical range of 5.0-50.0 μg/kg ranged from 4 to 17%. The accuracy of the method ranged from 80 to 112%. Recoveries ranged from 47 to 99% with all but one recovery above 60%. This is the first report of a quantitative confirmatory method for gamithromycin, pirlimycin and tildipirosin in fish and shrimp. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  14. Comparison of different calibration approaches for chloramphenicol quantification in chicken muscle by ultra-high pressure liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Pan, Xiao-Dong; Jiang, Wei; Wu, Ping-Gu

    2015-01-07

    Matrix-dependent signal suppression often occurs in quantitative analysis by ultra-high pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS). In this study, we investigated three calibration methods for compensation of signal suppression on chloramphenicol (CAP) quantification in chicken muscle. The data showed that the spiking recoveries by solvent standard calibration with a stable isotope labelled internal standard (SIL-IS) and matrix-matched standard calibration with a SIL-IS were significantly higher than by external matrix-matched standard calibration (P 0.05). The limit of detection (LOD) for external matrix matched standard calibration was 0.1 μg kg(-1), and that for SIL-IS calibration (including matrix matched and solvent dissolved standard) was 0.03 μg kg(-1).

  15. Determination of Pesticide Residues in Honeybees using Modified QUEChERS Sample Work-Up and Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Żaneta Bargańska

    2014-03-01

    Full Text Available Increasing emissions of chemical compounds to the environment, especially of pesticides, is one of factors that may explain present honeybee colony losses. In this work, an analytical method employing liquid chromatography-tandem mass spectrometry (LC-MS/MS was optimized for the simultaneous screening of 19 pesticides which have not been yet determined in honeybee samples from northern Poland (Pomerania. The sample preparation, based on the QuEChERS method combining salting-out liquid-liquid extraction to acetonitrile and a dispersive-SPE clean-up, was adjusted to honeybee samples by adding a small amount of hexane to eliminate beeswax. The recovery of analytes ranged from 70% to 120% with relative standard deviation ≤20%. The limits of detection were in the range of 0.91–25 ng/g. A total of 19 samples of honeybees from suspected pesticide poisoning incidents were analyzed, in which 19 different pesticides were determined.

  16. Rapid and easy multiresidue method for the analysis of antibiotics in meats by ultrahigh-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yamaguchi, Takahiro; Okihashi, Masahiro; Harada, Kazuo; Uchida, Kotaro; Konishi, Yoshimasa; Kajimura, Keiji; Hirata, Kazumasa; Yamamoto, Yoshimasa

    2015-06-03

    This study involved the development of a multiresidue method for the rapid analysis of 43 antibiotics in meats using ultrahigh-performance liquid chromatography-tandem mass spectrometry. This method was performed using dispersive-solid phase extraction, which is able to analyze 20 samples within 2 h. All compounds were determined simultaneously on a C18 separation column with gradient elution. Validation of the analytical method was performed by carrying out linearity, limit of quantification (LOQ), accuracy, precision, and recovery tests in different meat products. The validation criteria were set according to AOAC International and Japanese validation guidelines. The linearity of each compound was almost the coefficient of determination (r(2)) > 0.98. The LOQs of all tested antibiotics were meats (pork, beef, and chicken).

  17. On-line immunoaffinity column-liquid chromatography-tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample.

    Science.gov (United States)

    Zhang, Xiuli; Martens, Dieter; Krämer, Petra M; Kettrup, Antonius A; Liang, Xinmiao

    2006-11-10

    An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC-MS/MS) method for the determination of diuron in water matrices was described. This method used a sol-gel immunoaffinity column (20 mm x 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm x 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy ( approximately 90% of recovery) and precision (effect, the on-line IAC-LC-MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.

  18. Product ion mass spectra of amphetamine-type substances, designer analogues, and ketamine using ultra-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Apollonio, Luigino G; Whittall, Ian R; Pianca, Dennis J; Kyd, Jennelle M; Maher, William A

    2006-01-01

    This paper describes the application of ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) technology to separate and identify amphetamine-type substances (amphetamine, methamphetamine), common and novel designer analogues (MDA, MDMA, PMA, 4-MTA, MBDB), and ketamine using Acquity UPLC/Micromass Quattro Micro API mass spectrometer instrumentation (Waters Corporation, USA). From injection of drug reference standards, it was demonstrated that these compounds can be identified by product ion mass spectra in less than 4 min total analysis time, indicating that the technological advancements associated with UPLC/MS/MS allow it to serve as a powerful analytical tool for high-throughput testing. In addition to demonstrating the separation and response of these drug compounds under the stated UPLC/MS/MS conditions, we believe the acquired product ion spectra will be a beneficial reference to laboratories interested in incorporating the use of this technology in the routine analysis of drugs of abuse.

  19. Simultaneous determination of 11 β-agonists in human urine using high-performance liquid chromatography/tandem mass spectrometry with isotope dilution.

    Science.gov (United States)

    Wang, Xiaoli; Guo, Tao; Wang, Shanshan; Yuan, Jinpeng; Zhao, Rusong

    2015-04-01

    The misuse of β-agonists constitutes a potential risk to public health and has been forbidden in many countries. In this study, we describe a method for specific, sensitive and rapid detection of β-agonists in human urine. Urine samples were extracted with ethyl acetate, without any additional purification step, and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) with Clenbuterol-D9 and Salbuterol-D3 as internal standards. The intra- and interday precision values of the method were all application of UPLC-MS-MS method in β-agonists detection of human urine will be helpful in veterinary control of β-agonists and for studying the effect of β-agonists on human health. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Kinetic study for a stress testing of L,L-ethylenedicysteine by ultra-performance liquid chromatography/tandem mass spectrometry analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sun Xiaotao [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Qiao Jinping, E-mail: Qiaojp920@gmail.co [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Zhu Lin; Qiao Hongwen [Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China); Zhong Jianguo [National Institute for the Control of Pharmaceutical and Biological Products, Beijing 100050 (China)

    2010-12-15

    This study proposed a stress testing to study oxidative stability and estimate the potential shelf-life of L,L-ethylenedicysteine (L,L-EC) under normal storage temperature condition (20-25 {sup o}C). L,L-EC was detected as a function of time at four different temperatures by ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS). The degradation of L,L-EC followed the first order kinetics, and the temperature-dependent kinetics was well described by the linear Arrhenius equation. The activation energy (E{sub a}) was calculated, and the shelf-life at 25 and 4 {sup o}C was predicted. The results are useful for the proper storage and quality evaluation of L,L-EC.

  1. Planet traps and first planets: The critical metallicity for gas giant formation

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Yasuhiro; Hirashita, Hiroyuki, E-mail: yasu@asiaa.sinica.edu.tw, E-mail: hirashita@asiaa.sinica.edu.tw [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2014-06-10

    The ubiquity of planets poses an interesting question: when are first planets formed in galaxies? We investigate this by adopting a theoretical model where planet traps are combined with the standard core accretion scenario in which the efficiency of forming planetary cores directly relates to the metallicity ([Fe/H]) in disks. Three characteristic exoplanetary populations are examined: hot Jupiters, exo-Jupiters around 1 AU, and low-mass planets in tight orbits, such as super-Earths. We statistically compute planet formation frequencies (PFFs), as well as the orbital radius (〈R{sub rapid}〉) within which gas accretion becomes efficient enough to form Jovian planets, as a function of metallicity (–2 ≤ [Fe/H] ≤–0.6). We show that the total PFFs for these three populations increase steadily with metallicity. This is the direct outcome of the core accretion picture. For the metallicity range considered here, the population of low-mass planets dominates Jovian planets. The Jovian planets contribute to the PFFs above [Fe/H] ≅ –1. We find that the hot Jupiters form more efficiently than the exo-Jupiters at [Fe/H] ≲ –0.7. This arises from the slower growth of planetary cores and their more efficient radial inward transport by the host traps in lower metallicity disks. We show that the critical metallicity for forming Jovian planets is [Fe/H] ≅ –1.2 by comparing 〈R{sub rapid}〉 of hot Jupiters and low-mass planets. The comparison intrinsically links to the different gas accretion efficiency between these two types of planets. Therefore, this study implies that important physical processes in planet formation may be tested by exoplanet observations around metal-poor stars.

  2. Pulmonary hyperinflation due to gas trapping and pulmonary artery size: The MESA COPD Study.

    Directory of Open Access Journals (Sweden)

    Hooman D Poor

    Full Text Available Pulmonary hypertension is associated with increased morbidity and mortality in chronic obstructive pulmonary disease (COPD. Since pulmonary artery (PA size increases in pulmonary hypertension, we measured PA cross-sectional area using magnetic resonance imaging (MRI to test the hypothesis that pulmonary hyperinflation due to gas trapping is associated with PA cross-sectional area in COPD.The MESA COPD Study recruited participants with COPD and controls from two population-based cohort studies ages 50-79 years with 10 or more pack-years and free of clinical cardiovascular disease. Body plethysmography was performed according to standard criteria. Cardiac MRI was performed at functional residual capacity to measure the cross-sectional area of the main PA. Percent emphysema was defined as the percentage of lung voxels less than -950 Hounsfield units as assessed via x-ray computed tomography. Analyses were adjusted for age, gender, height, weight, race-ethnicity, the forced expiratory volume in one second, smoking status, pack-years, lung function, oxygen saturation, blood pressure, left ventricular ejection fraction and percent emphysema.Among 106 participants, mean residual volume was 1.98±0.71 L and the mean PA cross-sectional area was 7.23±1.72 cm2. A one standard deviation increase in residual volume was independently associated with an increase in main PA cross-sectional area of 0.55 cm2 (95% CI 0.18 to 0.92; p = 0.003. In contrast, there was no evidence for an association with percent emphysema or total lung capacity.Increased residual volume was associated with a larger PA in COPD, suggesting that gas trapping may contribute to pulmonary hypertension in COPD.

  3. Planet traps and first planets: The critical metallicity for gas giant formation

    International Nuclear Information System (INIS)

    Hasegawa, Yasuhiro; Hirashita, Hiroyuki

    2014-01-01

    The ubiquity of planets poses an interesting question: when are first planets formed in galaxies? We investigate this by adopting a theoretical model where planet traps are combined with the standard core accretion scenario in which the efficiency of forming planetary cores directly relates to the metallicity ([Fe/H]) in disks. Three characteristic exoplanetary populations are examined: hot Jupiters, exo-Jupiters around 1 AU, and low-mass planets in tight orbits, such as super-Earths. We statistically compute planet formation frequencies (PFFs), as well as the orbital radius (〈R rapid 〉) within which gas accretion becomes efficient enough to form Jovian planets, as a function of metallicity (–2 ≤ [Fe/H] ≤–0.6). We show that the total PFFs for these three populations increase steadily with metallicity. This is the direct outcome of the core accretion picture. For the metallicity range considered here, the population of low-mass planets dominates Jovian planets. The Jovian planets contribute to the PFFs above [Fe/H] ≅ –1. We find that the hot Jupiters form more efficiently than the exo-Jupiters at [Fe/H] ≲ –0.7. This arises from the slower growth of planetary cores and their more efficient radial inward transport by the host traps in lower metallicity disks. We show that the critical metallicity for forming Jovian planets is [Fe/H] ≅ –1.2 by comparing 〈R rapid 〉 of hot Jupiters and low-mass planets. The comparison intrinsically links to the different gas accretion efficiency between these two types of planets. Therefore, this study implies that important physical processes in planet formation may be tested by exoplanet observations around metal-poor stars.

  4. A column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry method to determine anandamide and 2-arachidonoylglycerol in plasma samples.

    Science.gov (United States)

    Marchioni, Camila; de Souza, Israel Donizeti; Grecco, Caroline Fernandes; Crippa, José Alexandre; Tumas, Vitor; Queiroz, Maria Eugênia Costa

    2017-05-01

    This study reports a fast, sensitive, and selective column switching ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method to determine the endocannabinoids (eCBs), anandamide (AEA), and 2-arachidonoylglycerol (2-AG) in plasma samples. This bidimensional system used a restricted access media column (RP-8 ADS, 25 mm × 4 mm × 25 μM) in the first dimension and a core-shell Kinetex C18 (100 mm × 2, 1.7 mm × 1 μM) column in the second dimension, followed by detection in a mass spectrometer triple quadrupole (multiple reactions monitoring mode) operating in the positive mode. RP-8 ADS was used for trace enrichment of eCBs (reverse phase partitioning) and macromolecular matrix size exclusion; the core-shell column was used for the chromatographic separation. The column switching UHPLC-MS/MS method presented a linear range spanning from 0.1 ng mL -1 (LOQ) to 6 ng mL -1 for AEA and from 0.04 ng mL -1 (LOQ) to 10 ng mL -1 for 2-AG. Excluding the LLOQ values, the precision assays provided coefficients of variation lower than 8% and accuracy with relative standard error values lower than 14%. Neither carryover nor matrix effects were detected. This high-throughput column switching method compared to conventional methods is time saving as it involves fewer steps, consumes less solvent, and presents lower LLOQ. The column switching UHPLC-MS/MS method was successfully applied to determine AEA and 2-AG in plasma samples obtained from Alzheimer's disease patients. Graphical abstract A column switching ultra high-performance liquid chromatography-tandem mass spectrometry method using RP-8 ADS column and core shell column to determine endocannabinoids in plasma samples.

  5. Ultra-performance liquid chromatography tandem mass-spectrometry (uplc-ms/ms) for the rapid, simultaneous analysis of thiamin, riboflavin, flavin adenine dinucleotide, nicotinamide and pyridoxal in human milk

    Science.gov (United States)

    A novel, rapid and sensitive Ultra Performance Liquid-Chromatography tandem Mass-Spectrometry (UPLC-MS/MS) method for the simultaneous determination of several B-vitamins in human milk was developed. Resolution by retention time or multiple reaction monitoring (MRM) for thiamin, riboflavin, flavin a...

  6. A multidimensional liquid chromatography-tandem mass spectrometry platform to improve protein identification in high-throughput shotgun proteomics.

    Science.gov (United States)

    Capriotti, Anna Laura; Cavaliere, Chiara; Cavazzini, Alberto; Gasparrini, Francesco; Pierri, Giuseppe; Piovesana, Susy; Laganà, Aldo

    2017-05-19

    A new on-line multidimensional system for sequential trapping and individual elution and separation of peptides based on their molecular weight is described. By sequentially using two chemically different trapping columns, a polymethacrylate monolith and a packed C18 one, peptides from complex samples can be on-line trapped and divided into two fractions, containing respectively mainly medium-large peptides and smaller peptides. Then, by means of two switching valves working in parallel, the two fractions were individually separated by reversed phase chromatography. The whole gradient consisted of two subgradients, with the first one dedicated to the separation of smaller peptides and the second one to the separation of larger peptides. Such configuration allowed to identify up to 1476 proteins in a standard E. coli tryptic digest, with improved performance, increased average sequence coverage and reduced single unique peptide identifications compared to a conventional shotgun proteomics configuration comprising only the C18 trapping column and the analytical column. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Automated solid-phase extraction-liquid chromatography-tandem mass spectrometry analysis of 6-acetylmorphine in human urine specimens: application for a high-throughput urine analysis laboratory.

    Science.gov (United States)

    Robandt, P V; Bui, H M; Scancella, J M; Klette, K L

    2010-10-01

    An automated solid-phase extraction-liquid chromatography- tandem mass spectrometry (SPE-LC-MS-MS) method using the Spark Holland Symbiosis Pharma SPE-LC coupled to a Waters Quattro Micro MS-MS was developed for the analysis of 6-acetylmorphine (6-AM) in human urine specimens. The method was linear (R² = 0.9983) to 100 ng/mL, with no carryover at 200 ng/mL. Limits of quantification and detection were found to be 2 ng/mL. Interrun precision calculated as percent coefficient of variation (%CV) and evaluated by analyzing five specimens at 10 ng/mL over nine batches (n = 45) was 3.6%. Intrarun precision evaluated from 0 to 100 ng/mL ranged from 1.0 to 4.4%CV. Other opioids (codeine, morphine, oxycodone, oxymorphone, hydromorphone, hydrocodone, and norcodeine) did not interfere in the detection, quantification, or chromatography of 6-AM or the deuterated internal standard. The quantified values for 41 authentic human urine specimens previously found to contain 6-AM by a validated gas chromatography (GC)-MS method were compared to those obtained by the SPE-LC-MS-MS method. The SPE-LC-MS-MS procedure eliminates the human factors of specimen handling, extraction, and derivatization, thereby reducing labor costs and rework resulting from human error or technique issues. The time required for extraction and analysis was reduced by approximately 50% when compared to a validated 6-AM procedure using manual SPE and GC-MS analysis.

  8. Design report: An off gas trapping system for a voloxidizer in INL of US

    Energy Technology Data Exchange (ETDEWEB)

    Jung, I. H.; Shin, J. M.; Park, J. J.; Park, G. I.; Lee, H. H

    2006-09-15

    This reports on the 'Development of Voloxidation Process for Treatment of LWR Spent Fuel', and it is the second year since it has started from June 2004 as a tripartite cooperation project among KAERI(Korea Atomic Energy Research Institute), INL(Idaho National Laboratory) and ORNL(Oak Ridge National Laboratory). This report is described mainly for the Task B2 accomplished during the second project year. The Task B2 in proposal contains two sub-tasks. The first one is design of an off-gas treatment system for a voloxidizer to be used in HFEF of INL. For this, KAERI team developed the design of INL OTS (Off-gas Treatment System) for hot experiment in the HFEF. INL team modified and completed the design of the INL OTS. The second task is manufacturing and test operation of the INL OTS for a voloxidizer in the INL. Manufacturing of the OTS is accomplished by INL team with co-work of KAERI. KAERI provided four sets of trapping filters needed for conducting hot experiment in the INL HFEF.

  9. Acid Gas Emissions Measured by COSPEC, Volatile Trap, and Filter Pack at Volcán Villarrica, South Chile

    Science.gov (United States)

    Witter, J. B.; Kress, V. C.; Delmelle, P.; Hersum, T. G.

    2001-12-01

    Volcán Villarrica is a basaltic andesite stratovolcano 170 km SE of Temuco, Chile. Villarrica has been characterized by continuous degassing from a summit lava lake since 1985. We present new measurements of the flux of SO2, HCl, and HF from Villarrica using correlation spectrometry (COSPEC) combined with the method of volatile traps and filter packs. COSPEC measurements yielded an average SO2 flux of 460+/-260 tons/day SO2. This is greater than, but within error of, the 260+/-170 tons/day SO2 measured by us last year. We assume H2S emission is negligible. Volatile trap and filter pack measurements were made at the summit crater. To test for diffuse degassing on the flanks of the volcano, we conducted a soil CO2 flux survey. Using an accumulation chamber configured with a continuous infrared CO2 gas analyzer, we found diffuse degassing of CO2 to be undetectable. We assume flank degassing of other gases is similarly low. Four volatile traps (6N KOH solution in a plastic beaker) were deployed at the active crater on three occasions for periods ranging from 8 to 13 days. Acid gas species were absorbed into the alkaline solution and the relative concentrations of SO4, Cl, and F were obtained by ion chromatography. Volatile traps yielded an average SO2/HCl ratio of 5.9+/-1.2 and HCl/HF ratio of 4.1+/-0.7. This compares with an average SO2/HCl ratio of 9.3+/-2.6 and HCl/HF ratio of 3.0+/-0.4 obtained with volatile traps in the 2000 field season. Twenty-three gas measurements were made using filter packs during eight summit days. Using a small vacuum pump we filtered the gas through a series of three paper filters each impregnated with a saturated sodium bicarbonate solution. Total filtration time varied from 3 to 46.5 minutes. Filtration time was chosen so that nearly all of the acid gases were absorbed by the first two filters in the filter stack. Relative concentrations of the acid gas species (SO4, Cl, and F) absorbed onto the filter paper were obtained by ion

  10. Comparison of conventional liquid chromatography-tandem mass spectrometry versus microflow liquid chromatography-tandem mass spectrometry within the framework of full method validation for simultaneous quantification of 40 antidepressants and neuroleptics in whole blood.

    Science.gov (United States)

    Steuer, Andrea E; Poetzsch, Michael; Koenig, Magdalena; Tingelhoff, Eva; Staeheli, Sandra N; Roemmelt, Andreas T; Kraemer, Thomas

    2015-02-13

    Microflow liquid chromatography (MFLC) coupled to mass spectrometry (MS) is claimed to improve analysis throughput, reduce matrix effects and lower mobile phase consumption. This statement was checked within the framework of method validation of a multi-analyte procedure in clinical and forensic toxicology employing MFLC-MS/MS and conventional LC-MS/MS. 200 μL whole blood were spiked with 50 μL internal standard mixture and extracted by protein precipitation. The concentrated extract was separated into two vials. One was analyzed using a Thermo Fisher Ultimate liquid chromatography system coupled to an ABSciex 5500 QTrap mass spectrometer (LC-MS/MS) and one by an ABSciex Eksigent Microflow LC system coupled to an ABSciex 4500 linear ion trap quadrupole MS (MFLC-MS/MS). Both methods were fully validated and compared in terms of selectivity, stability, limits, calibration model, recovery (RE), matrix effects (ME), bias, imprecision and beta tolerance interval for 40 antidepressants and neuroleptics including 9 metabolites. Both methods had comparable LODs, LOQs and calibration models with some exceptions. The MFLC system showed slightly higher coefficients of variation (CVs) in the RE experiments. ME were reproducible in both systems but with lower CVs in the conventional LC system. Acceptance criteria for imprecision and bias were fulfilled for 32 analytes on the LC and for 28 analytes on the MFLC system. Beta tolerance intervals indicated better reproducibility in terms of narrower intervals for the conventional LC system. The advantages of the MFLC system were low mobile phase consumption, short run time, and better peak separation. The systems were comparable in terms of peak interference, LOD, ME, bias and imprecision. The advantages of the conventional LC system were more data points per peak, linear calibration models, stable retention times and better beta tolerance intervals. Due to higher robustness, the conventional LC system was finally chosen for

  11. Determination of household and industrial chemicals, personal care products and hormones in leafy and root vegetables by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Aparicio, Irene; Martín, Julia; Abril, Concepción; Santos, Juan Luis; Alonso, Esteban

    2018-01-19

    A multiresidue method has been developed for the determination of emerging pollutants in leafy and root vegetables. Selected compounds were 6 perfluoroalkyl compounds (5 perfluorocarboxylic acids and perfluorooctanesulfonic acid), 3 non-ionic surfactants (nonylphenol and nonylphenolethoxylates), 8 anionic surfactants (4 alkylsulfates and 4 linear alkylbenzene sulfonates), 4 preservatives (parabens), 2 biocides (triclosan and triclocarban), 2 plasticizers (bisphenol A and di-(2-ethylhexyl)phthalate), 6 UV-filters (benzophenones) and 4 hormones. The method is based on ultrasound-assisted extraction, clean-up by dispersive solid-phase extraction (d-SPE) and liquid chromatography-tandem mass spectrometry analysis. Due to the diversity of the physico-chemical properties of the target compounds, and to better evaluate the influence of sample treatment variables in extraction efficiencies, Box-Behnken design was applied to optimize extraction solvent volume, number of extraction cycles and d-SPE sorbent amount. Linearity (R 2 ) higher than 0.992, accuracy (expressed as relative recoveries) in the range from 81 to 126%, precision (expressed as relative standard deviation) lower than 19% and limits of detection between 0.025 and 12.5ngg -1 dry weight were achieved. The method was applied to leafy vegetables (lettuce, spinach and chard) and root vegetables (carrot, turnip and potato) from a local market. The highest concentrations corresponded to the surfactants reaching levels up to 114ngg -1 (dry weight), in one of the lettuce samples analyzed. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Residue Analysis of 60 Pesticides in Red Swamp Crayfish Using QuEChERS with High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Song, Shuangyu; Zhu, Kechen; Han, Lijun; Sapozhnikova, Yelena; Zhang, Zihao; Yao, Wei

    2018-02-05

    In this study, a multi-residue analytical method using quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and dispersive solid-phase extraction (d-SPE) cleanup, followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), was investigated for rapid determination of 60 pesticide residues in whole crayfish and crayfish meat. The final method used 10 mL of acetonitrile for extraction, 3 g of NaCl for partitioning, and 50 mg of primary secondary amine for d-SPE cleanup. The method was validated at three spiking levels (10, 50, and 100 ng/g) using triphenyl phosphate as an internal standard and both gradient and isocratic HPLC elution. Under gradient conditions, satisfactory recoveries (70-120%) and relative standard deviations of ≤20% were achieved for 83 and 88% of pesticides in whole crayfish and crayfish meat, respectively. Matrix effects were estimated using both gradient and isocratic HPLC elution. To our knowledge, this is the first study involving multi-residue analysis of HPLC-amenable pesticides in crayfish and mantis shrimp. The final method was successfully applied for analysis of 11 crayfish and mantis shrimp samples from markets in China, and propamocarb (shrimps.

  13. Simultaneous analysis of isomers of escin saponins in human plasma by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study after oral administration.

    Science.gov (United States)

    Wu, Xiujun; Liu, Lidong; Zhang, Mengliang; Wu, Dan; Wang, Yingwu; Sun, Yantong; Fawcett, J Paul; Gu, Jingkai; Zhang, Jiwen

    2010-04-01

    A rapid and sensitive bioassay based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of four isomeric escin saponins (escin Ia, escin Ib, isoescin Ia and isoescin Ib) in human plasma has been developed and validated. Sample preparation of plasma after addition of telmisartan as internal standard (I.S.) involved solid-phase extraction (SPE) on C18 cartridges. Separation was based on reversed phase chromatography using gradient elution with methanol-acetonitrile (50:50, v/v) and 10 mM ammonium acetate solution (pH 6.8). MS/MS detection in the positive ion mode used multiple reaction monitoring of the transition at m/z 1113.8-->807.6. Stability issues with the four saponins required the addition of formic acid to plasma samples prior to storage at -80 degrees C and analysis within 30 days. The method was linear at concentrations up to 10 ng/mL with correlation coefficients>0.996 for all analytes. The lower limit of quantitation (LLOQ) for all four saponins was 33 pg/mL. Intra- and inter-day precisions (as relative standard deviation) were all escins in healthy volunteers after oral administration of sodium aescinate tablets containing 60 mg escin saponins. 2010 Elsevier B.V. All rights reserved.

  14. [Simultaneous determination of zeranols and chloramphenicol in foodstuffs of animal origin by combination immunoaffinity column clean-up and liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Wang, Qing; Wang, Guomin; Xi, Cunxian; Li, Xianliang; Chen, Dongdong; Tang, Bobin; Zhang, Lei; Zhao, Hua

    2014-06-01

    A combination immunoaffinity column (IAC-CZ) clean-up and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method was successfully developed for zearalenol, beta-zearalenol and zearalenone) and chloramphenicol (CAP) in foodstuffs of animal origin. The samples (fish, liver, milk and honey) were enzymatically digested by beta-glucuronidase/sulfatase for about 16 h and then extracted with ether. The extracts were evaporated to dryness and then the residues were dissolved by 1.0 mL of 50% acetonitrile solution. After filtered and diluted with PBS buffer, the reconstituted solution were cleaned-up with a IAC-CZ and then analyzed by LC-MS/MS in multiple reaction monitoring (MRM) mode. The chromatographic separation was performed on a Shimadzu Shim-pack VP-ODS column with gradient elution by acetonitrile and 2 mmol/L ammonium acetate solution. The detection was carried out by electrospray negative ionization mass spectrometry in MRM mode. The proposed method was validated by the limit of detection (0.04-0.10 microg/kg), linearity (R2 > or = 0.999 0), average recoveries (70.9%-95.6%) and precisions (2.0% - 11.8%). The developed method is reliable, sensitive and has good applicability. The combination immunoaffinity column was proved to be an effective pretreatment technique to decrease the matrix effect, and it met the requirements of residue analysis of co-occurring zeranols and chloramphenicol.

  15. A multi-residue method for 17 anticoccidial drugs and ractopamine in animal tissues by liquid chromatography-tandem mass spectrometry and time-of-flight mass spectrometry.

    Science.gov (United States)

    Matus, Johanna L; Boison, Joe O

    2016-05-01

    A new and sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QToF-MS) method was developed and validated for the determination and confirmation of residues of 17 anticoccidials, plus free ractopamine in poultry muscle and liver, and bovine muscle, liver, and kidney tissues. The 17 anticoccidials are lasalocid, halofuginone, narasin, monensin, semduramicin, ethopabate, robenidine, buquinolate, toltrazuril as its sulfone metabolite, maduramicin, salinomycin, diclazuril, amprolium, decoquinate, dinitolmide, clopidol, and the nicarbazin metabolite DNC (N,N1-bis(4-nitrophenyl)urea). The analytes were extracted and cleaned up within a 3-hour period by simply extracting the analytes into a solvent mixture with salts followed by centrifugation, dilution, and filtration. The validated method was used in a pilot study for the analysis of 173 samples that included quail liver, bovine kidney, liver, muscle, and horse muscle. The predominant residues found in this study were monensin, ractopamine, and lasalocid. The results of this pilot study showed that this new method is applicable to real samples, and is fit for use in a regulatory testing programme. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis. © 2016 John Wiley & Sons, Ltd. © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis. © 2016 John Wiley & Sons, Ltd.

  16. [Liquid chromatography-tandem mass spectrometry method for determination of 10 macrolide antibiotics in pork samples using on-line solid phase extraction purification].

    Science.gov (United States)

    Zhang, Xiaoguang; Liu, Dong; Liu, Hongran; Li, Qiang; Li, Lili; Wang, Lixia; Zhang, Yan

    2017-10-08

    A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method based on-line solid phase extraction (SPE) purification was established to determine 10 macrolide antibiotics in pork samples. The samples were extracted with acetonitrile, and the extracts were dried with rotary evaporator at 40℃, then the analytes were dissolved with 2 mL phosphate buffer. The solutions were purified and concentrated by on-line SPE with HLB cartridges. The analytes were eluted with methanol, and then transferred to XBridge BEH C18 column, separated with the mobile phases of 10 mmol/L ammonium acetate aqueous solution and acetonitrile. Finally, the target analytes were detected by tandem mass spectrometry. The results showed that good linearity was obtained in the range of 0.1-200 μg/L for the 10 macrolide antibiotics with correlation coefficients better than 0.990. The limits of detection were in range of 0.05-0.30 μg/kg and the limits of quantitation were in range of 0.10-1.00 μg/kg. The recoveries of the method were in range of 69.6%-115.2% at the spiked levels of 0.10-10.0 μg/kg for all analytes, with the relative standard deviations less than 10%. The developed method can be used for the determination of the 10 macrolide antibiotics in pork samples.

  17. Multiresidue analysis of 24 Water Framework Directive priority substances by on-line solid phase extraction-liquid chromatography tandem mass spectrometry in environmental waters.

    Science.gov (United States)

    Rubirola, Adrià; Boleda, Mª Rosa; Galceran, Mª Teresa

    2017-04-14

    This paper reports the development of a fully multiresidue and automated on-line solid phase extraction (SPE) - liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of 24 priority substances (PS) belonging to different classes (pesticides, hormones or pharmaceuticals) included in the Directive 2013/39/UE and the recent Watch List (Decision 2015/495) in water samples (drinking water, surface water, and effluent wastewaters). LC-MS/MS conditions and on-line SPE parameters such as sorbent type, sample and wash volumes were optimized. The developed method is highly sensitive (limits of detection between 0.1 and 1.4ngL -1 ) and precise (relative standard deviations lower than 8%). As part of the method validation studies, linearity, accuracy and matrix effects were assessed. The main advantage of this method over traditional off-line procedures is the minimization of tedious sample preparation increasing productivity and sample throughput. The optimized method was applied to the analysis of water samples and the results revealed the presence of 16 PS in river water and effluent water of wastewater treatment plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Automated isotope dilution liquid chromatography-tandem mass spectrometry with on-line dilution and solid phase extraction for the measurement of cortisol in human serum sample.

    Science.gov (United States)

    Kawaguchi, Migaku; Eyama, Sakae; Takatsu, Akiko

    2014-08-05

    A candidate reference measurement procedure involving automated isotope dilution coupled with liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) with on-line dilution and solid phase extraction (SPE) has been developed and critically evaluated. We constructed the LC-MS/MS with on-line dilution and SPE system. An isotopically labelled internal standard, cortisol-d4, was added to serum sample. After equilibration, the methanol was added to the sample, and deproteination was performed. Then, the sample was applied to the LC-MS/MS system. The limit of detection (LOD) and limit of quantification (LOQ) were 0.2 and 1ngg(-1), respectively. Excellent precision was obtained with within-day variation (RSD) of 1.9% for ID-LC-MS/MS analysis (n=6). This method, which demonstrates simple, easy, good accuracy, high precision, and is free from interferences from structural analogues, qualifies as a reference measurement procedure. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Approach to improve compound recovery in a high-throughput Caco-2 permeability assay supported by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cai, Xianmei; Walker, Aaron; Cheng, Charles; Paiva, Anthony; Li, Ying; Kolb, Janet; Herbst, John; Shou, Wilson; Weller, Harold

    2012-08-01

    The Caco-2 cell culture system is widely employed as an in vitro model for prediction of intestinal absorption of test compounds in early drug discovery. Poor recovery is a commonly encountered issue in Caco-2 assay, which can lead to difficulty in data interpretation and underestimation of the apparent permeability of affected compounds. In this study, we systematically investigated the potential sources of compound loss in our automated, high-throughput Caco-2 assay, sample storage, and analysis processes, and as a result found the nonspecific binding to various plastic surfaces to be the major cause of poor compound recovery. To minimize the nonspecific binding, we implemented a simple and practical approach in our assay automation by preloading collection plates with organic solvent containing internal standard prior to transferring incubations samples. The implementation of this new method has been shown to significantly increase recovery in many compounds previously identified as having poor recovery in the Caco-2 permeability assay. With improved recovery, permeability results were obtained for many compounds that were previously not detected in the basolateral samples. In addition to recovery improvement, this new approach also simplified sample preparation for liquid chromatography-tandem mass spectrometric analysis and therefore achieved time and cost savings for the bioanalyst. Copyright © 2012 Wiley Periodicals, Inc.

  20. A Rapid Magnetic Solid Phase Extraction Method Followed by Liquid Chromatography-Tandem Mass Spectrometry Analysis for the Determination of Mycotoxins in Cereals

    Directory of Open Access Journals (Sweden)

    Giorgia La Barbera

    2017-04-01

    Full Text Available Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE, a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high–performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were >60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes.

  1. Online solid phase extraction with liquid chromatography-tandem mass spectrometry to analyze remoxipride in small plasma-, brain homogenate-, and brain microdialysate samples.

    Science.gov (United States)

    Stevens, Jasper; van den Berg, Dirk-Jan; de Ridder, Sanne; Niederländer, Harm A G; van der Graaf, Piet Hein; Danhof, Meindert; de Lange, Elizabeth C M

    2010-04-15

    Remoxipride is a selective dopamine D(2) receptor antagonist, and useful as a model compound in mechanism-based pharmacological investigations. To that end, studies in small animals with serial sampling over time are needed. For these small volume samples currently no suitable analytical methods are available. We propose analytical methods for the detection of low concentrations remoxipride in small sample volumes of plasma, brain homogenate, and brain microdialysate, using online solid phase extraction with liquid chromatography-tandem mass spectrometry. Method development, optimization and validation are described in terms of calibration curves, extraction yield, lower limit of quantification (LLOQ), precision, accuracy, inter-day- and intra-day variability. The 20 microl plasma samples showed an extraction yield of 76%, with a LLOQ of 0.5 ng/ml. For 0.6 ml brain homogenate samples the extraction yield was 45%, with a LLOQ of 1.8 ng/ml. The 20 microl brain microdialysate samples, without pre-treatment, had a LLOQ of 0.25 ng/ml. The precision and accuracy were well within the acceptable 15% range. Considering the small sample volumes, the high sensitivity and good reproducibility, the analytical methods are suitable for analyzing small sample volumes with low remoxipride concentrations. Copyright 2010 Elsevier B.V. All rights reserved.

  2. Simultaneous determination of tedizolid and linezolid in rat plasma by ultra performance liquid chromatography tandem mass spectrometry and its application to a pharmacokinetic study.

    Science.gov (United States)

    Yu, Hua-chen; Pan, Chen-wei; Xie, Qi-peng; Zheng, Yi; Hu, Yue-zheng; Lin, Yi-mu

    2016-02-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine tedizolid and linezolid in rat plasma simultaneously. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a XEVO TQD triple quadruple mass spectrometer coupled with an electrospray ionization (ESI) source in the positive ion mode. Multiple reaction monitoring (MRM) mode was used for quantification using target fragment ions m/z 371.4→343.2 for tedizolid, and m/z 338.3→56.1 for linezolid. This assay method has been fully validated in terms of selectivity, linearity, recovery and matrix effect, accuracy, precision and stability. The linearity of this method was found to be within the concentration range of 5-5000ng/mL for tedizolid, and 10-10,000ng/mL for linezolid in rat plasma, respectively. Only 3.0min was needed for an analytical run. This assay was used to support a preclinical study where multiple oral doses were administered to rats to investigate the pharmacokinetics of tedizolid and linezolid. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Simple and sensitive determination of hydrazine in drinking water by ultra-high-performance liquid chromatography-tandem mass spectrometry after derivatization with naphthalene-2,3-dialdehyde.

    Science.gov (United States)

    Oh, Jin-Aa; Shin, Ho-Sang

    2015-05-22

    An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to determine the level of hydrazine in drinking water. The method is based on the derivatization of hydrazine with naphthalene-2,3-dicarboxaldehyde (NDA) in water. The optimum conditions for UPLC-MS/MS detection were determined as follows: derivatization reagent dosage, 50mg/L of NDA; pH 2; and reaction time, 1min; room temperature. The formed derivative was injected into an LC system without extraction or purification procedures. Under the established conditions, the method was used to detect hydrazine in raw drinking water and chlorinated drinking water. The limits of detection and quantification for hydrazine in drinking water were 0.003μg/L and 0.01μg/L, respectively. The accuracy was in the range of 97-104%, and precision, expressed as relative standard deviation, was less than 9% in drinking water. Hydrazine was detected at a concentration of 0.13μg/L in one sample among 24 raw drinking water samples and in a range of 0.04-0.45μg/L in three samples among 24 chlorinated drinking water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Simple and sensitive analysis of blonanserin and blonanserin C in human plasma by liquid chromatography tandem mass spectrometry and its application.

    Science.gov (United States)

    Zheng, Yunliang; Hu, Xingjiang; Liu, Jian; Wu, Guolan; Zhou, Huili; Zhu, Meixiang; Zhai, You; Wu, Lihua; Shentu, Jianzhong

    2014-01-01

    A highly sensitive, simple, and rapid liquid chromatography tandem mass spectrometry method to simultaneously determine blonanserin and blonanserin C in human plasma with AD-5332 as internal standard (IS) was established. A simple direct protein precipitation method was used for the sample pretreatment, and chromatographic separation was performed on a Waters XBridge C8 (4.6 × 150 mm, 3.5  μ m) column. The mobile phase consists of a mixture of 10 mM ammonium formate and 0.1% formic acid in water (A) and 0.1% formic acid in methanol (B). To quantify blonanserin, blonanserin C, and IS, multiple reaction monitoring (MRM) was performed in positive ESI mode. The calibration curve was linear in the concentration range of 0.012-5.78 ng·mL(-1) for blonanserin and 0.023-11.57 ng·mL(-1) for blonanserin C (r (2) > 0.9990). The intra- and interday precision of three quality control (QC) levels in plasma were less than 7.5%. Finally, the current simple, sensitive, and accurate LC-MS/MS method was successfully applied to investigate the pharmacokinetics of blonanserin and blonanserin C in healthy Chinese volunteers.

  5. Simple and Sensitive Analysis of Blonanserin and Blonanserin C in Human Plasma by Liquid Chromatography Tandem Mass Spectrometry and Its Application

    Directory of Open Access Journals (Sweden)

    Yunliang Zheng

    2014-01-01

    Full Text Available A highly sensitive, simple, and rapid liquid chromatography tandem mass spectrometry method to simultaneously determine blonanserin and blonanserin C in human plasma with AD-5332 as internal standard (IS was established. A simple direct protein precipitation method was used for the sample pretreatment, and chromatographic separation was performed on a Waters XBridge C8 (4.6×150 mm, 3.5 μm column. The mobile phase consists of a mixture of 10 mM ammonium formate and 0.1% formic acid in water (A and 0.1% formic acid in methanol (B. To quantify blonanserin, blonanserin C, and IS, multiple reaction monitoring (MRM was performed in positive ESI mode. The calibration curve was linear in the concentration range of 0.012–5.78 ng·mL−1 for blonanserin and 0.023–11.57 ng·mL−1 for blonanserin C (r2>0.9990. The intra- and interday precision of three quality control (QC levels in plasma were less than 7.5%. Finally, the current simple, sensitive, and accurate LC-MS/MS method was successfully applied to investigate the pharmacokinetics of blonanserin and blonanserin C in healthy Chinese volunteers.

  6. Determination of 82 veterinary drugs in swine waste lagoon sludge by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Li, Xiaowei; Guo, Ping; Shan, Yawen; Ke, Yuebin; Li, Hui; Fu, Qin; Wang, Yingyu; Liu, Tianhe; Xia, Xi

    2017-05-26

    This work reports the development of a multi-residue method for the identification and quantification of 82 veterinary drugs belonging to different chemical classes in swine waste lagoon. The proposed method applies a solid-phase extraction procedure with Oasis PRiME HLB cartridges that combines isolation of the compounds and sample clean-up in a single step. Analysis is performed by ultra-high performance liquid chromatography-tandem mass spectrometry, in one single injection with a chromatographic run time of only 9.5min. Linearity was studied in the range between 1 and 500μgkg -1 using standards prepared both in pure solvent and in the presence of matrix, showing coefficients of determination higher than 0.99 for all the analytes except for cefapirin in matrix. The average recoveries were in the range of 60-110% for most of the compounds tested with inter-day relative standard deviations below 17%. More than 97% of the investigated compounds had less or equal to a 5μgkg -1 quantitation limit in the studied matrix. Finally, the method was used with success to detect and quantify veterinary drugs residues in real samples with sulfonamides, quinolones, and tetracyclines being the most frequently determined compound groups. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Using Light Microscopy and Liquid Chromatography Tandem Mass Spectrometry for Qualitative and Quantitative Control of a Combined Three-Herb Formulation in Different Preparations

    Directory of Open Access Journals (Sweden)

    Tun-Pin Hsueh

    2016-12-01

    Full Text Available Artemisia capillaries Thunb, Gardenia jasminoides Ellis, and Rheum officinale Baill have been combined to treat jaundice for thousands of years. Studies have revealed that these herbs induce anti-hepatic fibrosis and anti-hepatic apoptosis and alleviate hepatic oxidative stress. This study aims to determine the quality and quantity of an herbal formulation (Chinese name: Yin-Chen-Hao-Tang using physical and chemical examinations. Physical examination of Yin-Chen-Hao-Tang in pharmaceutical herbal products, raw fiber powders, and decoction preparations was performed using Congo red and iodine-potassium staining. A sensitive and validated method employing ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS was developed to simultaneously quantify the bioactive compounds scoparone, geniposide, and rhein in the Yin-Chen-Hao-Tang formulation in different preparations. Physical examination indicated that cellulose fibers with irregular round shapes were present in the pharmaceutical herbal products. The developed UHPLC-MS/MS method showed good linearity and was well validated. The quantification results revealed that the decoction preparations had the highest amounts of geniposide and rhein. Scoparone appeared in pharmaceutical herbal products from two manufacturers. This experiment provides a qualitative and quantitative method using physical and chemical examinations to test different preparations of herbal products. The results provide a reference for clinical herbal product preparations and further pharmacokinetic research.

  8. A fully automated on-line preconcentration and liquid chromatography-tandem mass spectrometry method for the analysis of anti-infectives in wastewaters.

    Science.gov (United States)

    Segura, Pedro A; Gagnon, Christian; Sauvé, Sébastien

    2007-12-05

    We developed and validated a novel on-line preconcentration liquid chromatography-tandem mass spectrometry method for the determination of anti-infectives in wastewaters. The presented method preconcentrates 1 mL of sample in a load column using a switching-valve technique. The method was optimized with respect to sample load flow rate, volume of the load column wash and organic solvent content of the load column wash. The sample is cleaned using a 30% organic solvent washing step and then gradually eluted to an analytical column for separation. To compensate for matrix effects, quantitation was performed using standard additions. Confirmation of the presence of the detected compounds was done using a second selective reaction monitoring transition. Method intra-day precision was less than 9% and inter-day precision %R.S.D. varied between 2.5 and 23%. Limits of detection for the selected anti-infective compounds ranged from 13 to 61 ng L(-1). All the target anti-infectives were found in the city of Montréal WWTP effluent in concentrations ranging from 71 to 289 ng L(-1). This automated method eases the rapid quantitation of those trace contaminants using small sample volumes.

  9. Simultaneous determination of Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in oral fluid using isotope dilution liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lee, Pin Duo; Chang, Yuan-Jhe; Lin, Keh-Liang; Chang, Yan-Zin

    2012-01-01

    The detection and confirmation of cannabinoids in oral fluid are important in forensic toxicology. Currently, the presence of Δ(9)-tetrahydrocannabinol (THC) is used for the detection of cannabis in oral fluid. A low concentration of 11-nor-9-carboxy-Δ(9)-tetrahydrocannabinol (THC-COOH) is found in oral fluid, which suggested a convenient and low-sensitivity confirmation assay can be used in a routine forensic laboratory. In this study, a highly sensitive isotope dilution liquid chromatography-tandem mass spectrometry method following dansylation was successfully developed for simultaneous determination of THC and THC-COOH in oral fluid. The dansylated derivatives dramatically demonstrated and enhanced the sensitivity of THC and THC-COOH. To avoid signal influenced by the matrix, a 5-min liquid chromatography gradient program was evaluated and optimized, which reduced the sample diffusion and caused sharp peaks (less than 12 s) and thus helped to achieve detection at a low level. The sensitivity, accuracy, and precision were also evaluated, and high quantitative accuracy and precision were obtained. The limit of quantitation of this approach was 25 pg/mL for THC and 10 pg/mL for THC-COOH in oral fluid. Finally, the method was successfully applied to eight suspected cannabis users. Among them, in six oral fluid samples THC-COOH was determined at a concentration from 13.1 to 47.2 pg/mL.

  10. A sensitive and selective quantification of catecholamine neurotransmitters in rat microdialysates by pre-column dansyl chloride derivatization using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nirogi, Ramakrishna; Komarneni, Prashanth; Kandikere, Vishwottam; Boggavarapu, Rajeshkumar; Bhyrapuneni, Gopinadh; Benade, Vijay; Gorentla, Srinivasarao

    2013-01-15

    A rapid and sensitive liquid chromatography tandem mass spectrometry method for simultaneous quantification of catecholamine neurotransmitters in microdialysates was developed. The catecholamine neurotransmitters dopamine (DA) and norepinephrine (NE) were pre-column derivatized with dansyl chloride and analyzed. A gradient elution method was used to separate the analytes from the interferences on an Agilent Poroshell 120 EC-C18 outer porous micro particulate column. The method was robust and sensitive to determine with the lower limit of quantification value of 0.068pmol/mL and 0.059pmol/mL for DA and NE, respectively. It has acceptable precision and accuracy for concentrations over the standard curve range. The method was successfully applied for simultaneous quantitation of DA and NE in the prefrontal cortex (PFC) dialysates of rats obtained from a microdialysis study dosed with vehicle and atomoxetine through intra peritoneal (i.p.) route at a dose of 3mg/kg to monitor the change in extracellular concentrations. Thus, accomplishment of this method would facilitate the neurochemical monitoring for discovery of new chemical entities targeted for the treatment of attention deficit hyperactivity disorder (ADHD). Copyright © 2012. Published by Elsevier B.V.

  11. [Determination of eleven steroid hormones in animal muscle tissues and eggs using ultra-performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    He, Limin; Huang, Xianhui; Fang, Binghu; Huang, Shixin; Cao, Ying; Chen, Jianxin; Zeng, Zhenling; Chen, Zhangliu

    2008-11-01

    A credible method was developed for the simultaneous determination of eleven steroid hormone residues in animal muscle tissues and eggs based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The eleven steroid hormones were testosterone, methyltestosterone, trenbolone, boldenone, nandrolone, methandienone, stanozolol, progesterone, nadrolone propionate, testosterone propionate and nadrolone phenylpropionate. The samples were extracted with tert-butyl methyl ether at alkaline pH and then cleaned up by freezing-lipid filtration. All these drugs can be assayed in 10 min by UPLC-MS/MS using electrospray ionization in positive ion mode and multiple reaction monitoring mode. The limits of detection were 0.3 microg/kg for testosterone, methyltestosterone, boldenone, methandienone and stanozolol, and 0.4 microg/kg for trenbolone nandrolone, progesterone, testosterone propionate and nadrolone phenylpropionate. Overall recoveries of testosterone, methyltestosterone, boldenone, methandienone and stanozolol were 62.3% - 105% from pork, beef, mutton and chicken muscle tissues, and eggs fortified at the 1, 2 and 10 microg/kg levels, and the relative standard deviations (RSDs) were 0.5% - 15%. The recoveries of trenbolone nandrolone, progesterone, testosterone propionate and nadrolone phenylpropionate were higher than 50.0%, and the RSDs were lower than 16%. The matrix calibration curve for each drug was linear (r > 0.99) from 1 to 100 microg/L. The established method is simple, rapid, sensitive and specific, and is appropriate for the identification and quantification of anabolic androgenic steroids in animal muscle tissues and eggs.

  12. Method validation and dissipation kinetics of four herbicides in maize and soil using QuEChERS sample preparation and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Pang, Nannan; Wang, Tielong; Hu, Jiye

    2016-01-01

    A versatile liquid chromatography tandem mass spectrometry method with modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation was developed for the determination of rimsulfuron, mesotrione, fluroxypyr-meptyl, and fluroxypyr. By adjusting the amount of graphitized carbon black, the herbicide analytes could be quantified with satisfactory recoveries in the range of 80-110%. A dissipation kinetics study conducted under open field conditions at two sites during 2014 showed first order equations with half-lives between 0.6d and 3.6d, illustrating an appropriate degree of stability and safety. The dissipation kinetics were different in the different matrices. Although the herbicides had higher initial residues in straw than those in soil, they degraded faster in straw. The terminal residues for the herbicides formulated in two water dispersible granules were all below maximum residue limits. These results not only gave insights about the analytes but also contributed to environmental protection and food safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Ultrasound-assisted surfactant-enhanced emulsification microextraction for the determination of carbamates in wines by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Moreno-González, David; Huertas-Pérez, José F; García-Campaña, Ana M; Bosque-Sendra, Juan M; Gámiz-Gracia, Laura

    2013-11-08

    A new sensitive multiresidue method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) has been developed for the detection, confirmation and quantification of twenty five carbamates in wine samples. The separation was achieved in 5.5 min, using a Zorbax Eclipse plus RRHD C18 column (50 mm×2.1 mm, 1.8 μm), with a mobile phase of water and methanol, both of them with 0.01% formic acid. The analytes were detected in positive mode with multiple reaction monitoring mode. Ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME), using a low-density extraction solvent has been optimized for the satisfactory extraction of carbamates and clean-up of extracts. The matrix effect was studied, showing that the proposed procedure provides very clean extracts. Under optimum conditions, recoveries for fortified wine samples ranged from 74 to 102%, with relative standard deviations lower than 6%. Limits of quantification ranged from 0.15 to 0.92 μgl(-1), showing the high sensitivity of this fast and simple method and its compliance with current requirements. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Analysis of new psychoactive substances in oral fluids by means of microextraction by packed sorbent followed by ultra-high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rocchi, Rachele; Simeoni, Maria Chiara; Montesano, Camilla; Vannutelli, Gabriele; Curini, Roberta; Sergi, Manuel; Compagnone, Dario

    2017-10-27

    In recent years, new drugs, commonly known as new psychoactive substances (NPS), appeared on the market, which include, among others, synthetic cannabinoids, cathinones, and tryptamine analogs of psilocin. The aim of this work was to develop and validate a new method for simultaneous screening and quantification of 31 NPS in oral fluid by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The chosen target analytes represented different chemical and toxicological NPS classes, such as synthetic cathinones, piperazines, phenethylamines, synthetic cannabinoids, and their metabolites. The procedure involved a rapid sample preparation based on protein precipitation followed by clean-up utilizing microextraction by packed sorbent (MEPS); the quantitative analysis was performed by UHPLC-MS/MS. The MEPS clean-up, regardless of non-quantitative recoveries for some analytes, provided an effective removal of interfering compounds, as demonstrated by reduced matrix effects found at different concentrations for all the analytes. The validation protocol, based on SWGTOX guidelines, demonstrated the suitability of the proposed method for quantitative analysis: linearity range ranged over 3 or 4 orders of magnitude; precision and accuracy tests gave RSD% values below 25%, and accuracy ranged from 85.9% to 107%, accomplishing SWGTOX requirements. Limits of detection (LODs) ranged between 0.005 ng/mL and 0.850 ng/mL and limits of quantification (LOQs) from 0.015 to 2.600 ng/mL. Copyright © 2017 John Wiley & Sons, Ltd.

  15. Ultra-high-performance liquid chromatography-tandem mass spectrometry measurement of climbazole deposition from hair care products onto artificial skin and human scalp.

    Science.gov (United States)

    Chen, Guoqiang; Hoptroff, Michael; Fei, Xiaoqing; Su, Ya; Janssen, Hans-Gerd

    2013-11-22

    A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal standard. Atmospheric pressure chemical ionization (APCI) in positive mode was applied for the detection of climbazole. For quantification, multiple reaction monitoring (MRM) transition 293.0>69.0 was monitored for climbazole, and MRM transition 296.0>225.1 for the deuterated climbazole. The linear range ran from 4 to 2000 ng mL(-1). The limit of detection (LOD) and the limit of quantification (LOQ) were 1 ng mL(-1) and 4 ng mL(-1), respectively, which enabled quantification of climbazole on artificial skin and human scalp at ppb level (corresponding to 16 ng cm(-2)). For the sampling of climbazole from human scalp the buffer scrub method using a surfactant-modified phosphate buffered saline (PBS) solution was selected based on a performance comparison of tape stripping, the buffer scrub method and solvent extraction in in vitro studies. Using this method, climbazole deposition in in vitro and in vivo studies was successfully quantified. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. [An ultrafast liquid chromatography-tandem mass spectrometric method for simultaneous determination of common artificial synthetic pigments in cooked meat products].

    Science.gov (United States)

    Chen, Xiaohong; Li, Xiaoping; Zhao, Yonggang; Pan, Shengdong; Jin, Micong

    2015-07-01

    A method based on ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) has been developed for the simultaneous determination of seven synthetic pigments in cooked meat product. After the cooked meat products were extracted by mixed extraction agent, purified by WAX column, the UFLC separation was performed on a Shim-pack XR-ODS II column (75 mm x 2.0 mm, 2.2 µm) with a linear gradient elution program of acetonitrile and ammonium acetate (AmAc, 5 mmol/L) as the mobile phase. Electrospray ionization was applied and operated in the negative ion mode. The limits of quantitation (LOQs) for the seven synthetic pigments were in the range of 0.7-5.0 µg/kg. The calibration curves showed good linearities for the seven analytes in their detection ranges, and the correlative coefficients (r) were more than 0.999. The recoveries were between 88.2%-106.5% with the RSDs in the range of 1.2%-5.0%. The method is sensitive, reproducible, quick and adapts to the simultaneous determination of the seven synthetic pigments in cooked meat product.

  17. [Simultaneous determination of ethephon, thidiazuron, diuroN residues in cotton by using high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Xie, Wen; Shi, Yingzhu; Hou, Jianbo; Huang, Chaoqun; Zhao, Dong; Pan, Lulu; Dong, Suozhuai

    2014-02-01

    A method for the determination of ethephon, thidiazuron and diuron in cotton samples has been developed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with methanol-water. The separation was carried out on a C8 column (150 mm x 4.6 mm, 5 microm) with methanol-water (6:4, v/v) as mobile phase at a flow rate of 0.4 mL/min, and the injection volume was 20 microL. Then the sample solution was analyzed by HPLC-MS/MS in negative ion mode with multiple reaction monitoring (MRM). There were one precursor/two product ion transitions for each pesticide. The results showed that the working curves were linear in the range of 0-10 microg/L for ethephon and thidiazuron, and 0-1 microg/L for diuron. The correlation coefficients (r) were all over 0. 999. The limits of quantitation (LOQ) of ethephon, diuron were 40 microg/kg, that of thidiazuron was 4 microg/kg. The average recoveries varied from 89.4% to 100.2% with the relative standard deviations (RSDs) of 5.7%-11.5% at three spiked levels (LOQ, 2LOQ and 4LOQ). The method is simple, rapid and accurate, and can meet the requirements of the domestic and international legislation. The method adapts to confirm the residues of ethephon, thidiazuron and diuron pesticides in cotton samples.

  18. Microwave-assisted extraction and determination of citrus red 2 dye in oranges and orange juice by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Han, Chao; Liu, Bin; Zhu, Zhenou; Huang, Fuzhen; Chen, Xiangzhun; Shen, Yan

    2012-12-01

    A fast, simple, low cost, and high-throughput method has been developed for the determination of citrus red 2 dye in orange and orange juice samples. The procedure is based on microwave-assisted extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The method was optimized, and the analyte was efficiently extracted from the samples in 30 min using hexane/acetone (v/v, 3 : 1). The method was validated and showed good linearity and selectivity. The limits of quantification (LOQs) were 5 μg/kg (sample size of 2 g) for both orange and orange juice samples. The average recoveries, measured at 3 concentration levels (5, 10, and 20 μg/kg), were in the range 77.5% to 87.6% for the compound tested with relative standard deviations below 7.3%. The proposed method is rapid, accurate, and could be utilized for the routine analysis of citrus red 2 dye in orange and orange juice samples. © 2012 Institute of Food Technologists®

  19. [Determination of linuron and its metabolite 3,4-dichloroaniline residues in meat and meat products using liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Guo, Dehua; Yi, Xionghai; Qu, Li

    2011-10-01

    A method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of linuron and its metabolite 3, 4-dichloroaniline residues in pork, liver, kidney, casings, canned steam pork and sausage. The sample was extracted with a mixture of acetone-acetonitrile (5: 95, v/v). Most of the lipids in the extract were eliminated by freezing-lipid filtration. After Florisil solid phase extraction cleanup, the linuron and its metabolite residues were determined by LC-MS/MS, and quantified by internal standard meth-od. In the range of 1 - 500 microg/L, both linuron and 3,4-dichloroaniline showed good linearity with the correlation coefficients (r) more than 0. 998. The limit of quantification (S/N > 10) was 10 microg/kg, and the limit of detection (S/N > 3) was 5 microg/kg for each analyte. The recoveries of linuron and 3,4-dichloroaniline in meat and meat products at three spiked levels were in the ranges of 88.3% - 101.2% and 91.6% - 101. 6%, and the relative standard deviations were in the ranges of 4. 8% - 13. 7% and 4. 7% - 11. 8%, respectively. The results demonstrated that the proposed method can meet the requirements for the determination of linuron and 3,4-dichloroaniline in meat and meat products.

  20. Simultaneous determination of three Curcuminoids in Curcuma wenyujin Y.H.chen et C.Ling. by liquid chromatography-tandem mass spectrometry combined with pressurized liquid extraction.

    Science.gov (United States)

    Shen, Yan; Han, Chao; Chen, Xiangzhun; Hou, Xiandeng; Long, Zhou

    2013-01-01

    A sensitive and efficient method based on pressurized liquid extraction (PLE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for simultaneous identification and quantification of three Curcuminoids in Curcuma wenyujin Y.H.chen et C.Ling., a well known traditional Chinese medicinal herb. PLE was performed using methanol as the extractant, and with the temperature set at 100 °C and the pressure at 1500 psi. Shorter extraction time and less solvent consumption were obtained compared to other extraction methods. LC was performed by using a Waters XBridge C18 column (150 mm × 2.1 mm i.d., 3.5 μm) and a mobile phase of acetonitrile containing 0.1% acetic acid. The operating parameters were thoroughly optimized. The recoveries ranged from 92.4% to 104.1% and relative standard deviations were lower than 3.6%. The method was applied to the determination of Curcumin, Demethoxycurcumin and Bisdemethoxycurcumin contained in Curcuma wenyujin Y.H.chen et C.Ling. samples, which provided a new analytical approach for analysis and quality assessment of traditional Chinese medicines. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Absolute quantification of Pru av 2 in sweet cherry fruit by liquid chromatography/tandem mass spectrometry with the use of a stable isotope-labelled peptide.

    Science.gov (United States)

    Ippoushi, Katsunari; Sasanuma, Motoe; Oike, Hideaki; Kobori, Masuko; Maeda-Yamamoto, Mari

    2016-08-01

    Pru av 2, a pathogenesis-related (PR) protein present in the sweet cherry (Prunus avium L.) fruit, is the principal allergen of cherry and one of the chief causes of pollen food syndrome (oral allergy syndrome). In this study, a quantitative assay for this protein was developed with the use of the protein absolute quantification (AQUA) method, which consists of liquid chromatography/tandem mass spectrometry (LC/MS/MS) employing TGC[CAM]STDASGK[(13)C6,(15)N2], a stable isotope-labelled internal standard (SIIS) peptide. This assay gave a linear relationship (r(2)>0.99) in a concentration range (2.3-600fmol/μL), and the overall coefficient of variation (CV) for multiple tests was 14.6%. Thus, the contents of this allergenic protein in sweet cherry products could be determined using this assay. This assay should be valuable for allergological investigations of Pru av 2 in sweet cherry and detection of protein contamination in foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Microwave-assisted extraction and determination of cyanuric acid residue in pet food samples by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Han, Chao; Zhou, Yongfang; Xia, Biqi; Zhu, Zhenou; Liu, Cuiping; Shen, Yan

    2011-02-01

    Cyanuric acid (CYA) is attracting more attention due to its potential toxicity. In the present work, microwave-assisted extraction method in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was proposed for the determination of CYA in pet food samples. Among different solvents, diethylamine-acetonitrile-water mixture (1:5:4, v/v) was found to be the best one as the extractant due to the strong polarity of CYA in the pet food. An internal standard, (13) C(3) -labeled CYA, was used in the extractions. The separation was performed on a MERCK ZIC HILIC column (150 mm × 2.1 mm id, 5 μm) with gradient elution of 20 mM ammonium acetate solution-acetonitrile. CYA was well retained (Rt = 5.10 min) and eluted with good peak shape. The method could respond linearly with CYA at concentrations from 1.0 to 50 ng/mL with a quantification limit of 0.25 mg/kg. The intra- and inter-day precision was less than 4.0% and the recovery of the assay was in the range of 90.4-108.1%. In the analysis of practical spiked pet food samples, the new method yielded satisfactory results. Due to its simplicity and accuracy the straightforward method is particularly suitable for routine CYA detection. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Dispersive Liquid-Liquid Microextraction Combined with Ultrahigh Performance Liquid Chromatography/Tandem Mass Spectrometry for Determination of Organophosphate Esters in Aqueous Samples

    Directory of Open Access Journals (Sweden)

    Haiying Luo

    2014-01-01

    Full Text Available A new technique was established to identify eight organophosphate esters (OPEs in this work. It utilised dispersive liquid-liquid microextraction in combination with ultrahigh performance liquid chromatography/tandem mass spectrometry. The type and volume of extraction solvents, dispersion agent, and amount of NaCl were optimized. The target analytes were detected in the range of 1.0–200 µg/L with correlation coefficients ranging from 0.9982 to 0.9998, and the detection limits of the analytes were ranged from 0.02 to 0.07 µg/L (S/N=3. The feasibility of this method was demonstrated by identifying OPEs in aqueous samples that exhibited spiked recoveries, which ranged between 48.7% and 58.3% for triethyl phosphate (TEP as well as between 85.9% and 113% for the other OPEs. The precision was ranged from 3.2% to 9.3% (n=6, and the interprecision was ranged from 2.6% to 12.3% (n=5. Only 2 of the 12 selected samples were tested to be positive for OPEs, and the total concentrations of OPEs in them were 1.1 and 1.6 µg/L, respectively. This method was confirmed to be simple, fast, and accurate for identifying OPEs in aqueous samples.

  4. Evaluation of different hydrophilic stationary phases for the simultaneous determination of iminosugars and other low molecular weight carbohydrates in vegetable extracts by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Rodríguez-Sánchez, S; Quintanilla-López, J E; Soria, A C; Sanz, M L

    2014-11-01

    Iminosugars are considered potential drug candidates for the treatment of several diseases, mainly as a result of their α-glycosidase inhibition properties. A method by hydrophilic interaction liquid chromatography tandem mass spectrometry has been optimized for the first time for the simultaneous determination of complex mixtures of bioactive iminosugars and other low molecular weight carbohydrates (LMWC) in vegetable extracts. Three hydrophilic stationary phases (sulfoalkylbetaine zwitterionic, polyhydroxyethyl aspartamide and ethylene bridge hybrid (BEH) with trifunctionally bonded amide) were compared under both basic and acidic conditions. The best sensitivity (limits of detection between 0.025 and 0.28ngmL -1 ) and overall chromatographic performance in terms of resolution, peak width and analysis time were obtained with the BEH amide column using 0.1% ammonium hydroxide as a mobile phase additive. The optimized method was applied to the analysis of extracts of hyacinth bulbs, buckwheat seeds and mulberry leaves. Iminosugar and other LMWC structures were tentatively assigned by their high resolution daughter ions mass spectra. Several iminosugars such as glycosyl-fagomine in mulberry extract were also described for the first time. Among the extracts analysed, mulberry showed the widest diversity of iminosugars, whereas the highest content of them was found in hyacinth bulb (2.5mgg -1 ) followed by mulberry (1.95 mgg -1 ). Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Simultaneous Determination of 13 Anticoagulant Rodenticidesin Human Blood by Liquid Chromatography-Tandem Mass Spectrometry and its Application in Three Poisoning Cases.

    Science.gov (United States)

    Qiao, Zheng; Xiang, Ping; Shen, Baohua; Shen, Min; Yan, Hui

    2018-05-01

    Anticoagulant rodenticides are widely used for rodent control around the world. A rapid and sensitive method was developed and validated for the simultaneous determination of 13 anticoagulant rodenticides (coumafuryl, pindone, valone, warfarin, coumatetralyl, coumachlor, diphacinone, dicumarol, chlorophacinone, bromadiolone, difenacoum, flocoumafen, and brodifacoum) in human blood by liquid chromatography-tandem mass spectrometry. After liquid-liquid extraction, the anticoagulant rodenticides were separated on an Eclipse Plus C18 column. Linearities were observed for each analyte in blood ranging from 0.5 to 50 ng/mL, with correlation coefficients over 0.99. The limits of detection ranged from 0.01 to 0.2 ng/mL, and the limits of quantification were 0.5 ng/mL for all analytes. The intraday and interday precisions were <15%, and accuracies ranged from 80.3% to 111.0%. This validated method with high sensitivity has been applied in three anticoagulant rodenticide poisoning cases and has been used successfully in monitoring blood concentrations for months. © 2017 American Academy of Forensic Sciences.

  6. Ultra-performance liquid chromatography-tandem mass spectrometry-based multiplex enzyme assay for six enzymes associated with hereditary hemolytic anemia.

    Science.gov (United States)

    Park, Chul Min; Lee, Kyunghoon; Jun, Sun-Hee; Song, Sang Hoon; Song, Junghan

    2017-08-15

    Deficiencies in erythrocyte metabolic enzymes are associated with hereditary hemolytic anemia. Here, we report the development of a novel multiplex enzyme assay for six major enzymes, namely glucose-6-phosphate dehydrogenase, pyruvate kinase, pyrimidine 5'-nucleotidase, hexokinase, triosephosphate isomerase, and adenosine deaminase, deficiencies in which are implicated in erythrocyte enzymopathies. To overcome the drawbacks of traditional spectrophotometric enzyme assays, the present assay was based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The products of the six enzymes were directly measured by using ion pairing UPLC-MS/MS, and the precision, linearity, ion suppression, optimal sample amounts, and incubation times were evaluated. Eighty-three normal individuals and 13 patients with suspected enzymopathy were analyzed. The UPLC running time was within 5min. No ion suppression was observed at the retention time for the products or internal standards. We selected an optimal dilution factor and incubation time for each enzyme system. The intra- and inter-assay imprecision values (CVs) were 2.5-12.1% and 2.9-14.3%, respectively. The linearity of each system was good, with R 2 values >0.97. Patient samples showed consistently lower enzyme activities than those from normal individuals. The present ion paring UPLC-MS/MS assay enables facile and reproducible multiplex evaluation of the activity of enzymes implicated in enzymopathy-associated hemolytic anemia. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Online turbulent flow extraction coupled with liquid chromatography-tandem mass spectrometry for high throughput screening of anabolic steroids in horse urine.

    Science.gov (United States)

    Shin, Hyun Du; Suh, Joon Hyuk; Kim, Junghyun; Cho, Hyun-Deok; Lee, Su Duk; Han, Kwan Seok; Wang, Yu; Han, Sang Beom

    2017-10-25

    A high throughput method for simultaneous screening of anabolic steroids and their metabolites (4-esterendione, trenbolone, boldenone, oxandrolone, nandrolone, methandrostenolone, testosterone, 1-androstendione, ethisterone, normethandrolone, methyltestosterone, 16β-Hydroxystanozolol, epitestosterone, bolasterone, norethandrolone, danazol, stanozolol and androstadienone) in equine urine by online turbulent flow extraction coupled with liquid chromatography-tandem mass spectrometry was developed. The use of turbulent flow chromatography could simplify pretreatment of horse urine, which has complex matrices as well as high viscosity. The urine was extracted by mixed-mode cation exchange solid phase extraction, and hydrolyzed using β-glucuronidase/arylsulfatase. Then, the sample was automatically loaded on the TurboFlow Cyclone extraction column for removal of further matrix, followed by separation on a fused core C18 column before MS/MS detection. Optimization and validation of the method were discussed in detail. All analytes were rapidly detected within 10min with high sensitivity (picogram to nanogram per milliliter level), and no interference was observed. The linearity range was from 0.1-10ng/mL for nine steroids and 1.0-50ng/mL for the others, with correlation of coefficient values over 0.995. Precision and accuracy ranged from 0.1 to 14.5% and 1.7 to 12.4%, respectively. The developed method was successfully applied to the analysis of anabolic steroids in horse urine after administration of a model drug. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Ultra-high performance liquid chromatography-tandem mass spectrometry in high-throughput confirmation and quantification of 34 anabolic steroids in bovine muscle.

    Science.gov (United States)

    Vanhaecke, Lynn; Vanden Bussche, Julie; Wille, Klaas; Bekaert, Karen; De Brabander, Hubert F

    2011-08-26

    An ultra-high performance liquid chromatography tandem mass spectrometry multi-residue method for the determination of 34 anabolic steroids (10 estrogens including stilbenes, 14 androgens and 10 gestagens) in meat of bovine origin is reported. The extraction and clean-up procedure involved homogenization with methanol, defatting with hexane, liquid/liquid extraction with diethylether and finally SPE clean-up with coupled Si and NH(2) cartridges. The analytes were separated on a 1.9 μm Hypersil Gold column (100×2.1 mm) and quantified on a triple quadrupole mass spectrometer (TSQ Vantage) operating simultaneously in both positive and negative atmospheric pressure chemical ionisation (APCI) modes. This analytical procedure was subsequently validated according to EU criteria (CD 2002/657/EC), resulting in decision limits and detection capabilities ranging between 0.04 and 0.88 μg kg(-1) and 0.12 and 1.9 μg kg(-1), respectively. The method obtained for all, natural and synthetic steroids, adequate precisions and intra-laboratory reproducibilities (relative standard deviation below 20%), and the linearity ranged between 0.991 and 0.999. The performance characteristics fulfill the recommended concentrations fixed by the Community Reference Laboratories. The developed analysis is sensitive, and robust and therefore useful for confirmation and quantification of anabolic steroids for research purposes and residue control programs. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. Investigation of the effect of plasma albumin levels on regorafenib-induced hepatotoxicity using a validated liquid chromatography-tandem mass spectrometry method.

    Science.gov (United States)

    Pang, Yi Yun; Tan, Yeong Lan; Ho, Han Kiat

    2017-09-01

    Regorafenib is an oral multikinase inhibitor indicated for metastatic colorectal cancer and gastrointestinal stromal tumour. Due to its extensive plasma protein binding and low calculated hepatic extraction ratio, the hepatotoxicity observed with usage of the drug may be related to its plasma exposure. To investigate the highly dynamic free:bound drug concentration for regorafenib in the plasma, a bioanalytical liquid chromatography-tandem mass spectrometric assay was developed and validated in human plasma. The concentration range of the assay was 2-1000ng/mL. Sample preparation was via protein precipitation using acetonitrile with sorafenib as the internal standard. The supernatant was injected into an ultra-performance liquid chromatographic system coupled to a triple quadrupole mass spectrometer. The analytes were separated on an AQUITY UPLC BEH C 18 column (120Å, 1.7μm, 2.1mm×50mm) and eluted with a gradient elution system. The ions were detected in multiple reaction monitoring mode. The linearity, lower limit of quantification, intra-day and inter-day precision and accuracy conformed to FDA guidelines. The validated method was successfully applied to determine the effect of albumin levels in plasma on the extent of protein binding of regorafenib. The results indicated that physiologically-relevant levels of albumin were found to have no significant effect on the extent of protein binding of regorafenib, hence imposing minimal effect on drug disposition. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Determination of Fusarium toxins in functional vegetable milks applying salting-out-assisted liquid-liquid extraction combined with ultra-high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Hamed, Ahmed M; Arroyo-Manzanares, Natalia; García-Campaña, Ana M; Gámiz-Gracia, Laura

    2017-11-01

    Vegetable milks are considered as functional foods due to their physiological benefits. Although the consumption of these products has significantly increased, they have received little attention in legislation with regard to contaminants. However, they may contain mycotoxins resulting from the use of contaminated raw materials. In this work, ultra-high-performance liquid chromatography tandem mass spectrometry has been proposed for the determination of the most relevant Fusarium toxins (fumonisin B 1 and B 2 , HT-2 and T-2 toxins, zearalenone, deoxynivalenol and fusarenon-X) in different functional beverages based on cereals, legumes and seeds. Sample treatment consisted of a simple salting-out-assisted liquid-liquid extraction with no further clean-up. The method provided limits of quantification between 3.2 and 57.7 µg L -1 , recoveries above 80% and precision with RSD lower than 12%. The method was also applied for studying the occurrence of these mycotoxins in market samples of vegetable functional beverages and deoxynivalenol was found in three oat-based commercial drinks.

  11. Development of liquid chromatography-tandem mass spectrometry method for analysis of polyphenolic compounds in liquid samples of grape juice, green tea and coffee.

    Science.gov (United States)

    Sapozhnikova, Yelena

    2014-05-01

    A simple and fast method for the analysis of a wide range of polyphenolic compounds in juice, tea, and coffee samples was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was based on a simple sample preparation "dilute and shoot" approach, and LC-MS/MS quantification using genistein-d4 as an internal standard. The performance of six different syringeless filter devices was tested for sample preparation. The method was evaluated for recoveries of polyphenols at three spiking levels in juice, tea, and coffee samples. The recoveries of the majority of polyphenols were satisfactory (70-120%), but some varied significantly (20-138%) depending on the matrix. NIST Standard Reference Materials (SRM) 3257 Catechin Calibration Solutions and 3255 Camellia sinensis (Green Tea) Extract with certified concentrations of catechin and epicatechin were used for method validation. The measurement accuracy in two SRMs was 71-113%. The method was successfully applied to the analysis of liquid samples of grape juice, green tea, and coffee. Published by Elsevier Ltd.

  12. Accurate Determination of Amino Acids in Serum Samples by Liquid Chromatography-Tandem Mass Spectrometry Using a Stable Isotope Labeling Strategy.

    Science.gov (United States)

    Song, Cuihua; Zhang, Shijuan; Ji, Zhongyin; Li, Yipeng; You, Jinmao

    2015-10-01

    An accurate and sensitive liquid chromatography-tandem mass spectrometry method was developed for the analysis of amino acids (isoleucine, leucine, valine, tyrosine, phenylalanine and tryptophan) in serum samples using a stable isotope labeling strategy. Amino acid samples and standards were, respectively, derivatized by 10-methyl-acridone-2-sulfonyl chloride (d0-MASC) and its deuterated counterpart d3-MASC to form isotopic pairs which co-eluted and were detected by an MS detector at the same time. Accurate internal standard-based quantification was thereby achieved without the use of any internal standard analogy. The labeling reaction of MASC with amino acids is fast, simple and robust. Besides, derivatization increased the molecular weight of amino acids, and therefore they were shifted out of the background noise which was often observed in low mass region. The instrument LODs were in the range of 1.0-2.5 nmol/L. Linearities calculated by comparing theoretical peak area ratios of d0-/d3-MASC derivatives with the experimental peak area ratios were excellent with correlation coefficients of >0.995. The proposed method was successfully applied to the analysis of amino acids in serum samples with high sensitivity and accuracy. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Rapid and precise measurement of serum branched-chain and aromatic amino acids by isotope dilution liquid chromatography tandem mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Ruiyue Yang

    Full Text Available BACKGROUND: Serum branched-chain and aromatic amino acids (BCAAs and AAAs have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. METHODS: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standards and the amino acids were extracted with acetonitrile, followed by analysis using LC/MS/MS. The LC separation was performed on a reversed-phase C18 column, and the MS/MS detection was performed via the positive electronic spray ionization in multiple reaction monitoring mode. RESULTS: Specific analysis of the amino acids was achieved within 2 min. Intra-run and total CVs for the amino acids were less than 2% and 4%, respectively, and the analytical recoveries ranged from 99.6 to 103.6%. CONCLUSION: A rapid and precise method for the measurement of serum BCAAs and AAAs was developed and may serve as a quick tool for screening serum BCAAs and AAAs in studies assessing diabetes risk.

  14. Method validation in quantitative analysis of phase I and phase II metabolites of mitragynine in human urine using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lee, Mei Jin; Ramanathan, Surash; Mansor, Sharif Mahsufi; Yeong, Keng Yoon; Tan, Soo Choon

    2018-02-15

    A method using solid phase extraction and liquid chromatography-tandem mass spectrometry to quantitatively detect mitragynine, 16-carboxy mitragynine, and 9-O-demethyl mitragynine in human urine samples was developed and validated. The relevant metabolites were identified using multiple reaction monitoring in positive ionization mode using nalorphine as an internal standard. The method was validated for accuracy, precision, recovery, linearity, and lower limit of quantitation. The intra- and inter-day accuracy and precision were found in the range of 83.6-117.5% with coefficient of variation less than 13%. The percentage of recovery for mitragynine, 16-carboxy mitragynine, and 9-O-demethyl mitragynine was within the range of 80.1-118.9%. The lower limit of quantification was 1 ng/mL for mitragynine, 2 ng/mL for 16-carboxy mitragynine, and 50 ng/mL for 9-O-demethyl mitragynine. The developed method was reproducible, high precision and accuracy with good linearity and recovery for mitragynine, 16-carboxy mitragynine, and 9-O-demethyl mitragynine in human urine. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. A serum and platelet-rich plasma serotonin assay using liquid chromatography tandem mass spectrometry for monitoring of neuroendocrine tumor patients.

    Science.gov (United States)

    Korse, Catharina M; Buning-Kager, Johanna C G M; Linders, Theodora C; Heijboer, Annemieke C; van den Broek, Daan; Tesselaar, Margot E T; van Tellingen, Olaf; van Rossum, Huub H

    2017-06-01

    Serotonin is used for the diagnosis and follow-up of neuroendocrine tumors (NET). We describe the analytical and clinical validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) based serotonin assay for serum and platelet-rich plasma (PRP). An LC-MS/MS based method for serum and PRP serotonin was validated by determination of assay imprecision, carry-over, linearity, interference, recovery, sample stability and a matrix/method comparison of serum and PRP serotonin was made with whole blood serotonin. Furthermore, upper limits of normal were determined and serotonin concentrations of healthy individuals, 14 NET patients without evidence of disease and 51 NET patients with evidence of disease were compared. For serum and PRP fractions, total assay imprecision was serotonin upper limit of normal were 5.5nmol/10 9 platelet and 5.1nmol/10 9 platelet, respectively. NET patients with confirmed evidence of disease had significantly higher serum and PRP serotonin levels when compared to NET patients without evidence of disease and healthy volunteers. LC-MS/MS based serum and PRP serotonin assays were developed with suitable analytical characteristics. Furthermore, serum and PRP serotonin was found to be useful for monitoring NET patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Determination of Ochratoxin A contamination in grapes, processed grape products and animal-derived products using ultra-performance liquid chromatography-tandem mass spectroscopy system.

    Science.gov (United States)

    Wei, Dongmei; Wu, Xiaohu; Xu, Jun; Dong, Fengshou; Liu, Xingang; Zheng, Yongquan; Ji, Mingshan

    2018-02-01

    We developed a sensitive and rapid analytical method to determine the level of Ochratoxin A contamination in grapes, processed grape products and in foods of animal origin (a total of 11 different food matrices). A pretreatment that followed a "quick, easy, cheap, effective, rugged, and safe" protocol was optimized to extract Ochratoxin A from the matrices, and the extracted Ochratoxin A was then detected with the use of a highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry system. Good linearities of Ochratoxin A were obtained in the range of 0.1-500 µg L -1 (correlation coefficient (R 2 ) > 0.9994 in each case). Mean recovery from the 11 matrices ranged from 70.3 to 114.7%, with a relative standard deviation ≤19.2%. The method is easy to use and yields reliable results for routine determination of Ochratoxin A in food products of grape and animal origin. In store-purchased foods and foods obtained from the field and wholesale suppliers, the Ochratoxin A concentration ranged from undetectable to 10.14 µg kg -1 , with the more contaminated samples being mainly those of processed grape products. Our results indicate that the necessity for regulation of and supervision during the processing of grape products.

  17. Simultaneous determination of fifteen illegal dyes in animal feeds and poultry products by ultra-high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Liu, Rongyuan; Hei, Wenjing; He, Pingli; Li, Zhen

    2011-08-15

    With the increasing presence of illegal dyes, such as sudan reds and malachite green, in animal feeds and food products during the last few years, there is an urgent need of accurate quantitative determination methods for these illicit compounds. Here we established an accurate method for the simultaneous determination of 15 illegal dyes in animal feeds, meat, eggs and other food products using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The samples were extracted with a simple procedure using acetonitrile and solid phase extraction cleaning up. The application of C(18) rapid column can achieve satisfactory separation of the 15 dyes within 16 min; and multiple reaction monitoring of positive ions ensure confirmative detection of these illegal dyes. With the developed method, a sample can be analyzed in less than 2h. Dyes spiked in feeds, poultry meat and eggs in the range of 0.1-5.0 mg kg(-1) were tested in terms of linearity, sensitivity, repeatability and recovery. Recoveries for the compounds ranged from 60 to 140%. Intra- and inter-day precisions (RSDs) were less than 15%. Limit of quantification ranged from 0.01 to 5.61 μg kg(-1) for different dyes. The developed UHPLC-MS/MS method could be used as a qualitative and quantitative technique for the simultaneous determination of illegal dyes in animal feeds and poultry products. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. A simple and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry method to determine plasma biotin in hemodialysis patients.

    Science.gov (United States)

    Yagi, Shigeaki; Nishizawa, Manabu; Ando, Itiro; Oguma, Shiro; Sato, Emiko; Imai, Yutaka; Fujiwara, Masako

    2016-08-01

    A simple, rapid, and selective method for determination of plasma biotin was developed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). After single-step protein precipitation with methanol, biotin and stable isotope-labeled biotin as an internal standard (IS) were chromatographed on a pentafluorophenyl stationary-phase column (2.1 × 100 mm, 2.7 μm) under isocratic conditions using 10 mm ammonium formate-acetonitrile (93:7, v/v) at a flow rate of 0.6 mL/min. The total chromatographic runtime was 5 min for each injection. Detection was performed in a positive electrospray ionization mode by monitoring selected ion transitions at m/z 245.1/227.0 and 249.1/231.0 for biotin and the IS, respectively. The calibration curve was linear in the range of 0.05-2 ng/mL using 300 μL of plasma. The intra- and inter-day precisions were all biotin concentrations in hemodialysis patients. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry Measurement of Caffeine in Caffeine-Laced Pants and in Urine and Skin of a Pants User

    Directory of Open Access Journals (Sweden)

    Manuela Pellegrini

    2014-04-01

    Full Text Available A fast and sensitive ultra-performance liquid chromatography tandem mass spectrometry method was developed for the measurement of caffeine in caffeine-laced pants and in urine and skin of a pants user. The substance and its internal standard (N-ethylnorcotinine were separated by reversed phase chromatography with 5 mM ammonium formate pH 3.0 and 0.3% formic acid in acetonitrile mobile phase (83:17 v/v by isocratic elution and detected by tandem mass spectrometry operated in multiple reaction monitoring mode via positive electrospray ionization. Linearity was studied from 1.4 to100 ng/mL range for urine, from 5 to 100 ng/cotton swab for skin caffeine and from 1.3 to 100 µg/samples for 4 cm2 textile samples. Good determination coefficients (r2 = 0.99 were found in all cases. At three concentrations spanning the linear dynamic ranges of different samples mean recoveries of caffeine were always higher than 80% and intra-assay and inter-assay imprecision and inaccuracy were always better than 105%. For the first time, caffeine content in this cosmetotextile was determined together with the measurement of caffeine released on the user skin, the absorbed amount with resulting urinary concentrations.

  20. Rapid determination of 12 antibiotics and caffeine in sewage and bioreactor effluent by online column-switching liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Lima Gomes, Paulo C F; Tomita, Inês N; Santos-Neto, Álvaro J; Zaiat, Marcelo

    2015-11-01

    This study presents a column-switching solid-phase extraction online-coupled to a liquid chromatography/tandem mass spectrometry (SPE-LC-MS/MS) method for simultaneous analysis of 12 antibiotics (7 sulfonamides and 5 fluoroquinolones) and caffeine detected in the sewage and effluent of a pilot anaerobic reactor used in sewage treatment. After acidification and filtration, the samples were directly injected into a simple and conventional LC system. Backflush and foreflush modes were compared based on the theoretical plates and peak asymmetry observed. The method was tested in terms of detection (MDL) and quantification limit (MQL), linearity, relative recovery, and precision intra- and inter-day in lab-made sewage samples. The method presented suitable figures of merit in terms of detection, varying from 8.00 × 10(-5) to 6.00 × 10(-2) ng (0.800 up to 600 ng L(-1); caffeine) with direct injection volume of only 100 μL and 13 min of total analysis time (sample preparation and chromatographic run). When the method was applied in the analysis of sewage and effluent of the anaerobic reactor (n = 15), six antibiotics and caffeine were detected in concentrations ranging from 0.018 to 1097 μg L(-1). To guarantee a reliable quantification, standard addition was used to overcome the matrix effect.

  1. Simultaneous analysis of eight phenolic environmental estrogens in blood using dispersive micro-solid-phase extraction combined with ultra fast liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhao, Yong-Gang; Chen, Xiao-Hong; Pan, Sheng-Dong; Zhu, Hao; Shen, Hao-Yu; Jin, Mi-Cong

    2013-10-15

    A novel, simple and sensitive method was developed for the simultaneous determination of eight phenolic environmental estrogens in blood by using the dispersive micro-solid-phase extraction (d-µ-SPE) procedure combined with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS). The excellent nanomaterials tetraethylenepentamine-functionalized magnetic polymer was used as an adsorbent, and the main factors affecting the extraction efficiency were investigated in detail. All target compounds showed good linearities in the tested range with correlation coefficients (r) higher than 0.999. The mean recoveries were in the range of 85.0-105.0%. The intra-day and inter-day relative standard deviations (RSDs) were lower than 4.9% and 5.2%, respectively. The limits of quantification for the eight phenolic environmental estrogens were between 0.075 and 0.42 µg L(-1). The developed method can be applied to the routine analyses for the determination of the eight phenolic environmental estrogens in blood samples. Crown Copyright © 2013 Published by Elsevier B.V. All rights reserved.

  2. Evaluating misoprostol content in pregnant women with hourly oral administration during labor induction by microElution solid phase extraction combined with liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Hung, Cheng-Han; Cheng, Shi-Yann; Chan, Tzu-Min; Lee, Maw-Rong

    2015-09-01

    Misoprostol is a widely used alternative of prostaglandin for labor induction. Based on previous studies, we envision that small and frequent oral dosage of misoprostol is an effective method for labor induction. To monitor the misoprostol content during labor induction, a rapid, sensitive, and selective microElution solid phase extraction (μElution SPE) combined with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed. Using μElution SPE could minimize the sample consumption and elution volume in order to maximize the sample enrichment and throughput. The misoprostol acid, a metabolite of misoprostol, was gradient separated in a Bidentate C18 column, then quantified by highly-selective reaction monitoring (H-SRM) in a total run time of 6min. The developed method was optimized and validated in human plasma, and showed linear range of 0.01-10ng/mL. The limit of detection (LOD) was 0.001ng/mL. The recovery ranged from 89.0 to 96.0%, and no significant matrix effect or carryover was observed. The precision, accuracy and stability were met with the criteria of U.S. FDA guidance. The developed method was successfully applied to evaluate misoprostol concentration during labor induction in pregnant women. The concentration-time profiles approves that hourly oral administration of misoprostol is a safe and effective method without drug accumulation for labor induction. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Evaluation of the New Siemens Tacrolimus Assay on the Dimension EXL Integrated Chemistry System Analyzer: Comparison With an Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry Method.

    Science.gov (United States)

    Bargnoux, Anne-Sophie; Sutra, Thibault; Badiou, Stéphanie; Kuster, Nils; Dupuy, Anne-Marie; Mourad, Georges; Pageaux, Georges-Philippe; Le Quintrec, Moglie; Cristol, Jean-Paul

    2016-12-01

    Many patients are maintained at the lower end of the tacrolimus (TAC) reference range (3-7 ng/mL), requiring the use of analytical methods displaying a very low limit of quantification for their follow-up. Therefore, the new Dimension TAC, based on affinity chrome-mediated immunoassay technology, was evaluated on the Dimension EXL Integrated Chemistry System (Siemens Healthcare Diagnostics Inc). The aims of this study were (1) to evaluate the analytical performances with special emphasis on sensibility at low levels of TAC, (2) to compare the results with an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) method. Analytical performance (imprecision, linearity, limit of detection, and limit of quantification) was evaluated. Comparison to UPLC/MS/MS was performed on 106 whole blood samples from 88 transplant recipients using regression analysis and Bland-Altman plot analysis. Repeatability and within-laboratory coefficients of variation were Siemens TAC assay in comparison with UPLC/MS/MS values displayed a slope of 1.09 and an intercept of -0.42. Using Bland-Altman analysis, the mean bias was 0.27 ng/mL with 1.96 SD limits of -2.14 and 2.67 ng/mL. The new Dimension TAC immunoassay on the EXL analyzer demonstrated reliable and reproducible performances allowing routine monitoring in transplant patients, even at TAC concentrations at the lower end of the therapeutic range.

  4. Performance evaluation of Siemens ADVIA Centaur enhanced estradiol assay and a split sample comparison with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Chen, Yu; Kinney, Lois; Soldin, Steven J

    2012-07-01

    The objective of this study was to evaluate the newly developed Siemens ADVIA Centaur enhanced Estradiol (eE2) assay and compare it with a well-established estradiol liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The Siemens eE2 assay was evaluated using the Clinical and Laboratory Standards Institute evaluation protocols. Split patient samples were compared with the eE2 assay, the current ADVIA Centaur E2-6 Ill assay; and LC-MS/MS method by API5000 mass spectrometer. Within-run and total imprecision of the eE2 assay demonstrated coefficient of variations of 5.7%, 3.2%, 1.5%, and 10.4%, 7.3%, and 6.8%, at levels of 380, 752, and 2051 pmol/L, respectively. The method comparisons showed: eE2=0.903(E2-6 III) -16.2, R(2)=0.938, average bias=-12.3%; and eE2=0.946(LC-MS/MS)+19.5, R(2)=0.925, average bias: 0%. The Siemens eE2 assay correlates well with LC-MS/MS. This method is reliable, and appropriate for routine clinical laboratory use. Copyright © 2012 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  5. Confirmation of sulfamethazine, sulfathiazole, and sulfadimethoxine residues in condensed milk and soft-cheese products by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Clark, Susan B; Turnipseed, Sherri B; Madson, Mark R; Hurlbut, Jeffrey A; Kuck, Laura R; Sofos, John N

    2005-01-01

    A liquid chromatography/tandem mass spectrometry method (LC/MS/MS) is described for the simultaneous detection of 3 sulfonamide drug residues at 1.25 ppb in condensed milk and soft-cheese products. The 3 sulfonamide drugs of interest are sulfathiazole (STZ), sulfamethazine (SMZ), and sulfadimethoxine (SDM). The method includes extraction of the product with phosphate buffer, centrifugation of the diluted product, and application of a portion of the extract onto a polymeric solid-phase extraction cartridge. The cartridge is washed with water, and the sulfonamides are eluted with methanol. After evaporation, the residue is dissolved in 0.1% formic acid solution, and the solution is filtered before analysis by LC/MS/MS. The LC/MS/MS program involved a series of time-scheduled selected-reaction monitoring transitions. The transitions of MH+ to the common product ions at m/z 156, 108, and 92 were monitored for each residue. In addition, SMZ and SDM had a fourth significant and unique product ion transition that could be measured. Validation was performed with control and fortified-control condensed bovine milk with 2.5, 5, and 10 ppb sulfonamides. This method was applied to imported flavored and unflavored condensed milk and cream cheese bars. The presence of STZ and SMZ residues was confirmed in 3 out of 6 products.

  6. Simultaneous determination of irbesartan and hydrochlorothiazide in human plasma by ultra high performance liquid chromatography tandem mass spectrometry and its application to a bioequivalence study.

    Science.gov (United States)

    Qiu, Xiangjun; Wang, Zhe; Wang, Bing; Zhan, Hui; Pan, Xiaofeng; Xu, Ren-ai

    2014-04-15

    An ultra high performance liquid chromatography tandem mass spectrometry (U-HPLC-MS/MS) method was developed and validated to determine irbesartan (IRB) and hydrochlorothiazide (HCTZ) in human plasma simultaneously. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard losartan were separated on an Acquity U-HPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the negative ion mode. The MRM transitions of m/z 427.2→206.9 and m/z 296.1→204.9 were used to quantify for IRB and HCTZ, respectively. The linearity of this method was found to be within the concentration range of 5-3000ng/mL for IRB, and 0.5-300ng/mL for HCTZ in human plasma, respectively. The lower limit of quantification (LLOQ) was 5ng/mL and 0.5ng/mL for IRB and HCTZ in human plasma, respectively. The relative standard deviations (RSD) of intra and inter precision were less than 12% for both IRB and HCTZ. The analysis time of per sample was 2.5min. The developed and validated method was successfully applied to a bioequivalence study of IRB (300mg) with HCTZ (12.5mg) tablet in Chinese healthy volunteers (N=20). Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Determination of endogenous inflammation-related lipid mediators in ischemic stroke rats using background subtracting calibration curves by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yang, Yang; Zhong, Qisheng; Mo, Canlong; Zhang, Hao; Zhou, Ting; Tan, Wen

    2017-11-01

    Accurate and reliable quantification of endogenous lipid mediators in complex biological samples is a daunting challenge. In this study, a robust and direct endogenous quantitative method using background subtracting calibration curves by liquid chromatography-tandem mass spectrometry was first developed for the determination of endogenous lipid mediators in ischemic stroke rats. Absolute quantification without surrogate matrix could be achieved by using background subtracting calibration curves, which were corrected and verified from standard curves constructed on original matrix. The recoveries of this method were in the range of 50.3-98.3%, the precision with the relative standard deviation was less than 13.8%, and the accuracy with the relative error was within ± 15.0%. In addition, background subtracting calibration curves were further verified by validation factors ranging from 90.3 to 110.9%. This validated method has been successfully applied to the analysis of seven endogenous inflammation-related lipid mediators in the brain tissues of ischemic stroke rats. The results indicated that prostaglandins as inflammatory factors and some lipid mediators with neuroprotective effects increased apparently (p endogenous compounds in the complex biological samples. Graphical abstract The analysis procedure of determining endogenous inflammation-related lipid mediators using BSCC by LC-MS/MS.

  8. Development of a multi-residue method for fast screening and confirmation of 20 prohibited veterinary drugs in feedstuffs by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Gui-Jun; Fang, Bing-Hu; Liu, Ya-Hong; Wang, Xu-Feng; Xu, Li-Xiao; Zhang, Ya-Ping; He, Li-Min

    2013-10-01

    A simple multiresidue method was developed for detecting and quantifying twenty analytes from 5 classes of prohibited veterinary drugs (β-agonists (9), anabolic hormones (4), quinoxalines (4), tranquilizers (1), cyproheptadine, and clonidine in animal feeds using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach. Feed samples were extracted by ultrasonic-assisted extraction with a mixture of methanol-acetonitrile (50:50, v/v), followed by a cleanup using a dispersive solid-phase extraction with PSA (primary secondary amine). Target compounds were separated and determined by a liquid chromatography tandem quadrupole mass spectrometer operating in positive electrospray ionization mode, using multiple reaction monitoring (MRM). The recoveries of these compounds were between 56.7% and 103% at three spiked levels. The repeatability was lower than 10%, whereas reproducibility was no more than 15% except for nandrolone (17% at 10μgkg(-1)) and diazepam (19% at 10μgkg(-1)). Decision limits (CCαs) and detection capabilities (CCβs) ranged from 0.42 to 5.74μgkg(-1) and 5.70-9.81μgkg(-1), respectively. The method was successfully applied to screening of real samples obtained from local feed markets and confirmation of the suspected target analytes. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Analysis of sulfonamides, tilmicosin and avermectins residues in typical animal matrices with multi-plug filtration cleanup by liquid chromatography-tandem mass spectrometry detection.

    Science.gov (United States)

    Qin, Yuhong; Jatamunua, Freedom; Zhang, Jingru; Li, Yanjie; Han, Yongtao; Zou, Nan; Shan, Jihao; Jiang, Yanbin; Pan, Canping

    2017-05-15

    The frequent use of various veterinary drugs could lead to residue bioaccumulation in animal tissues, which could cause dietary risks to human health. In order to quickly analyze the residues, a liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for detecting Sulfonamides, Tilmicosin and Avermectins (AVMs) residues in animal samples. For sample preparation, modified QuEChERS (quick, easy, cheap, effective, rugged and safe) and ultrasound-assisted extraction (UAE) methods were used. For sample cleanup, n-Hexane delipidation and multi-plug filtration cleanup (m-PFC) method based on primary-secondary amine (PSA) and octadecyl-silica (C18) were used, followed by LC-MS/MS analysis. It was validated on 7 animal matrices (bovine, caprine, swine meat and their kidneys, milk) at two fortified concentration levels of 5 and 100μg/kg. The recoveries ranged from 82 to 107% for all analytes with relative standard deviations (RSDs) less than 15%. Matrix-matched calibrations were performed with coefficients of determination above 0.998 for all analytes within concentration levels of 5-500μg/kg. The developed method was successfully used to analysis veterinary drugs of real animal samples from local markets. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Quantification of Oxidized and Unsaturated Bile Alcohols in Sea Lamprey Tissues by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Ke Li

    2016-08-01

    Full Text Available A sensitive and reliable method was developed and validated for the determination of unsaturated bile alcohols in sea lamprey tissues using liquid-liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS. The liver, kidney, and intestine samples were extracted with acetonitrile and defatted by n-hexane. Gradient UHPLC separation was performed using an Acquity BEH C18 column with a mobile phase of water and methanol containing 20 mM triethylamine. Multiple reaction monitoring modes of precursor-product ion transitions for each analyte was used. This method displayed good linearity, with correlation coefficients greater than 0.99, and was validated. Precision and accuracy (RSD % were in the range of 0.31%–5.28%, while mean recoveries were between 84.3%–96.3%. With this technique, sea lamprey tissue samples were analyzed for unsaturated bile alcohol analytes. This method is practical and particularly suitable for widespread putative pheromone residue analysis.

  11. Evaluation of treadmill exercise effect on muscular lipid profiles of diabetic fatty rats by nanoflow liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Lee, Jong Cheol; Kim, Il Yong; Son, Yeri; Byeon, Seul Kee; Yoon, Dong Hyun; Son, Jun Seok; Song, Han Sol; Song, Wook; Seong, Je Kyung; Moon, Myeong Hee

    2016-07-01

    We compare comprehensive quantitative profiling of lipids at the molecular level from skeletal muscle tissues (gastrocnemius and soleus) of Zucker diabetic fatty rats and Zucker lean control rats during treadmill exercise by nanoflow liquid chromatography-tandem mass spectrometry. Because type II diabetes is caused by decreased insulin sensitivity due to excess lipids accumulated in skeletal muscle tissue, lipidomic analysis of muscle tissues under treadmill exercise can help unveil the mechanism of lipid-associated insulin resistance. In total, 314 lipid species, including phospholipids, sphingolipids, ceramides, diacylglycerols (DAGs), and triacylglycerols (TAGs), were analyzed to examine diabetes-related lipid species and responses to treadmill exercise. Most lysophospholipid levels increased with diabetes. While DAG levels (10 from the gastrocnemius and 13 from the soleus) were >3-fold higher in diabetic rats, levels of most of these decreased after exercise in soleus but not in gastrocnemius. Levels of 5 highly abundant TAGs (52:1 and 54:3 in the gastrocnemius and 48:2, 50:2, and 52:4 in the soleus) displaying 2-fold increases in diabetic rats decreased after exercise in the soleus but not in the gastrocnemius in most cases. Thus, aerobic exercise has a stronger influence on lipid levels in the soleus than in the gastrocnemius in type 2 diabetic rats.

  12. Determination of rivaroxaban in patient's plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS).

    Science.gov (United States)

    Derogis, Priscilla Bento Matos; Sanches, Livia Rentas; de Aranda, Valdir Fernandes; Colombini, Marjorie Paris; Mangueira, Cristóvão Luis Pitangueira; Katz, Marcelo; Faulhaber, Adriana Caschera Leme; Mendes, Claudio Ernesto Albers; Ferreira, Carlos Eduardo Dos Santos; França, Carolina Nunes; Guerra, João Carlos de Campos

    2017-01-01

    Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p HPLC-MS/MS without interferences. The chromogenic and HPLC-MS/MS methods were highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels.

  13. Determination of rivaroxaban in patient’s plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS)

    Science.gov (United States)

    Derogis, Priscilla Bento Matos; Sanches, Livia Rentas; de Aranda, Valdir Fernandes; Colombini, Marjorie Paris; Mangueira, Cristóvão Luis Pitangueira; Katz, Marcelo; Faulhaber, Adriana Caschera Leme; Mendes, Claudio Ernesto Albers; Ferreira, Carlos Eduardo dos Santos; França, Carolina Nunes; Guerra, João Carlos de Campos

    2017-01-01

    Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p HPLC-MS/MS without interferences. The chromogenic and HPLC-MS/MS methods were highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels. PMID:28170419

  14. A validated liquid chromatography tandem mass spectrometry method for quantification of erlotinib, OSI-420 and didesmethyl erlotinib and semi-quantification of erlotinib metabolites in human plasma.

    Science.gov (United States)

    Svedberg, Anna; Gréen, Henrik; Vikström, Anders; Lundeberg, Joakim; Vikingsson, Svante

    2015-03-25

    A liquid chromatography tandem mass spectrometry method was developed and validated for quantification of erlotinib and its metabolites in human plasma. The method is suitable for therapeutic drug monitoring and pharmacokinetic studies. The substances were extracted using protein precipitation, separated on a BEH XBridge C18 column (100 ×2.1 mm, 1.7 μm) by gradient elution at 0.7 mL/min of acetonitrile and 5 mM ammonium acetate. The concentration was determined using a Waters Xevo triple quadrupole mass spectrometer in a multi reaction monitoring mode. The total run time was 7 min. Deuterated erlotinib and OSI-597 were used as internal standard for erlotinib and its metabolites, respectively. Erlotinib, OSI-420 and didesmethyl erlotinib were quantified in the concentration range 25-5000 ng/mL, 0.5-500 ng/mL and 0.15-10 ng/mL, respectively. Precision and accuracy was OSI-420 at LLOQ (17%). Extraction recovery was above 89%, 99% and 89% for erlotinib, OSI-420 and didesmethyl erlotinib, respectively. The human liver microsomes generated 14 metabolites, three of them not previously reported. Twelve metabolites were measured semi-quantitatively and validated with respect to selectivity, precision and stability. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Multi-residue determination of micropollutants in Phragmites australis from constructed wetlands using microwave assisted extraction and ultra-high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Petrie, Bruce; Smith, Benjamin D; Youdan, Jane; Barden, Ruth; Kasprzyk-Hordern, Barbara

    2017-03-22

    In constructed wetlands micropollutants can be removed from water by phytoremediation. However, micropollutant uptake and metabolism by plants here is poorly understood due to the lack of good analytical approaches. Reported herein is the first methodology developed and validated for the multi-residue determination of 81 micropollutants (pharmaceuticals, personal care products and illicit drugs) in the emergent macrophyte Phragmites australis. The method involved extraction by microwave accelerated extraction (MAE), clean-up using off-line solid phase extraction and analysis by ultra-high-performance liquid chromatography tandem mass spectrometry. Development of the MAE method found the influence of studied variables on micropollutant recovery to be: extraction temperature > sample mass > solvent composition. Validation of the developed extraction protocol revealed method recoveries were in the range 80-120% for the majority of micropollutants. Method quantitation limits (MQLs) were generally MQL, up to concentrations of 200 ng g -1 . Other than uptake, the presence of several metabolites (carbamazepine 10,11 epoxide, desvenlafaxine, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, N-desmethyltramadol and norketamine) indicated metabolism within the plant may also occur. This new analytical methodology will enable a process mass balance of the constructed wetland to be attained for the first time, and thus help understand the role of phytoremediation in micropollutant removal by such systems. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  16. Highly informative proteome analysis by combining improved N-terminal sulfonation for de novo peptide sequencing and online capillary reverse-phase liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Lee, Yong Ho; Kim, Min-Sik; Choie, Woo-Suk; Min, Hye-Ki; Lee, Sang-Won

    2004-06-01

    Recently, various chemical modifications of peptides have been incorporated into mass spectrometric analyses of proteome samples, predominantly in conjunction with matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS), to facilitate de novo sequencing of peptides. In this work, we investigate systematically the utility of N-terminal sulfonation of tryptic peptides by 4-sulfophenyl isothiocyanate (SPITC) for proteome analysis by capillary reverse-phase liquid chromatography/tandem mass spectrometry (cRPLC/MS/MS). The experimental conditions for the sulfonation were carefully adjusted so that SPITC reacts selectively with the N-terminal amino groups, even in the presence of the epsilon-amino groups of lysine residues. Mass spectrometric analyses of the modified peptides by cRPLC/MS/MS indicated that SPITC derivatization proceeded toward near completion under the experimental conditions employed here. The SPITC-derivatized peptides underwent facile fragmentation, predominantly resulting in y-series ions in the MS/MS spectra. Combining SPITC derivatization and cRPLC/MS/MS analyses facilitated the acquisition of sequence information for lysine-terminated tryptic peptides as well as arginine-terminated peptides without the need for additional peptide pretreatment, such as guanidination of lysine amino group. This process alleviated the biased detection of arginine-terminated peptides that is often observed in MALDI MS experiments. We will discuss the utility of the technique as a viable method for proteome analyses and present examples of its application in analyzing samples having different levels of complexity.

  17. Comparison of Electrospray Ionization and Atmospheric Chemical Ionization Coupled with the Liquid Chromatography-Tandem Mass Spectrometry for the Analysis of Cholesteryl Esters

    Directory of Open Access Journals (Sweden)

    Hae-Rim Lee

    2015-01-01

    Full Text Available The approach of two different ionization techniques including electrospray ionization (ESI and atmospheric pressure chemical ionization (APCI coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS was tested for the analysis of cholesteryl esters (CEs. The retention time (RT, signal intensity, protonated ion, and product ion of CEs were compared between ESI and APCI. RT of CEs from both ionizations decreased with increasing double bonds, while it increased with longer carbon chain length. The ESI process generated strong signal intensity of precursor ions corresponding to [M+Na]+ and [M+NH4]+ regardless of the number of carbon chains and double bonds in CEs. On the other hand, the APCI process produced a protonated ion of CEs [M+H]+ with a weak signal intensity, and it is selectively sensitive to detect precursor ions of CEs with unsaturated fatty acids. The ESI technique proved to be effective in ionizing more kinds of CEs than the APCI technique.

  18. Simultaneous determination of some phthalate metabolites, parabens and benzophenone-3 in urine by ultra high pressure liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Dewalque, Lucas; Pirard, Catherine; Dubois, Nathalie; Charlier, Corinne

    2014-02-15

    Phthalates, parabens and 2-hydroxy-4-methoxybenzophenone or benzophone-3 are thought to act as endocrine disrupting chemicals, being able to disrupt the endocrine balance and therefore able to lead to some hormonal diseases. Numerous large-scale biomonitoring studies have detected the biomarkers of these compounds in more than 75% of the general population. To assess the exposure to these chemicals, we developed an analytical method based on a Solid Phase Extraction (SPE) prior to ultra high pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the simultaneous measurement of seven phthalate metabolites (monobenzyl phthalate, mono-n-butyl phthalate, mono-iso-butyl phthalate, mono-2-ethylhexyl phthalate, mono-2-ethyl-5-hydroxyhexyl phthalate, mono-2-ethyl-5-oxohexyl phthalate, monoethyl phthalate), four parabens (methyl paraben, ethyl paraben, n-propyl paraben, n-butyl parabens) and benzophenone-3 in human urine. The distinction between unconjugated, glucuro- and sulfoconjugated forms was achieved using different enzymatic hydrolyses. The whole procedure was validated according to the total error approach, and was demonstrated to be linear (regression coefficient ranging from 0.987 to 0.998) and accurate (inter and intra assay precision parabens and benzophenone-3 were positively detected in almost all urine samples, with detection rates ranging from 40 to 100%. Levels measured ranged from parabens and benzophenone-3 were detected as glucuro- and sulfoconjugated species in variable proportions according to the target compound. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Assessment of parabens and ultraviolet filters in human placenta tissue by ultrasound-assisted extraction and ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Vela-Soria, F; Gallardo-Torres, M E; Ballesteros, O; Díaz, C; Pérez, J; Navalón, A; Fernández, M F; Olea, N

    2017-03-03

    Increasing concerns have been raised over recent decades about human exposure to Endocrine Disrupting Chemicals (EDCs), especially about their possible effects on embryo, foetus, newborn, and child. Parabens (PBs) and ultraviolet filters (UV-filters) are prevalent EDCs widely used as additives in cosmetics and personal care products (PCPs). The objective of this study was to determine the presence of four PBs and ten UV-filters in placental tissue samples using a novel analytical method based on ultrasound-assisted extraction (UAE) and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Multivariate optimization strategies were used to accurately optimize extraction and clean-up parameters. Limits of quantification ranged from 0.15 to 0.5μgkg -1 , and inter-day variability (evaluated as relative standard deviation) ranged from 3.6% to 14%. The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery percents ranged from 94.5% to 112%. The method was satisfactorily applied for the determination of the target compounds in human placental tissue samples collected at delivery from 15 randomly selected women. This new analytical procedure can provide information on foetal exposure to compounds, which has been little studied. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Pharmacokinetic study of 14-(3-methylbenzylmatrine and 14-(4-methylbenzylmatrine in rat plasma using liquid chromatography-tandem mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Minjie Jiang

    Full Text Available A rapid, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS was developed and validated to determine the 14-(3-methylbenzylmatrine (3MBM and 14-(4-methylbenzylmatrine (4MBM levels in rat plasma in the present study. The analytes were separated using a C18 column (1.9 μm, 2.1 mm × 100 mm equipped with a Security Guard C18 column (5 μm, 2.1 mm × 10 mm, followed by detection via triple-quadrupole mass spectrometry using an electrospray ionization (ESI source. Sample pretreatment involved one-step protein precipitation with isopropanol:ethyl acetate (v/v, 25:75, and pseudoephedrine hydrochloride was used as an internal standard. The method was linear in the concentration range of 5-2000 ng/ml for both compounds. The intra-day and inter-day relative standard deviations (RSDs were less than 15%, and all relative errors (REs were within 15%. The proposed method enables the unambiguous identification and quantification of these two compounds in vivo. This study is the first to determine the 3MBM and 4MBM levels in rat plasma after oral administration of these compounds. These results provide a meaningful basis for evaluating the clinical applications of these medicines.

  1. Middle-down hybrid chromatography/tandem mass spectrometry workflow for characterization of combinatorial post-translational modifications in histones.

    Science.gov (United States)

    Sidoli, Simone; Schwämmle, Veit; Ruminowicz, Chrystian; Hansen, Thomas A; Wu, Xudong; Helin, Kristian; Jensen, Ole N

    2014-10-01

    We present an integrated middle-down proteomics platform for sensitive mapping and quantification of coexisting PTMs in large polypeptides (5-7 kDa). We combined an RP trap column with subsequent weak cation exchange-hydrophilic interaction LC interfaced directly to high mass accuracy ESI MS/MS using electron transfer dissociation. This enabled automated and efficient separation and sequencing of hypermodified histone N-terminal tails for unambiguous localization of combinatorial PTMs. We present Histone Coder and IsoScale software to extract, filter, and analyze MS/MS data, including quantification of cofragmenting isobaric polypeptide species. We characterized histone tails derived from murine embryonic stem cells knockout in suppressor of zeste12 (Suz12(-/-) ) and quantified 256 combinatorial histone marks in histones H3, H4, and H2A. Furthermore, a total of 713 different combinatorial histone marks were identified in purified histone H3. We measured a seven-fold reduction of H3K27me2/me3 (where me2 and me3 are dimethylation and trimethylation, respectively) in Suz12(-) (/) (-) cells and detected significant changes of the relative abundance of 16 other single PTMs of histone H3 and other combinatorial marks. We conclude that the inactivation of Suz12 is associated with changes in the abundance of not only H3K27 methylation but also multiple other PTMs in histone H3 tails. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Mapping trapped atomic gas with spin-orbit coupling to quantum Rabi-like model

    OpenAIRE

    Hu, Haiping; Chen, Shu

    2013-01-01

    We construct a connection of the ultracold atomic system in a harmonic trap with Raman-induced spin-orbit coupling to the quantum Rabi-like model. By mapping the trapped atomic system to a Rabi-like model, we can get the exact solution of the Rabi-like model following the methods to solve the quantum Rabi model. The existence of such a mapping implies that we can study the basic model in quantum optics by using trapped atomic gases with spin-orbit coupling.

  3. Determination of three natural pesticides in processed fruit and vegetables using high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Sannino, Anna

    2007-01-01

    This paper describes a method for the sensitive and selective determination of two macrocyclic lactones (abamectin and spinosad) and azadirachtin in apple purée, concentrated lemon juice, tomato purée and canned peas. The general sample extraction-partitioning method for our gas chromatography and liquid chromatography multiresidue methods has been used. The analytical procedure involves an extraction with acetone and liquid-liquid partitioning with ethyl acetate/cyclohexane combined in one step. The extracts are analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) without any further clean-up step. The pesticides are separated on a reversed-phase C12 column using a gradient elution. Thirteen simultaneous MS/MS transitions of precursor ions were monitored. Studies at fortification levels of 2.5-10 microg/kg and 25-100 microg/kg gave mean recoveries ranging from 70-100% for all compounds with satisfactory precision (relative standard deviation (RSD) from 3-20%). The excellent selectivity and sensitivity allows quantification and identification of low levels of pesticides in canned peas, tomato and apple purées (limits of quantitation (LOQs) 1-5 microg/kg) and in concentrated lemon juice (LOQs 2-10 microg/kg). The quantification of analytes was carried out using the most sensitive transition for every compound and by 'matrix-matched' standards calibration. Copyright (c) 2007 John Wiley & Sons, Ltd.

  4. Application of a rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of bumetanide in human plasma for a bioequivalence study.

    Science.gov (United States)

    Patel, Dinesh S; Sharma, Naveen; Patel, Mukesh C; Patel, Bhavin N; Shrivastav, Pranav S; Sanyal, Mallika

    2012-07-01

    A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been proposed for the determination of bumetanide in human plasma using tamsulosin as internal standard (IS). The analyte and IS were extracted from 200 μL of human plasma via solid phase extraction and the chromatographic separation was achieved on Peerless Basic C18 (100 mm × 4.6 mm, 3 μm) column under isocratic conditions. Detection of bumetanide and IS was done by tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for bumetanide and IS were m/z 365.2→240.2 and 409.2→228.2 respectively. The method was fully validated as per the US FDA guidelines. The limit of detection and lower limit of quantitation of the method were 0.03 and 0.30 ng/mL respectively with a linear dynamic range of 0.30-200.0 ng/mL for bumetanide. The intra-batch and inter-batch precision (% CV) was ≤6.9% while the mean extraction recovery was >90% across quality control levels. The method is selective in presence of four diuretic drugs and some commonly used medications by healthy volunteers. It was successfully applied to a bioequivalence study of 2mg bumetanide tablet formulation in 10 healthy Indian male subjects under fasting condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 42 incurred samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Simultaneous determination of major type A and B trichothecenes, zearalenone and certain modified metabolites in Finnish cereal grains with a novel liquid chromatography-tandem mass spectrometric method.

    Science.gov (United States)

    Nathanail, Alexis V; Syvähuoko, Jenna; Malachová, Alexandra; Jestoi, Marika; Varga, Elisabeth; Michlmayr, Herbert; Adam, Gerhard; Sieviläinen, Elina; Berthiller, Franz; Peltonen, Kimmo

    2015-06-01

    A reliable and sensitive liquid chromatography-tandem mass spectrometric method was developed for the simultaneous quantitative determination in cereals of the Fusarium mycotoxins HT-2 toxin, T-2 toxin, deoxynivalenol, nivalenol and zearalenone, as well as the modified metabolites 3-acetyl-deoxynivalenol, α-zearalenol, β-zearalenol, deoxynivalenol-3-glucoside, HT-2-3-glucoside, nivalenol-3-glucoside, zearalenone-14-glucoside, zearalenone-14-sulphate, zearalenone-16-glucoside, α-zearalenol-14-glucoside and β-zearalenol-14-glucoside. The 'dilute and shoot' approach was used for sample preparation after extraction with acetonitrile:water:acetic acid (79:20:1, v/v/v). Separation was carried out using reversed-phase liquid chromatography, and detection was performed using tandem mass spectrometry in the selected reaction monitoring mode. The method was in-house validated according to performance characteristics, established in Commission Regulation EC No 401/2006 and Commission Decision EC No 657/2002, prior to its application in a nationwide survey for the analysis of barley, oat and wheat samples (n = 95) harvested in Finland during 2013. Deoxynivalenol and its glucosylated form were the most abundant of the analytes, being detected in 93 and 81 % of the samples, respectively. Concentrations of deoxynivalenol were unusually high in 2013, especially in oats, with some cases exceeding the maximum legislative limits for unprocessed oats placed on the market for first-stage processing. All modified mycotoxins analysed were detected, and the natural occurrence of some of these compounds (e.g. zearalenone-16-glucoside and nivalenol-3-glucoside) in barley, oats and/or wheat was documented for the first time.

  6. [Determination of zearalenone and related mycotoxins in grain and its products by solid-phase extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Meng, Juan; Zhang, Jing; Zhang, Nan; Shi, Jiachen; Shao, Bing

    2010-06-01

    A method was established for the determination of 6 zearalenonic compounds (alpha-zearalanol, beta-zearalanol, alpha-zearalenol, beta-zearalenol, zearalanone and zearalenone) in grain and its products based on solid-phase extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples was extracted by 84% (v/v) acetonitrile-water solution and further purified by an ENVI-Carb graphite carbon black (GCB) cartridge, which was eluted by 6 mL dichloromethane-methanol (7:3, v/v) solution. The target compounds were assayed by UPLC-MS/MS. The chromatographic separation was performed on an ACQUITY UPLC BEH C18 column with gradient elution using acetonitrile and water as mobile phases. The mass spectrometric acquisitions were carried out by means of multiple reaction monitoring (MRM) in electrospray negative ionization mode. The good linearities (R2 > 0.99) were achieved for the 6 compounds over the range of 0.1-50 microg/L based on the internal standard calibration of a-zearalenol-d4. The detection limits of the method were 0.1-0.2 microg/kg. The mean recoveries of the 6 target compounds (spiked at three concentration levels) ranged from 79.9% to 104.0%, with the relative standard deviations (RSDs) no more than 10%. It has been applied in the analysis of grain and related products taken from Beijing. As a result, zearalenone presented a highest detectable frequency, with a concentration range of 0.42-220.7 microg/kg. In addition, alpha-zearalenol and beta-zearalenol were also detected in this survey. This proposed method is simple, sensitive, reproducible, and complied with the regulations for the determination of trace contaminants residues in food matrices.

  7. Assesment of endocrinal and biochemical entities through liquid chromatography-tandem mass spectrometry/mass spectrometer: Inter-relative investigation of the interaction based cardiovascular formulation

    Directory of Open Access Journals (Sweden)

    Rakesh Das

    2015-01-01

    Full Text Available Background: Combinatory oral dosage treatment of atorvastatin (ATVS and olmesartan (OLM drugs to cardiovascular patients reflects unpredicted results instead of its individual therapy, which was accessed on quantification of endocrinal and biochemicals of plasma through liquid chromatography-tandem mass spectrometry/mass spectrometer (LCMS/MS. Objective: Mission was to track the remarkable biochemical variation in the plasma after induction of the combined formulation, to evaluate the pharma-market rumor on its efficiency. Methods: To fulfil undergoing research objectives for digging-up of market insult, human patient volunteers were chosen according to the required criteria along with bioethical regulation. A sensitive, rapid and precise method was developed and validated to estimate aldosterone (ALD, angiotensin (ANG-II and the Mevalonate (MVA not Mevalonic acid through LCMS/MS over least samples of cardiovascular patients. Level of each endogenous biochemicals were determined in three stages - without drugs, with a single drug (OLM/ATVS and with their combination that was then correlate with blood pressure of respective volunteers. Result and Discussion: Comparative and correlative studies panaroma among these analytes was detected. The selectivity, specificity, linearity, precision, accuracy, extraction recovery, limit of detection and limit of quantification, stability were the essential points of validation of the developed methodology. And the significance of each endogenous analyte data were based on P ≥ 0.001. Thus, low value of ALD and reciprocally higher in ANG-II on administered single drug than its combination and equal concentration of mevalonate in both stages, was discovered. Conclusion: This concludes that the cardiovascular dosage formulation entrenched in the market are not synergistic and effective compared with a single drug as antihypertensive drug.

  8. Determination of the maleic acid in rat urine and serum samples by isotope dilution-liquid chromatography-tandem mass spectrometry with on-line solid phase extraction.

    Science.gov (United States)

    Chen, Hsin-Chang; Wu, Charlene; Wu, Kuen-Yuh

    2015-05-01

    A rapid and simple on-line solid-phase extraction coupled with isotope dilution-liquid chromatography-tandem mass spectrometry (SPE-ID-LC-MS/MS) method was developed to quantitate maleic acid in serum and urine of SpragueDawley (SD) rats. The aforementioned biological samples were spiked with (13)C2-maleic acid, vigorously vortexed, added with acetonitrile to precipitate proteins, and then injected into the on-line SPE-LC-MS/MS system for quantification. Upon validation, this method demonstrated excellent feasibility and sensitivity: calibration curves for maleic acid in serum and urine display excellent linearity with the coefficient of determination (R(2)) greater than 0.999; the limits of detection and quantitation (LOD and LOQ) for maleic acid were determined at 0.2 and 0.5μg L(-1), respectively. Additionally, intra-day accuracy for maleic acid in serum and urine samples ranged from 94.0% to 100.2% and 101.3% to 104.4%, respectively. Furthermore, inter-day accuracy ranged from 93.6% to 101.0% and from 102.3% to 111.4% in serum and urine samples, respectively. Intra-day precision %RSD of maleic acid in serum and urine samples was 13.8% or less, whereas the inter-day precision was 6.1% or less. The matrix effects were not found to be statistically significant (p=0.9145 and p=0.5378, correspondingly) based on the calculations of recovery functions. The collected serum and urine samples were analyzed using SPE-ID-LC-MS/MS. Our results reveal trace levels of maleic acid in the control rats, demonstrating that this method is capable of analyzing background levels of contaminants in biofluids with excellent sensitivity and specificity at part-per-billion levels concentrations in complex matrices. Copyright © 2015. Published by Elsevier B.V.

  9. Validation of an accelerated solvent extraction liquid chromatography-tandem mass spectrometry method for Pacific ciguatoxin-1 in fish flesh and comparison with the mouse neuroblastoma assay.

    Science.gov (United States)

    Wu, Jia Jun; Mak, Yim Ling; Murphy, Margaret B; Lam, James C W; Chan, Wing Hei; Wang, Mingfu; Chan, Leo L; Lam, Paul K S

    2011-07-01

    Ciguatera fish poisoning (CFP) is a global foodborne illness caused by consumption of seafood containing ciguatoxins (CTXs) originating from dinoflagellates such as Gambierdiscus toxicus. P-CTX-1 has been suggested to be the most toxic CTX, causing ciguatera at 0.1 μg/kg in the flesh of carnivorous fish. CTXs are structurally complex and difficult to quantify, but there is a need for analytical methods for CFP toxins in coral reef fishes to protect human health. In this paper, we describe a sensitive and rapid extraction method using accelerated solvent extraction combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the detection and quantification of P-CTX-1 in fish flesh. By the use of a more sensitive MS system (5500 QTRAP), the validated method has a limit of quantification (LOQ) of 0.01 μg/kg, linearity correlation coefficients above 0.99 for both solvent- and matrix-based standard solutions as well as matrix spike recoveries ranging from 49% to 85% in 17 coral reef fish species. Compared with previous methods, this method has better overall recovery, extraction efficiency and LOQ. Fish flesh from 12 blue-spotted groupers (Cephalopholis argus) was assessed for the presence of CTXs using HPLC-MS/MS analysis and the commonly used mouse neuroblastoma assay, and the results of the two methods were strongly correlated. This method is capable of detecting low concentrations of P-CTX-1 in fish at levels that are relevant to human health, making it suitable for monitoring of suspected ciguateric fish both in the environment and in the marketplace.

  10. Citrinin Determination in Red Fermented Rice Products by Optimized Extraction Method Coupled to Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS).

    Science.gov (United States)

    Ji, Xiaofeng; Xu, Junfeng; Wang, Xiaofu; Qi, Peipei; Wei, Wei; Chen, Xiaoyun; Li, Rui; Zhou, Yu

    2015-06-01

    A rapid and sensitive method was developed and validated for citrinin determination in red fermented rice products by liquid chromatography tandem mass spectrometry (LC-MS/MS) under the selected reaction monitoring mode. Sample preparation was especially focused, and the quantitative methods of LC-MS/MS and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) were compared. In red fermented rice samples, the limit of detection was 1.0 μg/kg for LC-MS/MS compared to 250 μg/kg for HPLC-FLD, the limit of quantification was 3.0 μg/kg for LC-MS/MS compared to 825 μg/kg for HPLC-FLD. High correlation coefficient was obtained (R(2) = 0.999) within the linear range (0.1 to 100 μg/L) in the MS method. The recoveries ranging from 80.9% to 106.5% were obtained in different spiking concentrations. The average intra- and inter-day accuracy ranged from 75.4% to 103.1%, and the intra- and inter-day precisions were from 3.3% to 7.9%. The developed method was applied to 12 commercial red fermented rice products, and citrinin was found in 10 samples ranging from 0.14 to 44.24 mg/kg. Compared to traditional qualitative and quantitative methods, the newly developed LC-MS/MS method for citrinin determination includes the merits of using a small amount of extraction solvent, simple preparation steps, and high sensitivity. © 2015 Institute of Food Technologists®

  11. Determination of gamithromycin in an injection by ultra-performance liquid chromatography-tandem quadrupole-time-of-flight mass spectrometry.

    Science.gov (United States)

    Wu, Jia-Xin; Zhang, Gang; Song, Min; Liu, Min; Liang, Jing-Le; Xu, Jin-Lei; Shang, Fei; Qi, Peng

    2016-07-07

    In this study, a sensitive and precise method was developed for the determination of gamithromycin in an injection using ultra-performance liquid chromatography-tandem quadrupole-time-of-flight mass spectrometry (UPLC-QTOF-MS) and the results were compared with a similar analysis for the ion fragments of gamithromycin in MS/ MS. The sample was dissolved in methanol then filtered and separated on a C18 column using acetonitrile-0.1% formic acid (containing 2 mmol/L ammonium acetate) as the mobile phase. The flow rate was 0.4 mL/min and the column temperature was 40 °C. The mass spectrometry conditions were electrospray ionization (ESI) operated in positive ion full scan mode and quantified using external calibration. Subsequently, ion fragments of the MS/MS were compared and analyzed. The linear range was 10 ∼ 200 μg/L with a correlation coefficient of 0.9992. The limit of detection (LOD) was 0.77 μg/L and the limit of quantitation (LOQ) was 2.55 μg/L. The average recoveries of the intra-assay were 98.8%-105.6% with a relative standard deviation ranging from 1.79% to 2.38% and the inter-assay were 89.3%-110.7% with a relative standard deviation ranging from 4.93% to 6.27%. After the comparative analysis of the fragments with a Molecular Structure Correlator, the score of the total matching degree reached 83.19 and the scores of each ion fragment matching degree were all greater than 90, which supplied the basis for the confirmation of gamithromycin. The results indicated that the method was simple, sensitive and precise and could be applied in the determination of gamithromycin in real samples.

  12. Determination of Phenolic Acids and Flavonoids in Taraxacum formosanum Kitam by Liquid Chromatography-Tandem Mass Spectrometry Coupled with a Post-Column Derivatization Technique

    Directory of Open Access Journals (Sweden)

    Hung-Ju Chen

    2011-12-01

    Full Text Available A liquid chromatography-tandem mass spectrometry method (LC-MS/MS was developed for the determination of phenolic acids and flavonoids in a medicinal Chinese herb Taraxacum formosanum Kitam. Initially, both phenolic acids and flavonoids were extracted with 50% ethanol in a water-bath at 60 °C for 3 h and eventually separated into acidic fraction and neutral fraction by using a C18 cartridge. A total of 29 compounds were separated within 68 min by employing a Gemini C18 column and a gradient solvent system of 0.1% formic acid and acetonitrile at a flow rate of 1.0 mL/min. Based on the retention behavior as well as absorption and mass spectra, 19 phenolic acids and 10 flavonoids were identified and quantified in T. formosanum, with the former ranging from 14.1 μg/g to 10,870.4 μg/g, and the latter from 9.9 μg/g to 325.8 μg/g. For further identification of flavonoids, a post-column derivatization method involving shift reagents such as sodium acetate or aluminum chloride was used and the absorption spectral characteristics without or with shift reagents were compared. An internal standard syringic acid was used for quantitation of phenolic acids, whereas (± naringenin was found suitable for quantitation of flavonoids. The developed LC-MS/MS method showed high reproducibility, as evident from the relative standard deviation (RSD values for intra-day and inter-day variability being 1.0–6.8% and 2.0–7.7% for phenolic acids and 3.7–7.4% and 1.5–8.1% for flavonoids, respectively, and thus may be applied for simultaneous determination of phenolic acids and flavonoids in Chinese herb and nutraceuticals.

  13. Determination of natamycin in rabbit cornea by high-performance liquid chromatography-tandem mass spectrometry with protective soaking extraction technology.

    Science.gov (United States)

    Tianyang, Zhou; Ling, Zhu; Huiyun, Xia; Jijun, He; Junjie, Zhang

    2014-10-15

    A new selective and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the quantification of natamycin (NAT) in rabbit corneas with amphotericin B as the internal standard (IS). The cornea samples were processed by a simple and protective methanol soaking extraction technology. The NAT could be extracted completely from rabbit cornea after 24h of soaking with methanol under a mild condition. Chromatographic separation was performed on a C18 column (2.1mm×50mm, 3.5μm) using mobile phase with ammonium acetate buffer (pH 4.5; 4.0mM):acetonitrile (40:60, v/v) at a flow rate of 0.25ml/min. Quantification was performed using the transitions 666.2→503.2 m/z for NAT and 924.5→906.6 m/z for IS by positive ion electrospray ionization in multiple reaction monitoring mode. The assay was validated over a concentration range of 8.64ng/ml to 843ng/ml with lower limit of detection of 4.32ng/ml. The method was validated with respect to linearity, accuracy, precision, recovery, stability and extracting efficiency. The extraction recovery of NAT from cornea samples was approximately 100% with the new methanol soaking extraction procedure. The method has been successfully applied to the ocular pharmacokinetic studies of NAT eye drops in the cornea of Japanese white rabbit. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Simultaneous determination of blonanserin and its metabolite in human plasma and urine by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study.

    Science.gov (United States)

    Wen, Yu-Guan; Ni, Xiao-Jia; Zhang, Ming; Liu, Xia; Shang, De-Wei

    2012-08-15

    Blonanserin is a novel atypical antipsychotic with highly selective receptor antagonist activity to dopamine D₂ and 5-HT(2A). N-desethyl blonanserin (blonanserin C) is its major active metabolite in human plasma. Herein we report a new highly sensitive, selective, and rapid liquid chromatography-tandem mass spectrometry method to determine blonanserin and blonanserin C simultaneously in human plasma and urine, with N-desethyl-chlor-blonanserin (blonanserin D) as internal standard (IS). Blonanserin and blonanserin C were extracted from aliquots of plasma and urine with ethyl acetate and dichloromethane (4:1) as the solvent and chromatographic separation was performed using an Agilent Eclipse Plus C₁₈ column. The mobile phase was composed of: acetonitrile and ammonium formate-formic acid buffer containing 5mM ammonium formate and 0.1% formic acid (87:13, v/v). To quantify blonanserin, blonanserin C, and blonanserin D, respectively, multiple reaction monitoring (MRM) transition of m/z 368.2→297.2, m/z 340.2→297.1, and m/z 356.2→313.3 was performed in positive mode. The analysis time was about 5.5 min. The calibration curve was linear in the concentration range of 0.01-2 ng/ml. The lower limit of quantification reached 0.01 ng/ml. The intra and inter-day precision and relative errors were less than 8.0% and 6.6% for three QC levels in plasma and urine. The current LC-MS/MS method was validated as simple, sensitive, and accurate and has been successfully applied to investigate the pharmacokinetics of blonanserin and blonanserin C in humans. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Multi-dye residue analysis of triarylmethane, xanthene, phenothiazine and phenoxazine dyes in fish tissues by ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Reyns, Tim; Belpaire, Claude; Geeraerts, Caroline; Van Loco, Joris

    2014-03-15

    Beside the possible illegal use of malachite green in aquaculture, other familiar dyes could also been applied by fraudulent producers due to their antiseptic and antibacterial activity. In this contribution, a new sensitive multi-residue method was developed to determine triarylmethane, xanthene, phenothiazine and phenoxazine dyes in fish by ultra-performance liquid chromatography-tandem mass spectrometry. Samples were extracted with acetonitrile, followed by an oxidation step using 2,3-dichloro-5,6-dicyanobenzoquinone. Further clean-up was performed by tandem solid phase extraction using weak and strong cation exchange cartridges. Extracts were analysed by UPLC-MS(n) operating in the positive electrospray ionisation mode (ESI+). The fourteen dyes were separated within only 12min on a C18 BEH column using 1mM ammonium acetate in water at pH 4.5 and acetonitrile as mobile phases at a flowrate of 0.4mLmin(-1). The presented method was validated as defined by the European Union and scientific literature. Good linearity (R ≥0.99 and goodness-of-fit (g) ≤10%) was achieved over the tested concentration range (0.25-2ngg(-1)). Limit of quantification was 0.25ngg(-1) for all dyes, with a signal-to-noise ratio of at least 10/1. This is at least 5 to 10 times lower than previous published methods. Limits of detection were all dyes, the two rhodamine dyes could only be determined above 0.75ngg(-1). For these dyes, the method can only be used for screening purposes. To show the applicability of the method, a monitoring study was performed to investigate the occurrence of artificial dyes in wildlife European eel in Flemish rivers. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. A rapid and sensitive method for the identification of delta-9-tetrahydrocannabinol in oral fluid by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Molnar, Anna; Lewis, John; Doble, Philip; Hansen, Glyn; Prolov, Tatiana; Fu, Shanlin

    2012-02-10

    A fast and sensitive method was developed for detecting delta-9-tetrahydrocannabinol (THC) in oral fluid by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method is suitable for samples of small volume and low concentration. For method development and validation, neat oral fluid (200 μL) spiked with THC and d(3)-THC (internal standard) was extracted via liquid-liquid extraction (LLE). The LLE method had an extraction efficiency of 75% with no significant matrix effects observed in either diluted or neat oral fluid samples. LC was performed on a Zorbax Eclipse XDB-C18 Rapid Resolution HT column (2.1 mm × 50 mm, 1.8 μm particle size) with positive electrospray ionisation and selected reaction monitoring. The total run time was an efficient 3.5 min in isocratic elution mode. The limit of quantification was 1 ng/mL and the analysis was linear over the range of 1-500 ng/mL with a correlation coefficient of 0.9998. The imprecision (RSD) of the method was 13% and inaccuracy (MRE) was 4%. The method was subsequently applied to two neat oral fluid samples taken from a chronic cannabis smoker. It was also applied to buffer diluted residual oral fluid samples (n=48) collected using the Cozart RapiScan(®) system through the Roadside Drug Testing Program (RDTP) in NSW, Australia. A stability study was performed that revealed freezing or refrigerating resulted in comparable decreases in THC recovery from neat oral fluid at the end of two weeks of storage. Storage at room temperature even for one day invoked significant losses and is not recommended. Crown Copyright © 2011. Published by Elsevier Ireland Ltd. All rights reserved.

  17. Sensitive and convenient method for the quantification of clonidine in serum of pediatric patients using liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Müller, C; Ramic, M; Harlfinger, S; Hünseler, C; Theisohn, M; Roth, B

    2007-01-19

    An improved and easy to use liquid chromatography/tandem mass spectrometric (LC/MS/MS) method in human serum was developed for the quantification of clonidine (CLD), an alpha2-/alpha1-adrenoceptor agonist, used for analgo-sedation and the therapy of opioid withdrawal in pediatric patients. Sample preparation consisted of precipitation of serum proteins by adding acetonitrile and centrifugation of the sample subsequently. [(2)H4]Clonidine (CLD4) served as internal standard. Chromatographic separation of the supernatant was achieved using a 100mmx3mm, 5microm Thermo Electron BetaBasic C4 column with isocratic flow and elution consisting of 0.1% formic acid/acetonitrile (85/15, v/v) and a flow-rate of 350microl/min resulting in a column pressure of 280-420kPa. LC/MS/MS detection was performed by using a triple-stage quadrupole mass spectrometer (TSQ Quantum, Thermo Electron) working in selected reaction monitoring mode with positive electrospray ionization. The analyte was quantified in a single run within 5min. Linearity was demonstrated over the expected concentration range 0.15-50microg/l CLD. The lower limit of quantification (LLOQ) and the limit of detection were 0.1microg/l and 0.01microg/l, respectively. None of the drugs used concomitantly during analgesic therapy interfered in the assay in vitro. Intra-day precision expressed as RSD was 9.6% or less for CLD, while inter-day result was 10.0% or less for CLD. Intra-day and inter-day accuracy was within +/-4.9% and +/-1.8%, respectively. The method was validated according to the international guidelines of the International Conference on Harmonisation (ICH) and the US Food and Drugs Administration (FDA). The described method is suitable to analyse serum samples with very small volumes and sets the stage for pharmacokinetic studies in pediatric studies.

  18. Quantitation of donepezil and its active metabolite 6-O-desmethyl donepezil in human plasma by a selective and sensitive liquid chromatography-tandem mass spectrometric method

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Bhavin N. [Chemistry Department, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380 009, Gujarat (India); Analytical Laboratory, BA Research India Ltd., Bodakdev, Ahmedabad 380 054, Gujarat (India); Sharma, Naveen [Analytical Laboratory, BA Research India Ltd., Bodakdev, Ahmedabad 380 054, Gujarat (India); Sanyal, Mallika [Chemistry Department, St. Xaviers' College, Navrangpura, Ahmedabad 380 009, Gujarat (India); Shrivastav, Pranav S. [Chemistry Department, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380 009, Gujarat (India)], E-mail: pranav_shrivastav@yahoo.com

    2008-11-23

    A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous determination of donepezil (D) and its pharmacologically active metabolite, 6-O-desmethyl donepezil (6-ODD) in human plasma is developed using galantamine as internal standard (IS). The analytes and IS were extracted from 500 {mu}L aliquots of human plasma via solid-phase extraction (SPE) on Waters Oasis HLB cartridges. Chromatographic separation was achieved in a run time of 6.0 min on a Waters Novapak C18 (150 mm x 3.9 mm, 4 {mu}m) column under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for D, 6-ODD and IS were at m/z 380.1 {yields} 91.2, 366.3 {yields} 91.3 and 288.2 {yields} 213.2, respectively. The method was fully validated for its selectivity, interference check, sensitivity, linearity, precision and accuracy, recovery, matrix effect, ion suppression/enhancement, cross-specificity, stability and dilution integrity. A linear dynamic range of 0.10-50.0 ng mL{sup -1} for D and 0.02-10.0 ng mL{sup -1} for 6-ODD was evaluated with mean correlation coefficient (r) of 0.9975 and 0.9985, respectively. The intra-batch and inter-batch precision (%CV, coefficient of variation) across five quality control levels was less than 7.5% for both the analytes. The method was successfully applied to a bioequivalence study of 10 mg donepezil tablet formulation in 24 healthy Indian male subjects under fasting condition.

  19. Matrix solid-phase dispersion combined to liquid chromatography-tandem mass spectrometry for the determination of paraben preservatives in mollusks.

    Science.gov (United States)

    Villaverde-de-Sáa, Eugenia; Rodil, Rosario; Quintana, José Benito; Cela, Rafael

    2016-08-12

    A method for the extraction and determination of seven parabens, esters of 4-hydroxybenzoic acid, widely used as preservatives in personal care products, pharmaceuticals, etc., and two chlorinated derivatives (mono- and di-chloro methyl paraben) from mollusk samples was developed by combining matrix solid-phase dispersion (MSPD) and liquid chromatography-tandem mass spectrometry. MSPD parameters, such as solvent, solid support and clean-up sorbent, were optimized. Besides, since blank problems were observed for some parabens, these were investigated and blanks were tackled by precleaning all sorbents prior to use. Under final conditions, 0.5g of freeze-dried mollusk were dispersed with 1.2g of silica and packed into a cartridge containing 3g of C18, as on-line clean-up sorbent. This cartridge was eluted with 10mL of acetonitrile, evaporated and reconstituted in methanol for analysis. In the validation stage, successful linearity (R(2)>0.999), recoveries (between 71 and 117% for most analytes), precision (RSD lower than 21%) and limits of detection and quantification (LOD and LOQ, lower than 0.4 and 1.4ngg(-1) dry weight respectively) levels were achieved. Finally, the new methodology was applied to mussel, clam and cockle samples. Methyl paraben was above the LOQ in five of the six samples (not found in one clam sample) at concentrations up to 7ngg(-1) dry weight. Ethyl paraben was found above the LOQ in mussel and cockle samples at a concentration level around 0.3ngg(-1). n-Propyl paraben was only above the LOQ in one mussel sample. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Nicotine and metabolites determination in human plasma by ultra performance liquid chromatography-tandem mass spectrometry: a simple approach for solving contamination problem and clinical application.

    Science.gov (United States)

    Liachenko, Natalia; Boulamery, Audrey; Simon, Nicolas

    2015-10-01

    A quantitative method using ultra performance liquid chromatography-tandem mass spectrometry is described for simultaneous determination of nicotine and its metabolites (cotinine and trans-3'- hydroxycotinine) in human plasma. Aliquots of 0.25 mL of plasma specimens were used for analysis, and 3 analytes were extracted by liquid-liquid extraction. The main problem was blank plasma contamination with environmental nicotine. Activated charcoal was used to avoid this analytical interference. For optimized chromatographic performance, a basic mobile phase consisting of 0.2% ammonia in water (mobile phase A, pH10.6) and acetonitrile (mobile phase B) was selected. The analytes were separated on a 50 mm × 2.1 mm BEH C18 column, 1.7 μm particle size, and quantified by MS/MS using multiple-reaction monitoring (MRM) in positive mode. The chromatographic separation was achieved in 3 min followed by 1.2 min of column equilibration. The calibration curves were linear in the concentration range of 10-1000 ng/mL with correlation coefficients exceeding 0.99. Within-day precisions and between-day precisions (CV, %) were 129.7; 176.9 > 79.7; 192.9 > 79.7 m/z, respectively. The original blank sample preparation solved the problem of contamination in a cost-effective and efficient way. The validated method has been routinely used for analysis of nicotine and metabolites and determination of hydroxycotinine/cotinine metabolic ratio. This biomarker seems to be interesting at predicting response of nicotine patch replacement therapies. © 2015 Société Française de Pharmacologie et de Thérapeutique.

  1. An integrated metabolomics workflow for the quantification of sulfur pathway intermediates employing thiol protection with N-ethyl maleimide and hydrophilic interaction liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Ortmayr, Karin; Schwaiger, Michaela; Hann, Stephan; Koellensperger, Gunda

    2015-11-21

    The sulfur metabolic pathway is involved in basic modes of cellular metabolism, including methylation, cell division, respiratory oscillations and stress responses. Hence, the implicated high reactivity of the sulfur pathway intermediates entails challenges for their quantitative analysis. In particular the unwanted oxidation of the thiol group-containing metabolites glutathione, cysteine, homocysteine, γ-glutamyl cysteine and cysteinyl glycine must be prevented in order to obtain accurate snapshots of this important part of cellular metabolism. Suitable analytical methodologies are therefore needed to support studies of drug metabolism and metabolic engineering. In this work, a novel sample preparation strategy targeting thiolic metabolites was established by implementing thiol group protection with N-ethyl maleimide using a cold methanol metabolite extraction procedure. It was shown that N-ethyl maleimide derivatization is compatible with typical metabolite extraction procedures and also allowed for the stabilization of the instable thiolic metabolites in a fully (13)C-labeled yeast cell extract. The stable isotope labeled metabolite analogs could be used for internal standardization to achieve metabolite quantification with high precision. Furthermore, a dedicated hydrophilic interaction liquid chromatography tandem mass spectrometry method for the separation of sulfur metabolic pathway intermediates using a sub-2 μm particle size stationary phase was developed. Coupled with tandem mass spectrometry, the presented methodology proved to be robust, and sensitive (absolute detection limits in the low femtomole range), and allowed for the quantification of cysteine, cysteinyl glycine, cystathionine, cystine, glutamic acid, glutamyl cysteine, reduced glutathione, glutathione disulfide, homocysteine, methionine, S-adenosyl homocysteine and serine in a human ovarian carcinoma cell model.

  2. [Determination of 21 plant growth regulator residues in fruits by QuEChERS-high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Huang, Hehe; Zhang, Jin; Xu, Dunming; Zhou, Yu; Luo, Jia; Li, Meiling; Chen, Shubin; Wang, Lianzhu

    2014-07-01

    A method for the simultaneous detection of 21 plant growth regulators in fruits by QuEChERS-high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The samples were initially extracted with acetonitrile containing 1% (v/v) acetic acid, followed by clean-up using the powder of magnesium sulfate and C18. The resulting samples were separated on a C18 column, and detected under positive and negative multiple reactions monitoring (MRM) mode through polarity switching between time segments. The matrix-matched external standard calibration curves were used for quantitative analysis. The linearities of chlormequat chloride, mepiquat chloride, choline chloride, cyclanilide, forchlorfenuron, thidiazuron, inabenfide, paclobutrazol, uniconazole and triapenthenol were in the concentration range of 0.1-500 microg/L, daminozide and 6-benzylaminopurine in the concentration range of 1.0-500 microg/L, 2,3,5-triiodobenzoic acid, 2,4-D, cloprop, 4-chlorophenoxyacetic acid (4-CPA) and trinexapac-ethyl in the concentration range of 2.0-1 000 microg/L, abscisic acid (ABA), gibberellic acid (GA3), 1-naphthaleneacetic acid (NAA) and indol-3-ylacetic acid (IAA) in the concentration range of 10-1000 microg/L, with the correlation coefficients higher than 0.990. The limits of detection and the limits of quantification of the method were 0.020-6.0 microg/kg and 0.10-15.0 microg/kg, respectively. For all the samples, the average spiked recoveries ranged from 73.0% to 111.0%, and the relative standard deviations (RSDs, n = 6) were in the range of 3.0% - 17.2%. The method is quick, easy, effective, sensitive and accurate, and can meet the requirements for the determination of the 21 plant growth regulator residues in fruits.

  3. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for analysis of endogenous steroids in the luteal phase and early pregnancy in dogs: a pilot study.

    Science.gov (United States)

    Holst, Bodil S; Kushnir, Mark M; Bergquist, Jonas

    2015-12-01

    Blood samples from dogs are often limited in volume, only allowing few steroids to be quantified with immunoassays. In addition, immunoassays may be compromised by interferences such as anti-reagent antibodies. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) can be used for the simultaneous quantitation of several steroids. This has not been described in dogs before. The aims were to use LC-MS/MS to study steroid profiles in early pregnancy and luteal phase in dogs, and to determine if differences exist between pregnant (P) and nonpregnant (NP) dogs. Nine female dogs were included, 4 during a NP luteal phase, 4 during a P luteal phase, and one during one NP and one P luteal phase. Blood samples were collected around the time of the LH surge (Day 0) and on Day 26. Serum was analyzed for 5 classes of steroids, including glucocorticoids, androgens, estrogens, pregnanes, and progestins, using LC-MS/MS methods. The concentration of progesterone was significantly higher on Day 26 in P than in NP bitches. Distribution of concentrations of glucocorticoids, androgens, estrogens, or pregnanes in P and NP dogs were not statistically different. The predominating glucocorticoid was cortisol, and dihydroepiandrosterone (DHEA) was the predominating androgen. Concentration of estrone was comparable to oestradiol, whereas concentrations of pregnenolone were higher than those of 17-OH pregnenolone. Only concentration of progesterone differed between P and NP bitches, being significantly higher on Day 26 in P than in NP bitches. LC-MS/MS offers interesting possibilities for studies of canine reproductive endocrinology. © 2015 American Society for Veterinary Clinical Pathology.

  4. Standardization of misleading immunoassay based 25-hydroxyvitamin D levels with liquid chromatography tandem-mass spectrometry in a large cohort study.

    Directory of Open Access Journals (Sweden)

    Ben Schöttker

    Full Text Available BACKGROUND: The interest in vitamin D measurement has strongly increased in recent years. The best indicator for circulating vitamin D levels is 25-hydroxy-vitamin D (25(OHD which is often measured by different immunoassays. We demonstrate problems in comparability of measures by different immunoassays and the need for standardization in the context of a large population-based cohort study. METHODS: 25(OHD was measured with the immunoassays Diasorin Liaison in 2006 in 5,386 women and in the context of another project with IDS-iSYS in 4,199 men in 2009-2010 (when the Diasorin Liaison was no longer available in the version utilized in 2006. Standardization was performed by re-measuring of 25(OHD levels in 97 men and 97 women with liquid chromatography tandem-mass spectrometry (LC-MS/MS to obtain linear regression conversion equations. RESULTS: Applying a 30 nmol/L cut-off value for vitamin D deficiency would have resulted in 48.3% of women and 12.1% of men with vitamin D deficiency ahead of standardization. The large gender difference was strongly attenuated after standardization of the assays with only 15.7% of women and 14.3% of men with vitamin D deficiency. Standardization on average increased the 25(OHD levels by 10.3 nmol/L in women and decreased 25(OHD levels by 2.9 nmol/L in men. CONCLUSION: The standardization with LC-MS/MS revealed that much of the observed gender difference was only assay-driven and the extremely high proportion of 48.3% vitamin D deficient women proved to be an exaggeration of the old version of the Diasorin-Liaison immunoassay. Standardization of 25(OHD immunoassay results by LC-MS/MS is recommended to improve their accuracy and comparability, provided the LC-MS/MS method itself is adequately validated and standardized.

  5. Determination of fluoroquinolone antibiotics in environmental water samples based on magnetic molecularly imprinted polymer extraction followed by liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ligang; Zhang Xiaopan; Xu Yang [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China); Du Xiaobo; Sun Xin [College of Physics, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Sun Lei; Wang Hui; Zhao Qi; Yu Aimin; Zhang Hanqi [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China); Ding Lan, E-mail: dinglan@jlu.edu.cn [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China)

    2010-03-03

    A simple method based on magnetic separation for selective extraction of fluoroquinolones (FQs) from environmental water samples has been developed using magnetic molecularly imprinted polymer (MMIP) as sorbent. The MMIP has been prepared using ciprofloxacin as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent and Fe{sub 3}O{sub 4} magnetite as magnetic component. The polymer has been characterized by scanning electron microscopy, Fourier-transform infrared spectrometry and vibrating sample magnetometry. Various parameters affecting the extraction efficiency were evaluated in order to achieve optimal concentration and reduce non-specific interactions. The analytes desorbed from the polymers were determined by liquid chromatography-tandem mass spectrometry. The matrix effect was evaluated by using different washing solvents for removing interfering compounds from the MMIPs after sample loading. Under the optimal conditions, the linearity of the method obtained is in the range of 20-2000 ng L{sup -1}. The detection limits of FQs are in the range of 3.2-6.2 ng L{sup -1}. The relative standard deviations of intra- and inter-day tests ranging from 2.5 to 7.2% and from 3.6 to 9.1% are obtained. In all three spiked levels (20, 100 and 200 ng L{sup -1}), the recoveries of FQs are in the range of 76.3-94.2%. The proposed method was successfully applied to determine FQs including ciprofloxacin, enrofloxacin, lomefloxacin, levofloxacin, fleroxacin and sparfloxacin in different water samples, such as lake water, river water, primary and final sewage effluent. Ciprofloxacin and fleroxacin were found in primary and final sewage effluent samples with the contents in the range of 26-87 ng L{sup -1}.

  6. A novel liquid chromatography/tandem mass spectrometry method for the quantification of glycine as biomarker in brain microdialysis and cerebrospinal fluid samples within 5min.

    Science.gov (United States)

    Voehringer, Patrizia; Fuertig, René; Ferger, Boris

    2013-11-15

    Glycine is an important amino acid neurotransmitter in the central nervous system (CNS) and a useful biomarker to indicate biological activity of drugs such as glycine reuptake inhibitors (GRI) in the brain. Here, we report how a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the fast and reliable analysis of glycine in brain microdialysates and cerebrospinal fluid (CSF) samples has been established. Additionally, we compare this method with the conventional approach of high performance liquid chromatography (HPLC) coupled to fluorescence detection (FD). The present LC-MS/MS method did not require any derivatisation step. Fifteen microliters of sample were injected for analysis. Glycine was detected by a triple quadrupole mass spectrometer in the positive electrospray ionisation (ESI) mode. The total running time was 5min. The limit of quantitation (LOQ) was determined as 100nM, while linearity was given in the range from 100nM to 100μM. In order to demonstrate the feasibility of the LC-MS/MS method, we measured glycine levels in striatal in vivo microdialysates and CSF of rats after administration of the commercially available glycine transporter 1 (GlyT1) inhibitor LY 2365109 (10mg/kg, p.o.). LY 2365109 produced 2-fold and 3-fold elevated glycine concentrations from 1.52μM to 3.6μM in striatal microdialysates and from 10.38μM to 36μM in CSF, respectively. In conclusion, we established a fast and reliable LC-MS/MS method, which can be used for the quantification of glycine in brain microdialysis and CSF samples in biomarker studies. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Quantification of theobromine and caffeine in saliva, plasma and urine via liquid chromatography-tandem mass spectrometry: a single analytical protocol applicable to cocoa intervention studies.

    Science.gov (United States)

    Ptolemy, Adam S; Tzioumis, Emma; Thomke, Arjun; Rifai, Sami; Kellogg, Mark

    2010-02-01

    Targeted analyses of clinically relevant metabolites in human biofluids often require extensive sample preparation (e.g., desalting, protein removal and/or preconcentration) prior to quantitation. In this report, a single ultra-centrifugation based sample pretreatment combined with a designed liquid chromatography-tandem mass spectrometry (LC-MS/MS) protocol provides selective quantification of 3,7-dimethylxanthine (theobromine) and 1,3,7-trimethylxanthine (caffeine) in human saliva, plasma and urine samples. The optimized chromatography permitted elution of both analytes within 1.3 min of the applied gradient. Positive-mode electrospray ionization and a triple quadruple MS/MS instrument operated in multiple reaction mode were used for detection. (13)C(3) isotopically labeled caffeine was included as an internal standard to improve accuracy and precision. Implementing a 20-fold dilution of the isolated low MW biofluid fraction prior to injection effectively minimized the deleterious contributions of all three matrices to quantitation. The assay was linear over a 160-fold concentration range from 2.5 to 400 micromol L(-1) for both theobromine (average R(2) 0.9968) and caffeine (average R(2) 0.9997) respectively. Analyte peak area variations for 2.5 micromol L(-1) caffeine and theobromine in saliva, plasma and urine ranged from 5 and 10% (intra-day, N=10) to 9 and 13% (inter-day, N=25) respectively. The intra- and inter-day precision of theobromine and caffeine elution times were 3 and theobromine ranged from 114 to 118% and 99 to 105% at concentration levels of 10 and 300 micromol L(-1). This validated protocol also permitted the relative saliva, plasma and urine distribution of both theobromine and caffeine to be quantified following a cocoa intervention. 2009 Elsevier B.V. All rights reserved.

  8. Quantification of piroxicam and 5'-hydroxypiroxicam in human plasma and saliva using liquid chromatography-tandem mass spectrometry following oral administration.

    Science.gov (United States)

    Calvo, Adriana Maria; Santos, Gabriel Mulinari; Dionísio, Thiago José; Marques, Maria Paula; Brozoski, Daniel Thomas; Lanchote, Vera Lúcia; Fernandes, Maria Helena Raposo; Faria, Flávio Augusto Cardoso; Santos, Carlos Ferreira

    2016-02-20

    Saliva sampling used to quantify piroxicam and 5'-hydroxypiroxicam is a noninvasive and painless method when compared to sequential blood sampling. For that, a rapid, selective and sensitive liquid chromatography-tandem mass spectrometric method for simultaneous determination of piroxicam and 5'-hydroxypiroxicam in saliva and human plasma was developed and validated. Piroxicam and its major metabolite were separated using a LiChroCART 125-4 RP Select-B Sorbent C18 column using a mixture of methanol and 2% phosphoric acid (pH 2.7) (70:30, v/v) for the mobile phase with a flow injection of 1mL/min. The run time was 4min. Volunteers had saliva and blood sampled before, 1, 2, 3, 4, 5, 6, 8, 11, 24, 48 and 72h after taking a 20mg oral dose of piroxicam. The pharmacokinetic parameters of piroxicam in plasma samples were as follows: AUC0-72 (64819hng/mL), predicted clearance (0.2L/h), distribution volume (14.8L), elimination half-life (50.7h) and saliva/plasma concentration ratio (0.003). The estimation of all pharmacokinetic parameters for 5'-hydroxypiroxicam would require collections beyond 72h; however, it was possible to quantify the mean maximum concentration (133ng/mL), time to peak concentration (53.6h), mean AUC0-72 (6213hng/mL), predicted clearance (110.3L/h) and saliva/plasma concentration ratio (0.04). The developed methods proved effective and sensitive for determining the lower quantification limit of piroxicam in plasma (6.1ng/mL) and saliva (0.15ng/mL) and of 5'-hydroxypiroxicam in plasma (1.2ng/mL) and saliva (0.15ng/mL). Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Performance Assessment and Comparability of a Commercial Enzyme-Linked Immunosorbent Assay Kit with Liquid Chromatography-Tandem Mass Spectrometry for Chloramphenicol Residues in Crab and Shrimp.

    Science.gov (United States)

    Jester, Edward L E; Loader, Jared I; El Said, Kathleen R; Abraham, Ann; Flores Quintana, Harold A; Plakas, Steven M

    2016-01-01

    Monitoring for chloramphenicol (CAP) in aquaculture products is primarily performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), which requires expensive equipment and specialized training. Many laboratories prefer to screen samples with facile and high-throughput enzyme-linked immunosorbent assay (ELISA) kits for CAP residues before submitting samples for LC-MS/MS quantification and confirmation. We evaluated the performance of a Ridascreen (R-Biopharm) ELISA kit for CAP in spiked and incurred crab and shrimp muscle at levels bracketing the minimum required performance level for analysis (0.3 ng/g). The Ridascreen ELISA kit incorporates antibody directed against CAP. Incurred CAP levels in crab and shrimp muscle were verified using LC-MS/MS. We found good repeatability (relative standard deviation) of the ELISA in spiked and incurred crab and shrimp muscle samples, with values ranging from 6.8 to 21.7%. Recoveries of CAP from tissues spiked at 0.15 to 0.60 ng/g ranged from 102 to 107%. Minimal cross-reactivity with blank crab and shrimp muscle matrix components was observed. ELISA data were highly correlated with those of LC-MS/MS for CAP in incurred muscle tissue. We believe this study to be the first evaluation of the performance and comparability of a CAP ELISA kit and LC-MS/MS for determination of CAP residues, as well as their elimination, in crab muscle. Our findings support the use of this ELISA kit for screening purposes and, when used in conjunction with validated instrumental methods, for regulatory monitoring of CAP in these species.

  10. Method development for the quantitation of ABT-578 in rabbit artery tissue by 96-well liquid-liquid extraction and liquid chromatography/tandem mass spectrometric detection.

    Science.gov (United States)

    Ji, Qin C; Zhang, Jun; Rodila, Ramona; Watson, Pamela; El-Shourbagy, Tawakol

    2004-01-01

    Quantitative determination of drug concentrations in tissue samples can provide critical information for drug metabolism, kinetics, and toxicity evaluations. For analysis of tissue samples using liquid chromatography/tandem mass spectrometric (LC/MS/MS) detection, homogenization is a critical step in achieving good assay performance. Assay performance can be closely evaluated by spiking the drug directly into tissue samples prior to homogenization. It is especially important to include this assay evaluation for the analysis of artery tissue samples because artery tissue is very elastic, making it quite a challenge to develop an effective procedure for homogenization. An LC/MS/MS assay in 96-well format using liquid-liquid extraction was developed for analyzing ABT-578 in rabbit artery samples. Tissue quality control samples were prepared by spiking ABT-578 stock solutions directly into the tissue before homogenization. The usage of the tissue control samples gives a thorough evaluation of the sample preparation process that includes both homogenization and sample extraction. A 20% blood in saline solution was used as a homogenization solution. Calibration standards were made by spiking ABT-578 into rabbit whole blood. Blood quality control samples were also prepared by spiking ABT-578 into rabbit whole blood. These blood QC samples were used to confirm the validity of the calibration curve. A lower limit of quantitation of 0.050 ng/mL was achieved. The linear dynamic range of blood standards was from 0.050-30.3 ng/mL with the correlation coefficient (r) ranging from 0.9969-0.9996. Overall %CV was between 1.3 and 7.0%, and analytical recovery was between 98.2 and 105.8% for blood QC samples. The %CVs for tissue QC samples were between 6.7 and 13.0%, and analytical recovery after correction was between 93.5 and 114.3%. Copyright 2004 John Wiley & Sons, Ltd.

  11. Method development for the concentration determination of a protein in human plasma utilizing 96-well solid-phase extraction and liquid chromatography/tandem mass spectrometric detection.

    Science.gov (United States)

    Ji, Qin C; Gage, Eric M; Rodila, Ramona; Chang, Min S; El-Shourbagy, Tawakol A

    2003-01-01

    Although liquid chromatography/tandem mass spectrometry (LC/MS/MS) technology has been widely used for quantitative analysis of small organic molecules, it has been a challenging task to quantitatively analyze protein samples utilizing this technology in biological matrices for pre-clinical and clinical studies. Here we present our initial results in method development for the quantitative determination of rK5 protein concentrations in human plasma samples utilizing LC/MS/MS technology. A protein similar in structure to rK5, but with a slightly reduced molecular weight, was used as internal standard. A 96-well solid-phase extraction procedure was developed to effectively extract protein analytes from plasma samples. Quantitative analysis was obtained by a novel approach of protein monitoring that employed selective reaction monitoring (SRM). Even though mass spectrometry of the internal standard protein gave no fragment ions, SRM monitoring greatly reduced background interference. Using samples prepared in human plasma with sodium EDTA as anticoagulant, a correlation coefficient (r(2)) of 0.9940 was obtained by producing a single standard curve with the injection of six rows of standards with a concentration range from 100 ng/mL to 10 microg/mL. The mean analytical recovery for these standards ranged from 91.5 to 103.6%. The CVs for individual standard levels ranged from 3.7 to 20.9%. The experiment was also repeated using samples prepared in human plasma with sodium heparin as anticoagulant, which produced a correlation coefficient (r(2)) of 0.9952 obtained from a single standard curve with the injection of four rows of standards with a concentration range from 50 ng/mL to 10 microg/mL. The mean analytical recovery for the standards ranged from 96.2 to 104.6%. The CVs for individual standard levels ranged from 2.6 to 15.6%. Copyright 2003 John Wiley & Sons, Ltd.

  12. Direct large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry determination of artificial sweeteners sucralose and acesulfame in well water.

    Science.gov (United States)

    Wu, Minghuo; Qian, Yichao; Boyd, Jessica M; Hrudey, Steve E; Le, X Chris; Li, Xing-Fang

    2014-09-12

    Acesulfame (ACE) and sucralose (SUC) have become recognized as ideal domestic wastewater contamination indicators. Liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) analysis is commonly used; however, the sensitivity of SUC is more than two orders of magnitude lower than that of ACE, limiting the routine monitoring of SUC. To address this issue, we examined the ESI behavior of both ACE and SUC under various conditions. ACE is ionic in aqueous solution and efficiently produces simple [M-H](-) ions, but SUC produces multiple adduct ions, limiting its sensitivity. The formic acid (FA) adducts of SUC [M+HCOO](-) are sensitively and reproducibly generated under the LC-MS conditions. When [M+HCOO](-) is used as the precursor ion for SUC detection, the sensitivity increases approximately 20-fold compared to when [M-H](-) is the precursor ion. To further improve the limit of detection (LOD), we integrated the large volume injection approach (500μL injection) with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), which reduced the method detection limit (MDL) to 0.2ng/L for ACE and 5ng/L for SUC. To demonstrate the applicability of this method, we analyzed 100 well water samples collected in Alberta. ACE was detected in 24 wells at concentrations of 1-1534ng/L and SUC in 8 wells at concentrations of 65-541ng/L. These results suggest that wastewater is the most likely source of ACE and SUC impacts in these wells, suggesting the need for monitoring the quality of domestic well water. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of sulfonamides, trimethoprim and dapsone in muscle, egg, milk and honey.

    Science.gov (United States)

    Varenina, Ivana; Bilandžić, Nina; Kolanović, Božica Solomun; Božić, Đurđica; Sedak, Marija; Đokić, Maja; Varga, Ines

    2016-01-01

    A quantitative multi-residue method that includes 13 sulfonamides, trimethoprim and dapsone was developed and validated according to Commission Decision 2002/657/EC for muscle, milk egg and honey samples. For all matrices, the same extraction procedure was used. Samples were extracted with an acetone/dichloromethane mixture and cleaned up on aromatic sulfonic acid (SO3H) SPE cartridges. After elution and concentration steps, analytes were identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Data were acquired according to the multiple reaction-monitoring approach (MRM) and analytes were quantified both by the isotope dilution and the matrix-matched approaches calculating the response factors for the scanned product ions. The developed method shows good linearity, specificity, precision (repeatability and within-laboratory reproducibility), and trueness. Estimated CCβ for sulfonamides ranged between 5.6 and 8.2 µg kg(-1) for eggs, between 11.1 and 69.9 µg kg(-1) for milk, between 64.7 and 87.9 µg kg(-1) for muscle, and between 2.7 and 5.3 µg kg(-1) for honey. CCβ values for dapsone were 3.1, 0.6, 0.7 and 1.5 µg kg(-1) and for trimethoprim were 3.1, 6.7, 81.7 and 3.0 µg kg(-1) calculated for eggs, milk, muscle and honey, respectively. Recovery for all matrices was in the range from 89.1% and 109.7%. In matrix effect testing, no significant deviations were found between different samples of muscle and milk; however, a matrix effect was observed when testing different types of honey. The validation results demonstrate that the method is suitable for routine veterinary drug analysis and confirmation of suspect samples.

  14. Confirmation of 13 sulfonamides in honey by liquid chromatography-tandem mass spectrometry for monitoring plans: validation according to European Union Decision 2002/657/EC.

    Science.gov (United States)

    Dubreil-Chéneau, Estelle; Pirotais, Yvette; Verdon, Eric; Hurtaud-Pessel, Dominique

    2014-04-25

    A rapid and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous confirmation of 13 sulfonamides in honey was developed and fully validated in accordance with the European Commission Decision No 2002/657/EC. The validation scheme was built in accordance with the target level of 50μgkg(-1) for all analytes. The sulfonamides investigated were as follows: sulfaguanidine (SGN), sulfanilamide (SNL), sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethizole (SMZ), sulfadimerazine (SDM), sulfamonomethoxine (SMNM), sulfamethoxypiridazine (SMP), sulfadoxine (SDX), sulfamethoxazole (SMX), sulfaquinoxaline (SQX) and sulfadimethoxine (SDT). Several extraction procedures were investigated during the development phase. Finally, the best results were obtained with a procedure using acidic hydrolysis and cation exchange purification. Chromatographic separation was achieved on a C18 analytical column. Matrix effects were also investigated. Data acquisition implemented for the confirmatory purpose was performed by monitoring 2 MRM transitions per analyte under the positive electrospray mode. Mean relative recoveries ranged from 85.8% to 110.2% and relative standard deviations lying between 2.6% and 19.8% in intra-laboratory reproducibility conditions. The decision limits (CCα) ranged from 1.8 to 15.5μgkg(-1). High resolution mass spectrometry was used to investigate the possible formation of sulfonamide metabolites in honey. The validation results proved that the method is suitable for the screening and confirmatory steps as implemented for the French monitoring residue plan for sulfonamides residue control in honeybees. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Simultaneous determination of morinidazole, its N-oxide, sulfate, and diastereoisomeric N(+)-glucuronides in human plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Gao, Ruina; Zhong, Dafang; Liu, Ke; Xia, Yu; Shi, Rongwei; Li, Hua; Chen, Xiaoyan

    2012-11-01

    Morinidazole is a new third-generation 5-nitroimidazole antimicrobial drug. To investigate the pharmacokinetic profiles of morinidazole and its major metabolites in humans, a liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous determination of morinidazole, its N-oxide metabolite (M4-1), a sulfate conjugate (M7), and two diastereoisomeric N(+)-glucuronides (M8-1 and M8-2) in human plasma. A simple acetonitrile-induced protein precipitation was employed to extract five analytes and internal standard metronidazole from 50μL human plasma. To avoid the interference from the in-source dissociation of the sulfate and achieve the baseline-separation of diastereoisomeric N(+)-glucuronides, all the analytes were separated from each other with the mobile phase consisting of 10mM ammonium formate and acetonitrile using gradient elution on a Hydro-RP C(18) column (50mm×2mm, 4μm) with a total run time of 5min. The API 4000 triple quadrupole mass spectrometer was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. The developed method was linear in the concentration ranges of 10.0-12,000ng/mL for morinidazole, 1.00-200ng/mL for M4-1, 2.50-500ng/mL for M7, 3.00-600ng/mL for M8-1, and 10.0-3000ng/mL for M8-2. The intra- and inter-day precisions for each analyte met the accepted value. Results of the stability of morinidazole and its metabolites in human plasma were also presented. The method was successfully applied to the clinical pharmacokinetic studies of morinidazole injection in healthy subjects, patients with moderate hepatic insufficiency, and patients with severe renal insufficiency, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Food Safety is an Important Public Health Issue: Chloramphenicol Residues Determination by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) in honey.

    Science.gov (United States)

    Krivohlavek, Adela; Žuntar, Irena; Ivešić, Martina; Andačić, Ivana Mandić; Šikić, Sandra

    2014-12-01

    Honey is used for nutritional, medicinal and industrial purposes and antibiotic residues may harm its quality and constitute a danger to human health. The broad spectrum antibiotic chloramphenicol (CAP) was used for curative purposes in veterinary medicine, but is now forbidden in European Union (EU) because of its many serious side effects (e.g. aplastic anaemia, grey syndrome, severe bone marrow depression and hypersensitivity). The aim of this study was to facilitate analyses of the quality and safety of Croatian honey distributed to whole European Union market; an assessment that has not previously been made. CAP in honey was qualifying and quantifying by validated liquid chromatography tandem mass spectrometry with negative electrospray ionisation method (LC-MS/MS). The target antibiotic was separated on chromatographic column Zorbax SB C18 (150 mm x 2.1 mm, 3.5 μm) with a gradient elution using acetonitrile - 0.1% formic acid mobile phase at a flow rate of 0.3 mL/min, with column temperature 35°C for CAP and 5D-CAP as internal standard. Homogenised honey samples were diluted with acetate buffer solution and extracted on Oasis Hydrophilic-Lipophilic-Balanced (HLB) sorbents. The method was used to analyse 280 domestic honey samples collected throughout Croatia between 2005.-2013. Recoveries of the method for real (acacia, chestnut, linden and flower) honey samples were 102% with RSD 8.4%. The value CCα and CCβ were 0.09 and 0.12 μg/kg, respectively. Results showed only three subsequent positive detections (1.1%) of CAP in honey. Analysed honey samples from Croatia showed good quality and safety what is the one of the main objective in consumer health policy in EU.

  17. Determination of methylmalonyl coenzyme A by ultra high-performance liquid chromatography tandem mass spectrometry for measuring propionyl coenzyme A carboxylase activity in patients with propionic acidemia.

    Science.gov (United States)

    Gotoh, Kana; Nakajima, Yoko; Tajima, Go; Watanabe, Yoriko; Hotta, Yuji; Kataoka, Tomoya; Kawade, Yoshihiro; Sugiyama, Naruji; Ito, Tetsuya; Kimura, Kazunori; Maeda, Yasuhiro

    2017-03-01

    Propionic acidemia (PA) is an inherited metabolic disease caused by low activity of propionyl coenzyme A (CoA) carboxylase (PCC), which metabolizes propionyl-CoA into methylmalonyl-CoA. Although many patients with PA have been identified by tandem mass spectrometry since the test was first included in neonatal mass screening in the 1990s, the disease severity varies. Thus, determining the specific level of PCC activity is considered to be helpful to grasp the severity of PA. We developed a new PCC assay method by the determination of methylmalonyl-CoA, which is formed by an enzyme reaction using peripheral lymphocytes, based on ultra high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). With methylmalonyl-CoA concentrations of 0.05, 0.5, and 5μmol/L, the intra-assay coefficients of variation (CVs) were 8.2%, 8.7%, and 5.1%, respectively, and the inter-assay CVs were 13.6%, 10.5%, and 5.9%, respectively. The PCC activities of 20 healthy individuals and 6 PA patients were investigated with this assay. Methylmalonyl-CoA was not detected in one PA patient with a severe form of the disease, but the remaining PA patients with mild disease showed residual activities (3.3-7.8%). These results demonstrate that determination of PCC activity with this assay would be useful to distinguish between mild and severe cases of PA to help choose an appropriate treatment plan. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Development of a new ultra-high performance liquid chromatography - tandem mass spectrometry method for determination of ambroxol hydrochloride in serum with pharmacokinetic application

    Directory of Open Access Journals (Sweden)

    Vujović Maja M.

    2016-01-01

    Full Text Available Ambroxol hydrochloride is an expectorant agent, successfully applied in mucolytic therapy for acute and chronic bronchopulmonary diseases. The drug regulates not only mucus secretion but also showed antioxidant, anti-inflammatory and local anesthetic properties. To supplement the pharmacokinetic and toxicological studies of ambroxol, a rapid ultra-high performance liquid chromatography-tandem mass spectrometry method for the quantitation of ambroxol in rabbit serum was developed. A validation of the method was performed as per the ICH guidelines for the validation of bioanalytical methods. The chromatographic separation was achieved in a submicron Kinetex RP - C18 - column (2.1 mm x 50 mm, 1.3μm using the no buffer mobile phase. The ESI mass spectrometry in the MRM mode was used with a typical transitions m/z 378.9→263.8 for ambroxol and m/z 455.2→165.0 for IS. Linearity was determined with an average coefficient of determination >0.999 over the dynamic range from 0.5 - 200 ng/mL with LOD and LOQ of 0.25 ng/mL and 0.5 ng/mL, respectively. The results of the intra- and inter-day precision and accuracy determined in different days were all found to be within the acceptable limits ±15%. The present method was successfully applied to pharmacokinetic study in the rabbits after a single oral dose administration. [Projekat Ministarstva nauke Republike Srbije, br. 175045

  19. Quantification of Cannabinoids and their Free and Glucuronide Metabolites in Whole Blood by Disposable Pipette Extraction and Liquid Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Scheidweiler, Karl B.; Newmeyer, Matthew N.; Barnes, Allan J.; Huestis, Marilyn A.

    2016-01-01

    Identifying recent cannabis intake is confounded by prolonged cannabinoid excretion in chronic frequent cannabis users. We previously observed detection times ≤2.1 h for cannabidiol (CBD) and cannabinol (CBN) and THC-glucuronide in whole blood after smoking, suggesting their applicability for identifying recent intake. However, whole blood collection may not occur for up to 4 h during driving under the influence of drugs investigations, making a recent-use marker with a 6-8 h detection window helpful for improving whole blood cannabinoid interpretation. Other minor cannabinoids cannabigerol (CBG), Δ9-tetrahydrocannabivarin (THCV), and its metabolite 11-nor-9-carboxy-THCV (THCVCOOH) might also be useful. We developed and validated a sensitive and specific liquid chromatography-tandem mass spectrometry method for quantification of THC, its phase I and glucuronide phase II metabolites, and 5 five minor cannabinoids. Cannabinoids were extracted from 200 μL whole blood via disposable pipette extraction, separated on a C18 column, and detected via electrospray ionization in negative mode with scheduled multiple reaction mass spectrometric monitoring. Linear ranges were 0.5-100 μg/L for THC and THCCOOH; 0.5-50 μg/L for 11-OH-THC, CBD, CBN, and THC-glucuronide; 1-50 μg/L for CBG, THCV, and THCVCOOH; and 5-500 μg/L for THCCOOH-glucuronide. Inter-day accuracy and precision at low, mid and high quality control (QC) concentrations were 95.1-113% and 2.4-8.5%, respectively (n=25). Extraction recoveries and matrix effects at low and high QC concentrations were 54.0-84.4% and −25.8-30.6%, respectively. By simultaneously monitoring multiple cannabinoids and metabolites, identification of recent cannabis administration or discrimination between licit medicinal and illicit recreational cannabis use can be improved. PMID:27236483

  20. Targeted screening and safety evaluation of 276 agrochemical residues in raisins using buffered ethyl acetate extraction and liquid chromatography-tandem mass spectrometry analysis.

    Science.gov (United States)

    Shabeer, T P Ahammed; Jadhav, Manjusha; Girame, Rushali; Hingmire, Sandip; Bhongale, Aarti; Pudale, Anjali; Banerjee, Kaushik

    2017-10-01

    A buffered ethyl acetate extraction method was optimized and validated in raisin matrix to monitor 276 pesticides by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The final method involved homogenization of raisinsalong with water 1:1 raisins: water followed by extraction using ethyl acetate (10 mL/10 g raisins homogenate in presence of 0.1 mL acetic acid, 0.5 g sodium acetate and 10 g sodium sulfate, and cleanup by dispersive solid phase extraction with primary secondary amine sorbent (25 mg/5 mL extract). 276 pesticides were estimated within 20 min of chromatographic run time by retention time dependent 'scheduled multiple reaction monitoring' (sMRM) by LC-MS/MS.The method was validated as per European guideline, DG-SANTE/11945/2015, at 2, 10, and 25 ng/g spiking levels where the method precision in terms of repeatability was <15% at 10 ng/g for 93.8% of the compounds. The Limit of quantification (LOQ) ranged between 0.01 and 10 ng/g with recoveries 70-120% with ≤20% RSD for 93.5% of compounds at regulatory default MRL of 10 ng/g. The matrix induced signal suppressions or enhancement were moderate (60-130% accuracy against solvent standard) for 85% compounds in white raisins and 67% compounds in black raisins. The method was successfully applied for screening of 94 market samples of raisins for the target analytes. The dietaryexposures calculated against the average concentrations detected were wellbelow the maximum permissible intake (MPI) values and the collected raisin samples were considered safe for human consumption without any acute toxicity hazard. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A simple automated solid-phase extraction procedure for measurement of 25-hydroxyvitamin D3 and D2 by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Knox, Susan; Harris, John; Calton, Lisa; Wallace, A Michael

    2009-05-01

    Measurement of 25-hydroxyvitamin D(3) (25OHD(3)) and D(2) (25OHD(2)) is challenging. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods have been described but they are often complex and difficult to automate. We have developed a simplified procedure involving an automated solid-phase extraction (SPE). Internal standard (hexadeuterated 25-hydroxyvitamin D(3)) was added to serum or plasma followed by protein precipitation with methanol. Following centrifugation, a robotic instrument (CTC PAL [Presearch] for ITSP SPE [MicroLiter Analytical Supplies, Inc]) performed a six-step SPE procedure and the purified samples were injected into the LC-MS/MS. Quantification of 25OHD(3) and 25OHD(2) was by electrospray ionization MS/MS in the multiple-reaction monitoring mode. The lower limit of quantitation was 4.0 nmol/L for 25OHD(3) and 7.5 nmol/L for 25OHD(2). Within- and between-assay precision was below 10% over the concentration range of 22.5-120 nmol/L for D(3) and 17.5-70 nmol/L for D(2) (n = 10). The calibration was linear up to 2500 nmol/L (r = 0.99). Recoveries ranged between 89% and 104% for both metabolites and no ion suppression was observed. The results obtained compared well (r = 0.96) with the IDS-OCTEIA 25-hydroxyvitamin D enzyme immunoassay for samples containing less than 125 nmol/L, at higher concentrations the immunodiagnostic system (IDS) method showed positive bias. Our simplified sample preparation and automated SPE method is suitable for the measurement of 25OHD(3) and D(2) in a routine laboratory environment. The system can process up to 300 samples per day with no cumbersome solvent evaporation step and minimal operator intervention.

  2. Sequential determination of fat- and water-soluble vitamins in Rhodiola imbricata root from trans-Himalaya with rapid resolution liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Tayade, Amol B; Dhar, Priyanka; Kumar, Jatinder; Sharma, Manu; Chaurasia, Om P; Srivastava, Ravi B

    2013-07-30

    A rapid method was developed to determine both types of vitamins in Rhodiola imbricata root for the accurate quantification of free vitamin forms. Rapid resolution liquid chromatography/tandem mass spectrometry (RRLC-MS/MS) with electrospray ionization (ESI) source operating in multiple reactions monitoring (MRM) mode was optimized for the sequential analysis of nine water-soluble vitamins (B1, B2, two B3 vitamins, B5, B6, B7, B9, and B12) and six fat-soluble vitamins (A, E, D2, D3, K1, and K2). Both types of vitamins were separated by ion-suppression reversed-phase liquid chromatography with gradient elution within 30 min and detected in positive ion mode. Deviations in the intra- and inter-day precision were always below 0.6% and 0.3% for recoveries and retention time. Intra- and inter-day relative standard deviation (RSD) values of retention time for water- and fat-soluble vitamin were ranged between 0.02-0.20% and 0.01-0.15%, respectively. The mean recoveries were ranged between 88.95 and 107.07%. Sensitivity and specificity of this method allowed the limits of detection (LOD) and limits of quantitation (LOQ) of the analytes at ppb levels. The linear range was achieved for fat- and water-soluble vitamins at 100-1000 ppb and 10-100 ppb. Vitamin B-complex and vitamin E were detected as the principle vitamins in the root of this adaptogen which would be of great interest to develop novel foods from the Indian trans-Himalaya. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Simultaneous determination of UV-filters and estrogens in aquatic invertebrates by modified quick, easy, cheap, effective, rugged, and safe extraction and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    He, Ke; Timm, Anne; Blaney, Lee

    2017-08-04

    Ultraviolet-filters (UV-filters) and estrogens have attracted increased attention as contaminants of emerging concern (CECs) due to their widespread occurrence in the environment. Most of these CECs are hydrophobic and have the potential to accumulate in aquatic organisms. To date, co-analysis of UV-filters and estrogens has not been reported due, in part, to the complex environmental matrices. Here, a multi-residue method has been developed for simultaneous determination of five UV-filters and three estrogens in tissue from aquatic and marine organisms. The procedure involved a modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction with a novel reverse-solid-phase extraction (reverse-SPE) cleanup in place of dispersive-SPE, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. The tissue mass, acetonitrile content, and salt conditions for QuEChERS extraction, along with the reverse-SPE cartridge material and elution conditions, were thoroughly investigated and optimized. Five UV-filters (i.e., 3-(4-methylbenzylidene) camphor, benzophenone-3, ethylhexylmethoxycinnamate, homosalate, and octocrylene) and three estrogens (i.e., estrone, 17β-estradiol, and 17α-ethinylestradiol) were simultaneously analyzed by taking advantage of wrong-way-round ionization in LC-MS/MS. The optimized analytical protocol exhibited good recoveries (>80%) for target compounds and enabled their detection at concentrations as low as 0.2ng/g in 50mg tissue samples. The method was applied to determine concentrations of target analytes in four invertebrates (i.e., Orconectes virilis, Procambarus clarkii, Crassostrea virginica, and Ischadium recurvum). All eight target analytes were detected at least once in the tissue samples, with the highest concentration being 399ng/g of homosalate in O. virilis. These results highlight the ubiquitous bioaccumulation of CECs in aquatic and marine invertebrates. Copyright © 2017 Elsevier B.V. All rights

  4. Method development and validation of liquid chromatography-tandem/mass spectrometry for aldosterone in human plasma: Application to drug interaction study of atorvastatin and olmesartan combination

    Directory of Open Access Journals (Sweden)

    Rakesh Das

    2014-01-01

    Full Text Available In the present investigation, a simple and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS method was developed for the quantification of aldosterone (ALD a hormone responsible for blood pressure in human plasma. The developed method was validated and extended for application on human subjects to study drug interaction of atorvastatin (ATSV and olmesartan (OLM on levels of ALD. The ALD in plasma was extracted by liquid-liquid extraction with 5 mL dichloromethane/ethyl ether (60/40% v/v. The chromatographic separation of ALD was carried on Xterra, RP-Column C18 (150 mm× 4.6 mm × 3.5 μm at 30°C followed by four-step gradient program composed of methanol and water. Step 1 started with 35% methanol for first 1 min and changed linearly to 90% in next 1.5 min in Step 2. Step 3 lasted for next 2 min with 90% methanol. The method finally concluded with Step 4 to achieve initial concentration of methanol that is, 35% thus contributing the total method run time of 17.5 min. The flow rate was 0.25 mL/min throughout the process. The developed method was validated for specificity, accuracy, precision, stability, linearity, sensitivity, and recovery. The method was linear and found to be acceptable over the range of 50-800 ng/mL. The method was successfully applied for the drug interaction study of ATSV + OLM in combination against OLM treatment on blood pressure by quantifying changes in levels of ALD in hypertensive patients. The study revealed levels of ALD were significantly higher in ATSV + OLM treatment condition when compared to OLM as single treated condition. This reflects the reason of low effectiveness of ATSV + OLM in combination instead of synergistic activity.

  5. Analysis of fenretinide and its metabolites in human plasma by liquid chromatography-tandem mass spectrometry and its application to clinical pharmacokinetics.

    Science.gov (United States)

    Cho, Hwang Eui; Min, H Kang

    2017-01-05

    A simple and accurate high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of N-(4-hydroxyphenyl)retinamide (fenretinide, 4-HPR) and its metabolites, 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR) and N-(4-methoxyphenyl)retinamide (4-MPR), in human plasma. Plasma samples were prepared using protein precipitation with ethanol. Chromatographic separation of the three analytes and N-(4-ethoxyphenyl)retinamide (4-EPR), an internal standard, was achieved on a Zorbax SB-C18 column (3.5μm, 50×2.1mm) using gradient elution with the mobile phase of 0.1% formic acid in water and acetonitrile (pH* 2.4) at a flow rate of 0.5mL/min. Electrospray ionization (ESI) mass spectrometry was operated in the positive ion mode with multiple reaction monitoring (MRM). The calibration curves obtained were linear over the concentration range of 0.2-50ng/mL with a lower limit of quantification of 0.2ng/mL. The relative standard deviation of intra-day and inter-day precision was below 7.64%, and the accuracy ranged from 94.92 to 105.43%. The extraction recoveries were found to be higher than 90.39% and no matrix effect was observed. The analytes were stable for the durations of the stability studies. The validated method was successfully applied to the analyses of the pharmacokinetic study for patients treated with 4-HPR in a clinical trial. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Pre-column dilution large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis of multi-class pesticides in cabbages.

    Science.gov (United States)

    Zhong, Qisheng; Shen, Lingling; Liu, Jiaqi; Yu, Dianbao; Li, Siming; Yao, Jinting; Zhan, Song; Huang, Taohong; Hashi, Yuki; Kawano, Shin-ichi; Liu, Zhaofeng; Zhou, Ting

    2016-04-15

    Pre-column dilution large volume injection (PD-LVI), a novel sample injection technique for reverse phase ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), was developed in this study. The PD-LVI UHPLC-MS/MS system was designed by slightly modifying the commercial UHPLC-MS/MS equipment with a mixer chamber. During the procedure of PD-LVI, sample solution of 200μL was directly carried by the organic mobile phase to the mixer and diluted with the aqueous mobile phase. After the mixture was introduced to the UHPLC column in a mobile phase of acetonitrile-water (15/85, v/v), the target analytes were stacked on the head of the column until following separation. Using QuEChERS extraction, no additional steps such as solvent evaporation or residue redissolution were needed before injection. The features of PD-LVI UHPLC-MS/MS system were systematically investigated, including the injection volume, the mixer volume, the precondition time and the gradient elution. The efficiency of this approach was demonstrated by direct analysis of 24 pesticides in cabbages. Under the optimized conditions, low limits of detection (0.00074-0.8 ng/kg) were obtained. The recoveries were in the range of 63.3-109% with relative standard deviations less than 8.1%. Compared with common UHPLC-MS/MS technique, PD-LVI UHPLC-MS/MS showed significant advantages such as excellent sensitivity and reliability. The mechanism of PD-LVI was demonstrated to be based on the column-head stacking effect with pre-column dilution. Based on the results, PD-LVI as a simple and effective sample injection technique of reverse phase UHPLC-MS/MS for the analysis of trace analytes in complex samples showed a great promising prospect. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Simultaneous determination of veterinary antibiotics and hormone in broiler manure, soil and manure compost by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ho, Y B; Zakaria, Mohamad Pauzi; Latif, Puziah Abdul; Saari, Nazamid

    2012-11-02

    A multi-residue analytical method was developed to quantify nine antibiotics and one hormone in soil, broiler manure and manure compost. The developed method was based on ultrasonic extraction with MeOH:ACN:EDTA:McIlvaine buffer, solid phase extraction (SPE) using HLB (3 cc/60 mg) cartridge, followed by instrumental analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with 25 min total run time. It was validated and tested on soil, broiler manure and manure compost samples and showed that the method is able to simultaneously detect and quantify the target analytes with good selectivity and sensitivity. The developed method was linear in a concentration range from its instrumental quantification limit (IQL) to 500 ng/mL, with correlation coefficients higher than 0.999. The overall method performance was good for the majority of the analytes, with recoveries range from 63% to 121% in all the sample matrices. The method quantification limit (MQL) for the 10 target analytes in the soil, broiler manure and manure compost samples were 2-10, 3-16 and 5-15 μg/kg dry weight (DW), respectively. The method has also included tilmicosin, an antibiotic known to be reported in the environment for the first time. The developed method was then applied on broiler manure samples and its relative manure amended agricultural soil samples to identify and quantify veterinary antibiotic and hormone residues in the environment. These analytes were detected in broiler manure and soil samples, with maximum concentrations reaching up to 78516.1 μg/kg DW (doxycycline) and 1331.4 μg/kg DW (flumequine), respectively. The results showed that the method can potentially be adopted for the analysis of veterinary antibiotic and hormone wastes in solid environmental matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Analysis of 17 neurotransmitters, metabolites and precursors in zebrafish through the life cycle using ultrahigh performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Santos-Fandila, A; Vázquez, E; Barranco, A; Zafra-Gómez, A; Navalón, A; Rueda, R; Ramírez, M

    2015-09-15

    An ultrahigh performance liquid chromatography-tandem mass spectrometry method for the identification and quantification of neurotransmitters, metabolites and precursors at different stages in zebrafish life was developed. Betaine, glutamine, glutamic acid, γ-aminobutyric acid, phosphocholine, glycerophosphocholine, cytidine 5'-diphosphocholine, choline, acetylcholine, dopamine, norepinephrine, serotonin, tyrosine, epinephrine, tryptophan, 5-hydroxyindolacetic acid and agmatine were selected as analytes. The method consisted of a simple deproteinization of samples using methanol and formic acid, subsequent injection onto the chromatographic equipment and quantification with a triple quadrupole mass spectrometer detector using an electrospray ionization interface in positive mode. Limits of detection ranged from 0.02 to 11ngmL(-1) and limits of quantification from 0.1 to 38ngmL(-1), depending on the analyte. The method was validated according to US Food and Drugs Administration (FDA) guideline for bioanalytical assays. Precision, expressed as relative standard deviation (%RSD), was lower than 15% in all cases, and the determination coefficient (R(2)) was equal or higher than 99.0% with a residual deviation for each calibration point lower than ±25%. Mean recoveries were between 85% and 115%. The method was applied to determine of these compounds in zebrafish from early stages of development to adulthood and showed the time-course of neurotransmitters and others neurocompounds through the life cycle. The possibility of measuring up to 17 compounds related with the main neurotransmitter systems in a simple analytical method will complement and reinforce the use of zebrafish in multiple applications in the field of neurosciences. The proposed method will facilitate future studies related with brain development. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Analysis of the flame retardant metabolites bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and diphenyl phosphate (DPP) in urine using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cooper, E M; Covaci, A; van Nuijs, A L N; Webster, T F; Stapleton, H M

    2011-10-01

    Organophosphate triesters tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and triphenyl phosphate are widely used flame retardants (FRs) present in many products common to human environments, yet understanding of human exposure and health effects of these compounds is limited. Monitoring urinary metabolites as biomarkers of exposure can be a valuable aid for improving this understanding; however, no previously published method exists for the analysis of the primary TDCPP metabolite, bis(1,3-dichloro-2-propyl) phosphate (BDCPP), in human urine. Here, we present a method to extract the metabolites BDCPP and diphenyl phosphate (DPP) in human urine using mixed-mode anion exchange solid phase extraction and mass-labeled internal standards with analysis by atmospheric pressure chemical ionization liquid chromatography tandem mass spectrometry. The method detection limit was 8 pg mL(-1) urine for BDCPP and 204 pg mL(-1) for DPP. Recoveries of analytes spiked into urine ranged from 82 ± 10% to 91 ± 4% for BDCPP and from 72 ± 12% to 76 ± 8% for DPP. Analysis of a small number of urine samples (n=9) randomly collected from non-occupationally exposed adults revealed the presence of both BDCPP and DPP in all samples. Non-normalized urinary concentrations ranged from 46-1,662 pg BDCPP mL(-1) to 287-7,443 pg DPP mL(-1), with geometric means of 147 pg BDCPP mL(-1) and 1,074 pg DPP mL(-1). Levels of DPP were higher than those of BDCPP in 89% of samples. The presented method is simple and sufficiently sensitive to detect these FR metabolites in humans and may be applied to future studies to increase our understanding of exposure to and potential health effects from FRs. © Springer-Verlag 2011

  10. Simultaneous determination of neonicotinoid insecticides in human serum and urine using diatomaceous earth-assisted extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yamamuro, Tadashi; Ohta, Hikoto; Aoyama, Mika; Watanabe, Daisuke

    2014-10-15

    A rapid and sensitive analytical method was developed for simultaneous determination of eight neonicotinoid insecticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam) and three specific metabolites of acetamiprid (N-desmethylacetamiprid, 5-(N-acetyl-N-methylaminomethyl)-2-chloropyridine and 5-(N-acetylaminomethyl)-2-chloropyridine) in human serum and urine. A diatomaceous earth-assisted extraction using Extrelut NT3 column with chloroform/2-propanol (3:1, v/v) as eluent was selected for the single step cleanup procedure for all the target compounds. Qualitative and quantitative analyses were conducted by liquid chromatography-tandem mass spectrometry with multiple reaction monitoring mode. The limits of detection and the limits of quantification of eleven compounds were in the ranges of 0.1-0.2ng/mL and 0.5-10ng/mL for serum, 0.1-1ng/mL and 1-10ng/mL for urine, respectively. The extraction recoveries were between 80.9% and 101.8% for serum samples, 91.9% and 106% for urine samples. The intra-day RSDs and the inter-day RSDs were less than 11.5% and 13.2% for serum, less than 8.3% and 8.8% for urine. The proposed procedure will be suitable for forensic investigations of human poisoning cases with neonicotinoid insecticides. This is the first report of simultaneous determination of eight neonicotinoids in serum and urine samples. Copyright © 2014. Published by Elsevier B.V.

  11. Development of a validated ultra-high-performance liquid chromatography tandem mass spectrometry method for determination of acid diterpenes in Copaifera oleoresins.

    Science.gov (United States)

    da Silva, Jonas Joaquim Mangabeira; Crevelin, Eduardo José; Carneiro, Luiza Junqueira; Rogez, Hervé; Veneziani, Rodrigo Cassio Sola; Ambrósio, Sérgio Ricardo; Beraldo Moraes, Luiz Alberto; Bastos, Jairo Kenupp

    2017-09-15

    Species of Copaifera genus (Fabaceae - Caesalpinoiodidaeae) produces an important commercial oleoresin that displays many medicinal properties. Copaifera oleoresins (COR) are composed mainly of a mixture of diterpenes and sequiterpenes, and the main reported acid diterpenes for this genus are kaurenoic, copalic, hardwickiic and polyaltic acids. An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for identification and quantification of nine acid diterpenes. The developed method was applied in the analyses of 10 authentic COR samples collected in the North and Southeast of Brazil and six commercial COR samples. Samples preparation consisted of simple dilution of oleoresins in methanol followed by filtration. Validation parameters of the method for nine acid diterpenes were satisfactory: selectivity/specificity was defined by retention time and MS/MS analyses for each analyte; generally all analytical curves presented r 2 >0.99, Lack-of-fit test not significant and RSDacid and ammonium hydroxide. Results of 16 analyzed samples of COR showed qualitative and quantitative differences of acid diterpenes among all samples. The diterpenes ent-kaurenoic acid 1, ent-polyalthic acid 3, ent-copalic acid 5 and, ent-3-β-acetoxy copalic acid 9 were found with more frequency in COR analyzed samples. Additionally, the content of the acid diterpenes found in 16 Copaifera oleoresin samples was analyzed by Principal Component Analysis (PCA), suggesting a botanical origin for the commercial samples. The developed UPLC method was shown to be reliable for the analysis of acid diterpenes in commercial Copaifera oleoresins. Copyright © 2017. Published by Elsevier B.V.

  12. Sensitive and selective liquid chromatography-tandem mass spectrometry method for the determination of five ganoderic acids in Ganoderma lucidum and its related species.

    Science.gov (United States)

    Liu, Yongli; Liu, Youping; Qiu, Feng; Di, Xin

    2011-03-25

    The present paper describes a novel, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of ganoderic acids C(2), B, A, H, D in Ganoderma lucidum and its related species. Ganoderma samples were prepared using simple ultrasonic extraction. Chromatographic separation was carried out on an Agilent Zorbax XDB C(18) column (250 mm × 4.6 mm i.d., 5μm) with an isocratic mobile phase consisting of acetonitrile, water and formic acid (42:58:0.5, v/v/v). Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an atmospheric pressure chemical ionization (APCI) interface operating in negative and positive ionization mode via a single within-run polarity switching. Quantitation of five ganoderic acids was performed using selective reaction monitoring (SRM) mode. The intra- and inter-day precision was less than 6.2% and the accuracy ranged from 90.0% to 105.7%. The limit of quantification (LOQ) was 20.0-40.0 ng/mL and the limit of detection (LOD) was 3.0-25.0 ng/mL. With this method, low levels of ganoderic acids in the fruiting bodies of Ganoderma sinense and Ganoderma applanatum were accurately quantified for the first time. Importantly, the method allows unequivocal quantification of the five ganoderic acids in the spores and fruiting bodies of Ganoderma lucidum, whereas the previously published methods have lacked the capability. The method presented will be a powerful tool for quality control of Ganoderma lucidum and its related species. Copyright © 2010 Elsevier B.V. All rights reserved.

  13. A new carbon-based magnetic material for the dispersive solid-phase extraction of UV filters from water samples before liquid chromatography-tandem mass spectrometry analysis.

    Science.gov (United States)

    Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

    2017-07-01

    Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4 -graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2  g -1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L -1 , with detection limits in the range of 1-5 ng L -1 . Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis. Graphical Abstract Workflow of the analytical method based on magnetic solid-phase extraction followed by LC-MS/MS determination.

  14. A new method for the determination of benzophenone-UV filters in human serum samples by dispersive liquid-liquid microextraction with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Vela-Soria, F; Ballesteros, O; Zafra-Gómez, A; Ballesteros, L; Navalón, A

    2014-04-01

    Benzophenone-UV filters (BP-UV filters) are extensively used in cosmetics products to avoid damaging effects of UV radiation. Despite their low toxicity, many research papers indicate that BP-UV filters are weak endocrine disruptors (EDCs). There are clear relationships between BP-UV filters exposure and several health disorders such as carcinogenesis and malformations observed in animals. In the present work, a new sample treatment procedure by dispersive liquid-liquid microextraction (DLLME) is proposed for the extraction of six BPs, namely benzophenone-1 (BP-1), benzophenone-2 (BP-2), benzophenone-3 (BP-3), benzophenone-6 (BP-6), benzophenone-8 (BP-8) and 4-hydroxybenzophenone (4-OH-BP), in human serum samples, followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. The method involves an enzymatic treatment to quantify the total content (free plus conjugated species) of BP-UV filters in serum. The extraction parameters were accurately optimized using multivariate optimization approach. Benzophenone-d₁₀ (BP-d₁₀) was used as surrogate. Limits of quantification (LOQs) ranged from 0.4 to 0.9 ng mL(-1) and inter-day precision (evaluated as relative standard deviation) ranged from 1.9% to 13.1%. The method was validated using matrix-matched calibration and a recovery assay. Recovery rates for spiked samples ranged from 97% to 106%, and acceptable linearity was obtained up to concentrations of 40 ng mL(-1). The method was applied to the determination of the target compounds in human serum samples from 20 randomly selected anonymous individuals. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. [Simultaneous determination of 18 β-agonist residues in feed using QuEChERS sample preparation and high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zheng, Ling; Wu, Yujie; Zhao, Yongfeng; Li, Lihua; Ma, Yanjuan

    2014-08-01

    A multi-residue method was developed for the simultaneous determination of 18 β-agonist residues (clenbuterol, ractopamine, penbutolol, tulobuterol, etc) in feed by using QuEChERS sample preparation and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The feed samples were dispersed by water, then the analytes were extracted with acetonitrile containing 4% (v/v) ammonia and cleaned up by QuEChERS method with 25 mg octadecylsilyl (C18) and 50 mg primary secondary amine (PSA) adsorbents. The separation of compounds was carried on an Agilent ZORBAX Eclipse XDB-C,8 column (50 mm x 4. 6 mm, 1. 8 μm) by a gradient elution using methanol-0. 1% (v/v) formic acid aqueous solution as mobile phase. The analytes were detected by tandem mass spectrometry under multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI+) and quantified by the matrix-matched external standard method. The results showed that the calibration curves of the 18 β-agonists were linear in the range of 5 - 200 μg/L with correlation coefficients of 0. 9912-0. 9995. The average recoveries of the 18 analytes at three spiked levels of 0.05, 0.1 and 0. 5 mg/kg ranged from 78. 4% to 107. 1% with the relative standard deviations (RSDs) of 3.5%-12.3%. The limit of quantification (LOQ, S/N≥10) was 0. 05 mg/kg for each analyte. The developed method is simple and sensitive, and can be applied as a screen and confirmatory method for the analysis of β-agonists in feed.

  16. Development and validation of a liquid chromatography tandem mass spectrometry method for the analysis of beta-agonists in animal feed and drinking water.

    Science.gov (United States)

    Juan, C; Igualada, C; Moragues, F; León, N; Mañes, J

    2010-09-24

    A reproducible, sensitive and selective multiresidue analytical method for seven beta-agonists: clenbuterol (CBT), clenpenterol (CPT), ractopamine (RTP), brombuterol (BBT), mabuterol (MBT), mapenterol (MPT), and hydroxymethylclenbuterol (HMCBT) was developed and validated by using liquid chromatography tandem mass spectrometry (LC-MS/MS) in feed and drinking water samples. The validation was achieved according to the criteria laid down in the Commission Decision 2002/657/EC, however it was necessary to use minimum required performance limits (MRPLs) proposed by the Community Reference Laboratories (CRLs) due to the lack of maximum residue limits (MRLs) for beta-agonists. By setting up these MRPLs, allows controlling their use in safe mode, since beta-agonists are commonly used in veterinary medicine sometime in a fraudulent manner, for increasing the weigh of animals. Values set for both matrices studied are 50 microg/kg for animal feed, and a range from 0.2 to 10 microg/L for drinking water. CCalpha values calculated were under the MRPLs suggested; for drinking water the lowest value obtained was 0.12 microg/L, and for animal feed 0.87 microg/kg. Values for CCbeta were ranged from 0.08 to 0.13 microg/L in drinking water and from 0.5 to 0.92 microg/kg in animal feed samples. The excellence values obtained, allowed us to conclude that the proposed analytical method is capable to control the beta-agonists studied in both matrices and that it can be successfully applied and used as a routine method in laboratories of residue analysis of veterinary food control. Copyright 2010 Elsevier B.V. All rights reserved.

  17. Quantitative analysis of penicillins in porcine tissues, milk and animal feed using derivatisation with piperidine and stable isotope dilution liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    van Holthoon, Frédérique; Mulder, Patrick P J; van Bennekom, Eric O; Heskamp, Henri; Zuidema, Tina; van Rhijn, Hans J A

    2010-04-01

    Penicillins are used universally in both human and veterinary medicine. The European Union (EU) has established maximum residue levels (MRLs) for most ss-lactam antibiotics in milk and animal tissues and included them in the National Residue Monitoring Programs. In this study, a novel method is described for the determination and confirmation of eight penicillins in porcine tissues, milk and animal feed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). To prevent degradation of penicillin residues during workup, a derivatisation procedure was developed, by which penicillins were converted to stable piperidine derivatives. Deuterated piperidine derivatives were synthesised for all relevant penicillins, enabling the use of isotope dilution for accurate quantification. Penicillin residues were derivatised in the crude extract with piperidine and isolated using solid-phase extraction. The penicillin piperidine derivatives were determined by LC-MS/MS. The method was validated at the current MRLs, which range from 25-300 microg kg(-1) in muscle and kidney to 4-30 microg kg(-1) in milk as well as at the target value of 100 microg kg(-1) chosen for animal feed, according to the EU requirements for a quantitative confirmatory method. Accuracy ranged from 94-113% (muscle), 83-111% (kidney) and 87-103% (milk) to 88-116% (animal feed). Intra-day precision (relative standard deviation (RSD)(r)) ranged from 5-13% (muscle, n = 18), 4-17% (kidney, n = 7) and 5-18% (milk, n = 7) to 11-32% (animal feed, n = 18). Inter-day precision (RSD(RL), n = 18) ranged from 6-23% (muscle) to 11-36% (animal feed). From the results, it was concluded that the method was fit for purpose at the target MRLs in animal tissue and target levels for animal feed.

  18. [Determination of 32 sulfonylurea herbicide residues in sweet corns and green soybeans by QuEChERS-liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Wang, Lianzhu; Huang, Xiaoyan; Wang, Dengfei; Chen, Yong; Xu, Dunming; Zhou, Yu

    2015-05-01

    A fast method based on QuEChERS methodology for the simultaneous determination of 32 sulfonylurea herbicide residues in sweet corns and green soybeans was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The clean-up effects of three dispersive sorbents were evaluated in terms of the residue mass for extracts after evaporation and recoveries. The three sorbents were C18, a mixture of two sorbents--silica coated with zirconium dioxide (Z-Sep) and C18, a bonded C18 zirconia-coated silica (Z-Sep+). As a result, the best effects were obtained from using Z-Sep/C18 sorbents. The samples were extracted with acetonitrile, and salted out with anhydrous magnesium sulphate and sodium chloride. The extracts were cleaned up with dispersive solid phase extraction using Z-Sep/C18 sorbents. Chromatographic analysis was carried out using a CSH C18 column with gradient elution. The pesticides were analyzed by negative electrospray ionization tandem mass spectrometry under scheduled multiple reaction monitoring mode. The quantification was achieved using matrix-matched standard calibrations as the external standard. The recoveries at fortification levels of 10, 20, 100 µg/kg in sweet corns and green beans ranged from 80.0% to 108.2% with the relative standard deviations of 1.2%-13.0%. The limits of quantification (S/N ≥ 10) were 0.2-5.0 µg/kg. The method has been proven to be simple, sensitive, environmental, and thus suitable for the determination of the 32 sulfonylurea herbicide residues in sweet corns and green soy- beans.

  19. Determination of drugs in plasma samples by disposable pipette extraction with C18-BSA phase and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Pinto, Mônia Ap Lemos; de Souza, Israel D; Queiroz, Maria Eugênia C

    2017-05-30

    This work describes restricted access material (RAM) constituted of porous octadecylsilane particles with the outer surface covered with bovine serum albumin (C18-BSA) as a stationary phase to extract drugs from plasma samples by disposable pipette extraction (DPX) for further analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The C18-BSA phase simultaneously excluded macromolecules by chemical diffusion barrier (BSA network) and enrichment of the interior phase (C18) with drug traces by sorption. The hydrophilic barrier of the C18-BSA allows small molecules (drugs) to permeate through the hydrophobic part (C18), while at the same time it excludes the macromolecules by chemical diffusion barrier (BSA network). Optimization of the DPX variables (sorption equilibration time, exclusion of endogenous compounds, and elution step) improved the sensitivity and selectivity of the method, which presented a linear range from the lower limit of quantification (0.5-20.0ngmL -1 ) to the upper limit of quantification (32.5-10,500ngmL -1 ), inter- and intra-assay precision with coefficients of variation (CV) lower than 15%, and relative standard error (RSE) of the accuracy ranging from -12% to 11%. The developed method was successfully used to determine five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, and fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients for therapeutic drug monitoring. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Determination of urinary cortisol, cortisone and 6-sulfatoxymelatonin using dilute and shoot ultra-high pressure liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Sniecinska-Cooper, Anna Maria; Shah, Ajit Jesang; Dimitriou, Dagmara; Iles, Ray Kruse; Butler, Stephen Andrew; Bayford, Richard

    2015-01-26

    Human sleep is a natural part of every individual's life. Clear relationship between sleep and endocrine system has been already established. In particular, melatonin and cortisol are known to affect and regulate sleep/wake patterns. Here we report the development of an ultra-high pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous measurement of 6-sulfatoxymelatonin (MT6s), cortisol and cortisone in urine. A separate method was developed for measurement of creatinine in urine. These levels were used to normalise the levels of analytes. First void morning urine samples were collected from 24 healthy volunteers. Samples were diluted 1:1 in water prior to injection onto reversed-phase C18 column and analysed using UHPLC-MS/MS method. Linear calibrations were obtained for all analytes with correlation coefficient in the range 0.998-0.999. The observed concentration was found to be in the range 92-105% for cortisol, 92-107% for cortisone and between 93 and 120% for MT6s of the reference levels. The total run time of 6 min with all peaks of interest eluting within 3 min was obtained. This demonstrates the feasibility of utilising the method for large multi-scale studies, where high throughput is required for studying the circadian rhythm of melatonin and cortisol secretion. These hormones play significant role in circadian rhythm and sleep/wake cycle; therefore it is important to monitor the levels of these endocrine markers in individuals suffering from sleep disorders. It is also beneficial with clinical applications to analyse melatonin and cortisol simultaneously in order to assess their interrelationships of these substances, such as their effect on diurnal rhythm and sleep. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. High-throughput determination of cortisol, cortisone, and melatonin in oral fluid by on-line turbulent flow liquid chromatography interfaced with liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Fustinoni, Silvia; Polledri, Elisa; Mercadante, Rosa

    2013-07-15

    Cortisol, cortisone, and melatonin (CORTol, CORTone, and MELA, respectively) are hormones related to stress and sleep disorders. Their detection is relevant to epidemiological studies aimed at investigating the effects of circadian cycle disruption. The aim of this study was to develop and evaluate a high-throughput assay for the detection of CORTol, CORTone, and MELA concentrations in non-invasively collected oral fluid samples. A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to measure levels of CORTol, CORTone, and MELA in oral fluid samples in the presence of deuterated analogs was optimized and validated. A 50 μL aliquot of oral fluid sample, obtained by centrifugation of a chewed swab, was purified using on-line turbulent flow liquid chromatography. Analytes were then separated using C18 reversed-phase chromatography, subjected to positive ionization using an electrospray source, then quantitated using a triple quadrupole mass detector in the selected reaction monitoring mode. Limits of quantification and linear dynamic ranges were found to be 0.55 nmol/L, 5.5 nmol/L, and 0.004 nmol/L, and up to 28 nmol/L, 277 nmol/L, and 0.43 nmol/L for CORTol, CORTone, and MELA, respectively. Inter- and intra-run precisions as relative standard deviation values were <5%, and accuracies were within 95-106% of theoretical concentrations. An evaluation of matrix effects showed that the use of deuterated analogs controlled sources of bias. Furthermore, the total analysis time per sample was 13 min, resulting in a throughput of approximately 100 samples/day. To our knowledge, this is the first automated, high-throughput assay for the simultaneous quantification of CORTol, CORTone, and MELA in oral fluid specimens. Copyright © 2013 John Wiley & Sons, Ltd.

  2. Direct analysis of ethylene glycol in human serum on the basis of analyte adduct formation and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Dziadosz, Marek

    2018-01-01

    The aim of this work was to develop a fast, cost-effective and time-saving liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method for the analysis of ethylene glycol (EG) in human serum. For these purposes, the formation/fragmentation of an EG adduct ion with sodium and sodium acetate was applied in the positive electrospray mode for signal detection. Adduct identification was performed with appropriate infusion experiments based on analyte solutions prepared in different concentrations. Corresponding analyte adduct ions and adduct ion fragments could be identified both for EG and the deuterated internal standard (EG-D4). Protein precipitation was used as sample preparation. The analysis of the supernatant was performed with a Luna 5μm C18 (2) 100A, 150mm×2mm analytical column and a mobile phase consisting of 95% A (H 2 O/methanol=95/5, v/v) and 5% B (H 2 O/methanol=3/97, v/v), both with 10mmolL -1 ammonium acetate and 0.1% acetic acid. Method linearity was examined in the range of 100-4000μg/mL and the calculated limit of detection/quantification was 35/98μg/mL. However, on the basis of the signal to noise ratio, quantification was recommended at a limit of 300μg/mL. Additionally, the examined precision, accuracy, stability, selectivity and matrix effect demonstrated that the method is a practicable alternative for EG quantification in human serum. In comparison to other methods based on liquid chromatography, the strategy presented made for the first time the EG analysis without analyte derivatisation possible. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Quantification of isoflavones in coffee by using solid phase extraction (SPE) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

    Science.gov (United States)

    Caprioli, Giovanni; Navarini, Luciano; Cortese, Manuela; Ricciutelli, Massimo; Torregiani, Elisabetta; Vittori, Sauro; Sagratini, Gianni

    2016-09-01

    A new method for extracting isoflavones from espresso coffee (EC) was coupled with high-performance liquid chromatography-tandem mass spectrometry (MS/MS) for the first time to analyse five isoflavones, which included both a glycosilated form, genistin and the aglycons daidzein, genistein, formononetin and biochanin A. Isoflavones were extracted from coffee samples using methanol, stored in a freezer overnight to precipitate proteic or lipidic residues and purified on SPE C18 cartridges before high-performance liquid chromatography-MS/MS analysis. The recovery percentages obtained by spiking the matrix at concentrations of 10 and 100 µg l(-1) with a standard mixture of isoflavones were in the range of 70 to 104%. The limits of detection and limits of quantification were in the range of 0.015-0.3 µg l(-1) and 0.05-1 µg l(-1) , respectively. Once validated, the method was used to analyze the concentrations of isoflavones in six ECs and ten ground coffee samples. Only formononetin and biochanin A were found, and their respective concentrations ranged from 0.36 to 0.41 µg l(-1) and from 0.58 to 3.26 µg l(-1) in ECs and from 0.36 to 4.27 µg kg(-1) and from 0.71 to 3.95 µg kg(-1) in ground coffees. This method confirms the high specificity and selectivity of MS/MS systems for detecting bioactives in complex matrices such as coffee.Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Quantification of cannabinoids and their free and glucuronide metabolites in whole blood by disposable pipette extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Scheidweiler, Karl B; Newmeyer, Matthew N; Barnes, Allan J; Huestis, Marilyn A

    2016-07-01

    Identifying recent cannabis intake is confounded by prolonged cannabinoid excretion in chronic frequent cannabis users. We previously observed detection times ≤2.1h for cannabidiol (CBD) and cannabinol (CBN) and Δ(9)-tetrahydrocannabinol (THC)-glucuronide in whole blood after smoking, suggesting their applicability for identifying recent intake. However, whole blood collection may not occur for up to 4h during driving under the influence of drugs investigations, making a recent-use marker with a 6-8h detection window helpful for improving whole blood cannabinoid interpretation. Other minor cannabinoids cannabigerol (CBG), Δ9-tetrahydrocannabivarin (THCV), and its metabolite 11-nor-9-carboxy-THCV (THCVCOOH) might also be useful. We developed and validated a sensitive and specific liquid chromatography-tandem mass spectrometry method for quantification of THC, its phase I and glucuronide phase II metabolites, and 5 five minor cannabinoids. Cannabinoids were extracted from 200μL whole blood via disposable pipette extraction, separated on a C18 column, and detected via electrospray ionization in negative mode with scheduled multiple reaction mass spectrometric monitoring. Linear ranges were 0.5-100μg/L for THC and 11-nor-9-carboxy-THC (THCCOOH); 0.5-50μg/L for 11-hydroxy-THC (11-OH-THC), CBD, CBN, and THC-glucuronide; 1-50μg/L for CBG, THCV, and THCVCOOH; and 5-500μg/L for THCCOOH-glucuronide. Inter-day accuracy and precision at low, mid and high quality control (QC) concentrations were 95.1-113% and 2.4-8.5%, respectively (n=25). Extraction recoveries and matrix effects at low and high QC concentrations were 54.0-84.4% and -25.8-30.6%, respectively. By simultaneously monitoring multiple cannabinoids and metabolites, identification of recent cannabis administration or discrimination between licit medicinal and illicit recreational cannabis use can be improved. Published by Elsevier B.V.

  5. Analysis of potential genotoxic impurities in rabeprazole active pharmaceutical ingredient via Liquid Chromatography-tandem Mass Spectrometry, following quality-by-design principles for method development.

    Science.gov (United States)

    Iliou, Katerina; Malenović, Anđelija; Loukas, Yannis L; Dotsikas, Yannis

    2018-02-05

    A novel Liquid Chromatography-tandem mass spectrometry (LC-MS/MS) method is presented for the quantitative determination of two potential genotoxic impurities (PGIs) in rabeprazole active pharmaceutical ingredient (API). In order to overcome the analytical challenges in the trace analysis of PGIs, a development procedure supported by Quality-by-Design (QbD) principles was evaluated. The efficient separation between rabeprazole and the two PGIs in the shortest analysis time was set as the defined analytical target profile (ATP) and to this purpose utilization of a switching valve allowed the flow to be sent to waste when rabeprazole was eluted. The selected critical quality attributes (CQAs) were the separation criterion s between the critical peak pair and the capacity factor k of the last eluted compound. The effect of the following critical process parameters (CPPs) on the CQAs was studied: %ACN content, the pH and the concentration of the buffer salt in the mobile phase, as well as the stationary phase of the analytical column. D-Optimal design was implemented to set the plan of experiments with UV detector. In order to define the design space, Monte Carlo simulations with 5000 iterations were performed. Acceptance criteria were met for C 8 column (50×4mm, 5μm) , and the region having probability π≥95% to achieve satisfactory values of all defined CQAs was computed. The working point was selected with the mobile phase consisting ‎of ACN, ammonium formate 11mM at a ratio 31/69v/v with pH=6,8 for the water phase. The LC protocol was transferred to LC-MS/MS and validated according to ICH guidelines. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. The use of dried blood spots for quantification of 15 antipsychotics and 7 metabolites with ultra-high performance liquid chromatography - tandem mass spectrometry.

    Science.gov (United States)

    Patteet, Lisbeth; Maudens, Kristof E; Stove, Christophe P; Lambert, Willy E; Morrens, Manuel; Sabbe, Bernard; Neels, Hugo

    2015-06-01

    Therapeutic drug monitoring of antipsychotics is important in optimizing individual therapy. In psychiatric populations, classical venous blood sampling is experienced as frightening. Interest in alternative techniques, like dried blood spots (DBS), has consequently increased. A fast and easy to perform DBS method for quantification of 16 antipsychotics (amisulpride, aripiprazole, asenapine, bromperidol, clozapine, haloperidol, iloperidone, levosulpiride, lurasidone, olanzapine, paliperidone, pipamperone, quetiapine, risperidone, sertindole and zuclopenthixol) and 8 metabolites was developed. DBS were prepared using 25 μL of whole blood and extraction of complete spots was performed using methanol: methyl-t-butyl-ether (4:1). After evaporation, the extract was reconstituted in the mobile phase and 10 μL were injected on an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Separation using a C18 column and gradient elution with a flow rate of 0.5 mL/min resulted in a 6-min run-time. Ionization was performed in positive mode and a dynamic MRM method was applied. Median recovery was 66.4 % (range 28.7-84.5%). Accuracy was within the acceptance criteria, except for pipamperone (LLOQ and low concentration) and lurasidone (low concentration). Imprecision was only aberrant for lurasidone at low and medium concentration. All compounds were stable during 1 month at room temperature, 4 °C and -18 °C. Lurasidone was unstable when the extract was stored for 12 h on the autosampler. Absolute matrix effects (ME) (median 66.1%) were compensated by the use of deuterated IS (median 98.8%). The DBS method was successfully applied on 25-μL capillary DBS from patients and proved to be a reliable alternative for quantification of all antipsychotics except for olanzapine and N-desmethylolanzapine. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Development of a modified QuEChERS method for the determination of veterinary antibiotics in swine manure by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Guo, Chunna; Wang, Mingru; Xiao, Hui; Huai, Binbin; Wang, Feng; Pan, Guangfang; Liao, Xiaoping; Liu, Yahong

    2016-08-01

    A QuEChERS (quick, easy, cheap, effective, rugged and safe) based methodology was developed for the rapid, simultaneous quantification and identification of 26 veterinary drugs in swine manure by liquid chromatography tandem mass spectrometry. The selected antibiotics included tetracyclines, sulfonamides, macrolides, fluoroquinolones, lincosamides and pleuromutilins. This is the first study to determine pleuromutilin levels in manure. The QuEChERS process involved two simple steps. First, sample extraction with methanol: acetonitrile: 0.1M EDTA-McIlvaine buffer followed by phase separation with MgSO4: NaCl addition. The supernatant was then extracted and cleaned by dispersive solid-phase extraction using a primary-secondary amine (PSA) and octadecylsilane (C18) support. The proposed method provides a linearity in the range of 1-500ngmL-1 and linear regression coefficients (r) were greater than 0.996. MDL and MQL ranged between 0.01-1.86μgkg(-1) and 0.05-5.91μgkg(-1), respectively. Recoveries ranged from 61.39 to 105.65% with the exception of sulfaquinoxaline (55.7-56.8%) and valnemulin (33.7-37.7%). This method resulted in good precision (repeatability and reproducibility) and relative standard deviations less than 17% within the same day, and lower than 20% between days. The method was then applied to study the swine manure samples collected from Guangdong, China. Chlortetracycline, tetracycline, doxycycline, sulfadimidine and tilmicosin were detected in all samples indicating high residuals in manure. In fact tilmicosin was detected at 14400μgkg(-1) suggesting that prudent treatment of manure should be conducted to prevent environmental contamination. In conclusion, this workflow can provide a simpler and more cost-effective alternative to conventional methods and is compatible with processing large sample numbers over a short time period. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Rapid screening for cyclo-dopa and diketopiperazine alkaloids in crude extracts of Portulaca oleracea L. using liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Xing, Jie; Yang, Zijuan; Lv, Beibei; Xiang, Lan

    2008-05-01

    A simple and rapid qualitative liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated for screening cyclo-dopa and diketopiperazine alkaloids in crude extracts of Portulaca oleracea L. at sub-ppm levels. An electrospray ionization orbitrap mass spectrometer, which provides accurate full scan MS and MS/MS data, was used in this study. After simple extraction with ethanol and purification by AB-8 resin, the extracts were subjected to LC/MS/MS analysis. A high mass tolerance (10 ppm) was used in the initial screening to filter the full scan MS data. The cyclo-dopa and diketopiperazine alkaloid standards gave limits of detection (LODs) at or below 5 ng/mL. The results also indicated that the method had an acceptable precision for day-to-day use in the identification of compounds. The alkaloids could be identified based on their MS/MS data, elemental compositions, and retention behavior. This system was used to assay trace amounts of cyclo-dopa and diketopiperazine alkaloids in crude extracts of Portulaca oleracea L., leading to the identification of 5/2 confirmed/unconfirmed cyclo-dopa and 7/6 confirmed/unconfirmed diketopiperazine alkaloids, respectively. The screening method considerably reduces the time and cost involved in the identification of cyclo-dopa and diketopiperazine alkaloids in Portulaca oleracea L., as well as being a simple and convenient approach to the identification of other structural families of natural products. Copyright (c) 2008 John Wiley & Sons, Ltd.

  9. Quantification of flavan-3-ols and phenolic acids in milk-based food products by reversed-phase liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Redeuil, Karine; Bertholet, Raymond; Kussmann, Martin; Steiling, Heike; Rezzi, Serge; Nagy, Kornél

    2009-11-20

    This article reports the development and validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the comprehensive quantification of flavan-3-ol and phenolic acid constituents of milk-based food products. Isotope dilution-based sample preparation consisted of protein precipitation using acidic methanol enriched with the stable isotope labelled internal standards and ultrafiltration to preserve overall polyphenol composition, but to eliminate milk proteins in order to comply with LC. Reversed-phase liquid chromatography was optimized to achieve separation of 22 analytes in 8 min in order to reduce suppression effects, achieve a wide dynamic range and, most importantly, to resolve isomeric compounds. Negative-ion electrospray mass spectrometric detection and fragmentation of analytes was optimized, final transitions were selected for maximized selectivity, reliable quantification and reduction of false positives. The quantitative performance of the method was validated, the main features include: (1) range of lower limits of detection 5-15 ng/mL for flavan-3-ols, 60-100 ng/mL for procyanidins, 1-60 ng/mL for other phenolic acids, (2) lower limits of quantification 15-45 ng/mL for flavan-3-ols, 200-300 ng/mL for procyanidins, 3-200 ng/mL for other phenolic acids, (3) averaged intra-day precision 9.5%, (4) calibrated range 60-300,000 ng/mL for flavan-3-ols, 900-900,000 ng/mL for procyanidins, 9-225,000 ng/mL for other phenolic acids, (5) averaged accuracy 99.5%. Applications for yoghurt and ice-cream products are given. The presented data suggest that this method will help to better characterize the polyphenol composition of milk-based food products for quality control, assessment of dietary intake and for polyphenol bioavailability/bioefficacy studies.

  10. Analysis of methyloxime derivatives of intact esters of testosterone and boldenone in equine plasma using ultra high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gray, Bobby P; Teale, Phil; Pearce, Clive M

    2011-04-01

    Analysis of equine plasma samples to detect the abuse of anabolic steroids can be complicated when the parent steroid is endogenous to the animal. Anabolic steroids are usually administered intramuscularly as synthetic esters and therefore detection of the exogenous esters provides unequivocal proof of illegal administration. An ultra high performance liquid chromatography tandem mass spectrometric (UPLC-MSMS) method for the analysis of esters of testosterone (propionate, phenylpropionate, isocaproate, and decanoate) and boldenone (undecylenate) in equine plasma has been developed. Esters were extracted from equine plasma using a mixture of hexane and ethyl acetate and treated with methoxyamine hydrochloride to form methyloxime derivatives. Metenolone enanthate was used as an internal standard. After chromatographic separation, the derivatized steroid esters were quantified using selected reaction monitoring (SRM). The limit of detection for all of the steroid esters, based on a signal to noise ratio (S/N) of 3:1, was 1-3 pg/mL. The lower limit of quantification (LLOQ) for the all of the steroid esters was 5 pg/mL when 2 mL of plasma was extracted. Recovery of the steroid esters was 85-97% for all esters except for testosterone decanoate which was recovered at 62%. The intra-day coefficient of variation (CV) for the analysis of plasma quality control (QC) samples was less than 9.2% at 40 pg/mL and less than 6.0% at 400 pg/mL. The developed assay was used to successfully confirm the presence of intact testosterone esters in equine plasma samples following intramuscular injection of Durateston® (mixed testosterone esters). Copyright © 2011 John Wiley & Sons, Ltd.

  11. Analysis of nifedipine in human plasma and amniotic fluid by liquid chromatography-tandem mass spectrometry and its application to clinical pharmacokinetics in hypertensive pregnant women.

    Science.gov (United States)

    Filgueira, Gabriela Campos de Oliveira; Filgueira, Osmany Alberto Silva; Carvalho, Daniela Miarelli; Marques, Maria Paula; Moisés, Elaine Christine Dantas; Duarte, Geraldo; Lanchote, Vera Lucia; Cavalli, Ricardo Carvalho

    2015-07-01

    Nifedipine is a dihydropyridine calcium channel blocker used for the treatment of hypertension in pregnant women. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for analysis of nifedipine in human plasma and amniotic fluid. Separation of nifedipine and nitrendipine (IS) was performed using a LiChroCART(®) RP-Select B column and a mixture of water:acetonitrile:glacial acetic acid (30:70:0.5 v/v) as the mobile phase. Aliquots of 500μL of biological samples were extracted at pH 13 using dichloromethane:n-pentane (3:7 v/v). The validated method was applied to a study of the pharmacokinetics of nifedipine in human plasma and amniotic fluid samples collected up to 12h after administration of the last slow-release nifedipine (20mg/12h) dose to 12 hypertensive pregnant women. The estimated pharmacokinetic parameters of nifedipine showed a mean AUC(0-12) of 250.2ngh/mL, ClT/F of 89.2L/h, Vd/F of 600.0L and t1/2 5.1h. The mean amniotic fluid/plasma concentration ratio was 0.05. The methods proved to be highly sensitive by showing a lower quantification limit of 0.1ng/mL for both matrices. And this study reports for the first time the complete development and validation of the method to quantify nifedipine in amniotic fluid using LC-MS-MS. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Rapid measurement of 8-oxo-7,8-dihydro-2'-deoxyguanosine in human biological matrices using ultra-high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lam, Patricia M W; Mistry, Vilas; Marczylo, Timothy H; Konje, Justin C; Evans, Mark D; Cooke, Marcus S

    2012-05-15

    Interaction of reactive oxygen species with DNA results in a variety of modifications, including 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), which has been extensively studied as a biomarker of oxidative stress. Oxidative stress is implicated in a number of pathophysiological processes relevant to obstetrics and gynecology; however, there is a lack of understanding as to the precise role of oxidative stress in these processes. We aimed to develop a rapid, validated assay for the accurate quantification of 8-oxodG in human urine using solid-phase extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and then investigate the levels of 8-oxodG in several fluids of interest to obstetrics and gynecology. Using UHPLC-MS/MS, 8-oxodG eluted after 3.94 min with an RSD for 15 injections of 0.07%. The method was linear between 0.95 and 95 nmol/L with LOD and LOQ of 5 and 25 fmol on-column, respectively. Accuracy and precision were 98.7-101.0 and seminal plasma>amniotic fluid>plasma>serum>peritoneal fluid, and it was not detected in saliva. Urine concentrations normalized to creatinine (n=15) ranged between 0.55 and 1.95 pmol/μmol creatinine. We describe, for the first time, 8-oxodG concentrations in human seminal plasma, peritoneal fluid, amniotic fluid, and breast milk, as well as in urine, plasma, and serum, using a rapid UHPLC-MS/MS method that will further facilitate biomonitoring of oxidative stress. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Quantitative analysis of 3,4-dimethylmethcathinone in blood and urine by liquid chromatography-tandem mass spectrometry in a fatal case.

    Science.gov (United States)

    Usui, Kiyotaka; Aramaki, Tomomi; Hashiyada, Masaki; Hayashizaki, Yoshie; Funayama, Masato

    2014-07-01

    We report here the quantitative analysis of cathinone-type designer drug 3,4-dimethylmethcathinone (3,4-DMMC) in blood and urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in a fatal case. Abuse of 3,4-DMMC is widespread and a global issue. However, to date, there have been no reports of 3,4-DMMC-related deaths. We encountered a death in which 3,4-DMMC was thought to play a causative role, and successfully identified this designer drug from biological samples by using LC-MS/MS and QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction method. For standard samples, detection of 3,4-DMMC in human blood and urine samples in the calibration range (5-400 ng/mL) was successful with recoveries of 85.9-89.4% (blood) and 95.8-101% (urine), limits of detection of 1.03 (blood) and 1.37 ng/mL (urine) and limits of quantification of 5.00 (blood) and 5.38 ng/mL (urine). The concentrations of 3,4-DMMC in blood (external iliac vein) and urine in the case were 27 mg/L and 7.6 mg/L, respectively. Some metabolites, including 3,4-dimethylcathione (DMC) and β-ketone reduced metabolites (β-OH-DMMC and β-OH-DMC), were detected in both blood and urine. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Investigation of Bose Condensation in Ideal Bose Gas Trapped under Generic Power Law Potential in d Dimension

    Science.gov (United States)

    Mehedi Faruk, Mir; Sazzad Hossain, Md.; Muktadir Rahman, Md.

    2016-02-01

    The changes in characteristics of Bose condensation of ideal Bose gas due to an external generic power law potential U=\\sumi=1dci\\vert xi/ai\\vertni are studied carefully. Detailed calculation of Kim et al. (J. Phys. Condens. Matter 11 (1999) 10269) yielded the hierarchy of condensation transitions with changing fractional dimensionality. In this manuscript, some theorems regarding specific heat at constant volume CV are presented. Careful examination of these theorems reveal the existence of hidden hierarchy of the condensation transition in trapped systems as well.

  15. Gas-Phase Hydrogen/Deuterium Exchange of Dinucleotides and 5′-Monophosphate Dinucleotides in a Quadrupole Ion Trap

    OpenAIRE

    Chipuk, Joseph E.; Brodbelt, Jennifer S.

    2009-01-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions of four deprotonated dinucleotides (dAA, dAG, dGA, dGG) and their 5′-monophosphate analogs (5′-dAA, 5′-dAG, 5′-dGA, 5′-dGG) with D2O were performed in a quadrupole ion trap mass spectrometer. Significant differences in the rates and extents of exchange were found when the 5′-hydroxyl group of the dinucleotides was replaced by a phosphate functionality. Extensive and nucleobase-dependent exchange occurred for the deprotonated 5′-monophospha...

  16. High performance liquid chromatography-tandem mass spectrometric assay of dexmedetomidine in plasma, urine and amniotic fluid samples for pregnant ewe model.

    Science.gov (United States)

    Cui, Z; Chow, D S-L; Wu, L; Lazar, D A; Rodrigo, R; Olutoye, O O; Olutoye, O A

    2014-06-15

    Dexmedetomidine (DEX; Precedex(®)), approved by the Food and Drug Administration (FDA) in 1999 as a sedative for use in the intensive care unit, is a potent and highly selective α2-adrenoceptor agonist with significant sedative, analgesic and anxiolytic effects. However, the research of DEX use during pregnancy is limited and the impact of DEX on the fetal development is unclear. This article describes a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) assay suitable for various biomatrices of plasma, urine and amniotic fluid, as a prerequisite for pharmacokinetic characterization of DEX in the pregnant ewe model. DEX and testosterone (internal standard; IS) were extracted from 200μL of plasma, urine or amniotic fluid with ethyl acetate. The HPLC resolution was achieved on an Agilent ZORBAX SB-CN column with a gradient elution at a flow rate of 0.5mL/min using a mobile phase of 5-100% of acetonitrile with 0.5% formic acid (mobile phase B) in water (mobile phase A). The detection was performed by a triple quadrupole tandem mass spectrometer with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode [M+H](+) were m/z 201.5→95.4 for DEX and m/z 289.2→109.1 for IS. The method was validated in the concentration range of 25 (lower limit of quantification; LLOQ)-5000pg/mL for both maternal and fetal plasma, and of 50 (LLOQ)-5000pg/mL for urine and amniotic fluid, respectively. The intra- and inter-day precision and accuracy were within ±9%. The overall recoveries of DEX were 82.9-87.2%, 85.7-88.4%, 86.2-89.7% and 83.7-88.1% for maternal plasma, urine, fetal plasma and amniotic fluid, respectively. The percentage matrix factors in different biomatrices were less than 120%. Stability studies demonstrated that DEX was stable after three freeze/thaw cycles, in the autosampler tray at 20°C for 24h and during the 3h sample preparation at room temperature. The validated HPLC-MS/MS method has been

  17. Liquid chromatography-tandem mass spectrometry method for the quantification of mycophenolic acid and its phenolic glucuronide in saliva and plasma using a standardized saliva collection device.

    Science.gov (United States)

    Wiesen, Martin H J; Farowski, Fedja; Feldkötter, Markus; Hoppe, Bernd; Müller, Carsten

    2012-06-08

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous quantification of mycophenolic acid (MPA) and its phenolic glucuronide (MPAG) in saliva and plasma. Saliva was collected and processed using a standardized commercially available collection device. Sample preparation comprised of protein precipitation with acetonitrile and subsequent centrifugation, followed by evaporation and reconstitution with mobile phase. A labeled isotope of MPA was used as internal standard, and chromatographic separation was achieved on a C18 column with an isocratic flow. LC-MS/MS detection was performed using a triple-stage quadrupole mass spectrometer working in selected reaction monitoring mode with positive electrospray ionization (ESI). The analytes were quantified in a single run within 2 min. For saliva, linearity was demonstrated over the concentration range of 5.0 to 400.0 ng/ml for both MPA and MPAG, and from 0.08 to 20.00 μg/ml for MPA and 0.4 to 100.0 μg/ml for MPAG in plasma. The lower limits of quantification for MPA and MPAG were 0.07 and 0.80 ng/ml in saliva, and 0.002 and 0.009 μg/ml in plasma, respectively. Inter- and intra-day precisions expressed as relative standard deviation (RSD) and accuracies were less than 15%. The recoveries for MPA and MPAG from the collection device's swab were higher than 90%. Sample stability was confirmed for bench times up to 24 h at room temperature. The method was validated according to International Conference on Harmonization (ICH) guidelines Q2 (R1) Validation of Analytical Procedures. The applicability of the method was tested in a renal pediatric patient. Based on a limited sampling strategy, MPA saliva and plasma concentrations were found in good agreement with each other. We suggest that the described method is suitable to analyze saliva and plasma samples of small volumes for therapeutic drug monitoring (TDM) and pharmacokinetic studies in pediatric patients. Copyright © 2012

  18. Simultaneous detection of ketamine, lorazepam, midazolam and sufentanil in human serum with liquid chromatography-tandem mass spectrometry for monitoring of analgosedation in critically ill patients.

    Science.gov (United States)

    Nosseir, N S; Michels, G; Binder, P; Wiesen, M H J; Müller, C

    2014-10-12

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination and quantification of four predominantly used analgosedatives in the intensive care unit: ketamine, lorazepam, midazolam and sufentanil in human serum. The extraction procedure consisted of protein precipitation of serum samples with acetonitrile and subsequent centrifugation. D 5 -fentanyl and D 4 -midazolam served as internal standards (ISTD). Separation of analytes was performed with a Hypersil C18 column and a mobile phase with acetonitrile and 0.1% formic acid (60/40, v/v) under isocratic conditions at a flow rate of 280μl/min. Analytes were simultaneously detected with a triple-stage quadrupole mass spectrometer (LC-MS/MS) in a selected reaction monitoring (SRM) mode with positive heated electrospray ionization (HESI) within a single 2-min run. Calibration curves were linear over a range of 50-2000 for ketamine, 10-1000 for lorazepam, 5-500 for midazolam and 1-100 for sufentanil (ng/ml). The limit of detection and the lower limit of quantification were 0.01 and 10.00 for ketamine, 0.005 and 10.00 for lorazepam, 0.018 and 5.00 for midazolam and 0.068 and 0.25 for sufentanil (ng/ml). Intra- and inter-day accuracies and precisions of all analytes were less than 15%. Bench stability with spiked serum samples was ensured after 12, 24 and 48h at room temperature, freeze- and thaw-stability after 3 cycles of thawing and freezing. The method was successfully established according to International Conference on Harmonization (ICH) guideline Q2 (R1) "Validation of Analytical Procedures" and applied in critically ill adult patients in the intensive care unit. We suggest its suitability for parallel quantification of the sedative analgesics ketamine, lorazepam, midazolam and sufentanil. The method serves as an instrumental tool for therapeutic drug monitoring (TDM) and pharmacokinetic studies [1]. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Determination of free thyroid hormones in animal serum/plasma using ultrafiltration in combination with ultra-fast liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Tanoue, Rumi; Kume, Imari; Yamamoto, Yasuo; Takaguchi, Kohki; Nomiyama, Kei; Tanabe, Shinsuke; Kunisue, Tatsuya

    2018-03-02

    Thyroid hormones (THs), which mainly consist of 3, 3', 5-triiodo-l-thyronine (T3) and L-thyroxine (T4), play a critical role in regulating biological processes such as growth and metabolism in various animal species. Thus, accurate measurement of T3 and T4, especially physiologically active free (protein-unbound) forms, in serum/plasma is needed for the evaluation of TH homeostasis. However, such high-precision determination of free THs is lacking for non-human species. The present study aimed to develop a highly sensitive and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of six free THs in serum/plasma, which is applicable to not only humans but also non-human species. Two different physical separation steps, ultrafiltration (UF) and equilibrium dialysis (ED), were examined to obtain the free TH fraction. Several experimental conditions were carefully optimized and validated for UF or ED using the commercially available bovine serum. As a result, UF at 1100 × g and 37 °C for 30 min with a 30 kDa ultrafiltration device (Centrifree YM-30, Millipore) yielded excellent precision (CV: <10%). The optimized ED step also yielded high precision (CV: <10%) and the measurement values were approximately equal to those of UF, but at least 16 h were required to reach equilibrium. Thus, UF combined with LC-MS/MS was finally chosen, in terms of the time needed for the measurement. Acceptable accuracy (recovery: 70%-110%) and intra- and inter-day precision (CV: <10% and <12%, respectively) were obtained, when triplicate analyses in three different days were conducted using the bovine serum. The developed analytical method was successfully applied to the determination of free THs in serum/plasma samples of humans, cats, and dogs. Furthermore, comparison with free T4 concentrations measured by a common immunoassay method evidently indicated that the ultrafiltration-LC-MS/MS method developed in this study can increase

  20. Determination of 74 new psychoactive substances in serum using automated in-line solid-phase extraction-liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lehmann, Sabrina; Kieliba, Tobias; Beike, Justus; Thevis, Mario; Mercer-Chalmers-Bender, Katja

    2017-10-01

    A detailed description is given of the development and validation of a fully automated in-line solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) method capable of detecting 90 central-stimulating new psychoactive substances (NPS) and 5 conventional amphetamine-type stimulants (amphetamine, 3,4-methylenedioxy-methamphetamine (MDMA), 3,4-methylenedioxy-amphetamine (MDA), 3,4-methylenedioxy-N-ethyl-amphetamine (MDEA), methamphetamine) in serum. The aim was to apply the validated method to forensic samples. The preparation of 150μL of serum was performed by an Instrument Top Sample Preparation (ITSP)-SPE with mixed mode cation exchanger cartridges. The extracts were directly injected into an LC-MS/MS system, using a biphenyl column and gradient elution with 2mM ammonium formate/0.1% formic acid and acetonitrile/0.1% formic acid as mobile phases. The chromatographic run time amounts to 9.3min (including re-equilibration). The total cycle time is 11min, due to the interlacing between sample preparation and analysis. The method was fully validated using 69 NPS and five conventional amphetamine-type stimulants, according to the guidelines of the Society of Toxicological and Forensic Chemistry (GTFCh). The guidelines were fully achieved for 62 analytes (with a limit of detection (LOD) between 0.2 and 4μg/L), whilst full validation was not feasible for the remaining 12 analytes. For the fully validated analytes, the method achieved linearity in the 5μg/L (lower limit of quantification, LLOQ) to 250μg/L range (coefficients of determination>0.99). Recoveries for 69 of these compounds were greater than 50%, with relative standard deviations≤15%. The validated method was then tested for its capability in detecting a further 21 NPS, thus totalling 95 tested substances. An LOD between 0.4 and 1.6μg/L was obtained for these 21 additional qualitatively-measured substances. The method was subsequently successfully applied to 28 specimens from

  1. Simultaneous Determination of Underivatized Vitamin B1 and B6 in Whole Blood by Reversed Phase Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Johan Puts

    Full Text Available Vitamin B1 (thiamine-diphosphate and B6 (pyridoxal-5'phosphate are micronutrients. Analysis of these micronutrients is important to diagnose potential deficiency which often occurs in elderly people due to malnutrition, in severe alcoholism and in gastrointestinal compromise due to bypass surgery or disease. Existing High Performance Liquid Chromatography (HPLC based methods include the need for derivatization and long analysis time. We developed an Ultra High Performance Liquid Chromatography Tandem Mass spectrometry (UHPLC-MS/MS assay with internal standards for simultaneous measurement of underivatized thiamine-diphosphate and pyridoxal-5'phosphate without use of ion pairing reagent.Whole blood, deproteinized with perchloric acid, containing deuterium labelled internal standards thiamine-diphosphate(thiazole-methyl-D3 and pyridoxal-5'phosphate(methyl-D3, was analyzed by UHPLC-MS/MS. The method was validated for imprecision, linearity, recovery and limit of quantification. Alternate (quantitative method comparisons of the new versus currently used routine HPLC methods were established with Deming regression.Thiamine-diphosphate and pyridoxal-5'phosphate were measured within 2.5 minutes instrumental run time. Limits of detection were 2.8 nmol/L and 7.8 nmol/L for thiamine-diphosphate and pyridoxal-5'phosphate respectively. Limit of quantification was 9.4 nmol/L for thiamine-diphosphate and 25.9 nmol/L for pyridoxal-5'phosphate. The total imprecision ranged from 3.5-7.7% for thiamine-diphosphate (44-157 nmol/L and 6.0-10.4% for pyridoxal-5'phosphate (30-130 nmol/L. Extraction recoveries were 101-102% ± 2.5% (thiamine-diphosphate and 98-100% ± 5% (pyridoxal-5'phosphate. Deming regression yielded slopes of 0.926 and 0.990 in patient samples (n = 282 and national proficiency testing samples (n = 12 respectively, intercepts of +3.5 and +3 for thiamine-diphosphate (n = 282 and n = 12 and slopes of 1.04 and 0.84, intercepts of -2.9 and +20 for

  2. Evaluation of on-line concentration coupled to liquid chromatography tandem mass spectrometry for the quantification of neonicotinoids and fipronil in surface water and tap water.

    Science.gov (United States)

    Montiel-León, Juan Manuel; Duy, Sung Vo; Munoz, Gabriel; Amyot, Marc; Sauvé, Sébastien

    2018-03-05

    A study was initiated to investigate a fast and reliable method for the determination of selected systemic insecticides in water matrixes and to evaluate potential sources of bias in their analysis. Acetamiprid, clothianidin, desnitro-imidacloprid, dinotefuran, fipronil, imidacloprid, nitenpyram, thiacloprid, and thiamethoxam were amenable to analysis via on-line sample enrichment hyphenated to ultra-high-performance liquid chromatography tandem mass spectrometry. The selection of on-line solid-phase extraction parameters was dictated by a multicriterion desirability approach. A 2-mL on-line injection volume with a 1500 μL min -1 loading flow rate met the objectives sought in terms of chromatographic requirements, extraction efficiency, sensitivity, and precision. A total analysis time of 8 min per sample was obtained with method limits of detection in the range of 0.1-5 ng L -1 for the scope of targeted analytes. Automation at the sample concentration step yielded intraday and interday precisions in the range of 1-23 and 2-26%, respectively. Factors that could affect the whole method accuracy were further evaluated in matrix-specific experiments. The impact of the initial filtration step on analyte recovery was evaluated in ultra-pure water, tap water, and surface water. Out of the nine membranes tested, glass fiber filters and polyester filters appeared as the most appropriate materials. Sample storage stability was also investigated across the three matrix types; the targeted analytes displayed suitable stability during 28 days at either 4 °C or - 20 °C, with little deviations (± 10%) with respect to the initial T 0 concentration. Method applicability was demonstrated in a range of tap water and surface water samples from the province of Québec, Canada. Results from the present survey indicated a predominance of thiamethoxam (tap water and river water, respectively), clothianidin (tap water and river water, respectively), and imidacloprid (tap

  3. An ultra-sensitive method for the analysis of perfluorinated alkyl acids in drinking water using a column switching high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Dasu, Kavitha; Nakayama, Shoji F; Yoshikane, Mitsuha; Mills, Marc A; Wright, J Michael; Ehrlich, Shelley

    2017-04-21

    In epidemiological research, it has become increasingly important to assess subjects' exposure to different classes of chemicals in multiple environmental media. It is a common practice to aliquot limited volumes of samples into smaller quantities for specific trace level chemical analyses. A novel method was developed for the determination of 14 perfluorinated alkyl acids (PFAAs) in small volumes (10mL) of drinking water using off-line solid phase extraction (SPE) pre-treatment followed by on-line pre-concentration on a WAX column before analysis on column-switching high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). In general, large volumes (100-1000mL) have been used for the analysis of PFAAs in drinking water. The current method requires approximately 10mL of drinking water concentrated by using an SPE cartridge and eluted with methanol. A large volume injection of the extract was introduced on to a column-switching HPLC-MS/MS using a mix-mode SPE column for the trace level analysis of PFAAs in water. The recoveries for most of the analytes in the fortified laboratory blanks ranged from 73±14% to 128±5%. The lowest concentration minimum reporting levels (LCMRL) for the 14 PFAAs ranged from 0.59 to 3.4ng/L. The optimized method was applied to a pilot-scale analysis of a subset of drinking water samples from an epidemiological study. These samples were collected directly from the taps in the households of Ohio and Northern Kentucky, United States and the sources of drinking water samples are both surface water and ground water, and supplied by different water distribution facilities. Only five PFAAs, perfluoro-1-butanesulfonic acid (PFBS), perfluoro-1- -hexanesulfonic acid (PFHxS), perfluoro-1-octanesulfonic acid (PFOS), perfluoro-n-heptanoic acid (PFHpA) and perfluoro-n-octanoic acid (PFOA) are detected above the LCMRL values. The median concentrations of these five PFAAs detected in the samples was ≤4.1ng/L with PFOS at 7.6ng

  4. Determination of mycotoxins in milk-based products and infant formula using stable isotope dilution assay and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Kai; Wong, Jon W; Hayward, Douglas G; Vaclavikova, Marta; Liao, Chia-Ding; Trucksess, Mary W

    2013-07-03

    A stable isotope dilution assay and liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of 12 mycotoxins, aflatoxins B₁, B₂, G₁, G₂, and M₁, deoxynivalenol, fumonisins B₁, B₂, and B₃, ochratoxin A, T-2 toxin, and zearalenone, in milk-based infant formula and foods. Samples were fortified with 12 ¹³C uniformly labeled mycotoxins ([¹³C]-mycotoxins) that correspond to the 12 target mycotoxins and prepared by dilution and filtration, followed by LC-MS/MS analysis. Quantitation was achieved using the relative response factors of [¹³C]-mycotoxins and target mycotoxins. The average recoveries in fortified milk, milk-based infant formula, milk powder, and baby yogurt of aflatoxins B₁, B₂, G₁, and G₂ (2, 10, and 50 μg/kg), aflatoxin M₁ (0.5, 2.5, and 12.5 μg/kg), deoxynivalenol, fumonisins B₁, B₂, and B₃ (40, 200, and 1000 μg/kg), ochratoxin A, T-2 toxin, and zearalenone (20, 100, and 500 μg/kg), range from 89 to 126% with RSDs of milk-based infant formula) to 136% (T-2 toxin, 20 μg/kg, milk powder), with RSDs ranging from 2 to 25%. The limits of quantitation (LOQs) were from 0.01 μg/kg (aflatoxin M₁) to 2 (fumonisin B₁) μg/kg. Aflatoxin M₁ was detected in two European Reference materials at 0.127 ± 0.013 μg/kg (certified value = 0.111 ± 0.018 μg/kg) and 0.46 ± 0.04 μg/kg (certified value = 0.44 ± 0.06 μg/kg), respectively. In 60 local market samples, aflatoxins B₁ (1.14 ± 0.10 μg/kg) and B₂ (0.20 ± 0.03 μg/kg) were detected in one milk powder sample. Aflatoxin M₁ was detected in three imported samples (condensed milk, milk-based infant formula, and table cream), ranging from 0.10 to 0.40 μg/kg. The validated method provides sufficient selectivity, sensitivity, accuracy, and reproducibility to screen for aflatoxin M₁ at nanograms per kilogram concentrations and other mycotoxins, without using standard addition or matrix-matched calibration

  5. [Optimization of sample pretreatment method for the determination of typical artificial sweeteners in soil by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Feng, Biting; Gan, Zhiwei; Hu, Hongwei; Sun, Hongwen

    2014-09-01

    The sample pretreatment method for the determination of four typical artificial sweeteners (ASs) including sucralose, saccharin, cyclamate, and acesulfame in soil by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was optimized. Different conditions of extraction, including four extractants (methanol, acetonitrile, acetone, deionized water), three kinds of ionic strength of sodium acetate solution (0.001, 0.01, 0.1 mol/L), four pH values (3, 4, 5 and 6) of 0.01 mol/L acetate-sodium acetate solution, four set durations of extraction (20, 40, 60, 120 min) and number of extraction times (1, 2, 3, 4 times) were compared. The optimal sample pretreatment method was finally set up. The sam- ples were extracted twice with 25 mL 0.01 mol/L sodium acetate solution (pH 4) for 20 min per cycle. The extracts were combined and then purified and concentrated by CNW Poly-Sery PWAX cartridges with methanol containing 1 mmol/L tris (hydroxymethyl) amino methane (Tris) and 5% (v/v) ammonia hydroxide as eluent. The analytes were determined by HPLC-MS/MS. The recoveries were obtained by spiked soil with the four artificial sweeteners at 1, 10, 100 μg/kg (dry weight), separately. The average recoveries of the analytes ranged from 86.5% to 105%. The intra-day and inter-day precisions expressed as relative standard deviations (RSDs) were in the range of 2.56%-5.94% and 3.99%-6.53%, respectively. Good linearities (r2 > 0.995) were observed between 1-100 μg/kg (dry weight) for all the compounds. The limits of detection were 0.01-0.21 kg/kg and the limits of quantification were 0.03-0.70 μg/kg for the analytes. The four artificial sweeteners were determined in soil samples from farmland contaminated by wastewater in Tianjin. This method is rapid, reliable, and suitable for the investigation of artificial sweeteners in soil.

  6. Differential extraction of endogenous and exogenous 25-OH-vitamin D from serum makes the accurate quantification in liquid chromatography-tandem mass spectrometry assays challenging.

    Science.gov (United States)

    Lankes, Ulrich; Elder, Peter A; Lewis, John G; George, Peter

    2015-01-01

    Extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis is the method of choice when it comes to the accurate quantification of 25-OH-vitamin D in blood samples. It is generally assumed that the addition of exogenous internal standard allows for the determination of the endogenous analyte concentration. In this study we investigated the extraction properties of endogenous and exogenous 25-OH-vitamin D. Eight samples were used for the evaluation of the extraction procedure and 59 patients' samples for a method comparison. The methanol-to-sample ratio (v/v) and the sample-to-hexane ratio (v/v) were varied and the LC-MS/MS signals of endogenous 25-OH-vitamin D3, spiked 25-OH-vitamin D2 and internal standard of the extracts recorded. The optimized 'in-house' LC-MS/MS assay was compared to two automated chemiluminescence immunoassays from DiaSorin and Abbott. Mathematical analysis of the data revealed a differential extraction of endogenous 25-OH-vitamin D3, spiked 25-OH-vitamin D2 and non-equilibrated internal standard. Exogenous 25-OH-vitamin D can be measured accurately if a definite methanol-to-sample ratio is used. Endogenous 25-OH-vitamin D is affected by critical quantification issues due to a differential slope in the extraction profile. The actual 25-OH-vitamin D concentration can be one-third above the measured extractable concentration. Results confirm that the 'in-house' LC-MS/MS assay provides reproducible 25-OH-vitamin D results. Discordant concentrations of 25-OH-vitamin D from LC-MS/MS assays can be caused by selection of suboptimal extraction conditions. Furthermore, a different sample pretreatment or solvent extraction system may result in a different dissociation and extraction yield of endogenous 25-OH-vitamin D and therefore contribute to variations of LC-MS/MS results. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  7. Development and validation of a liquid chromatography-tandem mass spectrometry assay for hair analysis of atomoxetine and its metabolites: Application in clinical practice.

    Science.gov (United States)

    Papaseit, Esther; Marchei, Emilia; Mortali, Claudia; Aznar, Gemma; Garcia-Algar, Oscar; Farrè, Magi; Pacifici, Roberta; Pichini, Simona

    2012-05-10

    Atomoxetine (ATX) is a potent inhibitor of the noradrenaline reuptake transporter approved since 2002 for the treatment of attention-deficit/hyperactivity disorder (ADHD) in children, adolescents, and adults as alternative treatment to methylphenidate. A procedure based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of ATX and its main metabolites (4-hydroxyatomoxetine - 4 hydroxyATX - and N-desmethylatomoxetine - des-methylATX) in hair of one treated child and five treated adolescents. Since hair samples can be easily collected without the need for specials skills and exposing a patient to discomfort, hair testing of ATX and eventually of its metabolites should be useful, especially in case of pediatric patients, to check compliance in a wider time-window. After addition of duloxetine as internal standard, hair samples were overnight digested with 2ml 1M NaOH at 45°C. Then, analytes were extracted from alkaline solution with two different 2ml aliquots of tert-butyl methyl ether. Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a mobile phase of 40% of water-60% 5mM ammonium acetate, 50mM formic acid, 4mM trifluoroacetic acid in acetonitrile-water (85:15, v/v). The mass spectrometer was operated in positive ion mode using multiple reaction monitoring. The method was linear over the concentration range 0.2-50ng/mg hair for the all analytes under investigation, with an intra- and inter-assay imprecision and inaccuracy always less than 20% and an analytical recovery between 33.1% and 76.1%, depending on the considered analyte. Only ATX and 4-hydroxyATX were detected in hair samples with concentrations varying from 0.2 to 2.0ng/mg hair and from 0.3 to 1.0ng/mg, respectively. Notwithstanding the absence of any dose-hair concentration relationship, hair monitoring of ATX and concomitant medications commonly administrated in ADHD children and adolescents can be crucial

  8. Experimental design for the optimization and robustness testing of a liquid chromatography tandem mass spectrometry method for the trace analysis of the potentially genotoxic 1,3-diisopropylurea.

    Science.gov (United States)

    Székely, György; Henriques, Bruno; Gil, Marco; Alvarez, Carlos

    2014-09-01

    This paper discusses a design of experiments (DoE) assisted optimization and robustness testing of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method development for the trace analysis of the potentially genotoxic 1,3-diisopropylurea (IPU) impurity in mometasone furoate glucocorticosteroid. Compared to the conventional trial-and-error method development, DoE is a cost-effective and systematic approach to system optimization by which the effects of multiple parameters and parameter interactions on a given response are considered. The LC and MS factors were studied simultaneously: flow (F), gradient (G), injection volume (Vinj), cone voltage (E(con)), and collision energy (E(col)). The optimization was carried out with respect to four responses: separation of peaks (Sep), peak area (A(p)), length of the analysis (T), and the signal-to-noise ratio (S/N). An optimization central composite face (CCF) DoE was conducted leading to the early discovery of carry-over effect which was further investigated in order to establish the maximum injectable sample load. A second DoE was conducted in order to obtain the optimal LC-MS/MS method. As part of the validation of the obtained method, its robustness was determined by conducting a fractional factorial of resolution III DoE, wherein column temperature and quadrupole resolution were considered as additional factors. The method utilizes a common Phenomenex Gemini NX C-18 HPLC analytical column with electrospray ionization and a triple quadrupole mass detector in multiple reaction monitoring (MRM) mode, resulting in short analyses with a 10-min runtime. The high sensitivity and low limit of quantification (LOQ) was achieved by (1) MRM mode (instead of single ion monitoring) and (2) avoiding the drawbacks of derivatization (incomplete reaction and time-consuming sample preparation). Quantitatively, the DoE method development strategy resulted in the robust trace analysis of IPU at 1.25 ng/mL absolute concentration

  9. Bisphenol A determination in baby bottles by chemiluminescence enzyme-linked immunosorbent assay, lateral flow immunoassay and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Maiolini, Elisabetta; Ferri, Elida; Pitasi, Agata Laura; Montoya, Angel; Di Giovanni, Manuela; Errani, Ermanno; Girotti, Stefano

    2014-01-07

    Two immunoassays, a Lateral Flow ImmunoAssay (LFIA) based on colloidal gold nanoparticle labels and an indirect competitive chemiluminescence enzyme-linked immunosorbent assay (CL-ELISA), were developed and a high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was optimized to assess the possible release of bisphenol A (BPA, 4,4'-isopropylidenediphenol) from different plastic baby bottles treated with simulating solutions. Coating conjugate concentration, anti-BPA antibody dilution, incubation time of the primary and secondary antibodies, and tolerance to different organic solvents were optimized to obtain the best performance of the ELISA with chemiluminescent end-point detection. The influence of different buffers on LFIA performance was also evaluated. Both methods showed good repeatability (mean CV value around 13%) and sensitivity. Reproducibility tests for CL-ELISA gave a mean CV value of about 25%. The IC50 and Limit of Detection (LOD) values of CL-ELISA were 0.2 and 0.02 ng mL(-1), respectively. The LOD of LFIA was 0.1 μg mL(-1). A LC-MS/MS method was also optimized. The separation was performed in a C18 column with a triple-quadrupole mass spectrometer with electrospray ionisation interface. The method showed a good linearity in the range 2 to 500 ng mL(-1), with a regression coefficient of 0.998. In the simulating solutions the detection and quantification limits, calculated by the signal to noise level of 3 (S/N = 3), were 5.8 ng mL(-1) and 17.4 ng mL(-1), respectively. This limit of quantification was about 3 and 35 times lower than the permitted limits set by the official method CEN/TS 13130-13 (0.05 μg mL(-1)) and by the Directive 2004/19/EC (0.6 μg mL(-1)), respectively. The methods were applied to determine BPA release from baby bottles, performing repeated procedures according to EU and national regulations. The results demonstrated that no BPA migration from the tested plastic materials occurred with only one

  10. Sensitive measurement of serum 1α,25-dihydroxyvitamin D by liquid chromatography/tandem mass spectrometry after removing interference with immunoaffinity extraction.

    Science.gov (United States)

    Yuan, Chao; Kosewick, Justin; He, Xiang; Kozak, Marta; Wang, Sihe

    2011-05-15

    Vitamin D plays important roles in bone health and a variety of other pathophysiological conditions. 1α,25-Dihydroxyvitamin D is the active form of vitamin D. Quantification of serum 1α,25-dihydroxyvitamin D is useful for evaluation of several diseases including chronic renal failure, hypoparathyroidism, sarcoidosis, and rickets. Measurement of 1α,25-dihydroxyvitamin D is very challenging due to its low circulating concentration and presence of interfering substances in serum. In this report, a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for quantifying serum 1α,25-dihydroxyvitamin D is described. Lithium adducts of 1α,25-dihydroxyvitamin D were formed prior to mass spectrometry analysis to improve ionization efficiency. We tested a number of different sample preparation procedures and found that immunoaffinity extraction was the method of choice because it completely removed isobaric interferences and matrix effects present in patient serum. Extraction efficiency, expressed as absolute recovery, was greater than 60% in both patient serum and charcoal-stripped serum. This method was linear from 3.4 to 206.2 pg/mL for 1α,25-dihydroxyvitamin D(3) and 3.9 to 212.6 pg/mL for 1α,25-dihydroxyvitamin D(2) with an accuracy of 89.8-98.4% and 97.5-115.7%, respectively. Inter-assay and intra-assay coefficients of variance (CVs) for both analytes at two different concentration levels ranged from 2.5-7.0%. Comparison with a radioimmunoassay for measuring total 1α,25-dihydroxyvitamin D concentration using 40 patient samples showed a Deming regression slope of 0.751, a y-intercept of 0.84 pg/mL, an r value of 0.7909, and a mean percentage difference of -27.1%. Comparison with a reference LC/MS/MS method (n = 20) showed a Deming regression slope of 1.020, a y-intercept of 1.32 pg/mL, an r value of 0.9797, and a mean percentage difference of -2.9%. In conclusion, usage of immunoaffinity extraction enabled a sensitive LC/MS/MS method for

  11. Trace analysis of fluoxetine and its metabolite norfluoxetine. Part I: development of a chiral liquid chromatography-tandem mass spectrometry method for wastewater samples.

    Science.gov (United States)

    Barclay, Victoria K H; Tyrefors, Niklas L; Johansson, I Monika; Pettersson, Curt E

    2011-08-19

    An enantioselective method for the determination of fluoxetine (a selective serotonin reuptake inhibitor) and its pharmacologically active metabolite norfluoxetine has been developed for raw and treated wastewater samples. The stable isotope-labeled fluoxetine and norfluoxetine were used in an extended way for extraction recovery calculations at trace level concentrations in wastewater. Wastewater samples were enriched by solid phase extraction (SPE) with Evolute CX-50 extraction cartridges. The obtained extraction recoveries ranged between 65 and 82% in raw and treated wastewater at a trace level concentration of 50 pM (15-16 ng L⁻¹). The target compounds were identified by the use of chiral liquid chromatography tandem mass spectrometry (LC-MS/MS) in selected reaction monitoring (SRM) mode. The enantiomers were successfully resolved on a chiral α₁-acid glycoprotein column (chiral AGP) with acetonitrile and 10 mM ammonium acetate buffer at pH 4.4 (3/97, v/v) as the mobile phase. The effects of pH, amount of organic modifier and buffer concentration in the mobile phase were investigated on the enantiomeric resolution (R(s)) of the target compounds. Enantiomeric R(s)-values above 2.0 (1.03 RSD%, n=3) were achieved for the enantiomers of fluoxetine and norfluoxetine in all mobile phases investigated. The method was validated by assessing parameters such as cross-contamination and carryover during SPE and during LC analysis. Cross-talk effects were examined during the detection of the analytes in SRM mode. In addition, the isotopic purity of fluoxetine-d₅ and norfluoxetine-d₅ were assessed to exclude the possibility of self-contamination. The interassay precision of the chromatographic separation was excellent, with relative standard deviations (RSD) equal to or lower than 0.56 and 0.81% in raw and treated wastewaters, respectively. The method detection and quantification limits (respectively, MDL and MQL) were determined by the use of fluoxetine-d₅ and

  12. Evaluation of cannabinoids concentration and stability in standardized preparations of cannabis tea and cannabis oil by ultra-high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Pacifici, Roberta; Marchei, Emilia; Salvatore, Francesco; Guandalini, Luca; Busardò, Francesco Paolo; Pichini, Simona

    2017-08-28

    Cannabis has been used since ancient times to relieve neuropathic pain, to lower intraocular pressure, to increase appetite and finally to decrease nausea and vomiting. The combination of the psychoactive cannabis alkaloid Δ9-tetrahydrocannabinol (THC) with the non-psychotropic alkaloids cannabidiol (CBD) and cannabinol (CBN) demonstrated a higher activity than THC alone. The Italian National Institute of Health sought to establish conditions and indications on how to correctly use nationally produced cannabis to guarantee therapeutic continuity in individuals treated with medical cannabis. The evaluation of cannabinoids concentration and stability in standardized preparations of cannabis tea and cannabis oil was conducted using an easy and fast ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) assay. Extraction efficiency of oil was significantly higher than that of water with respect to the different cannabinoids. This was especially observed in the case of the pharmacologically active THC, CBD and their acidic precursors. Fifteen minutes boiling was sufficient to achieve the highest concentrations of cannabinoids in the cannabis tea solutions. At ambient temperature, a significant THC and CBD decrease to 50% or less of the initial concentration was observed over 3 and 7 days, respectively. When refrigerated at 4 °C, similar decreasing profiles were observed for the two compounds. The cannabinoids profile in cannabis oil obtained after pre-heating the flowering tops at 145 °C for 30 min in a static oven resulted in a complete decarboxylation of cannabinoid acids CBDA and THCA-A. Nevertheless, it was apparent that heat not only decarboxylated acidic compounds, but also significantly increased the final concentrations of cannabinoids in oil. The stability of cannabinoids in oil samples was higher than that in tea samples since the maximum decrease (72% of initial concentration) was observed in THC coming from unheated flowering

  13. Method for detection of trace metal and metalloid contaminants in coal-generated fuel gas using gas chromatography/ion trap mass spectrometry.

    Science.gov (United States)

    Rupp, Erik C; Granite, Evan J; Stanko, Dennis C

    2010-07-15

    There exists an increasing need to develop a reliable method to detect trace contaminants in fuel gas derived from coal gasification. While Hg is subject to current and future regulations, As, Se, and P emissions may eventually be regulated. Sorbents are the most promising technology for the removal of contaminants from coal-derived fuel gas, and it will be important to develop a rapid analytical detection method to ensure complete removal and determine the ideal time for sorbent replacement/regeneration in order to reduce costs. This technical note explores the use of a commercial gas chromatography/ion trap mass spectrometry system for the detection of four gaseous trace contaminants in a simulated fuel gas. Quantitative, repeatable detection with limits at ppbv to ppmv levels were obtained for arsine (AsH(3)), phosphine (PH(3)), and hydrogen selenide (H(2)Se), while qualitative detection was observed for mercury. Decreased accuracy and response caused by the primary components of fuel gas were observed.

  14. Analytical and clinical performance of the new Fujirebio 25-OH vitamin D assay, a comparison with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and three other automated assays

    OpenAIRE

    Saleh, Lanja; Mueller, Daniel; von Eckardstein, Arnold

    2015-01-01

    BACKGROUND: We evaluated the analytical and clinical performance of the new Lumipulse® G 25-OH vitamin D assay from Fujirebio, and compared it to a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and three other commercial automated assays. METHODS: Total 25 hydroxy vitamin D (25(OH)D) levels were measured in 100 selected serum samples from our routine analysis with Fujirebio 25(OH)D assay. The results were compared with those obtained with LC-MS/MS and three other automat...

  15. Assessment of circulating sex steroid levels in prepubertal and pubertal boys and girls by a novel ultrasensitive gas chromatography-tandem mass spectrometry method

    DEFF Research Database (Denmark)

    Courant, Frédérique; Aksglæde, Lise; Antignac, Jean-Philippe

    2010-01-01

    Estrogens and androgens play key roles for pubertal onset and sexual maturation. Most currently used immunoassays are not sensitive enough to accurately measure the low circulating levels of sex steroids in children without any signs of puberty. However, this does not exclude that sex steroids ha...

  16. A method for the simultaneous quantification of eight metabolites of synthetic pyrethroids in urine of the general population using gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Schettgen, Thomas; Dewes, Petra; Kraus, Thomas

    2016-08-01

    Synthetic pyrethroids are highly effective, widespread insecticides applied worldwide for different purposes. Among the possible sources of exposure for the general population, pyrethroid residues in food and their prominent use for the conservation of wool carpets or in indoor pest control might play a major role. On the basis of previous works, we have developed and validated a highly sensitive and specific GC/MS/MS-method to simultaneously quantify the metabolites of the most common synthetic pyrethroids in urine, namely cis- and trans-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (DCCA), cis-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylic acid (DBCA), 4-fluoro-3-phenoxybenzoic acid (F-PBA), 3-phenoxybenzoic acid (3-PBA) as well as the metabolites cis-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl-cyclopropanecarboxylic acid (ClF3CA, λ-cyhalothrin/bifenthrin), 4-chloro-α-isopropylbenzene acetic acid (CPBA, esfenvalerate), and 2-methyl-3-phenylbenzoic acid (MPB, bifenthrin). After acidic hydrolysis to cleave conjugates in urine, the analytes are subjected to a pH-controlled extraction into n-hexane. After concentration, the analytes are derivatised using MTBSTFA and finally quantified by GC/MS/MS in EI-mode using d6-trans-DCCA and (13)C6-3-PBA as internal standards. The limit of quantification for these metabolites was 0.01 μg/L urine. Precision within and between series was determined to range between 1.6 and 10.7 % using a native quality control sample as well as a urine sample spiked with 0.3 μg/L of the analytes. To investigate possible background excretions, we analysed spot urine samples of 38 persons of the general population in a pilot study. cis- and trans-DCCA as well as 3-PBA could be quantified in every urine sample investigated, while MPB and F-PBA could only be detected in two samples. The median levels for excretion of cis-DCCA, trans-DCCA, 3-PBA, ClF3CA, DBCA, CPBA, F-PBA and MPA were 0.08, 0.17, 0.22, 0.04, 0.04, pyrethroids in environmental medicine. Remarkable are the high detection rates for the metabolites ClF3CA (90 %) and CPBA (40 %), proving that their parent pyrethroids have entered the market in Germany.

  17. Fast, sensitive, and selective gas chromatography tandem mass spectrometry method for the target analysis of chemical secretions from femoral glands in lizards.

    Science.gov (United States)

    Sáiz, Jorge; García-Roa, Roberto; Martín, José; Gómara, Belén

    2017-09-08

    Chemical signaling is a widespread mode of communication among living organisms that is used to establish social organization, territoriality and/or for mate choice. In lizards, femoral and precloacal glands are important sources of chemical signals. These glands protrude chemical secretions used to mark territories and also, to provide valuable information from the bearer to other individuals. Ecologists have studied these chemical secretions for decades in order to increase the knowledge of chemical communication in lizards. Although several studies have focused on the chemical analysis of these secretions, there is a lack of faster, more sensitive and more selective analytical methodologies for their study. In this work a new GC coupled to tandem triple quadrupole MS (GC-QqQ (MS/MS)) methodology is developed and proposed for the target study of 12 relevant compounds often found in lizard secretions (i.e. 1-hexadecanol, palmitic acid, 1-octadecanol, oleic acid, stearic acid, 1-tetracosanol, squalene, cholesta-3,5-diene, α-tocopherol, cholesterol, ergosterol and campesterol). The method baseline-separated the analytes in less than 7min, with instrumental limits of detection ranging from 0.04 to 6.0ng/mL. It was possible to identify differences in the composition of the samples from the lizards analyzed, which depended on the species, the habitat occupied and the diet of the individuals. Moreover, α-tocopherol has been determined for the first time in a lizard species, which was thought to lack its expression in chemical secretions. Globally, the methodology has been proven to be a valuable alternative to other published methods with important improvements in terms of analysis time, sensitivity, and selectivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Assessment of circulating sex steroid levels in prepubertal and pubertal boys and girls by a novel ultrasensitive gas chromatography-tandem mass spectrometry method

    DEFF Research Database (Denmark)

    Courant, Frédérique; Aksglæde, Lise; Antignac, Jean-Philippe

    2010-01-01

    Estrogens and androgens play key roles for pubertal onset and sexual maturation. Most currently used immunoassays are not sensitive enough to accurately measure the low circulating levels of sex steroids in children without any signs of puberty. However, this does not exclude that sex steroids have...

  19. Rapid analytical method for the determination of pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction prior to gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Prados-Rosales, R C; Luque García, J L; Luque de Castro, M D

    2003-04-18

    A rapid analytical method for determination of organochlorine pesticide residues in sunflower seeds based on focused microwave-assisted Soxhlet extraction has been developed. The main factors affecting the extraction efficiency--namely microwave power, irradiation time, volume of extractant and number of cycles--were optimized by a two-level factorial fractional design. After extraction, a liquid-liquid extraction and a clean-up step including the use of Florisil macrocolumns were required prior to injection of the extracts into the chromatograph in order to isolate the pesticide residues from the lipid fraction of the original extract. The MS-MS ion preparation mode was selected due to the high sensitivity and selectivity it provides. Seed samples were used collected near a crop subjected to aerial pesticide application. Residues of hexachlorocyclohexane isomers and endosulfan were found in the seeds although they were not subjected to pesticide application, thus showing the spray-drift contamination. The validation of the proposed approach was carried out by comparison with the ISO 659-1988 reference extraction method obtaining similar, or even better efficiencies by the proposed approach.

  20. Endogenous steroid profiling by gas chromatography-tandem mass spectrometry and multivariate statistics for the detection of natural hormone abuse in cattle

    NARCIS (Netherlands)

    Blokland, M.H.; Tricht, van E.F.; Rossum, van H.J.; Sterk, S.S.; Nielen, M.W.F.

    2012-01-01

    For years it has been suspected that natural hormones are illegally used as growth promoters in cattle in the European Union. Unfortunately there is a lack of methods and criteria that can be used to detect the abuse of natural hormones and distinguish treated from non-treated animals. Pattern

  1. Clean-up of cereal extracts for gas chromatography-tandem quadrupole mass spectrometry pesticide residues analysis using primary secondary amine and C18

    DEFF Research Database (Denmark)

    Herrmann, Susan Strange; Poulsen, Mette Erecius

    2015-01-01

    The level of co-extracted matrix in wheat and oat extracts obtained by the QuEChERS method (EN 15662) is high and the occurrence of free fatty acids generates a major matrix peak in TIC chromatograms (rt. 13-22min). Matrix can compromise the analytical performance in pesticide analysis using GC-MS/MS...... low intensity of the matrix peak. For oat the analytical responses of the target pesticides generally increased with increasing amount of PSA. C18 had no significant effect on the intensity of the major matrix peaks and even resulted in lower analytical responses for several of the target pesticides...

  2. Unstable Simple Volatiles and Gas Chromatography-Tandem Mass Spectrometry Analysis of Essential Oil from the Roots Bark of Oplopanax Horridus Extracted by Supercritical Fluid Extraction

    Directory of Open Access Journals (Sweden)

    Li Shao

    2014-11-01

    Full Text Available Volatile oil from the root bark of Oplopanax horridus is regarded to be responsible for the clinical uses of the title plant as a respiratory stimulant and expectorant. Therefore, a supercritical fluid extraction method was first employed to extract the volatile oil from the roots bark of O. horridus, which was subsequently analyzed by GC/MS. Forty-eight volatile compounds were identified by GC/MS analysis, including (S,E-nerolidol (52.5%, τ-cadinol (21.6% and S-falcarinol (3.6%. Accordingly, the volatile oil (100 g was subjected to chromatographic separation and purification. As a result, the three compounds, (E-nerolidol (2 g, τ-cadinol (62 mg and S-falcarinol (21 mg, were isolated and purified from the volatile oil, the structures of which were unambiguously elucidated by detailed spectroscopic analysis including 1D- and 2D-NMR techniques.

  3. Observation of trapped gas during electrical resistance heating of trichloroethylene under passive venting conditions

    Science.gov (United States)

    Martin, E. J.; Kueper, B. H.

    2011-11-01

    A two-dimensional experiment employing a heterogeneous sand pack incorporating two pools of trichloroethylene (TCE) was performed to assess the efficacy of electrical resistance heating (ERH) under passive venting conditions. Temperature monitoring displayed the existence of a TCE-water co-boiling plateau at 73.4 °C, followed by continued heating to 100 °C. A 5 cm thick gas accumulation formed beneath a fine-grained capillary barrier during and after co-boiling. The capillary barrier did not desaturate during the course of the experiment; the only pathway for gas escape being through perforated wells traversing the barrier. The thickness of the accumulation was dictated by the entry pressure of the perforated well. The theoretical maximum TCE soil concentration within the region of gas accumulation, following gas collapse, was estimated to be 888 mg/kg. Post-heating soil sampling revealed TCE concentrations in this region ranging from 27 mg/kg to 96.7 mg/kg, indicating removal of aqueous and gas phase TCE following co-boiling as a result of subsequent boiling of water. The equilibrium concentrations of TCE in water corresponding to the range of post-treatment concentrations in soil (6.11 mg/kg to 136 mg/kg) are calculated to range from 19.8 mg/l to 440 mg/l. The results of this experiment illustrate the importance of providing gas phase venting during the application of ERH in heterogeneous porous media.

  4. The injection of inert gas ions into solids: their trapping and escape

    International Nuclear Information System (INIS)

    Carter, G.; Armour, D.G.; Donnelly, S.E.; Ingram, D.C.; Webb, R.P.

    1980-01-01

    Basic information is required to understand fission gas generation and its consequence for swelling and embrittlement in fission reactors, for understanding and controlling first wall problems in fusion reactors and for attempting to design storage for active gas waste. In all of these areas the rare gas atoms are generated with kinetic energy and may thus interact differently, during their slowing down, with the solid than if they had been introduced more gently (e.g. via diffusion) into the solid. An important method of simulating the behaviour of such energetic rare gas atoms in solids is via external irradiation of the solid with rare gas ions of appropriate species and energies and it is the purpose of this review to evaluate studies of this nature. The review is divided into three parts. The first describes experimental techniques, discusses the results of measurements of how ions penetrate into and may be retained in a solid, and outlines theoretical interpretations of the data. The mechanisms of gas atom dissolution and thermal transport in solids are of profound importance and so, in the second part of this review, attention is devoted to how the technique of post-implantation thermal evolution spectrometry can be employed to attempt to understand some of these processes. Particular attention is paid to the difficulties of unique interpretation of evolution spectra. In the final section, consideration will be given to the processes which lead to the inevitable saturation of solids undergoing continued irradiation with rare gas ions and experimental measurements and their probable interpretation will be discussed. Since many materials are of importance in the context of this symposium, reference will be made to as broad a range of studies as possible. (author)

  5. Spontaneous Separation in Trapped Fermi Gas with p-Wave Interactions: Due to the Mass-Imbalance

    Science.gov (United States)

    Kang, Yanshuang; Sun, Zongli; Kang, Yanmei; Li, Yushan; Tan, Shanshan

    2018-03-01

    Based on density functional theory, the spontaneous separation in the mass-imbalanced Fermi-Fermi mixture is studied. The ground-state energy density functional is constructed with the effective contact interaction, with which the ground-state density profiles of the mixture are calculated under different conditions of mass-imbalance and coupling strength. The influence of mass-imbalance on the separation and the cloud size is analyzed. In addition, the system with both mass- and population-imbalance is also calculated and studied. Despite our rough treatment in the Thomas-Fermi approximation, it is hoped that the results may provide new clues to understand the nature of phase separation of a trapped ultracold gas in both theoretical and experimental researches in the future.

  6. Solar wind rare gas analysis: Trapped solar wind helium and neon in Surveyor 3 material

    Science.gov (United States)

    Buehler, F.; Eberhardt, P.; Geiss, J.; Schwarzmueller, J.

    1972-01-01

    The He-4 and Ne-20 contents in sections of the Surveyor 3 support strut samples were determined by optical and scanning electron microscopy and are compared to the results of the Apollo solar wind composition (SWC) experiments. The He-4/Ne-20 ratio in the samples from the sunlit side of the strut was approximately 300; the ratios determined in Apollo 12 lunar fines and SWC foil were below 100. The He-4/He-3 ratios were also determined, and the ratio obtained from Surveyor 3 material is higher than those found with Apollo 11 and 12 SWC experiments. The effects of spallation by cosmic rays or solar protons, stripping by cosmic ray or energetic solar alpha particles, recycling of solar wind He and radiogenic Ne, He from terrestrial atmosphere, mass discrimination near the moon, mass dependence of trapping probability, diffusion, and contamination by lunar dust are considered.

  7. Use of CFD to predict trapped gas excitation as source of vibration and noise in screw compressors

    Science.gov (United States)

    Willie, James

    2017-08-01

    This paper investigates the source of noise in oil free screw compressors mounted on highway trucks and driven by a power take-off (PTO) transmission system. Trapped gas at the discharge side is suggested as possible source of the excitation of low frequency torsional resonance in these compressors that can lead to noise and vibration. Measurements and lumped mass torsional models have shown low frequency torsional resonance in the drive train of these compressors when they are mounted on trucks. This results in high torque peak at the compressor input shaft and in part to pulsating noise inside the machine. The severity of the torque peak depends on the amplitude of the input torque fluctuation from the drive (electric motor or truck engine). This in turn depends on the prop-shaft angle. However, the source of the excitation of this low torsional resonance inside the machine is unknown. Using CFD with mesh motion at every 1° rotation of the rotors, it is shown that the absence of a pressure equalizing chamber at the discharge can lead to trapped gas creation, which can lead to over-compression, over-heating of the rotors, and to high pressure pulsations at the discharge. Over-compression can lead to shock wave generation at the discharge plenum and the pulsation in pressure can lead to noise generation. In addition, if the frequency of the pressure pulsation in the low frequency range coincides with the first torsional frequency of the drive train the first torsional resonance mode can be excited.

  8. Buffer gas cooling of polyatomic ions in rf multi-electrode traps.

    Science.gov (United States)

    Gerlich, D; Borodi, G

    2009-01-01

    Cooling all degrees of freedom of a molecule, a cluster, or even a nanoparticle which is suspended in a vacuum, is an experimental challenge. Without suitable schemes, cold or ultracold chemical reactions are not feasible. Methods such as laser based preparation of very slow atoms, decelerating molecules to low velocities with electric fields or freezing molecular ions into Coulomb crystals, are generally not suitable to cool the vibrational or rotational motion of molecules. This contribution describes a new method in which a beam of slow atoms or molecules (H, He, H2, or D2) is used for cooling charged particles confined in a multi-electrode rf trap. For reaching sub-K temperatures, the fast part of a cold effusive beam is removed with a shutter before the slow remaining neutrals interact with the ion cloud. The development of a pulsed cold beam source is discussed as well as suitable methods for determining the ion temperature. A challenging application is to prepare internally cold CH5+ for spectroscopy or chemistry. New experimental results for hydrogen abstraction in collisions with slow H atoms are reported at energies of a few meV. For evaluating these measurements and for predicting effective rate coefficients at lower energies, the kinematic conditions of the slow neutral beam-ion trap arrangement have been analyzed in detail. The potential of cooling ions such as protonated methane or H3+ with slow energy selected H atoms is briefly mentioned. An interesting process is the formation of weakly bound ions such as H4+ or CH6+ via radiative or ternary association. Such ions are ideal candidates for preparing the corresponding collision complexes very close (microeV) to the dissociation continuum using infrared transitions.

  9. Rapid screening of anabolic steroids in horse urine with ultra-high-performance liquid chromatography/tandem mass spectrometry after chemical derivatisation.

    Science.gov (United States)

    Wong, Colton H F; Leung, David K K; Tang, Francis P W; Wong, Jenny K Y; Yu, Nola H; Wan, Terence S M

    2012-04-06

    Liquid chromatography/mass spectrometry (LC/MS) has been successfully applied to the detection of anabolic steroids in biological samples. However, the sensitive detection of saturated hydroxysteroids, such as androstanediols, by electrospray ionisation (ESI) is difficult because of their poor ability to ionise. In view of this, chemical derivatisation has been used to enhance the detection sensitivity of hydroxysteroids by LC/MS. This paper describes the development of a sensitive ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) method for the screening of anabolic steroids in horse urine by incorporating a chemical derivatisation step, using picolinic acid as the derivatisation reagent. The method involved solid-phase extraction (SPE) of both free and conjugated anabolic steroids in horse urine using a polymer-based SPE cartridge (Abs Elut Nexus). The conjugated steroids in the eluate were hydrolysed by methanolysis and the resulting extract was further cleaned up by liquid-liquid extraction. The resulting free steroids in the extract were derivatised with picolinic acid to form the corresponding picolinoyl esters and analysed by UHPLC/MS/MS in the positive ESI mode with selected-reaction-monitoring. Separation of the targeted steroids was performed on a C18 UHPLC column. The instrument turnaround time was 10.5 min inclusive of post-run equilibration. A total of thirty-three anabolic steroids (including 17β-estradiol, 5(10)-estrene-3β,17α-diol, 5α-estrane-3β,17α-diol, 17α-ethyl-5α-estran-3α,17β-diol, 17α-methyl-5α-androstan-3,17β-diols, androstanediols, nandrolone and testosterone) spiked in negative horse urine at the QC levels (ranging from 0.75 to 30 ng/mL) could be consistently detected. The intra-day and inter-day precisions (% RSD) for the peak area ratios were around 7-51% and around 1-72%, respectively. The intra-day and inter-day precisions (% RSD) for the relative retention times were both less than 1% for

  10. Determination of Glyphosate, its Degradation Product Aminomethylphosphonic Acid, and Glufosinate, in Water by Isotope Dilution and Online Solid-Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry

    Science.gov (United States)

    Meyer, Michael T.; Loftin, Keith A.; Lee, Edward A.; Hinshaw, Gary H.; Dietze, Julie E.; Scribner, Elisabeth A.

    2009-01-01

    The U.S. Geological Survey method (0-2141-09) presented is approved for the determination of glyphosate, its degradation product aminomethylphosphonic acid (AMPA), and glufosinate in water. It was was validated to demonstrate the method detection levels (MDL), compare isotope dilution to standard addition, and evaluate method and compound stability. The original method USGS analytical method 0-2136-01 was developed using liquid chromatography/mass spectrometry and quantitation by standard addition. Lower method detection levels and increased specificity were achieved in the modified method, 0-2141-09, by using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The use of isotope dilution for glyphosate and AMPA and pseudo isotope dilution of glufosinate in place of standard addition was evaluated. Stable-isotope labeled AMPA and glyphosate were used as the isotope dilution standards. In addition, the stability of glyphosate and AMPA was studied in raw filtered and derivatized water samples. The stable-isotope labeled glyphosate and AMPA standards were added to each water sample and the samples then derivatized with 9-fluorenylmethylchloroformate. After derivatization, samples were concentrated using automated online solid-phase extraction (SPE) followed by elution in-line with the LC mobile phase; the compounds separated and then were analyzed by LC/MS/MS using electrospray ionization in negative-ion mode with multiple-reaction monitoring. The deprotonated derivatized parent molecule and two daughter-ion transition pairs were identified and optimized for glyphosate, AMPA, glufosinate, and the glyphosate and AMPA stable-isotope labeled internal standards. Quantitative comparison between standard addition and isotope dilution was conducted using 473 samples analyzed between April 2004 and June 2006. The mean percent difference and relative standard deviation between the two quantitation methods was 7.6 plus or minus 6.30 (n = 179), AMPA 9.6 plus or minus 8

  11. Neutral gas sympathetic cooling of an ion in a Paul trap.

    Science.gov (United States)

    Chen, Kuang; Sullivan, Scott T; Hudson, Eric R

    2014-04-11

    A single ion immersed in a neutral buffer gas is studied. An analytical model is developed that gives a complete description of the dynamics and steady-state properties of the ions. An extension of this model, using techniques employed in the mathematics of economics and finance, is used to explain the recent observation of non-Maxwellian statistics for these systems. Taken together, these results offer an explanation of the long-standing issues associated with sympathetic cooling of an ion by a neutral buffer gas.

  12. Two-step condensation of the ideal Bose gas in highly anisotropic traps

    NARCIS (Netherlands)

    van Druten, N.J.; Ketterle, W.

    1997-01-01

    The ideal Bose gas in a highly anisotropic harmonic potential is studied. It is found that Bose-Einstein condensation occurs in two distinct steps as the temperature is lowered. In the first step the specific heat shows a sharp feature, but the system still occupies many one-dimensional quantum

  13. Yang-Yang thermometry and momentum distribution of a trapped one-dimensional Bose gas

    NARCIS (Netherlands)

    Davis, M.J.; Blakie, P.B.; van Amerongen, A.H.; van Druten, N.J.; Kheruntsyan, K.V.

    2012-01-01

    We describe the use of the exact Yang-Yang solutions for the one-dimensional Bose gas to enable accurate kinetic-energy thermometry based on the root-mean-square width of an experimentally measured momentum distribution. Furthermore, we use the stochastic projected Gross-Pitaevskii theory to provide

  14. High-harmonic generation in a quantum electron gas trapped in a nonparabolic and anisotropic well

    Science.gov (United States)

    Hurst, Jérôme; Lévêque-Simon, Kévin; Hervieux, Paul-Antoine; Manfredi, Giovanni; Haas, Fernando

    2016-05-01

    An effective self-consistent model is derived and used to study the dynamics of an electron gas confined in a nonparabolic and anisotropic quantum well. This approach is based on the equations of quantum hydrodynamics, which incorporate quantum and nonlinear effects in an approximate fashion. The effective model consists of a set of six coupled differential equations (dynamical system) for the electric dipole and the size of the electron gas. Using this model we show that: (i) high harmonic generation is related to the appearance of chaos in the phase space, as attested to by related Poincaré sections; (ii) higher order harmonics can be excited efficiently and with relatively weak driving fields by making use of chirped electromagnetic waves.

  15. Hydrogen trapping properties of Zr-based intermetallic compounds in the presence of CO contaminant gas

    Energy Technology Data Exchange (ETDEWEB)

    Prigent, Jocelyn [Chimie Metallurgie des Terres Rares, ICMPE-UMR 7182, CNRS, 2-8 rue Henri Dunant, 94320 Thiais (France); Latroche, Michel, E-mail: latroche@icmpe.cnrs.fr [Chimie Metallurgie des Terres Rares, ICMPE-UMR 7182, CNRS, 2-8 rue Henri Dunant, 94320 Thiais (France); Leoni, Elisa; Rohr, Valentin [AREVA NC, 1, rue des Herons, 78182 Montigny Le Bretonneux (France)

    2011-09-15

    Research highlights: > Hydrogen absorption in the presence of carbon monoxide is reported for several Zr rich intermetallic compounds. > Absorption rates have been determined and compared for pure and CO-containing hydrogen gases. > Using intermetallic compounds as getter materials in the presence of contaminant gases has been demonstrated. - Abstract: Intermetallic compounds, as hydrogen getters, are considered to control the quantity of hydrogen generated in radioactive waste packaging. The compounds ZrCo, Zr{sub 2}Fe and a Zr-rich Zr-Ti-V alloy have been chosen as they form very stable hydrides at ambient temperature. However, other gases are produced in the packaging such as carbon monoxide, a gas known to poison the surface of intermetallic compounds and to hinder the hydrogen sorption reaction. The three Zr-based compounds have been first characterized regarding their metallurgical state and their gas sorption properties toward pure hydrogen. Then, the sorption properties of the activated materials have been studied using a mixture of 5 vol.% CO + 95 vol.% H{sub 2}. We demonstrated that though the presence of CO sharply slows down the reaction rate the activated compounds still show significant sorption properties. Therefore, the presence of contaminant gases is not detrimental for the target application.

  16. VACUUM TRAP

    Science.gov (United States)

    Gordon, H.S.

    1959-09-15

    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  17. Identification and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide (THC-COOH-glu) in hair by ultra-performance liquid chromatography tandem mass spectrometry as a potential hair biomarker of cannabis use.

    Science.gov (United States)

    Pichini, Simona; Marchei, Emilia; Martello, Simona; Gottardi, Massimo; Pellegrini, Manuela; Svaizer, Fiorenza; Lotti, Andrea; Chiarotti, Marcello; Pacifici, Roberta

    2015-04-01

    We developed and validated an ultra-high-pressure liquid chromatography-tandem mass spectrometry method to identify and quantify 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in hair of cannabis consumers. After hair washing with methyl alcohol and diethyl ether and subsequent addition of amiodarone as internal standard hair samples were treated with 500 μl VMA-T M3 buffer reagent for 1 h at 100 °C. After cooling, 10 μl VMA-T M3 extract were injected into chromatographic system. Chromatographic separation was carried out on a reversed phase column using a linear gradient elution with two solvents: 5 mM ammonium formate pH 3.0 (solvent A) and 0.1% formic acid in acetonitrile (solvent B). The flow rate was kept constant at 0.4 ml/min during the analysis. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode via positive electrospray ionization. Linear calibration curves were obtained for 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide with correlation coefficients (r(2)) of 0.99 and a limit of quantification of 0.25 pg/mg hair. Analytical recovery was between 79.6% and 100.7% and intra- and inter-assay imprecision and inaccuracy were always lower than 15%. Ultra-high-pressure liquid chromatography-tandem mass spectrometry analysis of 20 different hair samples of cannabis consumers disclosed the presence of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in the range of 0.5-8.6 pg/mg hair. These data provided a good start to consider 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide as alternative hair biomarker of cannabis consumption. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Gas-phase hydrogen/deuterium exchange of dinucleotides and 5'-monophosphate dinucleotides in a quadrupole ion trap

    Science.gov (United States)

    Chipuk, Joseph E.; Brodbelt, Jennifer S.

    2009-10-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions of four deprotonated dinucleotides (dAA, dAG, dGA, dGG) and their 5'-monophosphate analogs (5'-dAA, 5'-dAG, 5'-dGA, 5'-dGG) with D2O were performed in a quadrupole ion trap mass spectrometer. Significant differences in the rates and extents of exchange were found when the 5'-hydroxyl group of the dinucleotides was replaced by a phosphate functionality. Extensive and nucleobase-dependent exchange occurred for the deprotonated 5'-monophosphate dinucleotides, whereas the dinucleotides all exhibited essentially the same limited exchange. Results for the isomeric 5'-monophosphates, 5'-dAG and 5'-dGA, were remarkably different, indicating that the H/D exchange reaction was sequence dependent. An elaborate array of computations was performed to investigate the gas-phase structures of the ions individually and also as participants in ion-molecule complexes with D2O. Integration of the experimental and theoretical results supports a relay exchange mechanism and suggests that the exchange behavior depends highly on the identity and sequence of the nucleobases as well as their ability to interact with the deprotonation site. Finally, a shuttling mechanism is proposed to possibly account for the bimodal H/D exchange behavior observed for deprotonated 5'P-dGA. In this case, hydrogen bonding between the nucleobases in concert with interaction from the deuterating agent creates an ion-molecule complex in which hydrogen and deuterium atoms may be shuttled amongst the hydrogen-bonded participants.

  19. Investigation of the gas-phase hydrogen/deuterium exchange behavior of aromatic dicarboxylic acids in a quadrupole ion trap

    Science.gov (United States)

    Chipuk, Joseph E.; Brodbelt, Jennifer S.

    2007-11-01

    Gas-phase hydrogen/deuterium (H/D) exchange reactions of four deprotonated aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid and 2,6-naphthalic acid) with D2O were performed in a quadrupole ion trap mass spectrometer. Experimental results showed significant differences in the rate and extent of exchange when the relative position of the carboxylic acid groups varied. Spontaneous and near complete exchange of one aromatic hydrogen atom occurred when the carboxylic acid groups were in the meta-position, whereas no additional exchange was observed for either the ortho- or para-isomers or for the structurally similar naphthalic acid. Computational investigations support the participation of several possible exchange mechanisms with the contribution of each relying heavily on the relative orientation of the acid moieties. A relay mechanism that bridges the deprotonation site and the labile hydrogen site appears to be responsible for the H/D exchange of not only the labile hydrogen atom of isophthalic acid, but also for the formation of a stable carbanion and corresponding subsequent exchange of one aromatic hydrogen atom. The impact of hydrogen bonding on the relay mechanism is demonstrated by the reaction of phthalic acid as the extent and rate of reaction are greatly retarded by the favorable interaction of the two carboxylic acid groups. Finally, a flip-flop mechanism is likely responsible for the exchange of both terephthalic acid and 2,6-naphthalic acid where the reactive sites are too remote for exchange via relay.

  20. Headspace-trap gas chromatography-mass spectrometry for determination of sulphur mustard and related compounds in soil.

    Science.gov (United States)

    Røen, Bent T; Unneberg, Erik; Tørnes, John Aa; Lundanes, Elsa

    2010-04-02

    Methods for trace determination of sulphur mustard (HD) and some related cyclic sulphur compounds in soil samples have been developed using headspace-trap in combination with gas chromatography-mass spectrometry (GC-MS). Two quite different types of soil were employed in the method optimisation (sandy loam and silty clay loam). Prior to analysis, water saturated with sodium chloride was added to the samples, at a water to soil ratio of 1:1. A detection limit of 3 ng/g was achieved for HD, while the cyclic sulphur compounds 1,4-thioxane, 1,3-dithiolane and 1,4-dithiane could be detected at 0.2-0.7 ng/g. The methods were validated in the concentration range from the limit of quantification (LOQ) to hundred times LOQ. The within assay precision at fifty times LOQ was 6.9-7.3% relative standard deviation (RSD) for determination of the cyclic sulphur compounds, and 15% RSD for determination of HD. Recoveries were in the range of 43-60% from the two soil types. As the technique requires very little sample preparation, the total time for sample handling and analysis was less than 1h. The technique was successfully employed for the determination of cyclic sulphur compounds in a sediment sample from an old dumping site for chemical munitions, known to contain HD degradation products. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  1. Determining the Henry's Law constants of THMs in seawater by means of purge-and-trap gas chromatography (PT-GC): the influence of seawater as sample matrix.

    Science.gov (United States)

    Ruiz-Bevia, Francisco; Fernandez-Torres, Maria J

    2010-01-01

    The influence of seawater salts as salting out agents on the purge-and-trap gas chromatography (PT-GC) determination of trihalomethanes (THMs) was studied. This is particularly important since seawater is chlorinated when used as a cooling agent in coastal nuclear power stations. The chlorination produces unwanted THMs as by-products. A PT-GC apparatus was used to determine the Henry's Law constant of each THM, with seawater as the sample matrix.

  2. Miniaturized GC/MS instrumentation for in situ measurements: micro gas chromatography coupled with miniature quadrupole array and paul ion trap mass spectrometers

    Science.gov (United States)

    Holland, P.; Chutjian, A.; Darrach, M.; Orient, O.

    2002-01-01

    Miniaturized chemical instrumentation is needed for in situ measurements in planetary exploration and other spaceflight applications where factors such as reduction in payload requirements and enhanced robustness are important. In response to this need, we are 'continuing to develop miniaturized GC/MS instrumentation which combines chemical separations by gas chromatography (GC) with mass spectrometry (MS) to provide positive identification of chemical compounds in complex mixtures of gases, such as those found in the International Space Station's cabin atmosphere. Our design approach utilizes micro gas chromatography components coupled with either a miniature quadrupole mass spectrometer array (QMSA) or compact, high-resolution Paul ion trap.

  3. Characterization of the synthesis of N,N-dimethyltryptamine by reductive amination using gas chromatography ion trap mass spectrometry.

    Science.gov (United States)

    Brandt, Simon D; Moore, Sharon A; Freeman, Sally; Kanu, Abu B

    2010-07-01

    The present study established an impurity profile of a synthetic route to the hallucinogenic N,N-dimethyltryptamine (DMT). The synthesis was carried out under reductive amination conditions between tryptamine and aqueous formaldehyde in the presence of acetic acid followed by reduction with sodium cyanoborohydride. Analytical characterization of this synthetic route was carried out by gas chromatography ion trap mass spectrometry using electron- and chemical-ionization modes. Methanol was employed as a liquid CI reagent and the impact of stoichiometric modifications on side-products formation was also investigated. Tryptamine 1, DMT 2, 2-methyltetrahydro-β-carboline (2-Me-THBC, 3), N-methyl-N-cyanomethyltryptamine (MCMT, 4), N-methyltryptamine (NMT, 5), 2-cyanomethyl-tetrahydro-β-carboline (2-CM-THBC, 6) and tetrahydro-β-carboline (THBC, 7) have been detected under a variety of conditions. Replacement of formaldehyde solution with paraformaldehyde resulted in incomplete conversion of the starting material whereas a similar replacement of sodium cyanoborohydride with sodium borohydride almost exclusively produced THBC instead of the expec