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Sample records for chromatography tandem mass

  1. Protein identification using nano liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Negroni, Luc

    2007-01-01

    Tandem mass spectrometry is an efficient technique for the identification of peptides on the basis of their fragmentation pattern (MS/MS scan). It can generate individual spectra for each peptide, thereby creating a powerful tool for protein identification on the basis of peptide characterization. This important advance in automatic data acquisition has allowed an efficient association between liquid chromatography and tandem mass spectrometry, and the use of nanocolumns and nanoelectrospray ionization has dramatically increased the efficiency of this method. Now large sets of peptides can be identified at a femtomole level. At the end of the process, batch processing of the MS/MS spectra produces peptide lists that identify purified proteins or protein mixtures with high confidence.

  2. Discrimination of eight chloramphenicol isomers by liquid chromatography tandem mass spectrometry in order to investigate the natural occurence of chloramphenicol

    NARCIS (Netherlands)

    Berendsen, B.J.A.; Zuidema, T.; Jong, de J.; Stolker, A.A.M.; Nielen, M.W.F.

    2011-01-01

    This paper describes the discrimination of eight different isomers of chloramphenicol (CAP), an antibiotic banned for use in food producing animals, by reversed phase and chiral liquid chromatography in combination with tandem mass spectrometric detection. Previously, by liquid chromatography couple

  3. Fully automated screening of veterinary drugs in milk by turbulent flow chromatography and tandem mass spectrometry

    NARCIS (Netherlands)

    Stolker, A.A.M.; Peters, R.J.B.; Zuiderent, R.; DiBussolo, J.M.; Martins, C.P.B.

    2010-01-01

    There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied for the first time as an efficient screening met

  4. 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...

  5. Gas Chromatography/Atmospheric Pressure Chemical Ionization Tandem Mass Spectrometry for Fingerprinting the Macondo Oil Spill.

    Science.gov (United States)

    Lobodin, Vladislav V; Maksimova, Ekaterina V; Rodgers, Ryan P

    2016-07-05

    We report the first application of a new mass spectrometry technique (gas chromatography combined to atmospheric pressure chemical ionization tandem mass spectrometry, GC/APCI-MS/MS) for fingerprinting a crude oil and environmental samples from the largest accidental marine oil spill in history (the Macondo oil spill, the Gulf of Mexico, 2010). The fingerprinting of the oil spill is based on a trace analysis of petroleum biomarkers (steranes, diasteranes, and pentacyclic triterpanes) naturally occurring in crude oil. GC/APCI enables soft ionization of petroleum compounds that form abundant molecular ions without (or little) fragmentation. The ability to operate the instrument simultaneously in several tandem mass spectrometry (MS/MS) modes (e.g., full scan, product ion scan, reaction monitoring) significantly improves structural information content and sensitivity of analysis. For fingerprinting the oil spill, we constructed diagrams and conducted correlation studies that measure the similarity between environmental samples and enable us to differentiate the Macondo oil spill from other sources.

  6. Analysis of acrylamide in cooked foods by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Rosén, Johan; Hellenäs, Karl-Erik

    2002-07-01

    A method using liquid chromatography tandem mass spectrometry (LC-MS-MS) with electrospray for the analysis of acrylamide in foods is reported. The method comprises the addition of deuterium-labelled acrylamide-d3, extraction with water, mixed mode solid phase extraction, ultrafiltration and a graphitised carbon column for chromatography. The transitions m/z 72 > 55, 72 > 54, 72 > 44, 72 > 27, 72 > 72 and 75 > 58 were recorded in multiple reaction monitoring mode for identification and quantification. In-house validation data for products from potatoes and cereals (30 to 10,000 microg kg(-1)) are presented (accuracy 91 to 102%, relative standard deviation 3 to 21%). Interlaboratory validation data (comparison with gas chromatography mass spectrometry, 25 to 2000 microg kg(-1)) showed excellent results (r2 = 0.998).

  7. Novel liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for measuring steroids.

    Science.gov (United States)

    Keevil, Brian G

    2013-10-01

    Liquid chromatography tandem mass spectrometry (LC-MS/MS) is increasingly becoming the method of choice for steroid hormone measurements due to small sample volumes, fast analysis times and improved specificity compared to immunoassays. Achievement of demanding analytical targets for steroid analysis is now becoming possible because of improvements in sample preparation technology, liquid chromatography column technology and mass spectrometer design. The most popular sample treatment strategies comprise protein precipitation (PP), solid-phase extraction (SLE) and liquid-liquid extraction (LLE). Modern liquid chromatography columns can ensure the adequate separation of isobaric compounds e.g. 21 Deoxycortisol, 11 Deoxycortisol and Corticosterone. The most appropriate method may be chosen to improve assay sensitivity by reducing matrix effects (LLE, SPE) or simplicity and speed (PP). Specific examples of some clinically important steroids including oestradiol, aldosterone, renin, serum cortisol, salivary cortisol and salivary testosterone will be described.

  8. Arsenic speciation by liquid chromatography coupled with ionspray tandem mass spectrometry

    DEFF Research Database (Denmark)

    Corr, J. J.; Larsen, Erik Huusfeldt

    1996-01-01

    fragmentation patterns showing molecular dissociation through an expected common product ion were obtained for the four arsenosugars, Molecular mode detection was utilized for qualitative verification of speciation analysis by high-performance liquid chromatography coupled to inductively coupled plasma mass......Ionspray mass spectrometry, a well established organic analysis technique, has been coupled to high-performance liquid chromatography for speciation of organic arsenic compounds, The ionspray source and differentially pumped interface of the mass spectrometer were operated in dual modes...... for elemental and molecular analysis, Tandem mass spectrometry was employed to increase selectivity, Dual mode detection was applied to demonstrate the utility of the technique for analysis of nine organoarsenic standards, including four dimethylarsinylriboside derivatives (arsenosugars), Structural...

  9. Analysis of pesticide residues in tobacco with online size exclusion chromatography with gas chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Guo, Weiyun; Bian, Zhaoyang; Tang, Gangling; Wang, Deguo; Li, Guanghui; Wang, Jianlong

    2016-07-01

    An ultrasensitive method for the simultaneous analysis of pesticides residues in tobacco was developed with online size exclusion chromatography with gas chromatography and tandem mass spectrometry. Tobacco samples were extracted with the solvent mixture of cyclohexane and acetone (7:3, v/v) and centrifuged. Then, the supernatant liquors were injected directly into the online size exclusion chromatography with gas chromatography and tandem mass spectrometry without any other purification procedures after being filtered with a 0.22 μm organic phase filter. The matrix interferences were effectively removed and recoveries of most pesticides were in the range of 72-121%. Especially, for chlorothalonil, the analysis efficiency of this method was much more favorable than that of the general method, in which dispersive solid-phase extraction was used as an additional purified procedure. In addition, the limits of quantitation of this method were from 1 to 50 μg/kg. Therefore, a rapid, cost-effective, labor-saving method was proposed in the present work, which was suitable for the analysis of 41 pesticide residues in tobacco.

  10. Plasma lipid analysis by hydrophilic interaction liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Sonomura, Kazuhiro; Kudoh, Shinobu; Sato, Taka-Aki; Matsuda, Fumihiko

    2015-06-01

    A novel method for the analysis of endogenous lipids and related compounds was developed employing hydrophilic interaction liquid chromatography with electrospray ionization tandem mass spectrometry. A hydrophilic interaction liquid chromatography with carbamoyl stationary phase achieved clear separation of phosphatidylcholine, lysophosphatidylcholine, sphingomyelin, ceramide, and mono-hexsosyl ceramide groups with good peak area repeatability (RSD% 0.99). The established method was applied to human plasma assays and a total of 117 endogenous lipids were successfully detected and reproducibly identified. In addition, we investigated the simultaneous detection of small polar metabolites such as amino and organic acids co-existing in the same biological samples processed in a single analytical run with lipids. Our results show that hydrophilic interaction liquid chromatography is a useful tool for human plasma lipidome analysis and offers more comprehensive metabolome coverage.

  11. 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).

  12. Determination of bromate in drinking water by ultraperformance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Alsohaimi, Ibrahim Hotan; Alothman, Zeid Abdullah; Khan, Mohammad Rizwan; Abdalla, Mohammad Abulhassan; Busquets, Rosa; Alomary, Ahmad Khodran

    2012-10-01

    Bromate is a byproduct formed as a result of disinfection of bromide-containing source water with ozone or hypochlorite. The International Agency for Research on Cancer has recognized bromate as a possible human carcinogen, thus it is essential to determine in drinking water. Present work highlights a development of sensitive and fast analytical method for bromate determination in drinking water by using ultraperformance liquid chromatography-tandem mass spectrometry. The quality parameters of the developed method were established, obtaining very low limit of detection (0.01 ng/mL), repeatability and reproducibility have been found to be less than 3% in terms of relative standard deviation when analyzing a bromate standard at 0.05 μg/mL with 0.4 min analysis time. Developed method was applied for the analysis of metropolitan and bottled water from Saudi Arabia; 22 samples have been analyzed. Bromate was detected in the metropolitan water samples (from desalinization source) at concentrations ranging between 3.43 and 75.04 ng/mL and in the bottled water samples at concentrations ranging between 2.07 and 21.90 ng/mL. Moreover, in comparison to established analytical methods such as liquid chromatography-tandem mass spectrometry, the proposed method was found to be very sensitive, selective and rapid for the routine analysis of bromate at low level in drinking water.

  13. Recent advances of liquid chromatography-(tandem) mass spectrometry in clinical and forensic toxicology - An update.

    Science.gov (United States)

    Remane, Daniela; Wissenbach, Dirk K; Peters, Frank T

    2016-09-01

    Liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) is a well-established and widely used technique in clinical and forensic toxicology as well as doping control especially for quantitative analysis. In recent years, many applications for so-called multi-target screening and/or quantification of drugs, poisons, and or their metabolites in biological matrices have been developed. Such methods have proven particularly useful for analysis of so-called new psychoactive substances that have appeared on recreational drug markets throughout the world. Moreover, the evolvement of high resolution MS techniques and the development of data-independent detection modes have opened new possibilities for applications of LC-(MS/MS) in systematic toxicological screening analysis in the so called general unknown setting. The present paper will provide an overview and discuss these recent developments focusing on the literature published after 2010.

  14. Determination of albendazole sulfoxide in human plasma by using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Saraner, Nihal; Özkan, Güler Yağmur; Güney, Berrak; Alkan, Erkin; Burul-Bozkurt, Nihan; Sağlam, Onursal; Fikirdeşici, Ezgi; Yıldırım, Mevlüt

    2016-06-01

    A rapid, simple and sensitive method was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination of albendazole sulfoxide (ABZOX) in human plasma. The plasma samples were extracted by protein precipitation using albendazole sulfoxide-d3 as internal standard (IS). The chromatographic separation was performed on Waters Xbridge C18Column (100×4.6mm, 3.5μm) with a mobile phase consisting of ammonia solution, water and methanol at a flow rate of 0.70mL/min. ABZOX was detected and identified by mass spectrometry with electrospray ionization (ESI) in positive ion and multiple-reaction monitoring (MRM) mode. The method was linear in the range of 3-1500ng/mL for ABZOX. This method was successfully applied to the bioequivalence study in human plasma samples.

  15. A New Liquid Chromatography-Tandem Mass Spectrometry Method for Determination of Bisoprolol in Human Plasma Samples

    OpenAIRE

    Gabriela Peste; Nela Bibire; Mihai Apostu; Aurel Vlase; Corneliu Oniscu

    2009-01-01

    Liquid chromatography (LC) coupled with mass spectrometry (MS) detection is one of the most powerful analytical tools for organic compound analysis. The advantages of using LC/MS methods over HPLC methods include: selectivity, chromatographic integrity, peak assignment, structural information, and rapid method development. In this paper, a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of bisoprolol in human plasma s...

  16. Determination of Candesartan in Human Plasma with Liquid Chromatography - Tandem Mass Spectrometry.

    Science.gov (United States)

    Forjan, Vanja; Cvitkovič Maričič, Lea; Prosen, Helena; Brodnjak Vončina, Darinka

    2016-01-01

    A sensitive, specific and rapid liquid chromatography - tandem mass spectrometry method was developed and validated for the determination of candesartan in human plasma. Analyte was separated from endogenous components present in plasma by solid phase extraction. Chromatographic separation was performed on Gemini C18 analytical column using mobile phase acetonitrile - 5 mM ammonium formate pH 2 (90:10, v/v) at flow rate of 0.3 mL/min. For detection, tandem mass spectrometry in SRM mode with positive electrospray ionization was used. The mass transitions m/z 441.1 > 263.1 and 445.1 > 267.1 were used to determine candesartan by using candesartan-d4 as an internal standard. After development, the method was validated according to the requirements of EMA regulatory guidelines in the concentration range 1 - 400 ng/ml in human plasma. Limit of quantification (LLOQ) was 1 ng/ml. The developed and validated method proved to be very fast and reproducible and was therefore successfully implemented in pharmacokinetic and bioequivalence studies with large number of study samples.

  17. Determination of tolperisone in human plasma by liquid chromatography/tandem mass spectrometry for clinical application.

    Science.gov (United States)

    Choi, Chang-Ik; Park, Jung-In; Lee, Hye-In; Lee, Yun-Jeong; Jang, Choon-Gon; Bae, Jung-Woo; Lee, Seok-Yong

    2012-12-12

    We have developed and validated a simple, rapid, and sensitive liquid chromatography analytical method employing tandem mass spectrometry (LC-MS/MS) for the determination of tolperisone, a centrally acting muscle relaxant, in human plasma. After liquid-liquid extraction with methyl t-butyl ether, chromatographic separation of tolperisone was performed using a reversed-phase Luna C(18) column (2.0mm×50mm, 5μm particles) with a mobile phase of 10mM ammonium formate buffer (pH 3.5) - methanol (12:88, v/v) and quantified by tandem mass detection in ESI positive ion mode. The flow rate of the mobile phase was 250μL/min and the retention times of tolperisone and the internal standard (IS, dibucaine) were both 0.6min. The calibration curves were linear over a range of 0.5-300ng/mL (r>0.999). The lower limit of quantification, using 200μL human plasma, was 0.5ng/mL. The mean accuracy and precision for intra- and inter-day validation of tolperisone were within acceptable limits. The LC-MS/MS method reported here showed improved sensitivity for quantification of tolperisone in human plasma compared with previously described analytical methods. Lastly, the validated method was successfully applied to a pharmacokinetic study in humans.

  18. Liquid chromatography/tandem mass spectrometry assay for the quantification of troxerutin in human plasma.

    Science.gov (United States)

    Liu, Fei; Xu, Yu; Rui, Lei; Gao, Shu; Dong, Haijun; Guo, Qingxiang

    2006-01-01

    A simple, rapid, sensitive and specific liquid chromatography/tandem mass spectrometry method was developed and validated to quantify troxerutin in human plasma. The analyte and rutin, used as the internal standard, were analyzed on a Phenomenex Synergi Fusion RP column interfaced with a triple-quadrupole tandem mass spectrometer using positive electrospray ionization. Acetonitrile/water (20:80 v/v) was used as the isocratic mobile phase, with 0.1% formic acid in water. A simple sample preparation method of protein precipitation with perchloric acid was employed. The assay was linear over the concentration range 31.25-4000 pg/mL. Correlation coefficients generated by linear regression with a 1/x(2) weighting factor ranged from 0.9991 to 0.9996. The intra- and inter-day precision over the entire concentration range were less than 12.28%. The method was successfully applied to a pharmacokinetic study after oral administration of a 300 mg troxerutin drop pill to 18 healthy volunteers.

  19. Confirmatory analysis of firocoxib in bovine milk by rapid resolution liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Dowling, Geraldine; Gallo, Pasquale; Regan, Liam

    2009-02-15

    A rapid method has been developed to analyse for firocoxib (FIRO) residue in bovine milk. Milk samples were extracted with acetonitrile and sample extracts were purified on Evolute ABN solid phase extraction cartridges. Aliquots were analysed by rapid resolution liquid chromatography tandem mass spectrometry (RRLC-MS/MS). The method was validated in bovine milk, according to the criteria defined in Commission Decision 2002/657/EC. The decision limit (CCalpha) was 1.18ng/mL and for the detection capability a (CCbeta) value of 2.02ng/mL was obtained. The measurement uncertainty of the method was 27%. Fortifying bovine milk samples (n=18) in three separate assays, show the accuracy of the method to be between 96 and 105%. The precision of the method, expressed as RSD values for the within-lab reproducibility at the three levels of fortification (5, 7.5 and 10ng/mL) was less than 11% respectively.

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

    Science.gov (United States)

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

    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, CCalpha is 0.12 microgkg(-1), and the detection capability; CCbeta value is 0.16 microgkg(-1).

  1. 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}.

  2. 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.

  3. Determination of Sex Hormones in Antler Velvet by High Performance Liquid Chromatography Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    LU Chun-mei; WANG Ming-tai; MU Jun; BAI Yu-ping; DU Jian-shi; ZHANG Han-qi; WANG Jian-wei

    2012-01-01

    Eighteen sex hormones in antler velvet were determined by high performance liquid chromatography tandem mass spectrometry.The solid phase extraction was applied to eliminating the matrix effect.The experimental conditions were examined and optimized.Under the optimal conditions,the proposed method provides the good linearities and determination limits(0.2-1.0 μg/kg)of the analytes investigated.The recoveries ranging from 72.3% to 149.5% were obtained for the target analytes at two concentration levels.This method was applied to the determination of eighteen sex hormones in different kinds of antler velvet samples and the obtained results are satisfactory.The results indicate that the proposed method is suitable for the determination of sex hormones in antler velvet samples.

  4. Pressurized liquid extraction followed by liquid chromatography with tandem mass spectrometry to determine pharmaceuticals in mussels.

    Science.gov (United States)

    Núñez, Mireia; Borrull, Francesc; Pocurull, Eva; Fontanals, Núria

    2016-02-01

    An analytical method based on pressurized liquid extraction and solid-phase extraction with a mixed-mode Oasis(®) MAX sorbent as cleanup, followed by liquid chromatography with electrospray ionization and tandem mass spectrometry was developed and validated for the determination of seven widely used pharmaceuticals in mussel species. The optimization of the pressurized liquid extraction and the solid-phase extraction parameters is described. The method provided extraction recoveries ranging from 61 to 90%, and limits of detection ranging from 2 to 50 ng/g (dry weight). The repeatability and reproducibility of the method, expressed as relative standard deviation, were lower than 15 and 19%, respectively. The method was successfully applied to the analysis of mussel samples from different locations. The analyses showed that salicylic acid was present in mussels at concentrations up to 177 ng/g (dry weight).

  5. 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 ...

  6. Liquid chromatography-tandem mass spectrometry assay for the quantification of free and total sialic acid in human cerebrospinal fluid.

    NARCIS (Netherlands)

    Ham, M. van der; Koning, T.J. de; Lefeber, D.J.; Fleer, A.; Prinsen, B.H.; Sain-van der Velden, M.G. de

    2010-01-01

    BACKGROUND: Analysis of sialic acid (SA) metabolites in cerebrospinal fluid (CSF) is important for clinical diagnosis. In the present study, a high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS/MS) method for free sialic acid (FSA) and total sialic acid (TSA) in human CSF was v

  7. Structural Elucidation of DNA-Protein Crosslinks Using Reductive Desulfurization and Liquid Chromatography-Tandem Mass Spectrometry

    OpenAIRE

    Wickramaratne, Susith; Tretyakova, Natalia Y.

    2014-01-01

    Structural characterization of DNA-protein crosslinks involving cysteine using reductive desulfurization in combination with liquid chromatography-tandem mass spectrometry is highlighted. The novel approach was used to identify hydrolytically stable DNA-protein lesions involving alkylguanine DNA alkyltransferase (AGT).

  8. 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...

  9. Determination of kava lactones in food supplements by liquid chromatography-atmospheric pressure chemical ionisation tandem mass spectrometry

    NARCIS (Netherlands)

    Bobeldijk, I.; Boonzaaijer, G.; Spies-Faber, E.J.; Vaes, W.H.J.

    2005-01-01

    Reversed-phase liquid chromatography and detection with atmospheric pressure chemical ionisation tandem mass spectrometry was used for the determination of kava extracts in herbal mixtures. One percent of kava extract can be detected, corresponding to approximately 0.05-0.2 mg/g of the individual ka

  10. 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...

  11. CREATININE DETERMINATION IN URINE BY LIQUID CHROMATOGRAPHY-ELECTROSPRAY IONIZATION-TANDEM MASS SPECTROMETRY METHOD.

    Science.gov (United States)

    Dereziński, Paweł; Klupczyńska, Agnieszka; Sawicki, Wojciech; Kokot, Zenon J

    2016-01-01

    Creatinine determination in urine is used to estimate the completeness of the 24-h urine collection, compensation for variable diuresis and as a preliminary step in protein profiling in urine. Despite the fact that a wide range of methods of measuring creatinine level in biofluids has been developed, many of them are adversely affected by interfering substances. A new liquid chromatography-tandem mass spectrometry method for creatinine determination in urine has been developed. Chromatographic separation was performed by applying C18 column and a gradient elution. Analyses were carried out on a triple quadrupole mass spectrometer equipped with an electrospray ion source. The developed method was fully validated according to the international guidelines. The quantification range of the method was 5-1500 ng/mL, which corresponds to 1-300 mg/dL in urine. Limit of detection and quantitation were 2 and 5 ng/mL, respectively. Additionally, the comparison of creatinine determination by newly developed method to the colorimetric method was performed. The method enables the determination of creatinine in urine samples with a minimal sample preparation, excellent sensitivity and prominent selectivity. Since mass spectrometry allows to measure a number of compounds simultaneously, a future perspective would be to incorporate the determination of other clinically important compounds excreted in urine.

  12. Liquid chromatography coupled to tandem mass spectrometry for the analysis of acrylamide in typical Spanish products.

    Science.gov (United States)

    Bermudo, E; Moyano, E; Puignou, L; Galceran, M T

    2008-07-15

    This paper describes the use of liquid chromatography coupled to tandem mass spectrometry for the determination of acrylamide in several typical foods produced and consumed in Spain. Christmas sweets, olives, traditionally made potato crisps, pastry products, sweet fritters ("churros") and one of Spain's most famous dishes, Spanish omelette, were selected. Using the mass spectra information provided by an ion trap analyzer in combination with the accurate mass measurements from time-of-flight (TOF) spectrometry a co-extractive interference present in some potato products was identified as valine. A porous graphitic carbon column, which enabled the co-extractive and acrylamide to be separated, and ion trap or triple quadrupole analyzers, depending on the acrylamide concentration, were used to determine this genotoxic compound in foodstuffs. The highest values were found in potato products, sweet fritters, Christmas sweets and pastry products, with values ranging between 70 and 2000 microg/g. Spanish omelette presented relatively low levels, similar to those obtained for dried fruits.

  13. Sensitive, Preclinical Detection of Prions in Brain by nanospray liquid chromatography/tandem mass spectrometry

    Science.gov (United States)

    More sensitive detection of prions in brain is important because it would allow early detection of disease in young animals and assure a safer food supply. We quantitated the amount of proteinase K-resistant prion protein (PrP 27-30) by use of nano-scale liquid chromatography coupled to a tandem ma...

  14. Liquid chromatography-mass spectrometric and liquid chromatography-tandem mass spectrometric determination of hallucinogenic indoles psilocin and psilocybin in "magic mushroom" samples.

    Science.gov (United States)

    Kamata, Tooru; Nishikawa, Mayumi; Katagi, Munehiro; Tsuchihashi, Hitoshi

    2005-03-01

    Accurate and sensitive analytical methods for psilocin (PC) and psilocybin (PB), tryptamine-type hallucinogens contained in "magic mushrooms," were investigated using liquid chromatography-mass spectrometry (LC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS-MS). The chromatographic separation on an ODS column and mass spectral information gave complete discrimination between PC and PB without derivatization. The mass spectrometric detection had a high sensitivity, and the tandem mass spectrometric detection provided more specificity and accuracy, as well as high sensitivity. The detection limits ranged from 1 to 25 pg by LC-MS in the selected ion monitoring mode, and the intra- and inter-day coefficients of variation were estimated to be 4.21-5.93% by LC-MS-MS in the selected reaction monitoring mode. By applying the present LC-MS-MS technique to four real samples, the contents of PC and PB were found to vary over a wide range (0.60-1.4 and 0.18-3.8 mg/g dry wt. for PC and PB, respectively) between samples.

  15. 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.

  16. Determination of mycophenolic acid in human plasma by ultra performance liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Vivek Upadhyay

    2014-06-01

    Full Text Available A simple, sensitive and high throughput ultra performance liquid chromatography tandem mass spectrometry method has been developed for the determination of mycophenolic acid in human plasma. The method involved simple protein precipitation of MPA along with its deuterated analog as an internal standard (IS from 50 µL of human plasma. The chromatographic analysis was done on Acquity UPLC C18 (100 mm×2.1 mm, 1.7 µm column under isocratic conditions using acetonitrile and 10 mM ammonium formate, pH 3.00 (75:25, v/v as the mobile phase. A triple quadrupole mass spectrometer operating in the positive ionization mode was used for quantitation. In-source conversion of mycophenolic glucuronide metabolite to the parent drug was selectively controlled by suitable optimization of cone voltage, cone gas flow and desolvation temperature. The method was validated over a wide concentration range of 15–15000 ng/mL. The mean extraction recovery for the analyte and IS was >95%. Matrix effect expressed as matrix factors ranged from 0.97 to 1.02. The method was successfully applied to support a bioequivalence study of 500 mg mycophenolate mofetil tablet in 72 healthy subjects.

  17. Determination of mycophenolic acid in human plasma by ultra performance liquid chromatography tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Vivek Upadhyay; Vikas Trivedi; Gaurang Shah; Manish Yadav; Pranav S. Shrivastav

    2014-01-01

    A simple, sensitive and high throughput ultra performance liquid chromatography tandem mass spectrometry method has been developed for the determination of mycophenolic acid in human plasma. The method involved simple protein precipitation of MPA along with its deuterated analog as an internal standard (IS) from 50 mL of human plasma. The chromatographic analysis was done on Acquity UPLC C18 (100mm*2.1mm,1.7mm) column under isocratic conditions using acetonitrile and 10 mM ammonium formate, pH 3.00 (75:25, v/v) as the mobile phase. A triple quadrupole mass spectrometer operating in the positive ionization mode was used for quantitation. In-source conversion of mycophenolic glucuronide metabolite to the parent drug was selectively controlled by suitable optimization of cone voltage, cone gas flow and desolvation temperature. The method was validated over a wide concentration range of 15–15000 ng/mL. The mean extraction recovery for the analyte and IS was 495%. Matrix effect expressed as matrix factors ranged from 0.97 to 1.02. The method was successfully applied to support a bioequivalence study of 500 mg mycophenolate mofetil tablet in 72 healthy subjects.

  18. Characterization of the limonene oxidation products with liquid chromatography coupled to the tandem mass spectrometry

    Science.gov (United States)

    Witkowski, Bartłomiej; Gierczak, Tomasz

    2017-04-01

    Composition of the secondary organic aerosol (SOA) generated during ozonolysis of limonene was investigated with liquid chromatography coupled to the negative electrospray ionization (ESI), quadrupole tandem mass spectrometry (MS/MS) as well as high resolution Time-of-Flight mass spectrometry. Aerosol was generated in the flow-tube reactor. HR-MS/MS analysis allowed for proposing structures for the several up-to-date unknown limonene oxidation products. In addition to the low MW limonene oxidation products, significant quantities of oligomers characterized by elemental compositions: C19H30O5, C18H28O6, C19H28O7, C19H30O7 and C20H34O9 were detected in the SOA samples. It was concluded that these compounds are most likely esters, aldol reaction products and/or hemiacetals. In addition to detailed study of the limonene oxidation products, the reaction time as well as initial ozone concentration impact on the limonene SOA composition was investigated. The relative intensities of the two esters of the limonic acid and 7-hydroxy limononic acid increased as a result of lowering the initial ozone concentration and shortening the reaction time, indicating that esterification may be an important oligomerization pathway during limonene SOA formation.

  19. [Determination of glyphosate and aminomethylphosphonic acid in rice using liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Cao, Zhaoyun; Mou, Renxiang; Chen, Mingxue

    2010-08-01

    A method was developed for the determination of glyphosate (GLY) and aminomethylphosphonic acid (AMPA) in rice using liquid chromatography tandem mass spectrometry (LC-MS/MS). The sample was extracted with water followed by a simple cleanup with a C18 solid phase extraction (SPE) cartridge, and then GLY and AMPA were derivatized using 9-fluorenylmethoxycarbonyl (FMOC-Cl) in borate buffer. The derivatives of GLY and AMPA were separated on a C18 column with gradient elution with the mobile phase of acetonitrile and 5 mmol/L ammonium acetate (pH 9), and finally detected with negative ion electrospray ionization-mass spectrometry (ESI-MS) in multiple reaction monitoring (MRM) mode. The results showed that the linearities of GLY and AMPA were in the concentration range of 0.000 50 to 1.0 mg/L with the correlation coefficients of 0.999 7 and 0.999 9, respectively. The mean spiked recoveries of GLY and AMPA at 3 spiked levels ranged from 72.5% to 113.6% with the relative standard deviations (RSD, n = 5) of 3.8% - 16.2%. The limits of detection were 2.0 and 3.0 microg/kg for GLY and AMPA, respectively. This method is rapid, sensitive, and suitable for simultaneous determination of GLY and AMPA in rice.

  20. Analysis of perfluoroalkyl substances in cord blood by turbulent flow chromatography coupled to tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Llorca, Marta; Perez, Francisca [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Farre, Marinella, E-mail: mfuqam@cid.csic.es [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Agramunt, Silvia [Centre for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); IMIM (Hospital del Mar Research Institute), Barcelona (Spain); Kogevinas, Manolis [Centre for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); IMIM (Hospital del Mar Research Institute), Barcelona (Spain); CIBER Epidemiologia y Salud Publica (CIBERESP), Barcelona (Spain); National School of Public Health, Athens (Greece); Barcelo, Damia [Department of Environmental Chemistry, IDAEA-CSIC, Barcelona (Spain); Catalan Institute for Water Research (ICRA), Girona (Spain); King Saud University, Riyadh (Saudi Arabia)

    2012-09-01

    A fast on-line analytical method based on turbulent flow chromatography (TFC) in combination with tandem mass spectrometry has been applied for the first time for the analysis of eighteen perfluoroalkyl substances (PFASs), in cord blood. A simple and rapid sample pre-treatment was optimised consisting on protein precipitation of 100 {mu}L of sample with acetonitrile (1:1) followed by centrifugation during 10 min. The method was adapted to be sensitive enough and robust with minimum sample injection volume requirements (20 {mu}L). The optimised methodology presented method limits of detection (MLOD) between 0.031 and 0.76 {mu}g/L, detection capabilities (CC{alpha}) in the range between 0.005 and 0.99 {mu}g/L and decision limits (CC{beta}) ranging from 0.006 to 1.16 {mu}g/L. The recoveries in blank blood were calculated by spiking experiments with a mixture of 18 PFASs and established between 70 and 126% for most of compounds. Isotopic dilution was carried out for quantification of selected analytes. In-house validation of this new approach was carried out according to the requirements in the 2002/657/EC Decision. Finally the good applicability of this new approach was proved by the analysis of 60 cord blood samples from two different Mediterranean cities, Barcelona (Spain) and Heraklion (Greece). Ions perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were found at highest concentration and the more frequently compounds were PFHxS, PFOS and perfluorooctanoic acid (PFOA). The newly developed method proved to be suitable for large-scale epidemiologic studies, and to the data on PFASs exposure during pregnancy. -- Highlights: Black-Right-Pointing-Pointer An on-line method has been developed for the analysis of 18 perfluoroalkyl substances. Black-Right-Pointing-Pointer The method is based on turbulent flow chromatography tandem mass spectrometry. Black-Right-Pointing-Pointer The method was applied in 60 cord blood samples from 2 Mediterranean cities

  1. Analysis of small carbohydrates in several bioactive botanicals by gas chromatography with mass spectrometry and liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Moldoveanu, Serban; Scott, Wayne; Zhu, Jeff

    2015-11-01

    Bioactive botanicals contain natural compounds with specific biological activity, such as antibacterial, antioxidant, immune stimulating, and taste improving. A full characterization of the chemical composition of these botanicals is frequently necessary. A study of small carbohydrates from the plant materials of 18 bioactive botanicals is further described. The study presents the identification of the carbohydrate using a gas chromatographic-mass spectrometric analysis that allows detection of molecules as large as maltotetraose, after changing them into trimethylsilyl derivatives. A number of carbohydrates in the plant (fructose, glucose, mannose, sucrose, maltose, xylose, sorbitol, and myo-, chiro-, and scyllo-inositols) were quantitated using a novel liquid chromatography with tandem mass spectrometric technique. Both techniques involved new method developments. The gas chromatography with mass spectrometric analysis involved derivatization and separation on a Rxi(®)-5Sil MS column with H2 as a carrier gas. The liquid chromatographic separation was obtained using a hydrophilic interaction type column, YMC-PAC Polyamine II. The tandem mass spectrometer used an electrospray ionization source in multiple reaction monitoring positive ion mode with the detection of the adducts of the carbohydrates with Cs(+) ions. The validated quantitative procedure showed excellent precision and accuracy allowing the analysis in a wide range of concentrations of the analytes.

  2. Multilaboratory validation of a method to confirm chloramphenicol in shrimp and crabmeat by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Hammack, Walter; Carson, Mary C; Neuhaus, Barbara K; Hurlbut, Jeffrey A; Nochetto, Cristina; Stuart, James S; Brown, Amy; Kilpatrick, Donna; Youngs, Kristl; Ferbos, Krystle; Heller, David N

    2003-01-01

    An existing method for chloramphenicol (CAP) determination in shrimp using a gas chromatograph with electron capture detector was adapted for confirmation of CAP with a liquid chromatograph interfaced to a triple quadrupole mass spectrometer. CAP residues are extracted from tissue with ethyl acetate, isolated via liquid-liquid extraction, and concentrated by evaporation. Extracts are chromatographed by using a reversed-phased column and analyzed by electrospray negative mode tandem mass spectrometry. Four product ions (m/z 152, 176, 194, and 257) of precursor m/z 321 were monitored. Moving from gas chromatography to liquid chromatography-tandem mass spectrometry improved the sensitivity of the method greatly, enabling reliable confirmation of CAP residues at 0.3 microg/kg (ppb). The method meets confirmation criteria recommended by the U.S. Food and Drug Administration and 4-point identification criteria established by the European Union. With slight modifications to accommodate different equipment, the method was validated in 3 laboratories.

  3. Anion exchange SPE and liquid chromatography-tandem mass spectrometry in GHB analysis.

    Science.gov (United States)

    Elian, Albert A; Hackett, Jeffery

    2011-12-01

    In this study, the extraction of γ-hydroxybutyrate (GHB) from urine using solid-phase extraction (SPE) is described. SPE was performed on anion exchange columns after samples of urine had been diluted with de-ionized water. After application of the diluted samples containing GHB-d(6) as an internal standard, the sorbent was washed with deionized water and methanol and dried. The GHB was eluted from the SPE column with a solvent consisting of methanol containing 6% glacial acetic acid. The eluent was collected, evaporated to dryness, and dissolved in mobile phase (100 μL) for analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in negative multiple reaction monitoring (MRM) mode. Liquid chromatography was performed in gradient mode employing a biphenyl column and a mobile phase consisting of acetontitrile (containing 0.1% formic acid) and 0.1% aqueous formic acid. The total run time for each analysis was less than 5 min. The limits of detection/quantification for this method were determined to be 50 and 100 ng/mL, respectively. The method was found to be linear from 500 ng/mL to 10,000 ng/mL (r(2)>0.995). The recovery of GHB was found to be greater than 75%. In this report, results of authentic urine samples analyzed for GHB by this method are presented. GHB concentrations in these samples were found to be range from less than 500 ng/mL to 5110 ng/mL.

  4. Proteomic analysis of Taenia ovis metacestodes by high performance liquid chromatography-coupled tandem mass spectrometry.

    Science.gov (United States)

    Zheng, Yadong

    2017-03-15

    Taenia ovis metacestodes reside in the muscle of sheep and goats, and may cause great economic loss due to condemnation of carcasses if not effectively controlled. Although advances have been made in the control of T. ovis infection, our knowledge of T. ovis biology is limited. Herein the protein profiling of T. ovis metacestodes was determined by liquid chromatography-linked tandem mass spectrometry. A total of 966 proteins were identified and 25.1% (188/748) were annotated to be associated with metabolic pathways. Consistently, GO analysis returned a metabolic process (16.27%) as one of two main biological process terms. Moreover, it was found that 24 proteins, including very low-density lipoprotein receptor, enolase, paramyosin and endophilin B1, were abundant in T. ovis metacestodes. These proteins may be associated with motility, metabolism, signaling, stress, drug resistance and immune responses. Furthermore, comparative analysis of 5 cestodes revealed the presence of Taenia-specific enolases. These data provide clues for better understanding of T. ovis biology, which is informative for effective control of infection.

  5. [Determination of seven toxaphene congeners in ginseng and milkvetch root by gas chromatography tandem mass spectrometry].

    Science.gov (United States)

    Tian, Shaoqiong; Mao, Xiuhong; Miao, Shui; Jia, Zhengwei; Wang, Ke; Ji, Shen

    2012-01-01

    A novel method for the determination of representative toxaphene congeners in traditional Chinese herbal medicines was developed. Ginseng and Milkvetch Root were selected as the samples and seven toxaphene congeners were selected as the monitoring objects. The samples were extracted by accelerated solvent extraction with cyclohexane-acetone (9:1, v/v), then cleaned-up by Florisil solid phase extraction with hexane as the eluent and the residues were detected by gas chromatography-electron ionization tandem mass spectrometry (GC-EI-MS/MS) in multiple reaction monitoring (MRM) mode. The performance was demonstrated by the analysis of Ginseng and Milkvetch Root samples spiked with toxaphene congeners at three concentration levels of 0.005, 0.01 and 0.1 mg/kg. The recoveries ranged from 72.4% to 105% with the relative standard deviations (RSDs) of 0.96%-10.4%. The limits of detection (LODs) were 0.2-1.7 microg/kg. This method is sensitive and efficient in the aspect of extraction, and can be applied to monitor the residue of toxaphene congeners in Ginseng and Milkvetch Root.

  6. Confirmatory method for the determination of nitroimidazoles in milk by liquid chromatography - tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Mitrowska Kamila

    2014-12-01

    Full Text Available A multiresidue method for the determination of seven nitroimidazoles and their hydroxy metabolites in milk was developed. Milk samples were extracted with acetonitrile and cleaned up on strong cation-exchange solid phase extraction cartridges. Evaporated to dryness first, the extracts obtained were then reconstituted in 0.1% formic acid and injected onto a liquid chromatography-tandem mass spectrometer (LC-MS/MS. The separation of analytes was achieved on gradient mode using a C18 column and a mobile phase consisting of 0.1% formic acid in acetonitrile and 0.1% formic acid in water. Multiple reaction monitoring mode was set for the MS/MS with positive electrospray ionisation. For quantification, the isotope dilution method was used with isotopically labeled analogues of the target analytes. The method was evaluated entirely in accordance with EU Commission Decision 2002/657/EC and all validation criteria were in the required ranges. The method can easily detect and confirm metronidazole, dimetridazole, ronidazole, ipronidazole, and their hydroxy metabolites below the recommended concentration level of 3 μg/kg. The decision limits and detection capabilities ranged from 0.11 μg/kg to 0.22 μg/kg and from 0.19 μg/kg to 0.37 μg/kg respectively. The overall recoveries were between 96.6% and 105.2% with a good coefficient of variation, less than 8.7% under within-laboratory reproducibility conditions.

  7. Determination of the Thyreostats in Animal Feeding Stuffs Using Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Woźniak Barbara

    2014-10-01

    Full Text Available A rapid liquid chromatography tandem mass spectrometry method was developed and validated to detect and confirm five thyreostatic drugs: tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil in animal feeding stuff samples. Thyreostats were extracted from feed with methanol, and then degreasing of the extract with petroleum ether was performed, followed by the derivatisation of the compounds with 3-iodobenzylbromide in basic medium (pH 8.0. The derivatives were extracted with diethyl ether and analysed by gradient elution on a Poroshell 120-EC C18 column with triple quadrupole MS detection with turbo spray source in positive ionisation mode. The method was validated in accordance with the Commission Decision 2002/657/EC. For validation level of 10 ļig kg-1, the recovery ranged from 82% to 97.5% for all examined compounds. The repeatability and reproducibility did not exceed the limit of 20% for all analytes. The linearity was good for all thyreostats in the whole range of tested concentrations, as proved by the correlation coefficients greater than 0.99. The decision limits (CCa ranged from 1.63 ļig kg-1 to 3.95 ļig kg-1, whereas the detection capabilities (CCß ranged from 2.74 ļig kg-1 to 6.73 ļig kg-1. The developed analysis is sensitive and robust, and therefore useful for quantification and confirmation of thyreostats in residue control programme.

  8. Global Analysis of the Membrane Subproteome of Pseudomonas aeruginosa using Liquid Chromatography-Tandem Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Blonder, Josip; Goshe, Michael B.; Xiao, Wenzhong; Camp, David G.; Wingerd, Mark A.; Davis, Ronald W.; Smith, Richard D.

    2004-05-30

    Pseudomonas aeruginosa is one of the most significant opportunistic bacterial pathogens in humans causing infections and premature death in patients with cystic fibrosis, AIDS, severe burns, organ transplants or cancer. Liquid chromatography coupled online with tandem mass spectrometry (LC-MS/MS) was used for the large-scale proteomic analysis of the P. aeruginosa membrane subproteome. Concomitantly, an affinity labeling technique, using iodoacetyl-PEO biotin to tag cysteinyl-containing proteins, permitted the enrichment and detection of lower abundance membrane proteins. The application of these approaches resulted in the identification of 786 proteins. A total of 333 proteins (42%) had a minimum of one transmembrane domain (TMD; ranging from 1 to 14) and 195 proteins were classified as hydrophobic based on their positive GRAVY values (ranging from 0.01 to 1.32). Key integral inner and outer membrane proteins involved in adaptation and antibiotic resistance were conclusively identified, including the detection of 53% of all predicted opr-type porins (outer integral membrane proteins) and all the components of the mexA-mexB-oprM transmembrane protein complex. This work represents the most comprehensive qualitative proteomic analysis of the membrane subproteome of P. aeruginosa and for prokaryotes in general to date.

  9. [Determination of 25 quinolones in cosmetics by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lin, Li; Zhang, Yi; Tu, Xiaoke; Xie, Liqi; Yue, Zhenfeng; Kang, Haining; Wu, Weidong; Luo, Yao

    2015-03-01

    An analytical method was developed for the simultaneous determination of 25 quinolones, including danofloxacin mesylate, enrofloxacin, flumequine, oxloinic acid, ciprofloxacin, sarafloxacin, nalidixic acid, norfloxacin, and ofloxacin etc in cosmetics using direct extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). Cosmetic sample was extracted by acidified acetonitrile, defatted by n-hexane and separated on Poroshell EC-C18 column with gradient elution program using acetonitrile and water (both containing 0. 1% formic acid) as the mobile phases and analyzed by LC-ESI-MS/MS under the positive mode using multiple reaction monitoring (MRM). The interference of matrix was reduced by the matrix-matched calibration standard curve. The method showed good linearities over the range of 1-200 mg/kg for the 25 quinolones with good linear correlation coefficients (r ≥ 0.999). The method detection limit of the 25 quinolones was 1.0 mg/kg, and the recoveries of all analytes in lotion, milky and cream cosmetics matrices ranged from 87.4% to 105% at the spiked levels of 1, 5 and 10 mg/kg with the relative standard deviations (RSD) of 4.54%-19.7% (n = 6). The results indicated that this method is simple, fast and credible, and suitable for the simultaneous determination of the quinolones in the above three types of cosmetics.

  10. Antibiotic toxicity and absorption in zebrafish using liquid chromatography-tandem mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    Full Text Available Evaluation of drug toxicity is necessary for drug safety, but in vivo drug absorption is varied; therefore, a rapid, sensitive and reliable method for measuring drugs is needed. Zebrafish are acceptable drug toxicity screening models; we used these animals with a liquid chromatography-tandem mass spectrometry (LC-MS/MS method in a multiple reaction monitoring mode to quantify drug uptake in zebrafish to better estimate drug toxicity. Analytes were recovered from zebrafish homogenate by collecting supernatant. Measurements were confirmed for drugs in the range of 10-1,000 ng/mL. Four antibiotics with different polarities were tested to explore any correlation of drug polarity, absorption, and toxicity. Zebrafish at 3 days post-fertilization (dpf absorbed more drug than those at 6 h post-fertilization (hpf, and different developmental periods appeared to be differentially sensitive to the same compound. By observing abnormal embryos and LD50 values, zebrafish embryos at 6 hpf were considered to be suitable for evaluating embryotoxicity. Also, larvae at 3 dpf were adapted to measure acute drug toxicity in adult mammals. Thus, we can exploit zebrafish to study drug toxicity and can reliably quantify drug uptake with LC-MS/MS. This approach will be helpful for future studies of toxicology in zebrafish.

  11. Determination of sulfonamides in beeswax by liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Mitrowska, Kamila; Antczak, Maja

    2015-12-01

    The manuscript presents the development of a new method for the quantification of 16 sulfonamides in beeswax. Different sample preparation techniques were tested and modified to maximise the recovery of the target analytes and minimise the amount of coeluted impurities under conditions that provide reproducible results. The proposed method consisted of melting and dilution of beeswax in a mixture of n-hexane and isopropanol followed by extraction with 2% acetic acid. The extract was cleaned up by solid-phase extraction using strong cation exchange phase. Determination of the sulfonamides was achieved by liquid chromatography coupled to tandem mass spectrometry with the use of a pentafluorophenyl analytical column and applying a gradient elution with acetonitrile and 0.01% acetic acid as mobile phases. The limits of detection and limits of quantification ranged from 1 to 2μg/kg and from 2 to 5μg/kg, respectively. The recoveries varied between 65.2% and 117.8% while coefficient of variation of the method was less than 24.2% under intermediate precision conditions. Finally, the method was applied to the analysis of real samples of beeswax from beekeepers and commercial foundations manufacturers.

  12. Determination of Residual Acrylamide in Medical Polyacrylamide Hydrogel by High Performance Liquid Chromatography tandem Mass Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    WEI-WEI LI; HUI LI; ZHI-FEI LIU; QUN QIAO

    2009-01-01

    Objective To determine residual acrylamide in medical polyacrylamide hydrogel by high performance liquid chromatography tandem mass spectroscopy (HPLC-MS). Methods After 13C3 labeled acrylamide was added, the sample was extracted with water and then cleaned up with ExtrelutTM 20. The polyaerylamide hydrogel sample and 20 clinical cases were analyzed by HPLC-MS/MS and isotope dilution quantifying technique in selected reaction monitoring (SRM) mode. Results Acrylamide was separated from polyacrylamide hydrogel. The concentration of acrylamide in polyacrylamide hydrogel ranged from 3.9×109 to 3.1×108g/L in the 20 clinical cases. The peak area was favorable linear and the range was up to 3 000 μg/L. The recovery rate was 103.1% with a relative standard deviation (RSD) of 6.20%, when the mark level was 50 μg/L. Conclusion HPLC-MS is a rapid, accurate, and sensitive method for the determination of residual acrylamide in medical polyacrylamide hydrogel.

  13. Multiresidue analysis of environmental pollutants in edible vegetable oils by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Rui-Ze; Jiang, Jie; Mao, Ting; Zhao, Ya-Song; Lu, Yong

    2016-09-15

    A novel multiresidue determination of polycyclic aromatic hydrocarbons (PAHs), phthalate esters (PAEs) and alkylphenols (APs) in edible vegetable oils was developed. The samples were extracted with hexane-saturated acetonitrile, and after concentration, the extract was directly qualitatively and quantitatively analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS) with multiple reaction monitoring (MRM) in positive ion mode. The calibration curve displayed good linearity in the range of 2-100 μg/L, with correlation coefficients greater than 0.99. The mean recoveries were 70.0-110.8% by analysis of spiked oil, and the relative standard deviations (RSDs) were 2.1-10.2% (n=6), respectively. The limits of detection (LODs) for the 23 PAHs, 17 PAEs and 3 APs were 0.1-1.0 μg/kg, 0.1-4.0 μg/kg and 1.2-3.0 μg/kg, respectively. The established method effectively avoided interference from large amounts of lipids and pigments. It was applied to real sample and shown to be a rapid and reliable alternative for determination and confirmation in routine analysis.

  14. Analysis of plant nucleotide sugars by hydrophilic interaction liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Ito, Jun; Herter, Thomas; Baidoo, Edward E K; Lao, Jeemeng; Vega-Sánchez, Miguel E; Michelle Smith-Moritz, A; Adams, Paul D; Keasling, Jay D; Usadel, Björn; Petzold, Christopher J; Heazlewood, Joshua L

    2014-03-01

    Understanding the intricate metabolic processes involved in plant cell wall biosynthesis is limited by difficulties in performing sensitive quantification of many involved compounds. Hydrophilic interaction liquid chromatography is a useful technique for the analysis of hydrophilic metabolites from complex biological extracts and forms the basis of this method to quantify plant cell wall precursors. A zwitterionic silica-based stationary phase has been used to separate hydrophilic nucleotide sugars involved in cell wall biosynthesis from milligram amounts of leaf tissue. A tandem mass spectrometry operating in selected reaction monitoring mode was used to quantify nucleotide sugars. This method was highly repeatable and quantified 12 nucleotide sugars at low femtomole quantities, with linear responses up to four orders of magnitude to several 100pmol. The method was also successfully applied to the analysis of purified leaf extracts from two model plant species with variations in their cell wall sugar compositions and indicated significant differences in the levels of 6 out of 12 nucleotide sugars. The plant nucleotide sugar extraction procedure was demonstrated to have good recovery rates with minimal matrix effects. The approach results in a significant improvement in sensitivity when applied to plant samples over currently employed techniques.

  15. Analysis of amphetamines and metabolites in urine with ultra performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Ramírez Fernández, María del Mar; Wille, Sarah M R; di Fazio, Vincent; Gosselin, Matthias; Samyn, Nele

    2010-06-01

    A simple, rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry method was developed and fully validated for the quantitative determination of seven amphetamines and metabolites in urine. The method was validated for selectivity, linearity, LOQ, LOD, imprecision, bias, analyte and processed sample stability, matrix effect, recovery, carryover and dilution integrity. A classic liquid-liquid extraction with ethyl acetate was used as sample preparation procedure. The compounds were separated on an Acquity UPLC HSS C18 column in 6.8 min. The linear dynamic range was established from 25 to 500 ng/mL. The limit of quantification was fixed to the lowest calibrator level and the limit of detection ranged from 0.125 to 2.5 ng/mL. The method presented an excellent intra- and inter-assay imprecision and bias (70%) were obtained for all the compounds. No carryover was observed after the analysis of high concentrated samples (8000 ng/mL). The method was subsequently applied to authentic samples.

  16. Measurement of phthalates diesters in food using gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cariou, Ronan; Larvor, Frédéric; Monteau, Fabrice; Marchand, Philippe; Bichon, Emmanuelle; Dervilly-Pinel, Gaud; Antignac, Jean-Philippe; Le Bizec, Bruno

    2016-04-01

    An analytical strategy dedicated to 4 major phthalate diesters (DiBP, DnBP, BBzP and DEHP) monitoring in food items has been developed and validated according to normalized guidelines. The method has been applied to a wide range of foodstuffs (n=54) to generate first-ever occurrence data at the French level. This method involves separation and detection using gas chromatography coupled to tandem mass spectrometry, in electron ionisation with highly specific selected reaction monitoring, quantification being performed according to the isotope dilution principle. A particular attention has been paid to background contamination management at any stage of the analytical process, from the sampling to the expression of the results. Limits of reporting, defined as statistically different from background contamination, were found to be 2.7, 0.53, 0.18 and 3.4 μg kg(-1), and relative combined uncertainties were finally found to be 7.6%, 12.2%, 12.0% and 14.1%, for DiBP, DnBP, BBzP and DEHP, respectively.

  17. Quantitation of Thioprolines in Grape Wine by Isotope Dilution-Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Liu, Jingjing; Meng, Xiangpeng; Chan, Wan

    2016-02-17

    Cysteine reacts with reactive carbonyls to form thioprolines, which have been demonstrated to possess various pharmaceutical properties. Therefore, thioproline formation is considered as a major detoxification pathway for carcinogenic reactive carbonyls. In this study, we report the initial identification of thiazolidine-4-carboxylic acid (1) and 2-methylthiazolidine-4-carboxylic acid (2), two very common thioprolines, formed by reacting formaldehyde and acetaldehyde with cysteine in grape wine samples. We have developed an isotope dilution-liquid chromatography-tandem mass spectrometry method featuring high sensitivity (limit of detection of ≤1.5 ng/mL) and selectivity to quantitate compounds 1 and 2. The method after validated to be highly accurate (recovery of ≥92%) and precise [intraday relative standard deviation (RSD) of ≤4.1% and interday RSD of ≤9.7%] was applied to determine the varying compound 1 and 2 contents in grape wine samples. Results revealed the grape type and storage duration-dependent formation of thioprolines in grape wines. Overall, the results are expected to facilitate compound-dependent investigations of the health benefits of grape wine, and our findings could be adopted to predict the age of grape wine.

  18. [Determination of clavulanic acid residue in milk by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Yang, Gang; Huang, Xianhui; Guo, Chunna; Fang, Qiuhua; He, Limin

    2012-06-01

    An analytical method was developed for the determination of clavulanic acid (CLAV) in milk by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). A 2 g milk sample was deproteinized by ethanol. The supernatant was transferred into a pear-shaped bottle to be evaporated to about 0.5 mL, and the residue was dissolved with ammonium acetate solution. The sample was determined by HPLC-MS/MS after the purification. The chromatographic separation was achieved on a Luna 5u C8 column using 0.1% formic acid in water and acetonitrile as mobile phases with gradient elution. The identification of CLAV was carried out by MS/MS equipped with electrospray ionization in negative scanning and multiple reaction monitoring (MRM) modes. Matrix-matched calibration standard was used for the quantification. The calibration curve showed perfect linear in the range of 10 - 400 microg/kg with the correlation coefficient of 0.999. The limit of detection (LOD, S/N > or = 3) was 10 microg/kg in milk, and the limit of quantification (LOQ, S/N > or = 10) was 20 microg/kg. The mean recoveries varied from 80.00% to 91.25% at the four spiked levels of LOQ, 1/2MRL (the maximum residue limit), MRL, and 2MRL with the relative standard deviations of 5.60% -8.77%. In conclusion, the established method can be applied for the determination of CLAV residues in milk.

  19. Validation of salivary cortisol and testosterone assays in chimpanzees by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kutsukake, Nobuyuki; Ikeda, Koki; Honma, Seijiro; Teramoto, Migaku; Mori, Yusuke; Hayasaka, Ikuo; Yamamoto, Rain; Ishida, Takafumi; Yoshikawa, Yasuhiro; Hasegawa, Toshikazu

    2009-08-01

    Owing to its high temporal sensitivity, saliva has distinct advantages for measuring steroids, compared with other noninvasive samples such as urine and feces. Here, we report the validity of assaying salivary cortisol (C) and testosterone (T) using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in captive male chimpanzees, Pan troglodytes. For both the C and T concentrations, we found positive relationships between saliva and plasma. The concentrations of C and T in saliva showed clear patterns of diurnal fluctuation, whereas those in urine and feces did not. These results suggest that the salivary steroid concentrations can be regarded as good indicators of circulating steroid levels. We also developed and validated an efficient method for collecting saliva samples from cotton rope. Although rope includes inherent steroid-like compounds and may affect the accuracy of steroid measurements, our rope-washing procedures effectively removed intrinsic steroidal materials. There was a significant association between the C and T concentrations measured from saliva collected from rope licked by the chimpanzees and those measured from saliva collected directly from the mouth. Salivary T values estimated by LC/MS-MS were similar to those measured by radioimmunoassay. The results indicate the usefulness of saliva as a noninvasive steroid measure and that steroids in the saliva of chimpanzees can be accurately measured by LC-MS/MS.

  20. Pharmacokinetic studies of novel berberine derivatives with ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Wenchao; Shen, Qin; Liang, Hui; Hua, Changlong; Liu, Yuhui; Li, Fengzhi; Li, Qingyong

    2016-09-15

    An ultra-performance liquid chromatography with tandem mass spectrometric detection method was developed for the detection of berberine and its derivatives (A4, B4) in rat plasma and other organs. This validated method was successfully applied to our pharmacokinetic study of BBR derivatives in rats. At the same dose of administration, the Cmax of B4 was about eight times higher than BBR, and its half-life was approximately two times longer than BBR, according to the bigger areas under plasma concentration curves. Inversely, the pharmacokinetic parameter levels of A4 were all inferior to BBR, suggesting a tight structure-activity relationship of these compounds. Small dose of parenteral administration was used for the study of absolute oral bioavailability of A4, B4, and BBR, and the results calculated were 0.12%, 3.4% and 0.7%, respectively. The accumulations of B4 among all organs were intestine>liver>heart>kidney>lung>spleen>plasma, proving a deeply targeting property of B4, which met our experimental assumption. Together, the experimental results proved that compared with BBR and A4, the derivative B4 had higher absolute oral bioavailability and the ability of deeply targeting so that can be likely used in some organ-targeted diseases.

  1. [Determination of five coumarins in toys by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Yang, Rongjing; Wei, Biwen; Gao, Huan; Yu, Wenjia

    2012-02-01

    A rapid analytical method for the determination of five coumarins (coumarin, 7-methoxycoumarin, dihydrocoumarin, 7-methyl coumarin and 7-ethoxy-4-methyl coumarin) in toys by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has been developed. After ultrasonic extraction in tetrahydrofuran, the samples were analyzed by HPLC-MS/MS in multi-reaction monitoring (MRM) mode. Acetonitrile and 0.1% acetic acid were used as the mobile phases with gradient elution. The linear ranges of calibration curves were 10 - 1 000 microg/L, and the limits of quantification (LOQ) (S/N > 10) were 2.0 microg/L for all the analytes, except that the LOQ for dihydrocoumarin was 5.0 microg/L. The recoveries of the five coumarins spiked in three types of samples were in the ranges of 93.2% - 105.8%, 97.3% - 103.2% and 96.8% - 102.9%, with the relative standard deviations in the ranges of 4.35% - 8.27%, 3.65% - 6.73% and 4.03% - 6.45%, respectively. The method was applied in the determination of 12 toy samples. The five analytes were found in 9 samples, and in some cases, the presence of quite high concentrations of these coumarins in the toys should be a matter of concern.

  2. Metabolism profiles of nuciferine in rats using ultrafast liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Ye, Lin-Hu; Xiao, Bing-Xin; Liao, Yong-Hong; Liu, Xin-Min; Pan, Rui-Le; Chang, Qi

    2016-08-01

    Nuciferine (NF) is one of the main aporphine alkaloids existing in the traditional Chinese medicine Folium Nelumbinis (lotus leaves). Modern pharmacological studies have demonstrated that NF has a broad spectrum of bioactivities, such as anti-HIV and anti-hyperlipidemic effects, and has been recommended as a leading compound for new drug development. However, the metabolites and biotransformation pathway of NF in vivo have not yet been comprehensively investigated. The present study was performed to identify the metabolites of NF for exploring in vivo fates. Rat plasma and urine samples were collected after oral administration and prepared by liquid-liquid extraction with ethyl acetate. A method based on ultrafast liquid chromatography with tandem mass spectrometry was applied to identify the metabolites. Q1 (first quadrupole) full scan combined with a multiple reaction monitoring (MRM) survey scan were used for the detection of metabolites. MRM-information-dependent acquisition of enhanced product ions was used for the structural identification of detected metabolites. A total of 10 metabolites were identified, including phase I (demethylation, oxidation and dehydrogenation) and phase II (glucuronidation, sulfation and glutathione) biotransformation products. Demethylation is the main metabolic pathway of NF in the body. These results can help in improving understanding of the disposition and pharmacological mechanism of NF in the body. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Determination of homocitrulline in urine of patients with HHH syndrome by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Al-Dirbashi, Osama Y; Al-Hassnan, Zuhair N; Rashed, Mohamed S

    2006-12-01

    A liquid chromatography tandem mass spectrometric method is described for the analysis of homocitrulline in human urine, a key metabolite in the differential diagnosis of hyperammonemia, hyperornithinemia, homocitrullinuria (HHH) syndrome. Urine samples were prepared by mere five-fold dilution with a mixture of internal standards (2H2-citrulline and 2H3-creatinine) used for the simultaneous quantification of creatinine. Analytes were separated on a cyano column and eluted isocratically within seven min. Detection was achieved by monitoring transitions of 190 > 84 and 190 > 127 for homocitrulline, 178 > 115 for 2H2-citrulline, 114 > 44 for creatinine and 117 > 47 for 2H3-creatinine. Calibration curves were linear up to 100 micromol/L. Intraday (n = 7) and interday (n = 6) variations were less than 10%. In urine samples from three siblings confirmed to have HHH syndrome, homocitrulline levels were at 13.3 (74), 21.1 (50) and 108.2 (103) mmol/mol creatinine (micromol/L). Control values were 0-9 mmol/mol creatinine (n = 120). The current method solves specificity issues in homocitrulline determination often encountered with some ninhydrin-based systems (coelution with methionine) and some o-phthalaldehyde-based ones (coelution with taurine), and presents an attractive alternative with a relatively high throughput.

  4. [Determination of gossypol in edible vegetable oil with high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Wenhua; Huang, Chaoqun; Xie, Wen; Shen, Li

    2014-06-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of gossypol in edible vegetable oil. The sample was extracted with ethyl alcohol by vortex-excited oscillation. The extract was cleaned up by 0.22 microm filter membrane and centrifuged for 5 min at 4 000 r/min after standing in a fridge at 4 degrees C for 30 min. The compound was separated on a C18 column (100 mm x 2.1 mm, 3.5 microm) with acetonitrile and 1% (v/v) formic acid aqueous solution as mobile phase. The detection of gossypol was carried out by LC-MS/MS with positive electrospray ionization under multiple reaction monitoring (MRM) mode using external standard method. The limits of quantification (S/N > 10) of gossypol in edible vegetable oil was 1 mg/kg. The recoveries were from 87.4% to 100% at the spiked levels of 1, 2, 200 mg/kg of gossypol in edible vegetable oil with the relative standard deviations (RSDs) between 3.9% and 12.2%. The method, with high sensitivity, good precision and high recovery, was suitable for the confirmation and quantification of gossypol residue in edible vegetable oil.

  5. Rhamnolipid biosurfactant analysis using online turbulent flow chromatography-liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Behrens, Beate; Helmer, Patrick O; Tiso, Till; Blank, Lars M; Hayen, Heiko

    2016-09-23

    Rhamnolipids are biosurfactants produced by a variety of bacterial species that present a promising alternative to surfactants from petrochemical or oleochemical origin. The success of the fermentation is evaluated by subsequent qualitative and quantitative analysis. However, the sample preparation for high numbers of samples is often laborious and inefficient. In this study an online sample preparation is developed for the qualitative and quantitative analysis of rhamnolipids by LC-MS/MS. Online sample preparation is carried out on a TurboFlow Cyclone MAX column using turbulent flow chromatography. Sample preparation prior the analysis is minimized to a dilution and syringe filtration step leading to an instrumental analysis time of 33min. The limit of detection and the limit of quantification were 0.4ng and 0.6ng on column, respectively. Recovery of the main mono- and di-rhamnolipids from a fermentation sample was 102-104%. Additionally, the rhamnolipid biosynthetic precursors 3-hydroxy(alkanoyloxy)alkanoic acids (HAAs) are covered, albeit extraction is not quantitative (85-90%). The analysis of rhamnolipids from four different microbial species was in good agreement with previous reports. The presented method allows rapid and comprehensive analysis of rhamnolipids with minimal sample preparation directly from the fermentation broth. The application of complementary data-dependent MS/MS acquisition enables non-target screening of rhamnolipids.

  6. Simultaneous determination of 14 β-lactam antibiotics in cosmetic products by liquid chromatography tandem mass spectrometry method

    Institute of Scientific and Technical Information of China (English)

    Cai Sheng Wu; Jin Lan Zhang; Yan Ling Qiao; Yi Lin Wang; Zhi Rong Chen

    2011-01-01

    In this study, a simple and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was established and validated to determine the 14 β-lactam antibiotics in cosmetic products, including 1 (ceftazidime), 2 (cefaclor), 3 (cefdinir), 4 (ampicillin), 5 (cefalexin), 6 (ceftezole), 7 (cefotaxim), 8 (cefradine), 9 (cefuroxime), 10 (cephazoline), 11 (cefathiamidine), 12 (cefoperazone), 13 (cafalotin), 14 (piperacillin).

  7. 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.

  8. [Determination of aflatoxins in cereals and oils by liquid chromatography-triple quadrupole tandem mass spectrometry].

    Science.gov (United States)

    Wang, Xiupin; Li, Peiwu; Yang, Yang; Zhang, Wen; Zhang, Qi; Fan, Sufang; Yu, Li; Wang, Lin; Chen, Xiaomei; Li, Ying; Jiang, Jun

    2011-06-01

    The high performance liquid chromatography (HPLC)-triple quadrupole tandem mass spectrometry was applied for the determination of the aflatoxins: B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2), in cereals and oils. The samples were first extracted by ultrasonic method. The optimized conditions of ultrasonic extraction were as follows: temperature of 50 degrees C, extraction time of 3 min, methanol-water (containing 40 g/L NaCl) (80: 20, v/v) solution as the medium and a ratio of sample to solvent of 1 : 3 (g: mL). The extracts were then purified using an immunoaffinity column. The separation was performed on a C18 column with mobile phases of 10 mmol/L ammonium acetate and methanol in gradient elution. The sensitive detection of the four AFT compounds by electrospray ionization mass spectrometry (ESI-MS) was carried out in selected reaction monitoring (SRM) mode with aflatoxin M1 (AFM1) as the internal standard. Under the optimized conditions, the limits of detection of AFB1, AFB2, AFG1 and AFG2 were 0.002, 0.004, 0.004 and 0.012 microg/kg, respectively. The recoveries of aflatoxins in different spiked cereals and oils were in the range from 87% to 111%. The intra-day and inter-day precisions were not more than 6.7% and 5.6%, respectively. In comparison with the external standard method, this method can effectively inhibit the matrix effects, and greatly improve the accuracy.

  9. [Determination of aflatoxins in cashew by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Bi, Ruifeng; Fan, Zhixian; Fu, Meng

    2011-12-01

    A method for the determination of four aflatoxins in cashew using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The sample was extracted with methanol-water (8: 2, v/v) solution, followed by a cleanup procedure with Florisil column. The target compounds were eluted using 5 mL acetone-water-formic acid (96: 3.5:0.5, v/v/v) solution. The eluate was dried under N2, then dissolved in 1 mL methanol. Four aflatoxins were separated in MG C18 column (100 mm x 3.0 mm, 3 microm) adopting a gradient program within 15 min. A triple quadrupole mass spectrometry equipped with an electrospray ionization source operated in the positive ion mode was used to detect the aflatoxins. The good correlation coefficients (r2 > 0.997) of the four aflatoxins were obtained within their respective linear ranges. The limits of detection (S/N = 3) were between 0.009 microg/kg and 0.04 microg/kg, and the limits of quantification (S/N = 10) were between 0.03 microg/kg and 0.12 microg/kg. The recoveries were in a range of 63.0% -78.5% with the relative standard deviations (RSDs) varied from 2.8% to 9.1%. The validation results meet the requirements of trace assay. Matrix effects were estimated and the signal suppression/enhancement ranged from 88.8% to 99.4%. The results indicate that the developed method is simple, fast, accurate, and can be applied for the determination of fours aflatoxins in cashew.

  10. 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 enzymati

  11. High Performance Liquid Chromatography Tandem Mass Spectrometry Assay for the Determination of Cobinamide in Pig Plasma

    Science.gov (United States)

    McCracken, Brent A.; Brittain, Matthew K.

    2015-01-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been widely utilized for the analysis of compounds in biological matrices due to its selectivity and sensitivity. This study describes the application of an LC-MS/MS-based approach toward the analysis of cobinamide in Yorkshire pig plasma. The selectivity, accuracy, precision, recovery, linearity, range, carryover, sensitivity, matrix effect, interference, stability, reproducibility, and ruggedness of the method were investigated in pig plasma. The accuracy and precision of the method was determined to be within 10% over three different days over a range of concentrations (25–10,000 ng/mL) that spanned more than two orders of magnitude. The lower limit of quantitation (LLOQ) for dicyanocobinamide was determined to be 25 ng/mL in pig plasma. Carryover was acceptable, as the area response of the carryover blanks were ≤15% of the area response of the nearest LLOQ standard for the analyte, while it was nonexistent for the internal standard. Specificity was ensured using six different lots of pig plasma. While the matrix effects of dicyanocobinamide in plasma were enhanced, ginsenoside Rb1 experienced signal suppression under the described conditions. The absolute recovery results for both compounds were consistent, precise, and reproducibly lower than expected at ~60% for dicyanocobinamide and ~22% for ginsenoside Rb1, confirming that a matrix standard curve was required for accurate quantitation. Cobinamide was shown to be very stable in matrix at various storage conditions including room temperature, refrigerated, and frozen at time intervals of 20 hours, 4 days, and 60 days respectively. This method was demonstrated to be sensitive, reproducible, stable, and rugged, and it should be applicable to the analysis of cobinamide in other biological matrices and species. PMID:26540437

  12. Validation of keratan sulfate level in mucopolysaccharidosis type IVA by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Tomatsu, Shunji; Montaño, Adriana M; Oguma, Toshihiro; Dung, Vu Chi; Oikawa, Hirotaka; de Carvalho, Talita Giacomet; Gutiérrez, María L; Yamaguchi, Seiji; Suzuki, Yasuyuki; Fukushi, Masaru; Kida, Kazuhiro; Kubota, Mitsuru; Barrera, Luis; Orii, Tadao

    2010-12-01

    Mucopolysaccharidosis type IVA (MPS IVA, Morquio A disease), a progressive lysosomal storage disease, causes skeletal chondrodysplasia through excessive storage of keratan sulfate (KS). KS is synthesized mainly in cartilage and released to the circulation. The excess storage of KS disrupts cartilage, consequently releasing more KS into circulation, which is a critical biomarker for MPS IVA. Thus, assessment of KS level provides a potential screening strategy and determines clinical course and efficacy of therapies. We have recently developed a tandem mass spectrometry liquid chromatography [LC/MS/MS] method to assay KS levels in blood. Forty-nine blood specimens from patients with MPS IVA [severe (n = 33), attenuated (n = 11) and undefined (n = 5)] were analyzed for comparison of blood KS concentration with that of healthy subjects and for correlation with clinical severity. Plasma samples were digested by keratanase II to obtain disaccharides of KS. Digested samples were assayed by LC/MS/MS. We found that blood KS levels (0.4-26 µg/ml) in MPS IVA patients were significantly higher than those in age-matched controls (0.67-4.6 µg/ml; P IVA peaked between 2 years and 5 years of age (mean 11.4 µg/ml). Blood KS levels in severe MPS IVA (mean 7.3 µg/ml) were higher than in the attenuated form (mean 2.1 µg/ml) (P = 0.012). We also found elevated blood KS levels in other types of MPS. These findings indicate that the new KS assay for blood is suitable for early diagnosis and longitudinal assessment of disease severity in MPS IVA.

  13. 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.

  14. Determination of loperamide in human plasma and saliva by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Arafat, Tawfiq; Arafat, Basil; awad, Riad; awwad, Ahmad Abu

    2014-12-01

    A simple and sensitive liquid chromatography-tandem mass spectrometric method for quantification of loperamide in human plasma and saliva was developed and validated, and then successfully applied in pharmacokinetic clinical study to investigate and correlate bioavailability of Imodium(®) 2mg quartet tablet dose in both human plasma and saliva. Loperamide with labeled internal standard was extracted from its biological matrix by methanol as protein direct precipitant in single extraction step. Adequate chromatographic separation for analytes from plasma and saliva matrices was achieved using ACE C18 (50mm×2.1mm, 5μm) column, eluted by water/methanol/formic acid (30:70:0.1%, v/v), delivered isocratically at constant flow rate of 0.75ml/min. The method validation intends to investigate specificity, sensitivity, linearity, precision, accuracy, recovery, matrix effect and stability according to European guideline, and partial validation was applied on saliva, specificity, matrix effect, recovery, sensitivity, within and between day precision and accuracy. The calibration curve was linear through the range of 20-3000pg/ml in both plasma and saliva using a 50μl sample volume. The partial validation sections outcome in saliva was so close to those in plasma. The within- and between-day precisions were all below 8.7% for plasma and below 11.4% for saliva. Accuracies ranged from 94 to 105% for both matrices. In this study, 26 healthy volunteers participated in the clinical study, and 6 of gave their saliva samples in addition to plasma at the same time schedule. The pharmacokinetic parameters of Cmax, AUC0-t and AUC0-∞, Tmax and T1/2 in both plasma and saliva were calculated and correlated.

  15. Detection of 36 antibiotics in coastal waters using high performance liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    NA Guangshui; GU Jia; GE Linke; ZHANG Peng; WANG Zhen; LIU Chunyang; ZHANG Lin

    2011-01-01

    Among pharmaceuticals and personal care products released into the aquatic environment,antibiotics are of particular concern,because of their ubiquity and health effects.Although scientists have recently paid more attention to the threat of antibiotics to coastal ecosystems,researchers have often focused on relatively few antibiotics,because of the absence of suitable analytical methods.We have therefore developed a method for the rapid detection of 36 antibiotic residues in coastal waters,including tetracyclines (TCs),sulfanilamides (SAs),and quinolones (QLs).The method consists of solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis,using electrospray ionization (ESI) in positive mode.The SPE was performed with Oasis HLB and Oasis MCX cartridges.Chromatographic separation on a C18 column was achieved using a binary eluent containing methanol and water with 0.1% formic acid.Typical recoveries of the analytes ranged from 67.4% to 109.3% at a fortification level of 100 ng/L.The precision of the method,calculated as relative standard deviation (RSD),was below 14.6% for all the compounds.The limits of detection (LODs) varied from 0.45 pg to 7.97 pg.The method was applied to determine the target analytes in coastal waters of the Yellow Sea in Liaoning,China.Among the tested antibiotics,31 were found in coastal waters,with their concentrations between the LOD and 212.5 ng/L.These data indicate that this method is valid for analysis of antibiotics in coastal waters.The study first reports such a large number of antibiotics along the Yellow Sea coast of Liaoning,and should facilitate future comprehensive evaluation of antibiotics in coastal ecosystems.

  16. Determination of sodium cromoglycate in human plasma by liquid chromatography with tandem mass.

    Science.gov (United States)

    Liu, Xiao-yan; Qu, Ting-ting; Wang, Ben-jie; Wei, Chun-min; Yuan, Gui-yan; Zhang, Rui; Guo, Rui-chen

    2008-09-01

    A sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed and validated for the determination of sodium cromoglycate (SCG) in human plasma after a nasal dose of 10.4 mg sodium cromoglycate nasal spray, using pravastatin sodium as the internal standard. The method was validated over a linear range of 0.300-20.0 ng/mL. SCG and I.S. were extracted from 1.0 mL of heparinized plasma by C(18) solid-phase extraction cartridges using methanol as eluting solvent. The dried residue was reconstituted with 100 microL of mobile phase, and 10 microL was injected onto the LC-MS/MS system. Chromatographic separation was achieved on a C(18) column (250 x 4.6 mm i.d., 5 microm particle size) with a mobile phase of methanol-acetonitrile-water (containing 2 mmol/L ammonium acetate; 42.5:42.5:15, v/v/v) at a flow rate of 0.4 mL/min. The analytes were detected with a triple quad LC-MS/MS using ESI with positive ionization. Ions monitored in the multiple reaction monitoring mode were m/z 469.0 (precursor ion) to m/z 245.0 (product ion) for SCG and m/z 447.2 (precursor ion) to m/z327.1 (product ion) for pravastatin sodium (internal standard) The average recovery of SCG from human plasma was 94.88% and the lower limit of quantitation was 0.3 ng/mL. Results from a 3-day validation study demonstrated excellent precision and accuracy across the calibration range of 0.3-20 ng/mL. The method was successfully applied to the pharmacokinetic study of SCG in healthy Chinese volunteers.

  17. [Determination of five pyrrolizidine alkaloids in honey by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lü, Chen; Ding, Tao; Ma, Xin; Chen, Guosong; Yuan, Fang; Wu, Bin; Shen, Chongyu; Zhang, Rui; Fei, Xiaoqing; Zhang, Xiaoyan; Chen, Lei; Li, Li

    2013-11-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of five pyrrolizidine alkaloids (PAs) (monocrotaline, senkirkine, retrorsine, seneciphylline and senecionine) in honey. The honey samples were dissolved in 0.1 mol/L hydrochloric acid solution and a strong-cation exchange column was used to purify and concentrate the target analytes. The separation of the analytes was carried out on a Phenomenex C18 column (100 mm x 4.6 mm, 2.6 microm) using the mobile phases of acetonitrile and 5 mmol/L ammonium acetate-0.1% (volume percentage) formic acid aqueous solution with gradient elution. The separated compounds were detected in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI+). The calibration curves were of good linearity in the range of 1-100 microg/L (r > 0.99). The limit of quantification of the method was 1.0 microg/kg. The average recoveries were between 73.1% to 107.1% at three spiked levels (1, 20 and 50 microg/kg) with the relative standard deviations (RSDs) in the range of 4.1% to 17.0%. The proposed method was applied to different kinds of honey from China, New Zealand, Spain and Australia. The samples included rape, vitex, sunflower, cotton, tilia tree, date, acacia, buckwheat, manuka and eucalyptus honey. Monocrotaline, senkirkine and retrorsine were not detected in the collected honey samples. However, seneciphylline and senecionine were found in most of the honey samples. The concentrations of seneciphylline and senecionine were 11.0 -31.1 microg/kg and 8.3-29.1 microg/kg, respectively.

  18. Detection of stanozolol in environmental waters using liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Petroczi Andrea

    2011-10-01

    Full Text Available Abstract Background Owing to frequent administration of a wide range of pharmaceutical products, various environmental waters have been found to be contaminated with pharmacologically active substances. For example, stanozolol, a synthetic anabolic steroid, is frequently misused for performance enhancement as well as for illegal growth promoting purposes in veterinary practice. Previously we reported stanozolol in hair samples collected from subjects living in Budapest. For this reason we initiated this study to explore possible environmental sources of steroid contamination. The aim of this study was to develop a method to monitor stanozolol in aqueous matrices using liquid chromatography tandem mass spectrometry (LC-MS/MS. Results Liquid-liquid extraction using pentane was found to be an efficient method for the extraction of stanozolol from water samples. This was followed by direct detection using LC-MS/MS. The method was capable of detecting 0.25 pg/mL stanozolol when only 5 mL water was processed in the presence of stanozolol D3 as internal standard. Fifteen bottled waters analysed were found to be negative for stanozolol. However, three out of six samples from the Danube river, collected from December '09 to November '10, were found to contain stanozolol at concentrations up to 1.82 pg/mL. In contrast, only one sample (out of six of urban tap water from Budapest city was found to contain stanozolol, at a concentration of 1.19 pg/mL. Conclusion The method developed is efficient, rapid, reproducible, sensitive and robust for the detection of stanozolol in aqueous matrices.

  19. Quantitation of Insulin Analogues in Serum Using Immunoaffinity Extraction, Liquid Chromatography, and Tandem Mass Spectrometry.

    Science.gov (United States)

    Van Der Gugten, J Grace; Wong, Sophia; Holmes, Daniel T

    2016-01-01

    Insulin analysis is used in combination with glucose, C-peptide, beta-hydroxybutyrate, and proinsulin determination for the investigation of adult hypoglycemia. The most common cause is the administration of too much insulin or insulin secretagogue to a diabetic patient or inadequate caloric intake after administration of either. Occasionally there is a question as to whether hypoglycemia has been caused by an exogenous insulin-whether by accident, intent, or even malicious intent. While traditionally this was confirmed by a low or undetectable C-peptide in a hypoglycemic specimen, this finding is not entirely specific and would also be expected in the context of impaired counter-regulatory response, fatty acid oxidation defects, and liver failure-though beta-hydroxybutyrate levels can lend diagnostic clarity. For this reason, insulin is often requested. However, popular automated chemiluminescent immunoassays for insulin have distinctly heterogeneous performance in detecting analogue synthetic insulins with cross-reactivities ranging from near 0 % to greater than 100 %. The ability to detect synthetic insulins is vendor-specific and varies between insulin products. Liquid Chromatography and Tandem Mass Spectrometry (LC-MS/MS) offers a means to circumvent these analytical issues and both quantify synthetic insulins and identify the specific type. We present an immunoaffinity extraction and LC-MS/MS method capable of independent identification and quantitation of native sequence insulins (endogenous, Insulin Regular, Insulin NPH), and analogues Glargine, Lispro, Detemir, and Aspart with an analytical sensitivity for endogenous insulin of between 1 and 2 μU/mL in patient serum samples.

  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. Determination of folic acid in human plasma using hydrophilic interaction chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Garbis, S.D.; Melse-Boonstra, A.; West, C.E.; Breemen, van R.B.

    2001-01-01

    Folic acid is an essential nutrient, and folate deficiency is associated with a variety of disorders including neural tube defects (during pregnancy) and heart disease. A fast, sensitive, and robust HPLC-tandem mass spectrometry (LC-MS-MS) method was developed for the quantification of free folic ac

  2. Multiresidue analysis of pesticides in straw roughage by liquid chromatography - tandem mass spectrometry

    Science.gov (United States)

    A multiresidue analytical method using a modification of the “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) sample preparation approach combined with liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis was established and validated for the rapid determination of 69 pesti...

  3. Validation of a confirmatory method for the determination of melamine in egg by gas chromatography-mass spectrometry and ultra-performance liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Xia Xi; Ding Shuangyang; Li Xiaowei; Gong Xiao; Zhang Suxia; Jiang Haiyang; Li Jiancheng [Department of Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing 100193 (China); Shen Jianzhong, E-mail: sjz@cau.edu.cn [Department of Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing 100193 (China)

    2009-10-05

    A sensitive and reliable method was developed and validated for detection and confirmation of melamine in egg based on gas chromatography-mass spectrometry (GC-MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Trichloroacetic acid solution was used for sample extraction and precipitation of proteins. The aqueous extracts were subjected to solid-phase extraction by mixed-mode reversed-phase/strong cation-exchange cartridges. Using ultra-performance liquid chromatography and electrospray ionization in the positive ion mode, melamine was determined by LC-MS/MS, which was completed in 5 min for each injection. For the GC-MS analysis, extracted melamine was derivatized with N,O-bis(trimethylsilyl)trifluoracetamide prior to selected ion monitoring detection in electron impact mode. The average recovery of melamine from fortified samples ranged from 85.2% to 103.2%, with coefficients of variation lower than 12%. The limit of detection obtained by GC-MS and UPLC-MS/MS was 10 and 5 {mu}g kg{sup -1}, respectively. This validated method was successfully applied to the determination of melamine in real samples from market.

  4. Liquid chromatography tandem mass spectrometry for measuring ¹³C-labeling in intermediates of the glycolysis and pentose phosphate pathway.

    Science.gov (United States)

    Cocuron, Jean-Christophe; Alonso, Ana Paula

    2014-01-01

    This chapter describes a procedure to analyze (13)C-labeled phosphorylated compounds by liquid chromatography tandem mass spectrometry. Phosphorylated compounds, intermediaries of the glycolysis and pentose phosphate pathway, are separated by anion exchange chromatography and their isotopic labeling is determined by mass spectrometry. A sensitivity in the fmole range is achieved using scheduled multiple reaction monitoring mode.

  5. A Supercritical Fluid Chromatography/Tandem Mass Spectrometry Method for the Simultaneous Quantification of Metformin and Gliclazide in Human Plasma

    Science.gov (United States)

    Agrawal, Y. K.; Gogoi, P. J.; Manna, K.; Bhatt, H. G.; Jain, V. K.

    2010-01-01

    Present study reports the development and validation of a simultaneous estimation of metformin and gliclazide in human plasma using supercritical fluid chromatography followed by tandem mass spectrometry. Acetonitrile:water (80:20) mixture was used as a mobile phase along with liquid CO2 in supercritical fluid chromatography and phenformin as an internal standard. The modified plasma samples were analyzed by electro-spray ionization method in selective reaction monitoring mode in tandem mass spectrometry. Supercritical fluid chromatographic separation was performed using nucleosil C18 containing column as a stationary phase. The separated products were identified by characteristic peaks and specific fragments peaks in tandem mass spectrometry as m/z 130 to 86 for metformin, m/z 324 to 110 for gliclazide and m/z 206 to 105 for phenformin. The present method was found linear in the concentration ranges of 6.0-3550 ng/ml and 7.5-7500 ng/ml for metformin and gliclazide, respectively. Pharmacokinetic study was performed after an oral administration of dispersible tablets containing 500 mg of metformin and 80 mg of gliclazide using same techniques. PMID:20582190

  6. Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

    2016-04-01

    In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures.

  7. [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.

  8. Screening antiallergic components from Carthamus tinctorius using rat basophilic leukemia 2H3 cell membrane chromatography combined with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Han, Shengli; Huang, Jing; Cui, Ronghua; Zhang, Tao

    2015-02-01

    Carthamus tinctorius, used in traditional Chinese medicine, has many pharmacological effects, such as anticoagulant effects, antioxidant effects, antiaging effects, regulation of gene expression, and antitumor effects. However, there is no report on the antiallergic effects of the components in C. tinctorius. In the present study, we investigated the antiallergic components of C. tinctorius and its mechanism of action. A rat basophilic leukemia 2H3/cell membrane chromatography coupled online with high-performance liquid chromatography and tandem mass spectrometry method was developed to screen antiallergic components from C. tinctorius. The screening results showed that Hydroxysafflor yellow A, from C. tinctorius, was the targeted component that retained on the rat basophilic leukemia 2H3/cell membrane chromatography column. We measured the amount of β-hexosaminidase and histamine released in mast cells and the key markers of degranulation. The release assays showed that Hydroxysafflor yellow A could attenuate the immunoglobulin E induced release of allergic cytokines without affecting cell viability from 1.0 to 50.0 μM. In conclusion, the established rat basophilic leukemia 2H3 cell membrane chromatography coupled with online high-performance liquid chromatography and tandem mass spectrometry method successfully screened and identified Hydroxysafflor yellow A from C. tinctorius as a potential antiallergic component. Pharmacological analysis elucidated that Hydroxysafflor yellow A is an effective natural component for inhibiting immunoglobulin E-antigen-mediated degranulation.

  9. Quantification of Neurotransmitters in Mouse Brain Tissue by Using Liquid Chromatography Coupled Electrospray Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Tae-Hyun Kim

    2014-01-01

    Full Text Available A simple and rapid liquid chromatography tandem mass spectrometry method has been developed for the determination of BH4, DA, 5-HT, NE, EP, Glu, and GABA in mouse brain using epsilon-acetamidocaproic acid and isotopically labeled neurotransmitters as internal standards. Proteins in the samples were precipitated by adding acetonitrile, and then the supernatants were separated by a Sepax Polar-Imidazole (2.1 mm × 100 mm, i.d., 3 μm column by adding a mixture of 10 mM ammonium formate in acetonitrile/water (75 : 25, v/v, 300 μl/min for BH4 and DA. To assay 5-HT, NE, EP, Glu, and GABA; a Luna 3 μ C18 (3.0 mm × 150 mm, i.d., 3 μm column was used by adding a mixture of 1% formic acid in acetonitrile/water (20 : 80, v/v, 350 μl/min. The total chromatographic run time was 5.5 min. The method was validated for the analysis of samples. The calibration curve was linear between 10 and 2000 ng/g for BH4 r2=0.995, 10 and 5000 ng/g for DA r2=0.997, 20 and 10000 ng/g for 5-HT r2=0.994, NE r2=0.993, and EP r2=0.993, and 0.2 and 200 μg/g for Glu r2=0.996 and GABA r2=0.999 in the mouse brain tissues. As stated above, LC-MS/MS results were obtained and established to be a useful tool for the quantitative analysis of BH4, DA, 5-HT, NE, EP, Glu, and GABA in the experimental rodent brain.

  10. Evaluation of propolis polyphenols absorption in humans by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Gardana, Claudio; Simonetti, Paolo; Berti, Cristiana; Pietta, Piergiorgio

    2007-01-01

    Propolis has various biological activities such as antibacterial, antiviral, antioxidant, immunostimulating and antiinflammatory, which are generally ascribed to the polyphenolic fraction. The aim of this study was to evaluate the absorption of the main polyphenols [caffeic acid (CA), pinobanksin-5methyl ether (P-5ME), pinobanksin (Pb), chrysin (C), pinocembrin (P), galangin (G), pinobanksin-3-acetate, pinobanksin esters and caffeic acid phenylethyl ester (CAPE)] from a dewaxed and standardized extract of propolis (EPID). Fifteen healthy volunteers consumed 5 mL EPID in water, corresponding to 125 mg of flavonoids. Blood samples were collected before, each hour for 8 h and 24 h after EPID intake. After deconjugation by beta-glucuronidase/sulfatase the plasma samples were analyzed by a selective liquid chromatography/tandem mass spectrometry (LC/MS/MS) method using morin as internal standard (I.S.). A kinetic profile characterized by two t(max), respectively at 1 h and about 5 h post-ingestion, was observed in all the subjects. The two peaks may be due to enterohepatic cycling. Among the various polyphenols ingested, only P-5ME, Pb, C, P and G were detected in plasma and C(max)t(1h) were 65.7 +/- 13.3, 46.5 +/- 12.7, 79.5 +/- 18.6, 168.1 +/- 16.3 and 113.7 +/- 16.8 ng/mL, respectively. These levels decreased significantly after 8 h and were no longer detectable 24 h after EPID intake. The recovery of the extraction for CA, Pb, C, P, G and I.S. from spiked plasma was 95.2 +/- 3.1, 93.1 +/- 3.6, 91 +/- 2.5, 96.4 +/- 4.2, 93.4 +/- 2.4 and 85.5 +/- 2.4%, respectively. The results of this study evidence that flavonoids from EPID are absorbed, metabolized and Pb-5ME and G seem to have apparent absorption, measured as (AUC/dose), higher than C, P and Pb.

  11. 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.

  12. Detection of Stimulants and Narcotics by Liquid Chromatography-Tandem Mass Spectrometry and Gas Chromatography-Mass Spectrometry for Sports Doping Control.

    Science.gov (United States)

    Ahrens, Brian D; Kucherova, Yulia; Butch, Anthony W

    2016-01-01

    Sports drug testing laboratories are required to detect several classes of compounds that are prohibited at all times, which include anabolic agents, peptide hormones, growth factors, beta-2 agonists, hormones and metabolic modulators, and diuretics/masking agents. Other classes of compounds such as stimulants, narcotics, cannabinoids, and glucocorticoids are also prohibited, but only when an athlete is in competition. A single class of compounds can contain a large number of prohibited substances and all of the compounds should be detected by the testing procedure. Since there are almost 70 stimulants on the prohibited list it can be a challenge to develop a single screening method that will optimally detect all the compounds. We describe a combined liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) testing method for detection of all the stimulants and narcotics on the World Anti-Doping Agency prohibited list. Urine for LC-MS/MS testing does not require sample pretreatment and is a direct dilute and shoot method. Urine samples for the GC-MS method require a liquid-liquid extraction followed by derivatization with trifluoroacetic anhydride.

  13. A New Liquid Chromatography-Tandem Mass Spectrometry Method for Determination of Bisoprolol in Human Plasma Samples

    Directory of Open Access Journals (Sweden)

    Gabriela Peste

    2009-01-01

    Full Text Available Liquid chromatography (LC coupled with mass spectrometry (MS detection is one of the most powerful analytical tools for organic compound analysis. The advantages of using LC/MS methods over HPLC methods include: selectivity, chromatographic integrity, peak assignment, structural information, and rapid method development. In this paper, a new liquid chromatography-tandem mass spectrometry (LC-MS/MS method has been developed and validated for the determination of bisoprolol in human plasma samples, using metoprolol as internal standard and liquid-liquid extraction procedure. The assay has proven to be sensitive, specific and reproducible, suitable to determine the bisoprolol concentration, following a single oral administration of a 10 mg bisoprolol tablet in 22 healthy volunteers, in the bioequivalence study of Bisoprolol 10 mg coated tablets, produced by Antibiotice S.A. versus Concor 10 mg, produced by Merck.

  14. The use of liquid chromatography tandem mass spectrometry to detect proteins in saliva from horses with and without systemic inflammation

    DEFF Research Database (Denmark)

    Jacobsen, Stine; Top Adler, Ditte Marie; Bundgaard, Louise

    2014-01-01

    The objective of the study was to assess global expression of proteins in equine saliva using liquid chromatography tandem mass spectrometry (LC-MS/MS). Saliva was obtained from seven horses with and six horses without evidence of systemic inflammatory disease. Tryptic peptides from saliva were......, and alpha1-acid glycoprotein. The study is the first to describe detection of inflammatory proteins in horse saliva. The proteins detected were similar to those described in saliva from cattle, small ruminants and pigs. Detection of APPs in horses with systemic inflammation suggests that saliva may be used...

  15. Colostrum protein uptake in neonatal lambs examined by descriptive and quantitative liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Hernandez-Castellano, Lorenzo E; Argueello, Anastasio; Almeida, Andre M

    2015-01-01

    Colostrum intake is a key factor for newborn ruminant survival because the placenta does not allow the transfer of immune components. Therefore, newborn ruminants depend entirely on passive immunity transfer from the mother to the neonate, through the suckling of colostrum. Understanding...... dodecyl sulfate-PAGE for protein separation and in-gel digestion, followed by liquid chromatography-tandem mass spectrometry of resulting tryptic peptides for protein identification. An isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomics approach was subsequently used to provide...

  16. Identification of Ceftiofur Oxidation Products by High-Performance Liquid Chromatography/Electrospray Ionization/Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Hye-Sung Cho

    2011-03-01

    Full Text Available Oxidation products of ceftiofur were formed in hydrogen peroxide solution. The structures of the ceftiofur oxidationproducts were characterized by high-performance liquid chromatography/electrospray ionization/tandem mass spectrometry(HPLC/ESI/MS/MS. The products were identified as compounds oxidized at the sulfur of a cephem ring. For further analysis,experiments were performed using O18-labeled hydrogen peroxide. In addition, density-functional calculations were carried out forsix possible oxidation products to support the experimental results.

  17. Separation and characterization of phenolic compounds in fennel (Foeniculum vulgare) using liquid chromatography-negative electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Parejo, Irene; Jauregui, Olga; Sánchez-Rabaneda, Ferran; Viladomat, Francesc; Bastida, Jaume; Codina, Carles

    2004-06-16

    Liquid chromatography (LC) diode array detection (DAD) coupled to negative electrospray ionization (ESI) tandem mass spectrometry (MS/MS) was used for the rapid and sensitive identification of water-soluble phenolic compounds in fennel waste. The plant material was first extracted and then chromatographed on Sephadex LH-20 to afford seven fractions, each of them being subjected to LC-MS analysis. Identification of the compounds was carried out by interpretation of UV, MS, and MS/MS spectra. Forty-two phenolic substances were identified, 27 of which had not previously been reported in fennel, including hydroxycinnamic acid derivatives, flavonoid glycosides, and flavonoid aglycons.

  18. Rapid quantification of the metabolite of valacyclovir hydrochloride in human plasma by liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Objective To establish a rapid,sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of acyclovir (the metabolite of valacyclovir hydrochloride) in human plasma. Methods After addition of ganciclovir as internal standard (IS),plasma samples were prepared by one-step protein precipitation using acetonitrile as precipitant,followed by an isocratic elution with 0.1% formic acid solution-methanol (95∶5,v/v) on an Agilent ZORBAX SB-C18 (150mm×2.1mm i.d.,3....

  19. Screening and determination of drugs in human saliva utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Abdel-Rehim, Abbi; Abdel-Rehim, Mohamed

    2013-09-01

    This study presents a new method for collecting and handling saliva samples using an automated analytical microsyringe and microextraction by packed syringe (MEPS). The screening and determination of lidocaine in human saliva samples utilizing MEPS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were carried out. An exact volume of saliva could be collected. The MEPS C8 -cartridge could be used for 50 extractions before it was discarded. The extraction recovery was about 60%. The pharmacokinetic curve of lidocaine in saliva using MEPS-LC-MS/MS is reported.

  20. Quantitation of organophosphorus nerve agent metabolites in human urine using isotope dilution gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Driskell, W Jack; Shih, Ming; Needham, Larry L; Barr, Dana B

    2002-01-01

    An isotope dilution gas chromatography-tandem mass spectrometric (GC-MS-MS) method was developed for quantitating the urinary metabolites of the organophosphorus nerve agents sarin, soman, tabun (GA), VX, and GF. Urine samples were concentrated by codistillation with acetonitrile, derivatized by methylation with diazomethane, and analyzed by GC-MS-MS. The limits of detection were less than 4 microg/L for all the analytes except for the GA metabolite, which had a limit of detection of less than 20 microg/L.

  1. The role of liquid chromatography-tandem mass spectrometry in the clinical laboratory

    NARCIS (Netherlands)

    van den Ouweland, Johannes M. W.; Kema, Ido P.

    2012-01-01

    Liquid chromatography coupled to mass spectrometry (LC-MS/MS) is increasingly used as a routine methodology in clinical laboratories for the analysis of low molecular weight molecules. The high specificity in combination with high sensitivity and multi-analyte potential makes it an attractive comple

  2. Simultaneous determination of seven flavonoids in Epimedium by liquid chromatography-tandem mass spectrometry method

    Institute of Scientific and Technical Information of China (English)

    Cai Sheng Wu; Bao Lin Guo; Yu Xin Sheng; Jin Lan Zhang

    2008-01-01

    In this paper, a sensitive and specific liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method has been developed and validated for the identification and determination of seven flavonoids, namely epimedin A, epimedin B, epimedin C, icariin, sagittatoside B, 2"-0-rhamnosyl icariside II, and baohuoside I in Epimedium from different sources.

  3. Enantioselective simultaneous analysis of selected pharmaceuticals in environmental samples by ultrahigh performance supercritical fluid based chromatography tandem mass spectrometry.

    Science.gov (United States)

    Camacho-Muñoz, Dolores; Kasprzyk-Hordern, Barbara; Thomas, Kevin V

    2016-08-31

    In order to assess the true impact of each single enantiomer of pharmacologically active compounds (PACs) in the environment, highly efficient, fast and sensitive analytical methods are needed. For the first time this paper focuses on the use of ultrahigh performance supercritical fluid based chromatography coupled to a triple quadrupole mass spectrometer to develop multi-residue enantioselective methods for chiral PACs in environmental matrices. This technique exploits the advantages of supercritical fluid chromatography, ultrahigh performance liquid chromatography and mass spectrometry. Two coated modified 2.5 μm-polysaccharide-based chiral stationary phases were investigated: an amylose tris-3,5-dimethylphenylcarbamate column and a cellulose tris-3-chloro-4-methylphenylcarbamate column. The effect of different chromatographic variables on chiral recognition is highlighted. This novel approach resulted in the baseline resolution of 13 enantiomers PACs (aminorex, carprofen, chloramphenicol, 3-N-dechloroethylifosfamide, flurbiprofen, 2-hydroxyibuprofen, ifosfamide, imazalil, naproxen, ofloxacin, omeprazole, praziquantel and tetramisole) and partial resolution of 2 enantiomers PACs (ibuprofen and indoprofen) under fast-gradient conditions (supercritical fluid based chromatography coupled with tandem mass spectrometry.

  4. [Determination of pesticide residues from seed coating reagent in agricultural products using ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Chen, Yue; Wang, Jinhua; Lu, Xiaoyu; Wang, Wanchun; Huang, Mei; Xu, Chaoyi

    2008-11-01

    An ultra performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) has been developed for the simultaneous determination of eight pesticide residues from seed coating in fruits, vegetable and grain. The sample was extracted by methanol-water (1:1, v/v) and determined by ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry in positive mode (ESI+) and multiple reaction monitoring (MRM) mode. The UPLC analyses were performed on an Acquity UPLC C18 column with gradient eluation. The utility of the method was demonstrated by the analysis of crude extracts, with no sample clean up, from soybean. The linear range was 1 - 200 microg/L. The correlation coefficients (r) were under 0.997. The average recoveries of eight pesticides in samples (from 0.006 to 1.2 mg/kg) ranged from 60% to 110%, and the relative standard deviations (RSDs) were less than 10%. The results indicate that the method is easier, faster, more sensitive, and suitable for the qualitative and quantitative confirmation of pesticide residues from seed coating reagent in fruit, vegetable and grain samples.

  5. High Performance Liquid Chromatography Tandem Mass Spectrometry Measurement of Bimatoprost, Latanoprost and Travoprost in Eyelash Enhancing Cosmetic Serums

    Directory of Open Access Journals (Sweden)

    Emilia Marchei

    2016-02-01

    Full Text Available Most common prostaglandin analogs, bimatoprost, latanoprost and travoprost, are licensed for the reduction of elevated intraocular pressure in patients with open angle glaucoma and ocular hypertension, but their non approved use as eyelash enhancers is becoming popular, especially in patients with eyelashes hypotrichosis. A fast and sensitive high performance liquid chromatography tandem mass spectrometry method was developed for the measurement of bimatoprost, latanoprost and travoprost in cosmetic serums freely web-sold to increase eyelash length, thickness and darkness. The analytes and the internal standard (reserpine were separated by reversed phase chromatography with 5 mM ammonium acetate with 0.02% formic acid (mobile phase A and 5 mM ammonium acetate in acetonitrile/water (95/5; v/v with 0.02% formic acid (mobile phase B by gradient elution and detected with tandem mass spectrometry operated in multiple reaction monitoring mode. Linearity between 1 and 500 μg/g shows good correlation coefficients (r2 = 0.99 for all substances. Analytical recovery of analytes under investigation were always higher than 90% and intra-assay and inter-assay precision and accuracy always better than 11%. This method was successfully applied to analyze cosmetic serums freely sold on the Internet websites.

  6. Improving quantitative precision and throughput by reducing calibrator use in liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Rule, Geoffrey S., E-mail: geoffrey.s.rule@aruplab.com [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Rockwood, Alan L. [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Department of Pathology, University of Utah School of Medicine, 2100 Jones Medical Research Bldg., Salt Lake City, UT 84132 (United States)

    2016-05-05

    To improve efficiency in our mass spectrometry laboratories we have made efforts to reduce the number of calibration standards utilized for quantitation over time. We often analyze three or more batches of 96 samples per day, on a single instrument, for a number of assays. With a conventional calibration scheme at six concentration levels this amounts to more than 5000 calibration points per year. Modern LC-tandem mass spectrometric instrumentation is extremely rugged however, and isotopically labelled internal standards are widely available. This made us consider whether alternative calibration strategies could be utilized to reduce the number of calibration standards analyzed while still retaining high precision and accurate quantitation. Here we demonstrate how, by utilizing a single calibration point in each sample batch, and using the resulting response factor (RF) to update an existing, historical response factor (HRF), we are able to obtain improved precision over a conventional multipoint calibration approach, as judged by quality control samples. The laboratory component of this study was conducted with an existing LC tandem mass spectrometric method for three androgen analytes in our production laboratory. Using examples from both simulated and laboratory data we illustrate several aspects of our single point alternative calibration strategy and compare it with a conventional, multipoint calibration approach. We conclude that both the cost and burden of preparing multiple calibration standards with every batch of samples can be reduced while at the same time maintaining, or even improving, analytical quality. - Highlights: • Use of a weighted single point calibration approach improves quantitative precision. • A weighted response factor approach incorporates historical calibration information. • Several scenarios are discussed with regard to their influence on quantitation.

  7. Morphine brain pharmacokinetics at very low concentrations studied with accelerator mass spectrometry and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Sadiq, Muhammad Waqas; Salehpour, Mehran; Forsgard, Niklas; Possnert, Göran; Hammarlund-Udenaes, Margareta

    2011-02-01

    Morphine has been predicted to show nonlinear blood-brain barrier transport at lower concentrations. In this study, we investigated the possibility of separating active influx of morphine from its efflux by using very low morphine concentrations and compared accelerator mass spectrometry (AMS) with liquid chromatography-tandem mass spectrometry (LC-MS/MS) as a method for analyzing microdialysis samples. A 10-min bolus infusion of morphine, followed by a constant-rate infusion, was given to male rats (n = 6) to achieve high (250 ng/ml), medium (50 ng/ml), and low (10 ng/ml) steady-state plasma concentrations. An additional rat received infusions to achieve low (10 ng/ml), very low (2 ng/ml), and ultralow (0.4 ng/ml) concentrations. Unbound morphine concentrations from brain extracellular fluid and blood were sampled by microdialysis and analyzed by LC-MS/MS and AMS. The average partition coefficient for unbound drug (K(p,uu)) values for the low and medium steady-state levels were 0.22 ± 0.08 and 0.21 ± 0.05, respectively, when measured by AMS [not significant (NS); p = 0.5]. For the medium and high steady-state levels, K(p,uu) values were 0.24 ± 0.05 and 0.26 ± 0.05, respectively, when measured by LC-MS/MS (NS; p = 0.2). For the low, very low, and ultralow steady-state levels, K(p,uu) values were 0.16 ± 0.01, 0.16 ± 0.02, and 0.18 ± 0.03, respectively, when measured by AMS. The medium-concentration K(p,uu) values were, on average, 16% lower when measured by AMS than by LC-MS/MS. There were no significant changes in K(p,uu) over a 625-fold concentration range (0.4-250 ng/ml). It was not possible to separate active uptake transport from active efflux using these low concentrations. The two analytical methods provided indistinguishable results for plasma concentrations but differed by up to 38% for microdialysis samples; however, this difference did not affect our conclusions.

  8. Identification of monomenthyl succinate, monomenthyl glutarate, and dimenthyl glutarate in nature by high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Hiserodt, Richard D; Adedeji, Jide; John, T V; Dewis, Mark L

    2004-06-01

    Menthol, menthone, and other natural compounds provide a cooling effect and a minty flavor and have found wide application in chewing gum and oral care products. Monomenthyl succinate, monomenthyl glutarate, and dimenthyl glutarate provide a cooling effect without the burning sensation associated with menthol. Additionally, because they do not have a distinct flavor, they can be used in applications other than mint flavors. Because these menthyl esters have not been reported in nature, we undertook to identify a natural source for these cooling compounds. Using high performance liquid chromatography-tandem mass spectrometry, monomenthyl succinate was identified in Lycium barbarum and Mentha piperita, and monomenthyl glutarate and dimenthyl glutarate were identified in Litchi chinesis. The identifications were based on the correlation of mass spectrometric and chromatographic retention time data for the menthyl esters in the extracts with authentic standards which resulted in a 99.980% confidence in the identifications.

  9. Characterization of isomeric VX nerve agent adducts on albumin in human plasma using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Saeidian, Hamid; Mirkhani, Valioallah; Mousavi Faraz, Sajjad; Taghi Naseri, Mohammad; Babri, Mehran

    2015-01-01

    This study includes the characterization of isomeric VX organophosphorus adducts on albumin in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). VX or its structural isomers were spiked into a vial containing plasma in order to obtain phosphorylated albumin. After pronase and trypsin digestion, the resulting solutions were analyzed to confirm adduct formation with the amino acid tyrosine on the albumin in human plasma. The LC-MS/MS experiments show that VX and its isomers can be attached to tyrosine on the albumin in human blood. Mass spectrometric studies revealed some interesting fragmentation pathways during the ionization process, such as ethylene, formic acid and ammonia elimination and an intermolecular electrophilic aromatic substitution reaction. The proposed mechanisms for the formation of the fragments were confirmed through the analysis of fragments of deuterated adducts.

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

    OpenAIRE

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

    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...

  11. Isocratic Solid Phase Extraction-Liquid Chromatography (SPE-LC) Interfaced to High-Performance Tandem Mass Spectrometry for Rapid Protein Identification

    DEFF Research Database (Denmark)

    Hørning, Ole B; Kjeldsen, Frank; Theodorsen, Søren

    2008-01-01

    the isocratic solid phase extraction-liquid chromatography (SPE-LC) technology for rapid separation ( approximately 8 min) of simple peptide samples. We now extend these studies to demonstrate the potential of SPE-LC separation in combination with a hybrid linear ion trap-Orbitrap tandem mass spectrometer......Reversed-phase liquid chromatography interfaced to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) allows analysis of very complex peptide mixtures at great sensitivity, but it can be very time-consuming, typically using 60 min, or more, per sample analysis. We recently introduced...

  12. Highly specific quantification of ergotamine in urine, blood, and hair samples by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

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

    2007-06-01

    Ergotamine has been used for therapeutic purposes since the 1950s, usually to treat vascular headache. It is highly toxic and in large, repeated doses can produce all the symptoms of ergot poisoning. A selective and sensitive method, based on liquid chromatography-tandem mass spectrometry (LC-MS2), has been developed for quantifying ergotamine in biological fluids with use of a quick and easy sample preparation. Ergotamine and the internal standard, trideuterated lysergic acid diethylamide, were extracted from human urine, blood, and hair by means of liquid-liquid extraction at alkaline pH. Gradient elution on a cyanopropyl column was used for chromatographic separation. Positive ion electrospray ionization and tandem mass spectrometry determination by collision-induced dissociation were performed in an ion trap mass spectrometer. The method was validated and successfully applied to a case of iatrogenic ergotism resulting from the intake of ergotamine tartrate for treating headache. For the first time, ergotamine was identified and quantified in hair. The ergotamine concentrations measured were 320 pg/mL in blood, 100 pg/mL in urine, 24 pg/mg in proximal hair, and 15 pg/mg in distal hair.

  13. 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.

  14. Determination of Metformin in Human Plasma by Liquid Chromatography-tandem Mass Spectrometric Assay

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; WANG Ying-wu; GU Jing-kai; WU Yi; WANG Yan

    2005-01-01

    @@ Introduction Metformin (1,1-dimethylbiguanide) (Fig. 1) is an oral anti-hyperglycemic agent used in the treatment of non-insulin-dependent diabetes mellitus (type Ⅱ). Owing to its weight-decreasing and serum lipid-normalizing effects, it is especially recommended for obese patients[1,2] Various analytical methods have been described for the measurement of metformin in biological fluids, including gas chromatography(GC)[3-5], capillary electrophoresis (CE)[6] and HPLC[7~16]with UV detection[7-12,17] HPLC-Mass spectrometry (LC/APCIMS/MS ) offers an attractive alternative to HPLC[18].

  15. Determination of muscimol and ibotenic acid in Amanita mushrooms by high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Tsujikawa, Kenji; Kuwayama, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Iwata, Yuko; Inoue, Hiroyuki; Yoshida, Takemi; Kishi, Tohru

    2007-06-01

    A reliable analytical method was developed for the quantification and identification of muscimol (MUS) and ibotenic acid (IBO), the toxic constituents of Amanita muscaria and Amanita pantherina. MUS and IBO were extracted from mushrooms by aqueous methanol and derivatized with dansyl chloride (DNS-Cl). After extraction with ethyl acetate and evaporation of the solvent, the residue was ethylated with 1.25 M hydrogen chloride in ethanol. The resulting derivatives were quantified by high-performance liquid chromatography with UV detection and identified by liquid chromatography electrospray ionization tandem mass spectrometry. Calibration curves were linear in the range of 25-2500 ppm for MUS and 40-2500 ppm for IBO, respectively. This method was successfully applied to identify and quantify MUS and IBO in Amanita mushrooms naturally grown and circulated in the drug market.

  16. Determination of doxepin and desmethyldoxepin in human plasma using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Badenhorst, D; Sutherland, F C; de Jager, A D; Scanes, T; Hundt, H K; Swart, K J; Hundt, A F

    2000-05-26

    A sensitive method for the simultaneous determination of doxepin and its active metabolite desmethyldoxepin in plasma was established, using high-performance liquid chromatographic separation with tandem mass spectrometric detection. The samples were extracted with hexane-isoamyl alcohol, separated on a Phenomenex Luna C18 5 microm, 150x2.1 mm column with a mobile phase consisting of methanol-water-formic acid (600:400:0.5, v/v) at a flow-rate of 0.25 ml/min. Detection was achieved by a Perkin-Elmer API 2000 mass spectrometer at unit resolution in multiple reaction monitoring mode monitoring the transition of the protonated molecular ions m/z 280.2, 266.2 and 250.1 to the product ions m/z 107.1, 107.1 and 191.0 for analyte, metabolite and internal standard (benzoctamine-HCl), respectively. TurbolonSpray ionisation was used for ion production. The mean recovery for doxepin and desmethyldoxepin was 90% and 75%, respectively, with a lower limit of quantification at 0.320 ng/ml and 0.178 ng/ml for the analyte and its metabolite, respectively, using 0.5 ml plasma for extraction. This is the first assay method described for the simultaneous determination of doxepin and desmethyldoxepin in plasma using LC-MS-MS. The method is sensitive enough to be used in drug bioavailability studies with doxepin.

  17. Determination of alkylphenol and alkylphenolethoxylates in biota by liquid chromatography with detection by tandem mass spectrometry and fluorescence spectroscopy

    Science.gov (United States)

    Schmitz-Afonso, I.; Loyo-Rosales, J.E.; de la Paz Aviles, M.; Rattner, B.A.; Rice, C.P.

    2003-01-01

    A quantitative method for the simultaneous determination of octylphenol, nonylphenol and the corresponding ethoxylates (1 to 5) in biota is presented. Extraction methods were developed for egg and fish matrices based on accelerated solvent extraction followed by a solid-phase extraction cleanup, using octadecylsilica or aminopropyl cartridges. Identification and quantitation were accomplished by liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) and compared to the traditional liquid chromatography with fluorescence spectroscopy detection. LC-MS-MS provides high sensitivity and specificity required for these complex matrices and an accurate quantitation with the use of 13C-labeled internal standards. Quantitation limits by LC-MS-MS ranged from 4 to 12 ng/g in eggs, and from 6 to 22 ng/g in fish samples. These methods were successfully applied to osprey eggs from the Chesapeake Bay and fish from the Great Lakes area. Total levels found in osprey egg samples were up to 18 ng/g wet mass and as high as 8.2 ug/g wet mass in the fish samples.

  18. 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

  19. High-performance liquid chromatography-electrospray ionization tandem mass spectrometry for metabolism study of timosaponin AIII.

    Science.gov (United States)

    Jia, Yao; Wu, Bin; Fan, Mingsong; Wang, Jinhui; Huang, Jian; Huang, Chenggang

    2014-01-01

    A sensitive method based on high-performance liquid chromatography-electrospray ionization tandem mass spectrometry was developed for the determination of timosaponin AIII (TA3) and its in vivo and in vitro metabolites. The rat plasma, urine, feces and tissue samples were collected after oral administration of TA3 at a single dose of 300 mg/kg. TA3 was incubated into artificial gastric juice and artificial intestinal juice. The in vivo and in vitro samples were purified by using liquid-liquid extraction. The structures of metabolites were elucidated by comparing their molecular weights, retention times and tandem mass spectrometric spectra with those of the parent drug. As a result, four metabolites (deglycosylated TA3, two hydroxylated TA3 and timosaponin BII) and the parent drug were found in in vivo and in vitro samples. In addition to the parent drug, one, one and two metabolites were identified in heart, urine and feces, respectively. Only the parent drug was detected in plasma, liver and kidney. One hydroxylation metabolite and TA3 were identified from incubation samples with AGJ, whereas two hydroxylation metabolites and TA3 were detected from the incubation with AIJ. This is the first systematic metabolism study of TA3. The biotransformation pathways of TA3 primarily included deglycosylation, hydroxylation and glycosylation.

  20. Hydrophilic interaction liquid chromatography-electrospray ionization-tandem mass spectrometry of a complex mixture of native and oxidized phospholipids.

    Science.gov (United States)

    Losito, I; Facchini, L; Diomede, S; Conte, E; Megli, F M; Cataldi, T R I; Palmisano, F

    2015-11-27

    A mixture of native and oxidized phospholipids (PLs), generated by the soybean lipoxygenase type V-catalyzed partial oxidation of a lipid extract obtained from human platelets, was analyzed by Hydrophilic Interaction Liquid Chromatography-ElectroSpray Ionization-Tandem Mass Spectrometry (HILIC-ESI-MS/MS). The complexity of the resulting mixture was remarkable, considering that the starting lipid extract, containing (as demonstrated in a previous study) about 130 native PLs, was enriched with enzymatically generated hydroperoxylated derivatives and chemically generated hydroxylated forms of PLs bearing polyunsaturated side chains. Nonetheless, the described analytical approach proved to be very powerful; indeed, focusing on phosphatidylcolines (PCs), the most abundant PL class in human platelets, about fifty different native/oxidized species could be identified in a single HILIC-ESI-MS/MS run. Low-energy collision induced dissociation tandem MS (CID-MS/MS) experiments on chromatographically separated species showed single neutral losses of H2O2 and H2O to be typical fragmentation pathways of hydroperoxylated PCs, whereas a single H2O loss was observed for hydroxylated ones. Moreover, diagnostic losses of n-hexanal or n-pentanol were exploited to recognize PCs hydroperoxylated on the last but five carbon atom of a ɷ-6 polyunsaturated side chain. Despite the low resolution of the 3D ion trap mass analyzer used, the described HILIC-ESI-MS/MS approach appears very promising for the identification of oxidized lipids in oxidatively stressed complex biological systems.

  1. Enantioselective determination of protein amino acids in fertilizers by liquid chromatography-tandem mass spectrometry on chiral teicoplanin stationary phase.

    Science.gov (United States)

    Taujenis, Lukas; Olšauskaitė, Vilma; Padarauskas, Audrius

    2014-11-19

    High-performance liquid chromatography on a glycopeptide antibiotic teicoplanin-based chiral stationary phase coupled with tandem mass spectrometry was developed for fast and reliable enantioseparation and determination of protein amino acids in hydrolyzed fertilizer samples. The effect of the mobile phase parameters (type and content of organic modifier and pH) and the column temperature on the enantioselectivity was investigated. Under optimized conditions, the majority (15 of 19) of d/l-amino acid pairs were resolved with a resolution factor (Rs) higher than 1.5 with a run time of 15 min. A triple quadrupole tandem mass spectrometer operating in multiple reaction monitoring mode with an electrospray ionization (ESI) ion source was employed for detection. The method was validated in terms of linearity, limits of detection, limits of quantitation, precision, and accuracy. Linear responses were obtained with determination coefficients higher than 0.998 for all analytes, and limits of detection were from 0.04 to 0.24 μg/mL. Sample spike/recovery experiments gave recovery values ranging from 73% for d-threonine to 116% for L-tryptophan. Relative standard deviations for inter- and intraday precision experiments were lower than 21.7%. The developed method was successfully applied for determination of the free amino acid enantiomers in five commercially available hydrolyzed protein fertilizer samples.

  2. [Simultaneous determination of four alkaloids in Corydalis decumbens (Thunb.) Pers. by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Shen, Yan; Han, Chao; Liu, Cuiping; Zhou, Yongfang; Xia, Biqi; Zhu, Zhenou; Liu, Aili

    2011-02-01

    A method for the analysis of 4 alkaloids in Corydalis decumbens (Thunb.) Pers. was developed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-MS/MS). The sample was extracted in methanol by ultrasonic, filtered and diluted with methanol for further analysis. The analysis was performed on a C18 column (150 mm x 2.1 mm, 3.5 microm) using a gradient elution program with the mobile phase of 0.2% acetic acid solution and acetonitrile. The analyte was determined by an electrospray ionization tandem mass spectrometry in multiple reactions monitoring (MRM) mode. The qualitative and quantitative analyses were based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions of the analyte. The limits of detection (LODs) for 4 alkaloids were in the range of 0.02 - 0.2 microg/L, and the limits of quantification (LOQs) were in the range of 0.07 - 0.66 microg/L. The average recoveries were in the range of 93.6% - 103.5% for 4 alkaloids with the relative standard deviations below 3.8%. This method is reliable, sensitive and reproducible, and it can be used for the quality control of Corydalis decumbens (Thunb.) Pers. sample.

  3. 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.

  4. How to identify and discriminate between the methyl quinates of chlorogenic acids by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jaiswal, Rakesh; Kuhnert, Nikolai

    2011-03-01

    The methyl esters of chlorogenic acids, methyl quinates, are widely distributed in plant materials and frequently appear as extraction artifacts in plant samples. This is the first time when liquid chromatography-tandem mass spectrometry methods have been used for the identification and characterization of the methyl quinates. For this purpose, methyl quinates of mono caffeoylquinic acids and mono feruloylquinic acids were synthesized as authentic standards. The methyl quinates of mono and diacyl chlorogenic acids have shown characteristic fragmentation pattern in their tandem mass spectra. MS(n + 1) spectra of the methyl quinates of diacyl chlorogenic acids were identical to MS(n) spectra of mono acyl derivatives. These quinates do not produce any methyl quinate peak at m/z 205 if compared with quinic acid peak at m/z 191 in negative ion mode. In the MS(n) spectra of these quinates, cinnamic acid part or cinnamoyl part was detected as a base peak in negative ion mode. The retention time, order of elution and fragmentation pattern were completely different if compared with LC-MS(n) methods developed for chlorogenic acids. These LC-MS(n) methods have been applied for the identification and regioisomeric characterization of the methyl quinates of chlorogenic acids in maté tea and woodruff (Galium odoratum). Two methyl caffeoylquinates (2 and 4) were identified as methyl 3-caffeoylquinate and methyl 5-caffeoylquinate.

  5. Utilization of micellar electrokinetic chromatography-tandem mass spectrometry employed volatile micellar phase in the analysis of cathinone designer drugs.

    Science.gov (United States)

    Švidrnoch, Martin; Lněníčková, Ludmila; Válka, Ivo; Ondra, Peter; Maier, Vítězslav

    2014-08-22

    A micellar electrokinetic chromatography method with tandem mass spectrometry has been developed for the selective separation, identification and determination of twelve new designer drugs from the group of synthetic cathinones. Ammonium salt of perfluorooctanoic acid at various concentrations as a volatile background electrolyte (BGE) to create micellar phase was studied for separation of selected synthetic cathinones with direct tandem mass spectrometry without significant loss of detection sensitivity. The optimized BGE contained 100 mM perfluorooctanoic acid with 200 mM ammonium hydroxide providing acceptable resolution of studied drugs in the MEKC step. In order to minimize interferences with matrix components and to preconcentrate target analytes, solid phase extraction was introduced as a clean-up step. The method was linear in the concentration range of 10-5000 ng mL(-1) and the limits of detection were in the range of 10-78 ng mL(-1). The method was demonstrated to be specific, sensitive, and reliable for the systematic toxicological analysis of these derivatives in urine samples.

  6. Quantitative Thin-Layer Chromatography/Mass Spectrometry Analysis of Caffeine Using a Surface Sampling Probe Electrospray Ionization Tandem Mass Spectrometry System

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Michael J [ORNL; Deibel, Michael A. [Earlham College; Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL

    2005-01-01

    Quantitative determination of caffeine on reversed-phase C8 thin-layer chromatography plates using a surface sampling electrospray ionization system with tandem mass spectrometry detection is reported. The thin-layer chromatography/electrospray tandem mass spectrometry method employed a deuterium-labeled caffeine internal standard and selected reaction monitoring detection. Up to nine parallel caffeine bands on a single plate were sampled in a single surface scanning experiment requiring 35 min at a surface scan rate of 44 {mu}m/s. A reversed-phase HPLC/UV caffeine assay was developed in parallel to assess the mass spectrometry method performance. Limits of detection for the HPLC/UV and thin-layer chromatography/electrospray tandem mass spectrometry methods determined from the calibration curve statistics were 0.20 ng injected (0.50 {mu}L) and 1.0 ng spotted on the plate, respectively. Spike recoveries with standards and real samples ranged between 97 and 106% for both methods. The caffeine content of three diet soft drinks (Diet Coke, Diet Cherry Coke, Diet Pepsi) and three diet sport drinks (Diet Turbo Tea, Speed Stack Grape, Speed Stack Fruit Punch) was measured. The HPLC/UV and mass spectrometry determinations were in general agreement, and these values were consistent with the quoted values for two of the three diet colas. In the case of Diet Cherry Coke and the diet sports drinks, the determined caffeine amounts using both methods were consistently higher (by 8% or more) than the literature values.

  7. Comparison of gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry with electron ionization for determination of N-nitrosamines in environmental water.

    Science.gov (United States)

    Chen, Wenwen; Li, Xiaoshui; Huang, Huanfang; Zhu, Xuetao; Jiang, Xiaoyu; Zhang, Yuan; Cen, Kuang; Zhao, Lunshan; Liu, Xiuli; Qi, Shihua

    2017-02-01

    N-nitrosamines are trace organic contaminants of environmental concern when present in groundwater and river water due to their potent carcinogenicity. Therefore, N-nitrosamine analysis is increasingly in demand. Gas chromatography-mass spectrometry (GC-MS) and GC-tandem mass spectrometry (GC-MS/MS), both with electron ionization (EI), were compared for analysis of nine N-nitrosamines extracted from environmental water matrices. A total of 20 fishpond water, river water, and groundwater samples from Sihui and Shunde, China were collected for a survey of N-nitrosamine concentrations in real water samples. Various solid-phase extraction (SPE) conditions and GC conditions were first examined for the pre-concentration and separation steps. The analysis of N-nitrosamines in environmental waters demonstrated that their quantification with GC-MS poses a challenge due to the occurrence of co-eluting interferences. Conversely, the use of GC-MS/MS increased selectivity because of the fragmentation generated from precursor ions in the 'multiple reaction monitoring' (MRM) mode, which is expected to extract target analytes from the environmental water matrix. Thus, the high performance of GC-MS/MS with EI was used to quantify nine N-nitrosamines in environmental waters with detection limits of 1.1-3.1 ng L(-1). N-nitrosodimethylamine (NDMA) concentrations were in the range of N.D. to 258 ng L(-1). Furthermore, other N-nitrosamines, except N-nitrosomethylethylamine (NMEA), N-nitroso-di-n-propylamine (NDPA) and N-nitrosopiperidine (NPIP), were also detected. Our findings suggest that GC-MS/MS with EI would be widely applicable in identifying N-nitrosamines in environmental waters and can be used for routine monitoring of these chemicals.

  8. Pharmacokinetics of HZ08 in rats by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Weng, Jing-yan; Song, Min; Hang, Tai-jun; Huang, Wen-long; Du, Yun

    2007-09-01

    A selective and sensitive liquid chromatographic method coupled with ion spray tandem mass spectrometry detection (LC-MS/MS) was developed for the determination and pharmacokinetic study of N-cyano-1-[(3,4-dimethoxyphenyl)methyl]-3,4-dihydro-6,7-dimethoxy-N'-octyl-2(1H)-isoquinoline-carboximidamide (HZ08, a candidate reversing agent for multidrug resistance of cancer) liposome injection in rat plasma. The analyte was extracted from plasma using liquid-liquid extraction by methyl tert-butyl ether with drotaverine as internal standard. The chromatographic separation was performed on a Kromasil-C18 column (150 mm x 4.6 mm, i.d., 5 microm) with gradient elution. The tandem mass detection was made with electrospray ionization in positive ion selected reaction monitoring mode with argon collision-induced dissociation. The ion transitions were m/z 523.1 to 342.1 for HZ08 at 27eV and m/z 398.1 to 326.1 at 35eV for the internal standard, respectively. The determination was validated to be accurate and precise for the analysis in the concentration range of 5-10,000 ng/ml for HZ08 with the lower limit of detection (LOD) being 1 ng/ml, when 0.1 ml of rat plasma sample was processed. The main pharmacokinetic parameters found for HZ08 after intravenous (i.v.) administration of its liposome injection at doses of 2, 4 and 8 mg/kg were as follows: C(max) (4511+/-681), (5553+/-1600) and (6444+/-950) ng/ml, T(max) (0.033+/-0), (0.056+/-0.048) and (0.033+/-0) h, t(1/2) (1.75+/-0.19), (1.63+/-0.12) and (1.56+/-0.18) h, AUC(0-6) (899+/-112), (1238+/-190) and (1707+/-307) h ng/ml, AUC(0-infinity) (917+/-110), (1256+/-189) and (1723+/-306) h ng/ml, MRT (1.14+/-0.21), (1.01+/-0.13) and (1.16+/-0.17) h, CL (2.90+/-0.15), (3.01+/-0.74) and (4.11+/-0.59)l/h/kg, respectively. The plasma concentration-time profiles of HZ08 were best fitted with two-compartment models. Linear pharmacokinetics was found for HZ08 in rats after intravenous administration of the liposome injection.

  9. Determination of seven bisphenol analogues in reed and Callitrichaceae by ultra performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lu, Libin; Yang, Yunjia; Zhang, Jing; Shao, Bing

    2014-03-15

    An analytical procedure was developed to simultaneously determine bisphenol S, bisphenol F, bisphenol B, bisphenol A, bisphenol AF, tetrachlorobisphenol A, and tetrabromobisphenol A in reed and Callitrichaceae. Homogenized samples were extracted with acetonitrile and purified using an ENVI™-Carb cartridge followed by an NH2 cartridge. The analytes were separated and quantified by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The recoveries at three fortified levels in reed and Callitrichaceae were 57-108% and 68-106%, respectively, with relative standard deviations of no more than 15% (n=6). The method limits of quantification and detection for the seven bisphenol analogues were 0.005-0.500μg/kg and 0.002-0.150μg/kg, respectively. This method was used to analyze the seven compounds in ten reed and Callitrichaceae samples collected from Zhejiang, China.

  10. Rapid determination of vitamin D₃ in milk-based infant formulas by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kwak, Byung-Man; Jeong, In-Seek; Lee, Moon-Seok; Ahn, Jang-Hyuk; Park, Jong-Su

    2014-12-15

    A rapid and simple sample preparation method for vitamin D3 (cholecalciferol) was developed for emulsified dairy products such as milk-based infant formulas. A sample was mixed in a 50 mL centrifuge tube with the same amount of water and isopropyl alcohol to achieve chemical extraction. Ammonium sulfate was used to induce phase separation. No-heating saponification was performed in the sample tube by adding KOH, NaCl, and NH3. Vitamin D3 was then separated and quantified using liquid chromatography-tandem mass spectrometry. The results for added recovery tests were in the range 93.11-110.65%, with relative standard deviations between 2.66% and 2.93%. The results, compared to those obtained using a certified reference material (SRM 1849a), were within the range of the certificated values. This method could be implemented in many laboratories that require time and labour saving.

  11. Determination of salbutamol and salbutamol glucuronide in human urine by means of liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Mareck, Ute; Guddat, Sven; Schwenke, Anne;

    2012-01-01

    The determination of salbutamol and its glucuronide in human urine following the inhalative and oral administration of therapeutic doses of salbutamol preparations was performed by means of direct urine injection utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) and employing d(3......)-salbutamol and d(3)-salbutamol glucuronide as internal standards. Unconjugated salbutamol was detected in all administration study urine samples. Salbutamol concentrations following inhalation were commonly (99%) below 1000 ng/ml whereas values after oral administration frequently (48%) exceeded...... this threshold. While salbutamol glucuronide was not detected in urine samples collected after inhalation of the drug, 26 out of 82 specimens obtained after oral application contained salbutamol glucuronide with a peak value of 63 ng/ml. The percentage of salbutamol glucuronide compared to unconjugated...

  12. 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.

  13. In vivo and in vitro metabolism of aspirin eugenol ester in dog by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Shen, Youming; Liu, Xiwang; Yang, Yajun; Li, Jianyong; Ma, Ning; Li, Bing

    2015-01-01

    Aspirin eugenol ester (AEE) is a promising drug candidate for treatment of inflammation, pain and fever and prevention of cardiovascular diseases with fewer side effects than its precursor, aspirin. Investigation into its metabolic process in target animal species will help to illustrate its mechanism of action and to establish its residual mark compound to formulate its dosage. Six beagle dogs were orally given a dose of 20 mg kg(-1) of AEE and one dog was used to prepare blank liver microsomes. Their liver microsomes were prepared for in vitro study and their plasma and urine were collected for in vivo metabolic analysis using liquid chromatography tandem mass spectrometry. In this study we identified 10 metabolites, M1, M2, M3, M4, M5 in phase I and M6, M7, M8, M9, M10 in phase II. Based on the metabolites of AEE, the pathways of AEE metabolism in dog were demonstrated.

  14. 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.

  15. Modernization of Chinese herbal compound and the high performance liquid chromatography tandem mass spectrometry (HPLC-MS)

    Institute of Scientific and Technical Information of China (English)

    LI Wen-lan; SUN Zhi; DU Juan

    2008-01-01

    Chinese herbal compound is playing an important role on curing human diseases. And it has been a trend that Chinese herbal compound is being used all over the world in 21 century. However, our Chinese herbal compound is facing serious challenge for the lack of canonical system of quality criterion for Chinese herbal compound so it has been a urgent problem to set up the quality control standards and reveal therapeutic basis of Chinese herbal compound. In order to give full play to the advantages of Chinese herbal compound, modern scientific and technological is used to research of Chinese herbal compound, especially the high performance liquid chromatography tandem mass spectrometry(HPLC-MS), because it is high sensitive, rapid, and obtain more information. It is very necessary that HPLC-MS is uesed to elucidate the effective components of basic substances of Chinese Herbal Compound, and endow traditional Chinese medicine with modern scientific connotation.

  16. Quantitative determination of five ergot alkaloids in rye flour by liquid chromatography-electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Mohamed, Rayane; Gremaud, Eric; Richoz-Payot, Janique; Tabet, Jean-Claude; Guy, Philippe A

    2006-05-05

    A confirmatory method for detecting five ergot alkaloids, ergocristine, ergotamine, ergonovine, ergocornine and alpha-ergokryptine, in rye flour is described using high performance liquid chromatography coupled to tandem mass spectrometry detection by monitoring two transition reactions per analyte. The procedure entails a liquid-liquid extraction followed by a clean-up step using a C18 solid-phase extraction (SPE) cartridge. An analogue compound, methysergide hydrogen maleinate, was used to assess both repeatability sample preparation and potential MS response fluctuations. The method was fully validated according to the European Union (EU) criteria. Detection and quantification limits of all analytes were calculated ranging from 7 to 11 microg/kg and from 23 to 37 microg/kg, respectively. Fifteen rye flour samples were investigated with the newly developed method, and none of them were above the current Swiss limits of 200mg/kg for total ergot alkaloids.

  17. Liquid chromatography tandem mass spectrometry applied to quantitation of the organophosphorus nerve agent VX in microdialysates from blood probes.

    Science.gov (United States)

    Stubbs, S J; Read, R W

    2010-05-15

    VX (O-ethyl-S-[2(di-isopropylamino)ethyl] methylphosphonothiolate) is a low volatility organophosphorus (OP) nerve agent and therefore the most likely route of exposure is via percutaneous absorption. Microdialysis has been used as a tool to study percutaneous poisoning by VX in the anesthetised guinea pig. A liquid chromatography tandem mass spectrometry (LC-MS-MS) method using positive electrospray ionisation (ESI) was used to quantitate VX in microdialysate samples collected from microdialysis probes, implanted into a blood vessel of anesthetised guinea pigs. The method resulted from modification of a LC-MS-MS method previously developed for the analysis of dermal microdialysates. Modification increased the sensitivity of the method, allowing quantitation of the trace levels of VX in blood microdialysates, over the range 0.002-1 ng/ml, with linear calibration. Quantitative results have been used to determine the time course of VX concentrations in the blood of guinea pigs following percutaneous poisoning.

  18. Determination of Six Pyrazole Fungicides in Grape Wine by Solid-Phase Extraction and Gas Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Shen, Yan; Li, Zhou; Ma, Qiang; Wang, Chuanxian; Chen, Xiangzhun; Miao, Qian; Han, Chao

    2016-05-18

    A gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for the first simultaneous identification and quantification of six pyrazole fungicides (furametpyr, rabenzazole, fluxapyroxad, penflufen, bixafen, and isopyrazam) in grape wine samples. The grape wine samples were first diluted with water, then purified by solid-phase extraction, and finally examined by GC-MS/MS in multiple reaction monitoring (MRM) mode. Matrix-matched calibration curves were used to correct the matrix effects. The limits of quantification (LOQs), calculated as 10 times the standard deviation, were 0.2-0.8 μg kg(-1) for the six pyrazole fungicides. The average recoveries were in the range of 74.3-94.5%, with relative standard deviations (RSDs) below 5.8%, measured at three concentration levels. The proposed method is suitable for the simultaneous determination of six pyrazole fungicides in grape wine samples.

  19. Improved analysis of vitamin D metabolites in plasma using liquid chromatography tandem mass spectrometry, and its application to cardiovascular research.

    Science.gov (United States)

    Sandhu, Jatinderpal K; Auluck, Janica; Ng, Leong L; Jones, Donald J L

    2014-06-01

    The accurate and specific measurement of vitamin D is increasingly important for determining the role of vitamin D in the pathogenesis of disease. Liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) has increasingly become the analytical modality of choice for the analysis of vitamin D. There are many advantages to using LC/MS/MS, such as high specificity and sensitivity to help distinguish the isomers of vitamin D. This rapid method, modified from a Waters Corporation application note, consists of minimal sample manipulation using liquid-liquid extraction and incorporates an internal standard. The supernatant is dried down and injected onto an ultra-high-performance liquid chromatography/electrospray ionization tandem mass spectrometer. The total analysis time is 10 min per injection, enabling high throughput of samples. This method also incorporates two commercial quality control standards to provide a robust system with acceptable coefficient of variation. The analysis of control and heart failure plasma samples showed significant differences in the levels of vitamin D3 between these two groups; however, in the control group, there were individuals who were vitamin D deficient. Overall, the vitamin D3 levels were higher in control samples than in heart failure individuals. As expected, vitamin D2 levels were not observed in many of the samples analysed. This modified method is quick and incorporates an internal standard to allow for any loss in the extraction procedure. The method also includes quality control samples to enable assay standardization. The assay involves inexpensive pre-sample clean-up, aiding high throughput, which is important in many laboratories.

  20. Characterization of polysorbate 85, a nonionic surfactant, by liquid chromatography vs. ion mobility separation coupled with tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Solak Erdem, Nilüfer; Alawani, Nadrah; Wesdemiotis, Chrys, E-mail: wesdemiotis@uakron.edu

    2014-01-15

    Graphical abstract: -- Highlights: •Liquid chromatography (LC) separates amphiphilic blends according to hydrophobicity. •Ion mobility (IM) spectrometry separates these blends based on molecular size/shape. •LC–MS provides the separation resolution needed for quantifying fatty acid content. •IM–MS enables rapid, solvent-free separation and the detection of trace components. •With either method, tandem MS allows to count the hydrophobic substituents. -- Abstract: Liquid chromatography (LC) and ion mobility (IM) separation have been coupled with mass spectrometry (MS) and tandem mass spectrometry (MS{sup 2}) to characterize a commercially important nonionic surfactant, polysorbate 85. The constituents of this amphiphilic blend contained a sorbitan or isosorbide core that was chain extended with poly(ethylene oxide) (PEO) and partially esterified at the PEO termini with oleic acid or, to a lesser extent, other fatty acids. Using interactive LC in reverse-phase mode, the oligomers of the surfactant were separated according to their hydrophobicity/hydrophilicity balance. On the other hand, IM spectrometry dispersed the surfactant oligomers by their charge and collision cross section (i.e. size/shape). With either separation method, an increased number of fatty ester groups and/or lack of the polar sorbitan (or isosorbide) core led to higher retention/drift times, enabling the separation of isobaric species or species with superimposed isotope patterns, so that their ester content could be conclusively identified by MS{sup 2}. LC–MS and IM–MS permitted the detection of several byproducts besides the major PEO-sorbitan oleate oligomers. LC–MS provides the separation resolution needed for quantitative determination of the degree of esterification. IM–MS, which minimizes analysis time and solvent use, is ideally suitable for a fast, qualitative survey of samples differing in their minor constituents or impurities.

  1. Discrimination of eight chloramphenicol isomers by liquid chromatography tandem mass spectrometry in order to investigate the natural occurrence of chloramphenicol.

    Science.gov (United States)

    Berendsen, Bjorn J A; Zuidema, Tina; de Jong, Jacob; Stolker, Linda A A M; Nielen, Michel W F

    2011-08-26

    This paper describes the discrimination of eight different isomers of chloramphenicol (CAP), an antibiotic banned for use in food producing animals, by reversed phase and chiral liquid chromatography in combination with tandem mass spectrometric detection. Previously, by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) the presence of CAP was confirmed in some grass and herb samples collected on Mongolian pastures up to concentrations of 450 μg kg(-1). It was not possible to establish the cause of CAP residues which has initiated research on the natural occurrence of this drug. CAP occurs in the para-configuration and in the meta-configuration and contains two chiral centers thus eight different isomeric configurations exist, namely four (RR, SS, RS, SR) meta-stereoisomers and four para-stereoisomers. It is known that only RR-p-CAP has antimicrobial properties. To find out if the CAP detected in the plant material samples is the active configuration, a high resolution reversed phase LC-MS/MS system was tested for its ability to separate the different isomers. This system proved to be able to discriminate between some isomers, but not between RR-p-CAP and SS-p-CAP, also called dextramycin. Despite a detailed elucidation of the product ions and the fragmentation patterns of all isomers, MS/MS did not add sufficient specificity for full discrimination of the isomers. Therefore a chiral liquid chromatographic separation with MS/MS detection that is able to distinguish all isomers was developed and finally the isomeric ratio of non-compliant plant material samples and some CAP formulations was determined using this system. This showed that Mongolian grass and herb samples only contain the biological active isomer of CAP as do the obtained formulations. Therefore the CAP present in the plant material might origin from the production by soil organisms or from a manufactured source.

  2. Analysis of perchlorate, thiocyanate, nitrate and iodide in human amniotic fluid using ion chromatography and electrospray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Blount, Benjamin C. [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States)]. E-mail: bblount@cdc.gov; Valentin-Blasini, Liza [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States)

    2006-05-10

    Because of health concerns surrounding in utero exposure to perchlorate, we developed a sensitive and selective method for quantifying iodide, as well as perchlorate and other sodium-iodide symporter (NIS) inhibitors in human amniotic fluid using ion chromatography coupled with electrospray ionization tandem mass spectrometry. Iodide and NIS inhibitors were quantified using a stable isotope-labeled internal standards (Cl{sup 18}O{sub 4} {sup -}, S{sup 13}CN{sup -} and {sup 15}NO{sub 3} {sup -} with excellent assay accuracy of 100%, 98%, 99%, 95% for perchlorate, thiocyanate, nitrate and iodide, respectively, in triplicate analysis of spiked amniotic fluid sample). Excellent analytical precision (<5.2% RSD for all analytes) was found when amniotic fluid quality control pools were repetitively analyzed for iodide and NIS-inhibitors. Selective chromatography and tandem mass spectrometry reduced the need for sample cleanup, resulting in a rugged and rapid method capable of routinely analyzing 75 samples/day. Analytical response was linear across the physiologically relevant concentration range for the analytes. Analysis of a set of 48 amniotic fluid samples identified the range and median levels for perchlorate (0.057-0.71, 0.18 {mu}g/L), thiocyanate (<10-5860, 89 {mu}g/L), nitrate (650-8900, 1620 {mu}g/L) and iodide (1.7-170, 8.1 {mu}g/L). This selective, sensitive, and rapid method will help assess exposure of the developing fetus to low levels of NIS-inhibitors and their potential to inhibit thyroid function.

  3. Multimycotoxin analysis in water and fish plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Tolosa, J; Font, G; Mañes, J; Ferrer, E

    2016-02-01

    High performance liquid chromatography-mass spectrometry was used for the determination of 15 mycotoxins in water and fish plasma samples, including aflatoxins, fumonisins, ochratoxin A, sterigmatocistin, fusarenon-X and emerging Fusarium mycotoxins. In this work, dispersive liquid-liquid microextraction (DLLME) was assessed as a sample treatment for the simultaneous extraction of mycotoxins. Results showed differences in recovery assays when different extraction solvents were employed. Ethyl acetate showed better recoveries for the major part of mycotoxins analyzed, except for aflatoxins B2, G1 and G2, which showed better recoveries when employing chloroform as extractant solvent. Fumonisins and beauvericin exhibited low recoveries in both water and plasma. This method was validated according to guidelines established by European Commission and has shown to be suitable to be applied in dietary and/or toxicokinetic studies in fish where is necessary to check mycotoxin contents in rearing water and fish plasma.

  4. Saffron authentication based on liquid chromatography high resolution tandem mass spectrometry and multivariate data analysis.

    Science.gov (United States)

    Rubert, Josep; Lacina, Ondrej; Zachariasova, Milena; Hajslova, Jana

    2016-08-01

    Saffron is one of the oldest and most expensive spices, which is often target of fraudulent activities. In this research, a new strategy of saffron authentication based on metabolic fingerprinting was developed. In the first phase, a solid liquid extraction procedure was optimized, the main aim was to isolate as maximal representation of small molecules contained in saffron as possible. In the second step, a detection method based on liquid chromatography coupled with high-resolution mass spectrometry was developed. Initially, principal component analysis (PCA) revealed clear differences between saffron cultivated and packaged in Spain, protected designation of origin (PDO), and saffron packaged in Spain of unknown origin, labeled Spanish saffron. Afterwards, orthogonal partial least square discriminant analysis (OPLS-DA) was favorably used to discriminate between Spanish saffron. The tentative identification of markers showed glycerophospholipids and their oxidized lipids were significant markers according to their origin.

  5. Stable Isotope Labeling Strategy for Curcumin Metabolite Study in Human Liver Microsomes by Liquid Chromatography-Tandem Mass Spectrometry

    Science.gov (United States)

    Gao, Dan; Chen, Xiaowu; Yang, Xiaomei; Wu, Qin; Jin, Feng; Wen, Hongliang; Jiang, Yuyang; Liu, Hongxia

    2015-04-01

    The identification of drug metabolites is very important in drug development. Nowadays, the most widely used methods are isotopes and mass spectrometry. However, the commercial isotopic labeled reagents are usually very expensive, and the rapid and convenient identification of metabolites is still difficult. In this paper, an 18O isotope labeling strategy was developed and the isotopes were used as a tool to identify drug metabolites using mass spectrometry. Curcumin was selected as a model drug to evaluate the established method, and the 18O labeled curcumin was successfully synthesized. The non-labeled and 18O labeled curcumin were simultaneously metabolized in human liver microsomes (HLMs) and analyzed by liquid chromatography/mass spectrometry (LC-MS). The two groups of chromatograms obtained from metabolic reaction mixture with and without cofactors were compared and analyzed using Metabolynx software (Waters Corp., Milford, MA, USA). The mass spectra of the newly appearing chromatographic peaks in the experimental sample were further analyzed to find the metabolite candidates. Their chemical structures were confirmed by tandem mass spectrometry. Three metabolites, including two reduction products and a glucuronide conjugate, were successfully detected under their specific HLMs metabolic conditions, which were in accordance with the literature reported results. The results demonstrated that the developed isotope labeling method, together with post-acquisition data processing using Metabolynx software, could be used for fast identification of new drug metabolites.

  6. Identification of di(ethylhexyl) phthalate as impurity in the analysis by using chromatography gas tandem mass spectrometry

    Science.gov (United States)

    Pusfitasari, Eka Dian; Hendarsyah, Hendris; Salahuddin, Ariani, Novita

    2017-01-01

    Di(ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in plastics. Physically DEHP has a low vapor pressure. DEHP can seep into the liquid in direct contact with the plastic wrapping materials, and typically can occur rapidly if extractable into food or non-polar solvents, such as oil, once the food is packaged in PVC packaging materials. DEHP has been analyzed by using gas chromatography which has a high sensitivity level. If the equipment used for the analysis is made from plastic containing DEHP, then it may be possible that DEHP can be extracted and appear on the outcome of the injection. It can interfere with the process of analysis, especially for the analysis of food samples. This study has identified the present of DEHP in the blank injection performed by Gas Chromatography tandem Mass Spectrometry with Selected Ion Monitoring mode (SIM). Researchers are required to verify whether the gas chromatographic system used is ready for the analysis process. In addition, the comparison and calculation of the intensity of the ion fragmentation spectra generated by mass spectrometry detector can be used for the qualitative determination to ensure the presence of the target compound. In this study is also discussed the differences between the high-intensity fragmentation of DEHP and dioctyl phthalate (DOP).

  7. Simultaneous quantification of amphetamine, opiates, ketamine and relative metabolites in urine for confirmatory analysis by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lin, Huei-Ru; Choi, Ka-Ian; Lin, Tzu-Chieh; Hu, Anren

    2013-06-15

    The rise in amphetamine, ketamine and opiates abuse in Taiwan has created a need for a reliable confirmatory assay. A method that combines superficially porous liquid chromatography tandem mass spectrometry (LC-MS/MS) with solid-phase extraction (SPE) was developed for the simultaneous quantification of amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), ketamine, opiates, and their corresponding metabolites in urine. The total run time of the method was 6.7min including equilibration time. The method was validated in accordance with the European Commission (EC) Decision 2002/642/EC. The within- and between-day precision was below 13.6% and the accuracy ranged from -17.1% to +9.9% for all analytes. Ion suppression was observed but compensated by using deuterated internal standards. No carryover was detected and the analytes were stable at room temperature for 16h, and for 72h at 4°C, and three-thaw cycles. The method was further validated by comparison with a reference gas chromatography-mass spectrometry (GC-MS) method, using 52 authentic urine samples. The results indicated that for the target analytes studied, the LC-MS/MS analysis was as precise, accurate, and specific as the GC-MS method. In conclusion, the present LC-MS/MS method is robust and reliable, and suitable for use as a confirmation assay in the simultaneous urine drug testing and quantification of amphetamines, ketamines, and opiates.

  8. Liquid chromatography-tandem mass spectrometric assay for the tyrosine kinase inhibitor afatinib in mouse plasma using salting-out liquid-liquid extraction

    NARCIS (Netherlands)

    Sparidans, Rolf W; van Hoppe, Stephanie; Rood, Johannes J M; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H

    2016-01-01

    A quantitative bioanalytical liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay for afatinib, an irreversible inhibitor of the ErbB (erythroblastic leukemia viral oncogene homolog) tyrosine kinase family, was developed and validated. Plasma samples were pre-treated using salting-out as

  9. Multiresidue analysis of beta-agonists in bovine and porcine unrine, feed and hair using liquid chromatography electrospray ionisation tandem mass spectrometry

    NARCIS (Netherlands)

    Nielen, M.W.F.; Lasaroms, J.J.P.; Essers, M.L.; Oosterink, J.E.; Meijer, T.; Sanders, M.B.; Zuidema, T.; Stolker, A.A.M.

    2008-01-01

    The use of ß-agonists as growth promoters in cattle breeding is forbidden in many countries for reasons of fair trade and consumer protection. In recent years the use of liquid chromatography (LC) tandem mass spectrometry (MS/MS) has been shown to be the method of choice for the control of ß-agonist

  10. Use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect carbapenemase production in Enterobacteriaceae by a rapid meropenem degradation assay.

    Science.gov (United States)

    Foschi, Claudio; Franza, Vincenzo; Conti, Matteo; Tamburini, Maria Vittoria; Roncarati, Greta; Cordovana, Miriam; Smirnova, Viktoria; Patrono, Daniela; Mancini, Rita; Landini, Maria Paola; Ambretti, Simone

    2015-10-01

    We evaluated the analytical performance of a liquid chromatography-tandem mass spectrometry assay to detect carbapenemase activity in a group of carbapenemase-producing Enterobacteriaceae by meropenem hydrolysis. This one-hour method showed a sensitivity of 94% and a specificity of 100%, representing a rapid and reliable option compared to conventional phenotypic assays.

  11. Specific determination of 20 primary aromatic amines in aqueous food simulants by liquid chromatography-electrospray ionization-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Mortensen, Sarah Kelly; Trier, Xenia Thorsager; Foverskov, Annie

    2005-01-01

    A multi-analyte method without any pre-treatment steps using reversed-phase liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) was developed and applied for the determination of 20 primary aromatic amines (PAA) associated with polyurethane (PUR) products or azo...

  12. Development of a new ultra-high performance liquid chromatography - tandem mass spectrometry method for determination of ambroxol hydrochloride in serum with pharmacokinetic application

    OpenAIRE

    Vujović Maja M.; Jokanović Milan; Nikolić Goran M.

    2016-01-01

    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 rabb...

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

    NARCIS (Netherlands)

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

    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 st

  14. 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 phen

  15. Liquid chromatography with tandem mass spectrometry quantification of urinary proanthocyanin A2 dimer and its potential use as a biomarker of cranberry intake

    Science.gov (United States)

    The lack of a biomarker for the consumption of cranberries has confounded the interpretation of several studies investigating the effect of cranberry products, especially juices, on health outcomes. The objectives of this pilot study were to develop a liquid chromatography tandem mass spectrometric ...

  16. Rapid qualitative and quantitative analysis of proanthocyanidin oligomers and polymers by ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS)

    Science.gov (United States)

    We developed a rapid method with ultra-performance liquid chromatographytandem mass spectrometry (UPLC-MS/MS) for the qualitative and quantitative analysis of plant proanthocyanidins (PAs) directly from crude plant extracts. The method utilizes a range of cone voltages to achieve the depolymeriza...

  17. Comprehensive analysis of B-Lactam antibiotics including penicillins, cephalosporins and carbapenems in poultry muscle using liquid chromatography coupled to tandem mass spectrometry

    NARCIS (Netherlands)

    Berendsen, B.J.A.; Gerritsen, H.W.; Wegh, R.S.; Lameris, S.L.; Sebille, van R.; Stolker, A.A.M.; Nielen, M.W.F.

    2013-01-01

    A comprehensive method for the quantitative residue analysis of trace levels of 22 ß-lactam antibiotics, including penicillins, cephalosporins, and carbapenems, in poultry muscle by liquid chromatography in combination with tandem mass spectrometric detection is reported. The samples analyzed for ß-

  18. 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...

  19. [Qualitative and quantitative analysis of amygdalin and its metabolite prunasin in plasma by ultra-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)

    Gao, Meng; Wang, Yuesheng; Wei, Huizhen; Ouyang, Hui; He, Mingzhen; Zeng, Lianqing; Shen, Fengyun; Guo, Qiang; Rao, Yi

    2014-06-01

    A method was developed for the determination of amygdalin and its metabolite prunasin in rat plasma after intragastric administration of Maxing shigan decoction. The analytes were identified by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the qualitative analysis of amygdalin and prunasin in the plasma sample was performed on a Shim-pack XR-ODS III HPLC column (75 mm x 2.0 mm, 1.6 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on a Triple TOF 5600 quadrupole time of flight mass spectrometer. The quantitative analysis of amygdalin and prunasin in the plasma sample was performed by separation on an Agilent C18 HPLC column (50 mm x 2.1 mm, 1.7 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on an AB Q-TRAP 4500 triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The qualitative analysis results showed that amygdalin and its metabolite prunasin were detected in the plasma sample. The quantitative analysis results showed that the linear range of amygdalin was 1.05-4 200 ng/mL with the correlation coefficient of 0.999 0 and the linear range of prunasin was 1.25-2 490 ng/mL with the correlation coefficient of 0.997 0. The method had a good precision with the relative standard deviations (RSDs) lower than 9.20% and the overall recoveries varied from 82.33% to 95.25%. The limits of detection (LODs) of amygdalin and prunasin were 0.50 ng/mL. With good reproducibility, the method is simple, fast and effective for the qualitative and quantitative analysis of the amygdalin and prunasin in plasma sample of rats which were administered by Maxing shigan decoction.

  20. Determination of triapine, a ribonucleotide reductase inhibitor, in human plasma by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Feng, Ye; Kunos, Charles A; Xu, Yan

    2015-09-01

    Triapine is an inhibitor of ribonucleotide reductase (RNR). Studies have shown that triapine significantly decreases the activity of RNR and enhanced the radiation-mediated cytotoxicity in cervical and colon cancer. In this work, we have developed and validated a selective and sensitive LC-MS/MS method for the determination of triapine in human plasma. In this method, 2-[(3-fluoro-2-pyridinyl)methylene] hydrazinecarbothioamide (NSC 266749) was used as the internal standard (IS); plasma samples were prepared by deproteinization with acetonitrile; tripaine and the IS were separated on a Waters Xbridge Shield RP18 column (3.5 µm; 2.1 × 50 mm) using a mobile phase containing 25.0% methanol and 75.0% ammonium bicarbonate buffer (10.0 mM, pH 8.50; v/v); column eluate was monitored by positive turbo-ionspray tandem mass spectrometry; and quantitation of triapine was carried out in multiple-reaction-monitoring mode. The method developed had a linear calibration range of 0.250-50.0 ng/mL with correlation coefficient of 0.999 for triapine in human plasma. The IS-normalized recovery and the IS-normalized matrix factor of triapine were 101-104% and 0.89-1.05, respectively. The accuracy expressed as percentage error and precision expressed as coefficient of variation were ≤±6 and ≤8%, respectively. The validated LC-MS/MS method was applied to the measurement of triapine in patient samples from a phase I clinical trial.

  1. Determination of deltamethrin residues in plant materials by liquid chromatography/tandem mass spectrometry with electrospray ionization.

    Science.gov (United States)

    Zimmer, Dieter; Philipowski, Christiane; Posner, Birgit; Gnielka, Agnes; Dirr, Edgar; Dorff, Mario

    2006-01-01

    This paper describes a selective and sensitive method that uses liquid chromatography/tandem mass spectrometry with positive electrospray ionization (ESI+) for the determination of deltamethrin in a variety of crops. Samples were extracted by conventional high-speed blending. Some samples required no further cleanup; others were cleaned up by gel permeation chromatography, strong cation-exchange cartridges, or partitioning with n-hexane. In the determinative step, the buffered neutral mobile phase, consisting of 10 mM ammonium acetate (pH 6.8) and methanol, and ESI+ provided strong ammonium adduct formation to [M+NH4]+ at m/z 523, and the multiple-reaction monitoring (MRM) transition at m/z 523/281 was used for the quantitation of deltamethrin. A second MRM transition at m/z 525/283 was used for confirmation. The limit of quantitation (LOQ) values were 0.01 mg/kg for edible materials and 0.05 mg/kg for nonedible materials. Mean overall recoveries at the LOQ and the 10-fold LOQ ranged from 73 to 96%, and the relative standard deviations were <10% for all samples materials analyzed.

  2. Quantification of antidepressants and antipsychotics in human serum by precipitation and ultra high pressure liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Hasselstrøm, Jørgen Bo

    2011-01-01

    precipitated with zinc sulphate and methanol containing a stable isotope labelled analog for each analyte. Quantitative analysis was performed by ultra high pressure liquid chromatography combined with a tandem mass spectrometer using a Zorbax SB-C8 column (2.0×50mm; 1.8m) with a mobile phase consisting of 0...... for therapeutic drug monitoring. The method was developed to replace old techniques which applied solid phase extraction and ultra-violet detection. The old methods had reached their limit of capacity regarding the number of samples and co-medicated drugs interfering with the detection. Serum samples were.......1% formic acid in water and methanol, respectively. The total run time of the chromatography was 4 min. Precision and trueness varied from 2.6% to 14.9% and 87.6% to 103.5%, respectively. At the lower limit of quantification, precision was up to 17.9% and trueness varied from 89.5% to 111.5%. A five point...

  3. Determination and confirmation of melamine residues in catfish, trout, tilapia, salmon, and shrimp by liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Andersen, Wendy C; Turnipseed, Sherri B; Karbiwnyk, Christine M; Clark, Susan B; Madson, Mark R; Gieseker, Charles M; Miller, Ron A; Rummel, Nathan G; Reimschuessel, Renate

    2008-06-25

    Pet and food animal (hogs, chicken, and fish) feeds were recently found to be contaminated with melamine (MEL). A quantitative and confirmatory method is presented to determine MEL residues in edible tissues from fish fed this contaminant. Edible tissues were extracted with acidic acetonitrile, defatted with dichloromethane, and cleaned up using mixed-mode cation exchange solid-phase extraction cartridges. Extracts were analyzed by liquid chromatography with tandem mass spectrometry with hydrophilic interaction chromatography and electrospray ionization in positive ion mode. Fish and shrimp tissues were fortified with 10-500 microg/kg (ppb) of MEL with an average recovery of 63.8% (21.5% relative standard deviation, n = 121). Incurred fish tissues were generated by feeding fish up to 400 mg/kg of MEL or a combination of MEL and the related triazine cyanuric acid (CYA). MEL and CYA are known to form an insoluble complex in the kidneys, which may lead to renal failure. Fifty-five treated catfish, trout, tilapia, and salmon were analyzed after withdrawal times of 1-14 days. MEL residues were found in edible tissues from all of the fish with concentrations ranging from 0.011 to 210 mg/kg (ppm). Incurred shrimp and a survey of market seafood products were also analyzed as part of this study.

  4. Quantitation of five organophosphorus nerve agent metabolites in serum using hydrophilic interaction liquid chromatography and tandem mass spectrometry

    Science.gov (United States)

    Hamelin, Elizabeth I.; Schulze, Nicholas D.; Shaner, Rebecca L.; Coleman, Rebecca M.; Lawrence, Richard J.; Crow, Brian S.; Jakubowski, E. M.; Johnson, Rudolph C.

    2015-01-01

    Although nerve agent use is prohibited, concerns remain for human exposure to nerve agents during decommissioning, research, and warfare. Exposure can be detected through the analysis of the hydrolysis products in urine as well as blood. An analytical method to detect exposure to five nerve agents, including VX, VR (Russian VX), GB (sarin), GD (soman) and GF (cyclosarin), through the analysis of the hydrolysis products, which are the primary metabolites, in serum has been developed and characterized. This method uses solid phase extraction coupled with high performance liquid chromatography for separation and isotopic dilution tandem mass spectrometry for detection. An uncommon buffer of ammonium fluoride was used to enhance ionization and improve sensitivity when coupled with hydrophilic interaction liquid chromatography resulting in detection limits from 0.3–0.5 ng/mL. The assessment of two quality control samples demonstrated high accuracy (101–105%) and high precision (5–8%) for the detection of these five nerve agent hydrolysis products in serum. PMID:24633507

  5. Simultaneous determination of acidic pesticides in vegetables and fruits by liquid chromatography--tandem mass spectrometry.

    Science.gov (United States)

    Shida, Shizuka S; Nemoto, Satoru; Matsuda, Rieko

    2015-01-01

    A sensitive and efficient method has been developed for the simultaneous determination of 73 multi-class acidic pesticides, such as phenoxy acid and sulfonylurea herbicides, in vegetables and fruits. The sample preparation procedure was carefully optimized for the efficient removal of co-extracted matrix components. The method involves extraction of acidic pesticides with acetonitrile containing hydrochloric acid, removal of water from crude extract by salting out, and sequential cleanup by octadecylsilyl silica gel and silica gel columns. For samples containing high amounts of pigments, such as spinach, additional cleanup using a graphitized carbon column was performed prior to liquid chromatography-mass spectrometry (LC-MS/MS) analysis. Recovery tests were performed for five times for each sample of cabbage, spinach, potato, eggplant, orange, and apple fortified at 0.01 mg kg-1. Out of the 73 tested pesticides, 70 for cabbage, 67 for spinach, 69 for potato, 67 for eggplant, 64 for orange, and 70 for apple were within the range of 70-120%, with relative standard deviations below 25%. Nitenpyram and pyrasulfotole showed low recoveries for all the samples tested, probably due to low recoveries from silica gel column. The developed method effectively removed co-extracted matrix components and was highly selective, with no interfering peaks found in the chromatograms of blank samples. The overall results indicate that the developed method is suitable for the quantitative analysis of acidic pesticide residues in vegetables and fruits.

  6. Analysis of daphnane orthoesters in poisonous Australian pimelea species by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Chow, Sharon; Fletcher, Mary T; McKenzie, Ross A

    2010-06-23

    Cattle grazing in arid rangelands of Australia suffer periodic extensive and serious poisoning by the plant species Pimelea trichostachya, P. simplex, and P. elongata. Pimelea poisoning (also known as St. George disease and Marree disease) has been attributed to the presence of the diterpenoid orthoester simplexin in these species. However, literature relating to previous studies is complicated by taxonomic revisions, and the presence of simplexin has not previously been verified in all currently recognized taxa capable of inducing pimelea poisoning syndrome, with no previous chemical studies of P. trichostachya (as currently classified) or P. simplex subsp. continua. We report here the isolation of simplexin from P. trichostachya and the development of a liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method to measure simplexin concentrations in pimelea plant material. Simplexin was quantified by positive-ion atmospheric pressure chemical ionization (APCI) LC-MS/MS with selected reaction monitoring (SRM) of the m/z 533.3 > 253.3 transition. LC-MS/MS analysis of the four poisonous taxa P. trichostachya, P. elongata, P. simplex subsp. continua, and P. simplex subsp. simplex showed similar profiles with simplexin as the major diterpenoid ester component in all four taxa accompanied by varying amounts of related orthoesters. Similar analyses of P. decora, P. haematostachya, and P. microcephala also demonstrated the presence of simplexin in these species but at far lower concentrations, consistent with the limited reports of stock poisoning associated with these species. The less common, shrubby species P. penicillaris contained simplexin at up to 55 mg/kg dry weight and would be expected to cause poisoning if animals consumed sufficient plant material.

  7. Antioxidant activity guided separation of major polyphenols of marjoram (Origanum majorana L.) using flash chromatography and their identification by liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Hossain, Mohammad B; Camphuis, Gabriel; Aguiló-Aguayo, Ingrid; Gangopadhyay, Nirupama; Rai, Dilip K

    2014-11-01

    Marjoram extracts have been separated into polar and nonpolar parts using liquid-liquid extraction. Both polar and nonpolar parts of the extracts were further fractionated by flash chromatography. The obtained fractions (90 polar and 45 nonpolar fractions) were investigated for their antioxidant activities by 2,2-diphenylpicrylhydrazyl and ferric ion reducing antioxidant power assays. A direct, positive, and linear relationship between antioxidant activity and total phenolic content of the fractions was observed. Based on antioxidant and total phenolic content data, the three fractions with the high antioxidant activities from polar and nonpolar part of the extract were analyzed for their constituent polyphenols by liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Compounds were identified by matching the mass spectral data and retention time with those of authentic standards. Identification of the compounds for which there were no "in-house" standards available was carried out by accurate mass measurement of the precursor ions and product ions generated from collision-induced dissociation. Rosmarinic acid was found to be the strongest antioxidant polyphenol conferring the highest antioxidant activity to fractions 47 and 17 of polar and nonpolar part of the extract, respectively. The identification of the rosmarinic acid was further confirmed by (1) H NMR spectroscopy.

  8. Determination of rutin in rat plasma by ultra performance liquid chromatography tandem mass spectrometry and application to pharmacokinetic study.

    Science.gov (United States)

    Chen, Mengchun; Zhang, Xiaoqian; Wang, Hao; Lin, Baoli; Wang, Shuanghu; Hu, Guoxin

    2015-04-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method for the determination of rutin in rat plasma was developed and validated. After addition of tolbutamide as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. The chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm particle size), using acetonitrile-0.1% formic acid as the mobile phase with gradient elution, delivered at a flow-rate of 0.4 mL/min. Mass spectrometric analysis was performed using a XEVO TQD mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 610.91→302.98 and m/z 271.2→155.1 were used to quantify for rutin and tolbutamide, respectively. This assay method has been fully validated in terms of specificity, linearity, recovery and matrix effect, accuracy, precision and stability. Calibration curves were linear in the concentration ranges of 25-2000 ng/mL for rutin. Only 3 min was needed for an analytical run. This developed method was successfully used for determination of rutin in rat plasma for pharmacokinetic study.

  9. Detection of Sulfur-Fumigated Paeoniae Alba Radix in Complex Preparations by High Performance Liquid Chromatography Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Song-Lin Li

    2012-07-01

    Full Text Available Detection of sulfur-fumigated Paeoniae Alba Radix (PAR in different complex preparations is challenging due to the relatively lower content of PAR and interference from more complicated components in complex preparations with different multiple constituent herbs. In this study, a high performance liquid chromatography- triple-quadrupole tandem mass spectrometry method was developed for detecting sulfur-fumigated PAR in different complex preparations. Paeoniflorin, the major component of PAR, and paeoniflorin sulfonate, the characteristic artifact transformed from paeoniflorin during sulfur-fumigation of PAR, were used as chemical markers. Multiple reaction monitoring (MRM scan was employed to maximize sensitivity and selectivity. Through optimizing full mass scan and daughter ion scan conditions, two mass transitions were selected and employed respectively for unequivocal identification of paeoniflorin and paeoniflorin sulfonate. The detection limits for paeoniflorin and paeoniflorin sulfonate using MRM were much lower than those detected with UV 270 nm. Paeoniflorin and paeoniflorin sulfonate could be simultaneously detected in different commercial PAR-containing complex preparations without interference of other components using the established method, indicating that the newly established method was selective and sensitive enough for screening sulfur-fumigated PAR in commercial complex preparations.

  10. Hydrophilic interaction liquid chromatography with tandem mass spectrometric detection applied for analysis of pteridines in two Graphosoma species (Insecta: Heteroptera).

    Science.gov (United States)

    Kozlík, Petr; Krajíček, Jan; Kalíková, Květa; Tesařová, Eva; Cabala, Radomír; Exnerová, Alice; Stys, Pavel; Bosáková, Zuzana

    2013-07-01

    A new separation method involving hydrophilic interaction chromatography with tandem mass spectrometric detection has been developed for the analysis of pteridines, namely biopterin, isoxanthopterin, leucopterin, neopterin, xanthopterin and erythropterin in the cuticle of heteropteran insect species. Two columns, Atlantis HILIC Silica and ZIC(®)-HILIC were tested for the separation of these pteridines. The effect of organic modifier content, buffer type, concentration and pH in mobile phase on retention and separation behavior of the selected pteridines was studied and the separation mechanism was also investigated. The optimized conditions for the separation of pteridines consisted of ZIC(®)-HILIC column, mobile phase composed of acetonitrile/5mM ammonium acetate, pH 6.80, 85/15 (v/v), flow rate 0.5mL/min and column temperature 30°C. Detection was performed by tandem mass spectrometry operating in electrospray ionization with Agilent Jet Stream technology using the selected reaction monitoring mode. The optimized method provided a linearity range from 0.3 to 5000ng/mL (r>0.9975) and repeatability with relative standard deviation<8.09% for all the studied pteridines. The method was applied to the analysis of pteridines in the cuticle of larvae and three adult color forms of Graphosoma lineatum and one form of Graphosoma semipunctatum (Insecta: Hemiptera: Heteroptera: Pentatomidae). The analysis shows that different forms of Graphosoma species can be characterized by different distribution of individual pteridines, which affects the coloration of various forms. Only isoxanthopterin was found in all the five forms tested.

  11. Rapid identification of erythrocyte phospholipids in Sprague-Dawley rats by ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Pi, Juanjuan; Wu, Xia; Yang, Shitian; Zeng, Pingyan; Feng, Yifan

    2015-03-01

    A rapid, sensitive, and reliable approach for analyzing five kinds of erythrocyte phospholipids in Sprague-Dawley rats was provided by ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry with MassLynx(TM) MassFragment. Improving conventional high performance liquid chromatography techniques, ultra high performance liquid chromatography integrated with quadrupole time-of-flight tandem mass spectrometry offers high sensitivity and increased analytical speed by using columns packed with sub-2 μm particles (1.7 μm), which allows a faster separation to be achieved. Through this method, 83 phospholipids were tentatively characterized based on their mass spectra and tandem mass spectra, as well as by matching the in-house formula database within a mass error of 5 ppm, including 40 phosphatidylcholines, 24 phosphatidyl ethanolamines, three phosphatidylinositols, six phosphatidylserines, and ten sphingomyelins. Our present results proved that the established method could be used to qualitatively analyze complex erythrocyte phospholipids in Sprague-Dawley rats and provide a useful data base for pharmacology and phospholipidomics to seek potential biomarkers of disease prediction.

  12. Determination of abacavir, tenofovir, darunavir, and raltegravir in human plasma and saliva using liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Yamada, Eiko; Takagi, Ritsuo; Sudo, Koji; Kato, Shingo

    2015-10-10

    A liquid chromatography-tandem mass spectrometry assay for the determination of abacavir (ABC), tenofovir (TFV), darunavir (DRV), and raltegravir (RAL) in human plasma and saliva was developed and validated to investigate the applicability of saliva as an appropriate specimen for therapeutic drug monitoring. As internal standards, TFV was chosen for ABC, ABC was chosen for TFV, RAL for DRV, and DRV for RAL. Sample preparation involved protein precipitation with acetonitrile, evaporation of solvent using a centrifugal evaporator, and reconstitution by dissolving the residue in mobile phase. Liquid chromatography was performed on a C18 reverse phase column (1.5 × 50 mm, 5 μm) isocratically at a flow rate of 0.2 mL/min using 5mM formic acid-3% (v/v) acetonitrile as the mobile phase for ABC and TFV and 5mM formic acid-35% (v/v) acetonitrile as the mobile phase for DRV and RAL. The run time was 6 min, and the retention time was approximately 2.0 min for TFV, 2.5 min for RAL, and 4-4.5 min for ABC and DRV. Analytes were detected using tandem mass spectrometry in positive electrospray ionization mode. The precursor/product ion transitions (m/z) were 287.3/191.2 for ABC, 288.5/176.2 for TFV, 548.3/392.3 for DRV, and 445.3/109.5 for RAL, and were monitored on a triple-quadrupole mass spectrometer operated in the multiple reaction monitoring mode. The linearity of the assay was assessed in the range 1-10,000 ng/mL for all four drugs. Within-run and between-run mean accuracy, precision, and the extraction recovery for all drugs were -14.5-18.1%, 1.2-13.1%, and 86.0-111.1%, respectively. The proposed assay is sufficiently sensitive and accurate to quantify these drugs in plasma and saliva, and is suitable for investigating the relationship between drug concentrations in plasma and saliva.

  13. Analysis of gibberellins as free acids by ultra performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Urbanová, Terezie; Tarkowská, Danuše; Novák, Ondřej; Hedden, Peter; Strnad, Miroslav

    2013-08-15

    A robust, reliable and high-throughput method for extraction and purification of gibberellins (GAs), a group of tetracyclic diterpenoid carboxylic acids that include endogenous growth hormones, from plant material was developed. The procedure consists of two solid-phase extraction steps (Oasis(®) MCX-HLB and Oasis(®) MAX) and gives selective enrichment and efficient clean-up of these compounds from complex plant extracts. The method was tested with plant extracts of Brassica napus and Arabidopsis thaliana, from which total recovery of internal standards of about 72% was achieved. A rapid baseline chromatographic separation of 20 non-derivatised GAs by ultra performance liquid chromatography is also presented where a reversed-phase chromatographic column Acquity CSH(®) and a mobile phase consisting of methanol and aqueous 10mM-ammonium formate is used. This method enables sensitive and precise quantitation of GAs by MS/MS in multiple-reaction monitoring mode (MRM) by a standard isotope dilution method. Optimal conditions, including final flow rate, desolvation temperature, desolvation gas flow, capillary and cone voltage for effective ionisation in the electrospray ion source were found. All studied GAs were determined as free acids giving dominant quasi-molecular ions of [M-H](-) with limits of detection ranging between 0.08 and 10 fmol and linear ranges over four orders of magnitude. Taking advantage of highly effective chromatographic separation of 20 GAs and very sensitive mass spectrometric detection, the presented bioanalytical method serves as a useful tool for plant biologists studying the physiological roles of these hormones in plant development.

  14. Human pharmacokinetics of the muscle relaxant, eperisone hydrochloride by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Melilli, Barbara; Piazza, Cateno; Vitale, Daniela Cristina; Marano, Maria Rosa; Pecori, Andrea; Mattana, Paolo; Volsi, Valentina Li; Iuculano, Carmelo; Cardì, Francesco; Drago, Filippo

    2011-06-01

    Eperisone hydrochloride (4'-ethyl-2-methyl-3-piperidinopropiophenone hydrochloride) is a muscle relaxant agent, widely used in the treatment of patients with muscular contractures, low back pain or spasticity. Because of its mechanism of action (inhibition of gamma-efferent firing and local vasodilatation activity), side effects on central nervous system are rarely observed. A sensitive liquid chromatography-electrospray ionization-mass spectrometry method for determination of eperisone in human plasma has been developed, with a lower limit of quantification of 0.01 ng/mL. The method was applied to a pharmacokinetic study in 12 healthy volunteers given eperisone 100 mg as single dose on day 1 and three times daily on days 2 to 4. Eperisone was rapidly absorbed after oral administration (T (max) = 1.6 h) as it was expected by its fast-onset relaxant activity. Moreover, eperisone underwent a rapid elimination from the body (biological half-life 1.87 h), which was not modified during the repeated dosing as suggested by the C (max) cumulation observed, not different from that expected for a t (1/2) of 1.87 h as suggested by the similar and negligible plasma concentration values (0.063 and 0.067 ng/mL) measured on day 4 before the morning dose and 12 h after evening dose, thus ruling out any potential risk for drug accumulation. Thus, the pharmacokinetic characteristics of eperisone provide further justification for its tolerability in patients with low back pain or spastic palsy, in which the drug is given for periods ranging from few days to several months, respectively.

  15. 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...

  16. Development of a comprehensive analytical method for phosphate metabolites in plants by ion chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Sekiguchi, Yoko; Mitsuhashi, Naoto; Kokaji, Tetsuo; Miyakoda, Hidekazu; Mimura, Tetsuro

    2005-08-26

    This paper describes the development of a practical method for the analysis of phosphorus compounds with a focus on sugar phosphates from the model higher plant Arabidopsis thaliana by ion chromatography coupled to electrospray ionization tandem mass spectrometry (IC-ESI-MS-MS). After the analytical separation, the potassium hydroxide eluent was converted to water with an anion suppressor allowing the effluent from the IC to be connected to the mass spectrometer directly. In the optimized method, 17 phosphorous compounds (adenosine diphosphate (ADP), fructose 1,6-bisphosphate, fructose 2,6-bisphosphate, fructose 6-phosphate, galactose 1-phosphate, glucose 1-phosphate, glucose 1,6-bisphosphate, glucose 6-phosphate, mannose 6-phosphate, phosphoenol pyrvate, 3-phosphoglyceric acid, ribulose 1,5-bisphosphate, ribulose 5-phosphate, ribose 5-phosphate, sucrose 6-phosophate and uridine 5'-diphosphate-glucose (UDPG)) were determined. The linearity of response for these phosphorous compounds over the concentration range of 0 and 10 microM was better than 0.9993 in all cases. The minimum detection limit was between 0.01 and 2.50 microM for a 25 microL injection, and recovery rates for standard addition to the sample were within the range from 93% to 110%.

  17. Fast quantification of endogenous carbohydrates in plasma using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Zhu, Bangjie; Liu, Feng; Li, Xituo; Wang, Yan; Gu, Xue; Dai, Jieyu; Wang, Guiming; Cheng, Yu; Yan, Chao

    2015-01-01

    Endogenous carbohydrates in biosamples are frequently highlighted as the most differential metabolites in many metabolomics studies. A simple, fast, simultaneous quantitative method for 16 endogenous carbohydrates in plasma has been developed using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. In order to quantify 16 endogenous carbohydrates in plasma, various conditions, including columns, chromatographic conditions, mass spectrometry conditions, and plasma preparation methods, were investigated. Different conditions in this quantified analysis were performed and optimized. The reproducibility, precision, recovery, matrix effect, and stability of the method were verified. The results indicated that a methanol/acetonitrile (50:50, v/v) mixture could effectively and reproducibly precipitate rat plasma proteins. Cold organic solvents coupled with vortex for 1 min and incubated at -20°C for 20 min were the most optimal conditions for protein precipitation and extraction. The results, according to the linearity, recovery, precision, matrix effect, and stability, showed that the method was satisfactory in the quantification of endogenous carbohydrates in rat plasma. The quantified analysis of endogenous carbohydrates in rat plasma performed excellently in terms of sensitivity, high throughput, and simple sample preparation, which met the requirement of quantification in specific expanded metabolomic studies after the global metabolic profiling research.

  18. Quantitative determination of oxytocin receptor antagonist atosiban in rat plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kannan, Vivekanandan; Gadamsetty, Deepak; Rose, Madhankumar; Maria, Stella; Mustafa, Imran; Khedkar, Anand; Dave, Nitesh; Arumugam, Muruganandam; Iyer, Harish

    2010-05-01

    A kinetic study of atosiban was conducted following repeated intravenous administration in Wistar rats. Sample analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) following full validation of an in-house method. Eptifibatide, a cyclic peptide, was used as an internal standard (IS). The analyte and internal standard were extracted using solid phase extraction (SPE) method. Chromatographic separation was carried out using an ACE C18 5 microm 50 mm x 4.6 mm column with gradient elution. Mass spectrometric detection was performed using TSQ Quantum ultra AM. The lower limit of quantification was 0.01 microg/ml when 100 microl rat plasma was used. Plasma concentrations of atosiban were measured at 0 (pre-dose), 2, 15, 30, 45, 60, 120 min at the dosage levels of 0.125 mg/kg (low dose), 0.250 mg/kg (mid dose), and 0.500 mg/kg (high dose), respectively. Atosiban plasma concentration measured at Day 1 showed mean peak atosiban concentration (C(max)) 0.40, 0.57, 1.95 microg/ml for low, mid and high dose treated animals and mean peak concentration on Day 28 was 0.41, 0.88, 1.31microg/ml on Day 28 for low, mid and high dose treated animals.

  19. Simultaneous determination of decitabine and vorinostat (Suberoylanalide hydroxamic acid, SAHA) by liquid chromatography tandem mass spectrometry for clinical studies.

    Science.gov (United States)

    Patel, Katan; Guichard, Sylvie M; Jodrell, Duncan I

    2008-02-15

    A reverse-phase high-performance liquid chromatography method with electrospray ionization and detection by tandem mass spectrometry is described for the simultaneous quantitative determination of decitabine (5-aza-2'-deoxycytidine) and vorinostat (Suberoylanalide hydroxamic acid, SAHA) in human plasma. The method involves a simple acetonitrile precipitation step and centrifugation followed by injection of the supernatant onto a C18 150mmx2.1mm I.D., 3microm HPLC column at 36 degrees C. Separation of decitabine, SAHA and their respective internal standards was achieved with a gradient elution and detection was via the mass spectrometer operated in selected reaction monitoring mode. The method was within the defined validation parameters for linearity, repeatability, reproducibility and stability. The limit of detection was determined as 1.0 and 0.125ngml(-1) and lower limits of quantitation were 10 and 1ngml(-1) for decitabine and SAHA, respectively. Effects of sample preparation on stability were also evaluated in human plasma. For clinical sample handling tetrahydrouridine, an inhibitor of cytidine deaminase was found to help prevent decitabine degradation. The method is currently being used in clinical pharmacokinetic studies for the evaluation of decitabine and SAHA combination therapies.

  20. Pharmacokinetics of honokiol after intravenous guttae in beagle dogs assessed using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Liang, Yi; Cui, Gang; Wang, Xiaoxue; Zhang, Wei; An, Quan; Lin, Zongtao; Wang, Hong; Chen, Shizhong

    2014-10-01

    A simple, rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of honokiol in beagle dog plasma after intravenous guttae. With addition of the internal standard magnolol, plasma samples were precipitated with methanol and separated on a Shim-pack XR-ODS II (2.0 × 100 mm, 2.2 µm) with isocratic elution of methanol and water (80:20) solution at a flow rate of 0.2 mL/min. A good separation of honokiol was achieved within 3.5 min. Quantification was performed on a Waters Quattro Premier XE triple quadrupole mass spectrometer with electrospray ionization inlet in the negative multiple reaction monitoring mode. Good linearity was obtained over the concentration range of 5.12-15580 ng/mL (r(2) > 0.998). Intra- and inter-day precisions were <13.10%, and accuracy ranged from 89.21 to 99.92%. The lower limit of quantification for honokiol was 5.12 ng/mL, and honokiol was stable under various conditions (three freeze-thaw cycles, short-term temperature, post-preparative and long-term temperature conditions.). This validated method was successfully applied to the pharmacokinetic study of honokiol in dogs by intravenous guttae.

  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. 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.

  3. Quantitation of protein S-glutathionylation by liquid chromatography-tandem mass spectrometry: correction for contaminating glutathione and glutathione disulfide.

    Science.gov (United States)

    Bukowski, Michael R; Bucklin, Christopher; Picklo, Matthew J

    2015-01-15

    Protein S-glutathionylation is a posttranslational modification that links oxidative stimuli to reversible changes in cellular function. Protein-glutathione mixed disulfide (PSSG) is commonly quantified by reduction of the disulfide and detection of the resultant glutathione species. This methodology is susceptible to contamination by free unreacted cellular glutathione (GSH) species, which are present in 1000-fold greater concentration. A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method was developed for quantification of glutathione and glutathione disulfide (GSSG), which was used for the determination of PSSG in biological samples. Analysis of rat liver samples demonstrated that GSH and GSSG coprecipitated with proteins similar to the range for PSSG in the sample. The use of [(13)C2,(5)N]GSH and [(13)C4,(5)N2]GSSG validated these results and demonstrated that the release of GSH from PSSG did not occur during sample preparation and analysis. These data demonstrate that GSH and GSSG contamination must be accounted for when determining PSSG content in cellular/tissue preparations. A protocol for rinsing samples to remove the adventitious glutathione species is demonstrated. The fragmentation patterns for glutathione were determined by high-resolution mass spectrometry, and candidate ions for detection of PSSG on protein and protein fragments were identified.

  4. Multi-residue analysis of eight thioamphetamine designer drugs in human urine by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Nieddu, Maria; Boatto, Gianpiero; Pirisi, Maria Antonietta; Baralla, Elena

    2009-10-01

    An analytical procedure for the simultaneous determination in human urine of several thioamphetamine designer drugs (2C-T and ALEPH series) is reported. The quantitative analysis was performed by liquid chromatography/tandem mass spectrometry and has been fully validated. The mass spectrometer was operated in positive-ion, selected reaction monitoring (SRM) mode. In order to minimize interferences with matrix components and to preconcentrate target analytes, solid-phase extraction was introduced in the method as a clean-up step. The entire method was validated for selectivity, linearity, precision and accuracy. The method turned out to be specific, sensitive, and reliable for the analysis of amphetamine derivatives in urine samples. The calibration curves were linear over the concentration range of 1 to 100 ng mL(-1) for all drugs with correlation coefficients that exceeded 0.996. The lower limits of detection (LODs) and quantification (LOQs) ranged from 1.2 to 4.9 ng mL(-1) and from 3.2 to 9.6 ng mL(-1), respectively.

  5. Simultaneous determination of piroxicam, meloxicam and tenoxicam in human plasma by liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Ji, Hye Young; Lee, Hye Won; Kim, Young Hoon; Jeong, Dong Won; Lee, Hye Suk

    2005-11-05

    A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of piroxicam, meloxicam and tenoxicam in human plasma was developed. Piroxicam, meloxicam, tenoxicam and isoxicam (internal standard) were extracted from human plasma with ethyl acetate at acidic pH and analyzed on a Sunfire column with the mobile phase of methanol:ammonium formate (15 mM, pH 3.0) (60:40, v/v). The analytes were detected using a mass spectrometer, equipped with electrospray ion source. The instrument was set in the multiple-reaction-monitoring (MRM) mode. The standard curve was linear (r=1.000) over the concentration range of 0.50-200 ng/ml. The coefficient of variation (CV) and relative error (RE) for intra- and inter-assay statistics at three QC levels were 1.0-5.4% and -5.9 to 2.8%, respectively. The recoveries of piroxicam, meloxicam and tenoxicam ranged from 78.3 to 87.1%, with that of isoxicam being 59.7%. The lower limit of quantification for piroxicam, meloxicam and tenoxicam was 0.50 ng/ml using a 100 microl plasma sample. This method was successfully applied to a pharmacokinetic study of piroxicam after application of transdermal piroxicam patches to humans.

  6. High-sensitivity simultaneous liquid chromatography-tandem mass spectrometry assay of ethinyl estradiol and levonorgestrel in human plasma

    Institute of Scientific and Technical Information of China (English)

    Abhishek Gandhi; Swati Guttikar; Priti Trivedi

    2015-01-01

    A sensitive and simultaneous liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of ethinyl estradiol and levonorgestrel. The analytes were extracted with methyl-tert-butyl ether: n-hexane (50:50, v/v) solvent mixture, followed by dansyl derivatization. The chromatographic separation was performed on a Kinetex C18 (50 mm × 4.6 mm, 2.6μm) column with a mobile phase of 0.1% (v/v) formic acid in water and acetonitrile in gradient composition. The mass transitions were monitored in electrospray positive ionization mode. The assay exhibited a linear range of 0.100-20.0 ng/mL for levonorgestrel and 4.00-500 pg/mL for ethinyl estradiol in human plasma. A run time of 9.0 min for each sample made it possible to analyze a throughput of more than 100 samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic and bioequivalence studies.

  7. Qualitative and quantitative analysis of glucosinolates and nucleosides in Radix Isatidis by HPLC and liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Xiuming Wang

    2013-09-01

    Full Text Available Multi-component fingerprinting and quantitation of the glucosinolates and nucleosides in samples of Radix Isatidis have been carried out using high-performance liquid chromatography with diode-array detection and electrospray ionization tandem mass spectrometry (HPLC–DAD–ESI/MS. Five nucleosides together with one glucosinolate were identified by comparing retention times, ultraviolet spectra, mass spectra and/or empirical molecular formulae of reference compounds. Quantitation of these six compounds was carried out simultaneously by HPLC on a Phenomenex Luna C18 column using gradient elution with methanol and water and detection at 254 nm. All calibration curves were linear (r>0.9994 within test ranges. Limits of detection and quantitation were 0.33 ng and 2.50 ng on column, respectively. Intra- and inter-day precision (as relative standard deviation for all analytes was <2.19% with recoveries in the range 99.6%–101.8% at three concentration levels. The validated method was successfully applied to fingerprinting and assay of 25 batches of Radix Isatidis sourced from different geographical regions of China. The method is simple and reliable and has potential value in the quality control of Radix Isatidis.

  8. Determination of residues of quaternary ammonium disinfectants in food products by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    van Bruijnsvoort, Michel; Rooselaar, Joop; Stern, Alfred G; Jonker, Klaas M

    2004-01-01

    A liquid chromatography-tandem mass spectrometry method has been developed for the determination of residues of alkylbenzyldimethylammonium, didecyldimethylammonium, didodecyldimethylammonium, and benzyldodecylhydroxyethylammonium compounds in various food matrixes. These quaternary ammonium compounds (QAs) are used in the food industry as disinfectants. According to the Dutch Food Law, the total mass (expressed as cetyltrimethylammonium chloride) of QAs in food products shall not exceed the legislative limit of 0.5 mg/kg. Samples were extracted by a simple salting-out procedure, using acetonitrile and sodium chloride; about 100 samples could be prepared and analyzed daily. Special care had to be taken to thoroughly homogenize samples and to avoid the use of contaminated labware. The method was validated by a procedure in compliance with EU Directive 2002/657. From the matrixes of ice cream and minced meat, recoveries of more than 95% with a relative standard deviation of about 3% were obtained by 3 different analysts (n = 54). Detection limits were in the low microg/kg range. The decision limit (CCalpha) was determined to be 0.55 mg/kg. Dairy and meat products, collected in The Netherlands, were analyzed (761 samples). In 1% of the meat samples, 2% of the ice cream and milkshake samples, and 24% of the whipped cream samples, the Dutch legislative limit was exceeded. Over 2000 injections could be performed on a single column without deterioration of the peak shapes or recoveries.

  9. Optimized ultra performance liquid chromatography tandem high resolution mass spectrometry method for the quantification of paraquat in plasma and urine.

    Science.gov (United States)

    Lu, Haihua; Yu, Jing; Wu, Linlin; Xing, Jingjing; Wang, Jun; Huang, Peipei; Zhang, Jinsong; Xiao, Hang; Gao, Rong

    2016-08-01

    A simple, sensitive and specific ultra performance liquid chromatography coupled to electrospray tandem high resolution mass spectrometry (UPLC-ESI-HRMS/MS) method has been developed and validated for quantification of paraquat in plasma and urine. The sample preparation was carried out by one-step protein precipitation with acetonitrile. The paraquat was separated with a HILIC column in 10min. Detection was performed using Q Exactive Orbitrap mass spectrometer by Targeted-MS/MS scan mode. Methodological parameters, such as ammonium formate concentration, formic acid concentration, spray voltage, capillary temperature, heater temperature and normalized collision energy were optimized to achieve the highest sensitivity. The calibration curve was linear over the concentration range of LOQ-1000ng/mL. LOD was 0.1 and 0.3ng/mL, LOQ was 0.3 and 0.8ng/mL for urine and plasma, respectively. The intra- and inter-day precisions were paraquat concentration in plasma samples with hemoperfusion from 5 suspected paraquat poisoning patients.

  10. Characterisation of a proposed internet synthesis of N,N-dimethyltryptamine using liquid chromatography/electrospray ionisation tandem mass spectrometry.

    Science.gov (United States)

    Martins, Cláudia P B; Freeman, Sally; Alder, John F; Brandt, Simon D

    2009-08-14

    The psychoactive properties of N,N-dimethyltryptamine (DMT) are known to induce altered states of consciousness in humans. These properties attract great interest from clinical, neuroscientific, clandestine and forensic communities. The Breath of Hope Synthesis was reported on an internet website as a convenient two-step methodology for the preparation of DMT. The analytical characterisation of the first stage was the subject of previous publications by the authors and involved the thermal decarboxylation of tryptophan and the formation of tryptamine. The present study reports on the characterisation of the second step of this procedure which was based on the methylation of tryptamine. This employed methyl iodide and benzyltriethylammonium chloride/sodium hydroxide as a phase transfer catalyst. The reaction product was characterised by liquid chromatography/electrospray ionisation tandem mass spectrometry and orthogonal acceleration time-of-flight mass spectrometry. Quantitative evaluation was carried out in positive multiple reaction monitoring mode (MRM), which included synthesis of the identified reaction products. MRM screening of the product did not lead to the detection of DMT. Instead, 11.1% tryptamine starting material, 21.0% N,N,N-trimethyltryptammonium iodide (TMT) and 47.4% 1-N-methyl-TMT were detected. A 0.5% trace of the monomethylated N-methyltryptamine was also detected. This study demonstrated the impact on product purity of doubtful synthetic methodologies discussed on the internet.

  11. Determination of polar pesticides in olive oil and olives by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry and high resolution mass spectrometry.

    Science.gov (United States)

    Nortes-Méndez, Rocío; Robles-Molina, José; López-Blanco, Rafael; Vass, Andrea; Molina-Díaz, Antonio; Garcia-Reyes, Juan F

    2016-09-01

    This article reports the development of two HPLC-MS methods for the determination of polar pesticides in olive oil and olive samples by hydrophilic interaction liquid chromatography (HILIC) separation followed by mass spectrometry detection with tandem mass spectrometry using a triple quadrupole instrument operated in multiple reaction monitoring mode (HILIC-MS/MS) or electrospray time-of-flight mass spectrometry (HILIC-TOFMS). The selected polar pesticides included in the study were: amitrol, cyromazine, diquat, paraquat, mepiquat, trimethylsulfonium (trimesium, glyphosate counterion) and fosetyl aluminium. The simple sample treatment procedure was based on liquid partitioning with methanol. The performance of the sample extraction was evaluated in terms of recovery rates and matrix effects in both olive oil and olives matrices. The results obtained for olive oil were satisfactory while, due to the high complexity of olives, poor recovery rates were obtained for the extraction of diquat, paraquat and amitrol, although with a reasonable precision enabling its use in routine analysis. Similarly, matrix effects were minor in the case of olive oil (ca. 20% suppression average), while significantly higher suppression was observed for olives (30-50% suppression average). The studied approaches were found to be useful for the determination of the pesticides studied in olive oil and olives with limits of quantitation below 5µgkg(-1) in most cases when tandem mass spectrometry was used, thus being in compliance with MRLs set by current EU regulation.

  12. Determination of mepitiostane metabolites in human urine by liquid chromatography/tandem mass spectrometry for sports drug testing.

    Science.gov (United States)

    Okano, Masato; Sato, Mitsuhiko; Kojima, Asami; Kageyama, Shinji

    2015-11-10

    Mepitiostane (2α,3α-epithio-17β-(1-methoxycyclopentyloxy)-5α-androstane), which is a prodrug of epitiostanol (2α,3α-epitio-5α-androstane-17β-ol), is an epitiosteroid having anti-estrogenic and weak androgenic anabolic activities. The World Anti-Doping Agency prohibits the misuse of mepitiostane by athletes. Detection of the urinary metabolites epitiostanol sulfoxide and epitiostanol was studied using liquid chromatography/mass spectrometry (LC-MS) for doping control purposes. The use of LC-MS provided advantages over gas chromatography/mass spectrometry for detecting heat labile steroids because epitiostanol and epitiostanol sulfoxide were primarily pyrolized to 5α-androst-2-en-17β-ol. The method consists of enzymatic hydrolysis using β-glucuronidase (Escherichia coli), liquid-liquid extraction, and subsequent ultra-performance liquid chromatography/electrospray-tandem mass spectrometry. Epitiostanol sulfoxide was determined at urinary concentrations of 0.5-50ng/mL, recovery was 76.2-96.9%, and assay precision was calculated as 0.9-1.7% (intra-day) and 2.0-6.6% (inter-day). Epitiostanol was determined at urinary concentrations of 0.5-50ng/mL, recovery was 26.1-35.6% and assay precision was calculated as 4.1-4.6% (intra-day) and 3.3-8.5% (inter-day). The limits of detection for epitiostanol sulfoxide and epitiostanol were 0.05ng/mL and 0.10ng/mL, respectively. Epitiostanol sulfoxide and epitiostanol, as their gluco-conjugates, were identified in human urine after oral administration of 10mg mepitiostane. Epitiostanol sulfoxide and epitiostanol could be detected up to 48h and 24h after administration, respectively. The results showed that the detection window of epitiostanol is much shorter than that of epitiostanol sulfoxide. The LC-MS detection of urinary epitiostanol sulfoxide, a specific metabolite with a sulphur atom in its molecular structure, is likely to be able to identify the abuse of mepitiostane.

  13. A high-throughput method for liquid chromatography-tandem mass spectrometry determination of plasma alkylresorcinols, biomarkers of whole grain wheat and rye intake

    DEFF Research Database (Denmark)

    Ross, Alastair B; Svelander, Cecilia; Savolainen, Otto I;

    2016-01-01

    supported extraction methods for extracting alkylresorcinols from plasma and improved a normal-phase liquid chromatography coupled to a tandem mass spectrometer method to reduce sample analysis time. The method was validated and compared with gas chromatography-mass spectrometry analysis. Sample preparation...... with HybridSPE supported extraction was most effective for alkylresorcinol extraction, with recoveries of 77-82% from 100 μl of plasma. The use of 96-well plates allowed extraction of 160 samples per day. Using a 5-cm NH2 column and heptane reduced run times to 3 min. The new method had a limit of detection...

  14. Simultaneous Determination of Perfluorinated Compounds in Edible Oil by Gel-Permeation Chromatography Combined with Dispersive Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Yang, Lili; Jin, Fen; Zhang, Peng; Zhang, Yanxin; Wang, Jian; Shao, Hua; Jin, Maojun; Wang, Shanshan; Zheng, Lufei; Wang, Jing

    2015-09-30

    A simple analytical method was developed for the simultaneous analysis of 18 perfluorinated compounds (PFCs) in edible oil. The target compounds were extracted by acetonitrile, purified by gel permeation chromatography (GPC) and dispersive solid-phase extraction (DSPE) using graphitized carbon black (GCB) and octadecyl (C18), and analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ES-MS/MS) in negative ion mode. Recovery studies were performed at three fortification levels. The average recoveries of all target PFCs ranged from 60 to 129%, with an acceptable relative standard deviation (RSD) (1-20%, n = 3). The method detection limits (MDLs) ranged from 0.004 to 0.4 μg/kg, which was significantly improved compared with the existing liquid-liquid extraction and cleanup method. The method was successfully applied for the analysis of all target PFCs in edible oil samples collected from markets in Beijing, China, and the results revealed that C6-C10 perfluorocarboxylic acid (PFCAs) and C7 perfluorosulfonic acid PFSAs were the major PFCs detected in oil samples.

  15. Determining indicator toxaphene congeners in soil using comprehensive two-dimensional gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhu, Shuai; Gao, Lirong; Zheng, Minghui; Liu, Huimin; Zhang, Bing; Liu, Lidan; Wang, Yiwen

    2014-01-01

    Toxaphene, which is a broad spectrum chlorinated pesticide, is a complex mixture of several hundred congeners, mainly polychlorinated bornanes. Quantifying toxaphene in environmental samples is difficult because of its complexity, and because each congener has a different response factor. Toxaphene chromatograms acquired using one-dimensional gas chromatography (1DGC) show that this technique cannot be used to separate all of the toxaphene congeners. We developed and validated a sensitive and quantitative method for determining three indicator toxaphene congeners in soil using an isotope dilution/comprehensive two-dimensional gas chromatography-tandem mass spectrometry (GC × GC-MS). The samples were extracted using accelerated solvent extraction, and then the extracts were purified using silica gel columns. (13)C₁₀-labeled Parlar 26 and 50 were used as internal standards and (13)C₁₀-labeled Parlar 62 was used as an injection standard. The sample extraction and purification treatments and the GC × GC-MS parameters were optimized. Subsequently the samples were determined by GC × GC-MS. The limits of detection for Parlar 26, 50, and 62 were 0.6 pg/g, 0.4 pg/g, and 1.0 pg/g (S/N=3), respectively, and the calibration curves had good linear correlations between 50 and 1000 μg/L (r(2)>0.99). Comprehensive two-dimensional GC gave substantial improvements over one-dimensional GC in the toxaphene analysis. We analyzed soil samples containing trace quantities of toxaphene to demonstrate that the developed method could be used to analyze toxaphene in environmental samples.

  16. Sensitive method for detection of cocaine and associated analytes by liquid chromatography-tandem mass spectrometry in urine.

    Science.gov (United States)

    Langman, Loralie J; Bjergum, Matthew W; Williamson, Christopher L; Crow, Frank W

    2009-10-01

    Cocaine (COC) is a potent CNS stimulant that is metabolized to benzoylecgonine (BE) and further metabolized to minor metabolites such as m-hydroxybenzoylecgonine (m-HOBE). COC is also metabolized to norcocaine (NC). Cocaethylene (CE) is formed when cocaine and ethyl alcohol are used simultaneously. Anhydroecgonine methyl ester (AEME) is a unique marker following smoked cocaine, and anhydroecgonine ethyl ester (AEEE) is found in cocaine smokers who also use ethyl alcohol. We developed a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the detection and quantitation of COC, BE, NC, CE, m-HOBE, AEME, and AEEE in urine. Two hundred samples previously analyzed by gas chromatography (GC) coupled with MS were extracted using solid-phase extraction. Chromatographic separation was achieved using a gradient consisting of mobile phase A [20 mM ammonium formate (pH 2.7)] and mobile phase B (methanol/acetonitrile, 50:50), an XDB-C(8) (50 x 2.1 mm, 1.8 microm) column and a flow rate of 270 microL/min. Concentrations were calculated by comparing the peak-area with the internal standard and plotted against a standard curve. The assay displayed linearity from 1.0 to 100 ng/mL. Within- and between-run coefficients of variation were < 10% throughout the linear range. A method comparison between GC-MS and LC-MS-MS showed good correlation for COC (r(2) = 0.982) and BE (r(2) = 0.955). We report here on a sensitive method to identify clinically and forensically relevant cocaine and associated analytes at concentrations as low as 1.0 ng/mL.

  17. Simultaneous quantitative analysis of eight vitamin D analogues in milk using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Gomes, Fabio P; Shaw, P Nicholas; Whitfield, Karen; Hewavitharana, Amitha K

    2015-09-01

    Milk is an important source of nutrients for various risk populations, including infants. The accurate measurement of vitamin D in milk is necessary to provide adequate supplementation advice for risk groups and to monitor regulatory compliance. Currently used liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods are capable of measuring only four analogues of vitamin D in unfortified milk. We report here an accurate quantitative analytical method for eight analogues of vitamin D: Vitamin D2 and D3 (D2 and D3), 25-hydroxy D2 and D3, 24,25-dihydroxy D2 and D3, and 1,25-dihydroxyD2 and D3. In this study, we compared saponification and protein precipitation for the extraction of vitamin D from milk and found the latter to be more effective. We also optimised the pre-column derivatisation using 4-phenyl-l,2,4-triazoline-3,5-dione (PTAD), to achieve the highest sensitivity and accuracy for all major vitamin D forms in milk. Chromatography was optimised to reduce matrix effects such as ion-suppression, and the matrix effects were eliminated using co-eluting stable isotope labelled internal standards for the calibration of each analogue. The analogues, 25-hydroxyD3 (25(OH)D3) and its epimer (3-epi-25(OH)D3) were chromatographically resolved, to prevent over-estimation of 25(OH)D3. The method was validated and subsequently applied for the measurement of total vitamin D levels in human, cow, mare, goat and sheep milk samples. The detection limits, repeatability standard deviations, and recovery ranges were from 0.2 to 0.4 femtomols, 6.30-13.5%, and 88.2-105%, respectively.

  18. Pharmacokinetics, tissue distribution, and excretion studies of l-isocorypalmine using ultra high performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Wang, Weihui; Liu, Jing; Zhao, Xiaoning; Peng, Yan; Wang, Nannan; Lee, David Y W; Dai, Ronghua

    2017-03-01

    l-Isocorypalmine is a newly identified metabolite of l-tetrahydropalmatine with a unique dual pharmacological profile as a partial dopamine receptor 1 agonist and dopamine receptor 2 antagonist properties for treating cocaine use disorder. The purpose of this study was to explore the pharmacokinetic profiles, tissue distribution, and excretion of l-isocorypalmine in Sprague-Dawley rats. A sensitive and reliable ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for determination of l-isocorypalmine in biological samples. The biological samples were extracted by liquid-liquid extraction and separated on a Bonshell ASB C18 column (2.1 × 100 mm, 2.7 μm, Agela) with gradient mobile phase at the flow rate of 0.2 mL/min. The detection was performed by positive electrospray ionization with multiple reaction monitoring mode. Satisfactory linearity, precision, accuracy, extraction recovery, and acceptable matrix effect were achieved. The quantitative method was successfully applied to the pharmacokinetics, tissue distribution, and excretion study of l-isocorypalmine. The results showed that l-isocorypalmine was rapidly distributed, and eliminated from rat plasma and manifested linear dynamics in a dose range of 7.5-15 mg/kg. In addition, the results would be helpful for further clinical reference of l-isocorypalmine as a potential candidate drug for the treatment of cocaine addiction.

  19. [Determination of 12 flavonoids in tobacco leaves using ultra-high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Li, Yong; Lin, Qian; Pang, Tao; Shi, Junli

    2015-07-01

    Flavonoids are very important secondary metabolites for tobacco plants. They are also considered as important flavor precursors for cigarettes. A method of ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established for the simultaneous determination of 12 flavonoids in tobacco leaves. The developed method determined 10 more flavonoids compared to the traditional method. A solution of methanol-water-chloroform (5:2:2, v/v/v) was used to extract the flavonoids from tobacco leaves and remove the pigment. Instrument analysis using the UPLC-MS/MS was completed in 13 min. The method validation was performed, and the results showed that the linear correlation coefficients (r2) of all the 12 flavonoids were more than 0.99. The limits of detection and the limits of quantification were in the range of 0.3-100 μg/L and 1.2-400 μg/L, respectively. Intra-day and Inter-day reproducibilities were in the range of 3.5%-7.4% and 5.2%-11.4%, respectively. The recoveries were 81.2%-111.9%. The established method was successfully used to analyze the flavonoids of tobacco leaves of 11 varieties. Significant concentration differences of the flavonoids were found among the determined varieties. Furthermore, significant positive correlation among the flavonoids with similar chemical structures (aglycones and their related glycosides, glycosides with the same aglycone, and similar aglycones) was found using the acquired data.

  20. Determination of polycyclic aromatic hydrocarbons in soy isoflavone nutraceutical products by gas chromatography coupled to triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Ruiz-Delgado, Ana; Martínez-Domínguez, Gerardo; Romero-González, Roberto; López-Ruiz, Rosalía; Frenich, Antonia Garrido

    2016-02-01

    Thirteen polycyclic aromatic hydrocarbons have been determined in soy-based nutraceutical products. First, an optimization of extraction procedure was performed, and a solid-liquid extraction assisted by sonication and a dilute and shoot procedure were compared, selecting the dilute and shoot approach for the extraction of target compounds, utilizing a mixture of acetone/n-hexane (1:1 v/v) as extractant solvent. After this, a clean-up step was needed bearing in mind the complexity of these matrices. Dispersive solid-phase extraction, using a mixture of C18 and Zr-Sep+ (25 mg/mL each) was used. The separation was achieved by gas chromatography and detection with triple quadrupole tandem mass spectrometry. For quantification purposes, matrix-matched calibration was used. The validation was applied at three concentration levels (20, 100 and 250 μg/kg), obtaining recoveries between 70 and 120% and precision values equal to or lower than 23%. Limits of detection and quantification were below 8 and 20 μg/kg, respectively. The method was applied in 11 samples, detecting five polycyclic aromatic hydrocarbons at concentrations ranging from 4.1 to 18.5 μg/kg.

  1. Analysis of thyreostatic drugs in thyroid samples by ultra-performance liquid chromatography tandem mass spectrometry detection.

    Science.gov (United States)

    Abuín, S; Centrich, F; Rúbies, A; Companyó, R; Prat, M D

    2008-06-09

    A method based on ultra-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry for the determination of six thyreostatic drugs in thyroid tissue has been optimised and validated in accordance with the Decision 2002/657/EC. Samples are extracted with methanol and the extracts cleaned-up on silica cartridges. The recoveries range from 40% for 6-phenyl-2-thiouracil to 79% for 2-thiouracil. Quantification is carried out with blank tissue samples spiked with the analytes in the range 25-500 microg kg(-1). 5,6-Dimethyl-2-thiouracil is used as internal standard. CCalpha and CCbeta are in the ranges 4.3-16.1 microg kg(-1) and 8.7-20.7 microg kg(-1), respectively. Accuracy, expressed as percentage of error, is lower than 6% and relative standard deviation in reproducibility conditions falls between 5.6 and 10.3%. Nowadays, the proposed method is routinely implemented in the laboratory of the Agència de Salut Pública de Barcelona and allows processing of up to 20 samples per day.

  2. A Quantitative Analysis of Memantine in Human Plasma Using Ultra Performance Liquid Chromatography/Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Sunil K. Dubey

    2009-01-01

    Full Text Available The aim of this study is to compare the single-dose oral bioavailability of memantine hydrochloride 10 mg tablets of Ranbaxy Laboratories Limited, with NAMENDA™ tablets (containing memantine hydrochloride 10 mg of Forest Pharmaceuticals Inc. in healthy, adult, human subjects under fasting condition. The study was carried out as 2-way crossover design on 8 subjects in fasting and fed conditions. The plasma samples were obtained over a 72 h post dose in each period. Plasma memantine samples were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS with positive ion electro spray ionization using multiple reactions monitoring (MRM. A sensitive, reproducible, accurate and validated LC-MS/MS method with limit of quantification (LOQ 0.200 ng/mL was used to analyze memantine. Ln transformed AUC0-72 and Cmax were assessed for bioequivalence using 90% confidence interval (CI. 90% confidence intervals for the ratio of test and reference (Ratio of least-squares mean for ln-transformed AUC0-72 and Cmax were within the regulatory acceptance criteria of 80-125%.

  3. [Determination of thiourea dioxide in lotus seed paste fillings by solid phase extraction-liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Wang, Hui; Zeng, Xiwen; Chang, Xiaotu; Peng, Xinkai; Xia, Lixin; Li, Yiwei

    2014-01-01

    A method of solid phase extraction-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) was developed to determine thiourea dioxide which was illegally added into lotus seed paste fillings. An amount of 0.05% (v/v) acetic acid was used to extract thiourea dioxide from fillings, and the BOND ELUT PLEXA column (60 mg/3 mL) was used as the SPE column to clean-up the extraction. Then, an Agilent HILIC column (100 mm x 2.1 mm, 3.5 microm) was applied to separate target compounds by using the mobile phases of 0.01 mol/L ammonium acetate (pH 3.5) and acetonitrile. Qualitative and quantitative analyses were operated by the multiple reaction monitoring (MRM) mode. The calibration curve showed a good linearity for the target compound in the detection range of 10 - 1 000 microg/L. The limit of detection (LOD) and limit of quantitation (LOQ) of this method were 8.0 microg/kg and 30.0 microg/kg, respectively. The recoveries were in the ranges of 75.3% - 80.7% with the RSDs of no more than 4.83%. This proposed method was rapid, highly specific and suitable for the confirmation and quantitative determination of thiourea dioxide in lotus seed paste fillings.

  4. Simultaneous quantitation of atorvastatin and its two active metabolites in human plasma by liquid chromatography/(-) electrospray tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Pankaj Partani; S. Manaswita Verma; Sanjay Gurule; Arshad Khuroo; Tausif Monif

    2014-01-01

    A sensitive, accurate and selective liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was developed and validated for the simultaneous quantitation of atorvastatin (AT) and its equipotent hydroxyl metabolites, 2-hydroxy atorvastatin (2-AT) and 4-hydroxy atorvastatin (4-AT), in human plasma. Electrospray ionization (ESI) interface in negative ion mode was selected to improve the selectivity and the sensitivity required for this application. Additionally, a solid phase extraction (SPE) step was performed to reduce any ion-suppression and/or enhancement effects. The separation of all compounds was achieved in less than 6 min using a C18 reverse-phase fused-cores column and a mobile phase, composed of a mixture of 0.005%formic acid in water:acetonitrile:methanol (35:25:40, v/v/v), in isocratic mode at a flow rate of 0.6 mL/min. The method has lower limit of quantitation (LLOQ) of 0.050 ng/mL for all analytes. The method has shown tremendous reproducibility, with intra-and inter-day precision less than 6.6%, and intra- and inter-day accuracy within 74.3% of nominal values, for all analytes, and has proved to be highly reliable for the analysis of clinical samples.

  5. [Simultaneous determination of eleven sex hormones in antler velvet health products by gas chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lu, Chunmei; Wang, Mingtai; Mu, Jun; Lu, Lijun; Zhou, Xiao

    2011-06-01

    A method for the simultaneous determination of 11 sex hormones in antler velvet health products by gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The sex hormones in antler velvet were enriched and purified by solid phase extraction and derivatized with heptafluorobutyric acid anhydride (HFBA). A DB-5 column (30 m x 0.25 mm, 0.25 microm) with nonlinear gradient program was used in GC separation. The sex hormones were determined in the multiple reaction monitoring mode. The method realized the complete separation of 11 sex hormones. The limits of detection of this method were from 1.0 to 5.0 microg/kg for the 11 sex hormones. The correlation coefficients were between 0.991 6 and 0.999 9. The recoveries were in the range of 67.4% - 99.1% with relative standard deviations (RSDs) of 2.6% - 13%. This method is accurate and reliable for the determination of the sex hormones in antler velvet health products.

  6. [Determination of 14 mycotoxins in Chinese herbs by liquid chromatography-tandem mass spectrometry with immunoaffinity purification].

    Science.gov (United States)

    Ge, Baokun; Zhao, Kongxiang; Wang, Wei; Mi, Jiebo

    2011-06-01

    A method was developed for the determination of 14 mycotoxins, aflatoxins, T-2, HT-2, fumonisins, ochratoxin A, zearalenone, etc. in Chinese herbs by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). The sample was extracted with phosphate buffer solution (PBS) and methanol in turn, and then purified by a high selective multi-functional immunoaffinity column. The column was washed by PBS (containing 0.1% Twain) and water, and then eluted by methanol. The eluate was dried under nitrogen, dissolved in methanol-10 mmol/L NH4Ac (40 : 60, v/v) solution. The mycotoxins were separated on a Waters Xterra C18 MS column (100 mm x 2.1 mm, 3.5 microm) and detected by MS/MS. The limits of quantification (LOQs) of the 14 mycotoxins were from 1.0 to 5.0 microg/kg. The average recoveries of the 14 mycotoxins spiked in Chinese herbs (Ginseng, Campanulaceae, Radix and Ophiopogonis) ranged from 71.9% to 99.7% at the three spiked levels of 1.0, 5.0, 10.0 microg/kg, and the relative standard deviations (RSDs, n = 6) were between 4.8% and 15.8%. The method is rapid, sensitive and accurate, and suitable for the determination of the 14 mycotoxins in Chinese medicines. The quantification limits of aflatoxins can meet the domestic and foreign requirements.

  7. A robust analytical method for measurement of phytoestrogens and related metabolites in serum with liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Jiang, Hongmei; Liao, Xiangjun; Wood, Carla M; Xiao, Chao-Wu; Feng, Yong-Lai

    2016-02-15

    A sensitive and robust method using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for quantitation of 13 phytoestrogens and related metabolites in rat serum samples. A new type of column, the Kinetex core-shell C18 column, was applied for rapid separation of the target analytes in 10min. Two enzymes, sulfatase H-1 and gulcuronidase H-5 from Helix pomatia were compared on the efficiency of releasing the conjugated forms of the target analytes to their free forms in serum samples. The method detection limit (MDL) defined as three times the signal to noise ratio in spiked serum matrix-based solutions was in the range of 0.1-3.5ng/mL. The linear dynamic calibration was in the broad range of 0.2-500ng/mL for all target compounds. Thirty-two rat serum samples from the rats that were fed with diets containing either casein or soy protein isolates with various amounts of isoflavones for 8 weeks were analyzed for the target analytes with the developed method. Nine target analytes were detected in the serum samples. Those detectable compounds are all the metabolites of the dietary isoflavones, suggesting that the diet isoflavones were mostly metabolized to their metabolites in rat.

  8. [Determination of rhodamine B in spices by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Yin, Feng; Ding, Zhaowei; Yang, Zhijian

    2012-07-01

    Rhodamine B (RB), as an unlawful colour, is forbidden to add into foods by Chinese government. A solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method for the determination of RB in spices has been developed. The sample was extracted by acetonitrile and then centrifugated, purified and enriched with a strong positive ion exchange SPE column (Bond Elut Plexa PCX SPE column) after adding 10 mL 1% trichloroacetic acid solution. The HPLC separation was performed on a Pursuit C18 column (100 mm x 2.0 mm, 3 microm) by gradient elution with 0.1% (v/v) formic acid solution and methanol as the mobile phase. The analyte was detected by electrospray ionization in positive ion mode-MS/MS in multiple reaction monitoring (MRM) mode. The good linearity (R2 > 0.99) was obtained over the range of 0.6-6 microg/L. The limit of quantification (LOQ) for RB was 1.2 microg/kg. The average recoveries were ranged from 80% to 121% at the spiked levels of 1.197, 2.992 and 5.985 microg/L, and the relative standard deviations (RSDs) were not more than 15%. The conditions of mobile phase elution gradients, extraction solvents, and SPE columns were optimized. This method is highly selective and has weak matrix effect for qualitative and quantitative analyses of RB in spices.

  9. Determination of perfluorooctane sulfonate and perfluorooctanoic acid in food packaging using liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Poothong, Somrutai; Boontanon, Suwanna Kitpati; Boontanon, Narin

    2012-02-29

    This research aimed to monitor the amounts of PFOS and PFOA in food packaging and study the migration of PFOS and PFOA from food packaging, using a saliva simulant and pressurized liquid extraction (PLE) technique. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was employed to determine residues of PFOS and PFOA by using a gradient reversed-phase method with ammonium acetate/acetonitrile buffer. A good linearity was established for PFOS and PFOA in a range of 0.05-10 μgL(-1), with R2 ≥ 0.9998. Of the samples extracted by methanol, the highest concentration of PFOS was found in fast-food container samples, at a level of 92.48 ng dm(-2). For PFOA, the highest concentration in samples extracted by methanol was found in ice cream cup samples, at a level of 16.91 ng dm(-2). The amounts of PFOS and PFOA that migrated from food packaging samples through contact with saliva simulant were 4.80 and 4.55 ng dm(-2), respectively. Saliva simulant could leach PFOS and PFOA from the group of the thickest paper samples (≤1 dm2 g(-1)) at levels of 7.01 and 6.41 ng dm(-2), respectively, indicating that paper with greater thickness and less area might release larger quantities of coated/added PFOS or PFOA.

  10. [Determination of dimethyl fumarate in leather and textiles by gas chromatography-tandem mass spectrometry with solid phase extraction].

    Science.gov (United States)

    Zhao, Yang; Qi, Xiaoxia

    2010-01-01

    An effective method for the determination of dimethyl fumarate (DMF) in leather and textiles by gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. Samples of leather or textiles were extracted with ethyl acetate and concentrated, DMF was separated on a VF-5 ms column and analyzed by GC-MS/MS after solid phase extraction (SPE) process. The result shows that this method is sensitive, accurate and reliable. The linear relationship was perfect and the interference with background signal was further eliminated after pretreatment, SPE and GC-MS/MS analytical conditions were optimized. The average recoveries of DMF in leather and textiles at three levels ranged from 84% to 93%, the relative standard deviations (n = 6) were lower than 7.2%, the limits of detection in the range from 0.012 to 0.039 mg/kg (S/N = 3) , the correlation coefficient was 0.999 0 over the range 0.05 - 100 mg/L. It has been applied to routine determination of DMF in leather and textiles with satisfactory results.

  11. Quantification of roxatidine in human plasma by liquid chromatography electrospray ionization tandem mass spectrometry: application to a bioequivalence study.

    Science.gov (United States)

    Ryu, Ju-Hee; Choi, Sang-Jun; Lee, Heon-Woo; Choi, Seung-Ki; Lee, Kyung-Tae

    2008-12-01

    A sensitive and specific method using a one-step liquid-liquid extraction (LLE) with ethyl acetate followed by high-performance liquid chromatography (HPLC) coupled with positive ion electrospray ionization tandem mass spectrometry (ESI-MS/MS) detection was developed and validated for the determination of roxatidine in human plasma using famotidine as an internal standard (IS). Data acquisition was carried out in multiple reaction monitoring (MRM) mode, by monitoring the transitions m/z 307.3-->107.1 for roxatidine and m/z 338.4-->189.1 for famotidine. Chromatographic separation was performed on a reverse phase Hydrosphere C(18) column at 0.2 mL min(-1) using a mixture of methanol-ammonium formate buffer as mobile phase (20:80, v/v; adjusted to pH 3.9 with formic acid). The achieved lower limit of quantification (LLOQ) was 1.0 ng mL(-1) and the standard calibration curve for roxatidine was linear (r(2)=0.998) over the studied range (1-1000 ng mL(-1)) with acceptable accuracy and precision. Roxatidine was found to be stable in human plasma samples under short-, long-term storage and processing conditions. The developed method was validated and successfully applied to the bioequivalence study of roxatidine administrated as a single oral dose (75 mg as roxatidine acetate hydrochloride) to healthy female Korean volunteers.

  12. Colostrum protein uptake in neonatal lambs examined by descriptive and quantitative liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Hernández-Castellano, Lorenzo E; Argüello, Anastasio; Almeida, André M; Castro, Noemí; Bendixen, Emøke

    2015-01-01

    Colostrum intake is a key factor for newborn ruminant survival because the placenta does not allow the transfer of immune components. Therefore, newborn ruminants depend entirely on passive immunity transfer from the mother to the neonate, through the suckling of colostrum. Understanding the importance of specific colostrum proteins has gained significant attention in recent years. However, proteomics studies of sheep colostrum and their uptake in neonate lambs has not yet been presented. The aim of this study was to describe the proteomes of sheep colostrum and lamb blood plasma, using sodium dodecyl sulfate-PAGE for protein separation and in-gel digestion, followed by liquid chromatography-tandem mass spectrometry of resulting tryptic peptides for protein identification. An isobaric tag for relative and absolute quantitation (iTRAQ)-based proteomics approach was subsequently used to provide relative quantification of how neonatal plasma protein concentrations change as an effect of colostrum intake. The results of this study describe the presence of 70 proteins in the ovine colostrum proteome. Furthermore, colostrum intake resulted in an increase of 8 proteins with important immune functions in the blood plasma of lambs. Further proteomic studies will be necessary, particularly using the selected reaction monitoring approach, to describe in detail the role of specific colostrum proteins for immune transfer to the neonate.

  13. [Determination of 99 pesticide residues in Paeoniae Radix Alba by gas chromatography-triple quadrupole tandem mass spectrometry].

    Science.gov (United States)

    Liu, Xiaoqin; Tong, Ling; Meng, Wenting; Sun, Guoxiang

    2015-08-01

    A method was established for the simultaneous determination of 99 pesticide residues with combination of solid-phase extraction technique ( SPE) and gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS). The sample was extracted with ethyl acetate, and cleaned-up by an amino SPE column. The extract was determined by GC-MS/MS in multi-reaction monitoring (MRM) mode, and matrix-matched internal standard method was applied to quantify the pesticides. The results of all the 99 pesticides showed good linearity in the range of 0.001-0.25 mg/L, with correlation coefficients (r2) > 0.99. The limits of quantification (LOQs) were between 0.001-0.050 mg/kg. The recoveries were between 66.7% and 128.0% with RSD values typically lower than 18.3% at three spiked levels of 0.05, 0.10 and 0.20 mg/kg. This method has been applied to determine thirteen batches of commercially available samples, chlorpyriphos-ethyl and p,p'-DDE were detected in four batches of Paeoniae Radix Alba. The method is highly accurate, reliable and sensitive for monitoring the 99 pesticide residues in Paeoniae Radix Alba.

  14. A Liquid ChromatographyTandem Mass Spectrometry Approach for the Identification of Mebendazole Residue in Pork, Chicken, and Horse

    Science.gov (United States)

    Lee, Ji Sun; Cho, Soo Hee; Lim, Chae Mi; Chang, Moon Ik; Joo, Hyun Jin; Park, Hyun Jin

    2017-01-01

    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. PMID:28085912

  15. Identification of stereoisomeric metabolites of meisoindigo in rat liver microsomes by achiral and chiral liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Huang, Meng; Goh, Lin Tang; Ho, Paul C

    2008-11-01

    N-methylisoindigotin, abbreviated as meisoindigo, has been a routine therapeutic agent in the clinical treatment of chronic myelogenous leukemia in China since the 1980s. However, information relevant to in vitro metabolism of meisoindigo is limited. In this study, in vitro stereoisomeric metabolites of meisoindigo in rat liver microsomes were identified for the first time by achiral and chiral liquid chromatography/tandem mass spectrometry, together with proton NMR spectroscopy and synchrotron infrared spectroscopy. The major in vitro phase I metabolites of meisoindigo were tentatively identified as stereoselective-reduced meisoindigo, which comprised a pair of (3-R, 3'-R) and (3-S, 3'-S) enantiomers with lower abundance, as well as another pair of (3-R, 3'-S) and (3-S, 3'-R) enantiomers with higher abundance. One type of minor in vitro metabolites was tentatively identified as stereoselective N-demethyl-reduced meisoindigo including a pair of (3-R, 3'-R) and (3-S, 3'-S) enantiomers, as well as one meso compound. Another type of minor in vitro metabolites was tentatively identified as both stereoselective and regioselective monohydroxyl-reduced meisoindigo. Based on the metabolite profiling, three parallel metabolic pathways of meisoindigo in rat liver microsomes were proposed.

  16. Simultaneous analysis of gamma-hydroxybutyric acid and its precursors in urine using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wood, Michelle; Laloup, Marleen; Samyn, Nele; Morris, Michael R; de Bruijn, Ernst A; Maes, Robert A; Young, Michael S; Maes, Viviane; De Boeck, Gert

    2004-11-12

    We have developed a rapid method that enables the simultaneous analysis of gamma-hydroxybutyrate (GHB) and its precursors, i.e. gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD) in urine. The method comprised a simple dilution of the urine sample, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Chromatographic separation was achieved using an Atlantis dC18 column, eluted with a mixture of formic acid and methanol. The method was linear from 1-80 mg/L for GHB and 1,4-BD and from 1-50 mg/L for GBL. The limit of quantification was 1 mg/L for all analytes. The procedure, which has a total analysis time (including sample preparation) of less than 12 min, was fully validated and applied to the analysis of 182 authentic urine samples; the results were correlated with a previously published GC-MS procedure and revealed a low prevalence of GHB-positive samples. Since no commercial immunoassay is available for the routine screening of GHB, this simple and rapid method should prove useful to meet the current increased demand for the measurement of GHB and its precursors.

  17. Determination of neonicotinoid insecticides and strobilurin fungicides in particle phase atmospheric samples by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Raina-Fulton, Renata

    2015-06-01

    A liquid chromatography-tandem mass spectrometry method has been developed for the determination of neonicotinoids and strobilurin fungicides in the particle phase fraction of atmosphere samples. Filter samples were extracted with pressurized solvent extraction, followed by a cleanup step with solid phase extraction. Method detection limits for the seven neonicotinoid insecticides and six strobilurin fungicides were in the range of 1.0-4.0 pg/m(3). Samples were collected from June to September 2013 at two locations (Osoyoos and Oliver) in the southern Okanagan Valley Agricultural Region of British Columbia, where these insecticides and fungicides are recommended for use on tree fruit crops (apples, pears, cherries, peaches, apricots) and vineyards. This work represents the first detection of acetamiprid, imidacloprid, clothianidin, kresoxim-methyl, pyraclostrobin, and trifloxystrobin in particle phase atmospheric samples collected in the Okanagan Valley in Canada. The highest particle phase atmospheric concentrations were observed for imidacloprid, pyraclostrobin, and trifloxystrobin at 360.0, 655.6, and 1908.2 pg/m(3), respectively.

  18. [Simultaneous determination of 11 bisphenols in plastic bottled drinking water by ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Gou, Xinlei; Gao, Xia; Hu, Guanghui; Chi, Haitao; Le, Shengfeng; Wang, Wei; Liu, Weili

    2014-09-01

    A sensitive method was developed for the simultaneous determination of 11 bisphenols in plastic bottled drinking water by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were freeze-dried under vacuum and then dissolved with methanol. The separation was performed on a UPLC BEH C18 column (100 mm x 2.1 mm, 1.7 μm) by using 0.1% (v/v) NH3 · H2O and methanol as mobile phases with gradient elution at a flow rate of 0.2 mL/min. The electrospray ionization (ESI) source in negative ion mode was used for the analysis of the 11 bisphenols in the multiple reaction monitoring (MRM) mode. The results verified that the standard curves for the 11 bisphenols were obtained with good correlation coefficients (R2) > 0.997 in their concentration ranges. The limits of detection (LOD, S/N = 3) for the 11 bisphenols were in the range of 0.01-1.00 μg/L. The mean recoveries for the 11 bisphenols at three spiked levels (low, middle, high) were 75.3%-102.1% with the relative standard deviations of 1.5%-8.9%. Seven plastic bottled drinking water samples were tested, and no bisphenol was found. The method is accurate, simple, rapid and feasible for the simultaneous determination of bisphenols in plastic bottled drinking water.

  19. Quantification of Docetaxel in Serum Using Turbulent Flow Liquid Chromatography Electrospray Tandem Mass Spectrometry (TFC-HPLC-ESI-MS/MS).

    Science.gov (United States)

    Crutchfield, Christopher A; Marzinke, Mark A; Clarke, William A

    2016-01-01

    Docetaxel is a second-generation taxane and is used clinically as an anti-neoplastic agent in cancer chemotherapy via an anti-mitotic mechanism. Its efficacy is limited to a narrow therapeutic window. Inappropriately high concentrations may cause erythema, fluid retention, nausea, diarrhea, and neutropenia. As a result, dosing recommendations have changed from high dosage loading every 3 weeks to lower dosage loading weekly. We describe a method that can be used for therapeutic drug monitoring of docetaxel levels using turbulent flow liquid chromatography electrospray tandem mass spectrometry (TFC-HPLC-ESI-MS/MS). The method is rapid, requiring only 6.3 min per analytical run following a simple protein crash. The method requires only 100 μL of serum. Concentrations of docetaxel were quantified by a calibration curve relating the peak-area ratio of docetaxel to a deuterated internal standard (docetaxel-D9). The method was linear from 7.8 to 1000 ng/mL, with imprecision ≤6.2 %.

  20. Quantification of Tricyclic Antidepressants in Serum Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

    Science.gov (United States)

    Crutchfield, Christopher A; Breaud, Autumn R; Clarke, William A

    2016-01-01

    Tricyclic antidepressants (TCA) are used to treat major depressive disorder and other psychological conditions. The efficacy of these drugs is tied to a narrow therapeutic window. Inappropriately high drug concentrations can result in serious side effects such as hypotension, tachycardia, or coma. As a result, concentrations of tricyclic antidepressants are routinely monitored to ensure compliance and to prevent adverse side effects by dose adjustments. We describe a method for the determination of concentrations of amitriptyline, desipramine, imipramine, and nortriptyline in human serum using high-performance liquid chromatography coupled to a tandem mass spectrometer with electrospray ionization (HPLC-ESI-MS/MS). The method is rapid, requiring only 3.5 min per analysis. The method requires 100 μL of serum. Concentrations of each TCA were quantified by a calibration curve relating the peak area ratio of each TCA analyte to a deuterated internal standard (amitriptyline-D3, desipramine-D3, imipramine-D3, and nortriptyline-D3). The method was linear from ~70 ng/mL to ~1000 ng/mL for all TCAs, with imprecision ≤ 12%.

  1. Quantification of Iohexol in Serum by High-Performance Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

    Science.gov (United States)

    Vicente, Faye B; Vespa, Gina; Miller, Alan; Haymond, Shannon

    2016-01-01

    Iohexol is a nonradioactive contrast medium, and its clearance from serum or urine is used to measure glomerular filtration rate (GFR). GFR is the most useful indicator of kidney function and progression of kidney disease. GFR determination using iohexol clearance is increasingly being applied in clinical practice, given its advantages over and correlation with inulin. We describe a high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method for iohexol clearance, requiring only 50 μL of serum. The sample preparation involves protein precipitation with LC/MS-grade methanol, containing ioversol as the internal standard. Samples are centrifuged and supernatant is dried under nitrogen gas at room temperature. Samples are reconstituted with mobile phase (ammonium acetate-formic acid-water). Iohexol is separated using an HPLC gradient method on a C-8 analytical column. MS/MS detection is in the multiple-reaction monitoring (MRM) mode and the transitions monitored are m/z 822.0 to m/z 804.0 and m/z 807.0 to m/z 588.0 for iohexol and ioversol, respectively.

  2. Simple determination of fluoride in biological samples by headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kwon, Sun-Myung; Shin, Ho-Sang

    2015-08-14

    A simple and convenient method to detect fluoride in biological samples was developed. This method was based on derivatization with 2-(bromomethyl)naphthalene, headspace solid phase microextraction (HS-SPME) in a vial, and gas chromatography-tandem mass spectrometric detection. The HS-SPME parameters were optimized as follows: selection of CAR/PDMS fiber, 0.5% 2-(bromomethyl)naphthalene, 250 mg/L 15-crown-5-ether as a phase transfer catalyst, extraction and derivatization temperature of 95 °C, heating time of 20 min and pH of 7.0. Under the established conditions, the lowest limits of detection were 9 and 11 μg/L in 1.0 ml of plasma and urine, respectively, and the intra- and inter-day relative standard deviation was less than 7.7% at concentrations of 0.1 and 1.0 mg/L. The calibration curve showed good linearity of plasma and urine with r=0.9990 and r=0.9992, respectively. This method is simple, amenable to automation and environmentally friendly.

  3. Quantitation of the immunodominant 33-mer peptide from α-gliadin in wheat flours by liquid chromatography tandem mass spectrometry

    Science.gov (United States)

    Schalk, Kathrin; Lang, Christina; Wieser, Herbert; Koehler, Peter; Scherf, Katharina Anne

    2017-01-01

    Coeliac disease (CD) is triggered by the ingestion of gluten proteins from wheat, rye, and barley. The 33-mer peptide from α2-gliadin has frequently been described as the most important CD-immunogenic sequence within gluten. However, from more than 890 published amino acid sequences of α-gliadins, only 19 sequences contain the 33-mer. In order to make a precise assessment of the importance of the 33-mer, it is necessary to elucidate which wheat species and cultivars contain the peptide and at which concentrations. This paper presents the development of a stable isotope dilution assay followed by liquid chromatography tandem mass spectrometry to quantitate the 33-mer in flours of 23 hexaploid modern and 15 old common (bread) wheat as well as two spelt cultivars. All flours contained the 33-mer peptide at levels ranging from 91–603 μg/g flour. In contrast, the 33-mer was absent (

  4. Simultaneous determination of mono- and disubstituted polyfluoroalkyl phosphates in drinking water by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Ding, Huanhuan; Peng, Hui; Yang, Min; Hu, Jianying

    2012-03-02

    A sensitive liquid chromatography-electrospray tandem mass spectrometry method was established for the simultaneous determination of five monosubstituted polyfluoroalkyl phosphates (monoPAPs) and eight disubstituted polyfluoroalkyl phosphates (diPAPs) in drinking water. Complete separation and good retention for 13 polyfluoroalkyls phosphates (PAPs) were achieved with a Waters ACUITY UPLC BEH C8 column using a mixture of methanol/water containing 0.1% NH₄OH as the mobile phases. Extraction of drinking water samples was performed on weak anion exchange (WAX) cartridges, and the recoveries of target compounds were from 65 to 110%. The limits of quantization (LOQs) for 13 analytes were in the range of 0.4-40 ng/L. This method was applied to analyze the PAPs in drinking water samples from three cities in China. Of the 13 PAPs, six PAPs including 6:2 monoPAP (13.0 ng/L), 8:2 monoPAP (3.6 ng/L), 10:1 monoPAP (4.3-70.3 ng/L), 10:2 monoPAP (1.4-5.6 ng/L), 8:2 diPAP (0.10 ng/L), and 10:1 diPAP (0.8-3.8 ng/L) were detected.

  5. Determination of salbutamol and salbutamol glucuronide in human urine by means of liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Mareck, Ute; Guddat, Sven; Schwenke, Anne; Beuck, Simon; Geyer, Hans; Flenker, Ulrich; Elers, Jimmi; Backer, Vibeke; Thevis, Mario; Schänzer, Wilhelm

    2011-01-01

    The determination of salbutamol and its glucuronide in human urine following the inhalative and oral administration of therapeutic doses of salbutamol preparations was performed by means of direct urine injection utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) and employing d(3)-salbutamol and d(3)-salbutamol glucuronide as internal standards. Unconjugated salbutamol was detected in all administration study urine samples. Salbutamol concentrations following inhalation were commonly (99%) below 1000 ng/ml whereas values after oral administration frequently (48%) exceeded this threshold. While salbutamol glucuronide was not detected in urine samples collected after inhalation of the drug, 26 out of 82 specimens obtained after oral application contained salbutamol glucuronide with a peak value of 63 ng/ml. The percentage of salbutamol glucuronide compared to unconjugated salbutamol was less than 3%. Authentic doping control urine samples indicating screening results for salbutamol less than 1000 ng/ml, showed salbutamol glucuronide concentrations between 2 and 6 ng/ml, whereas adverse analytical findings resulting from salbutamol levels higher than 1000 ng/ml, had salbutamol glucuronide values between 8 and 15 ng/ml. The approach enabled the rapid determination of salbutamol and its glucuronic acid conjugate in human urine and represents an alternative to existing procedures since time-consuming hydrolysis or derivatization steps were omitted. Moreover, the excretion of salbutamol glucuronide in human urine following the administration of salbutamol was proven.

  6. Determination of salbutamol in human plasma and urine using liquid chromatography coupled to tandem mass spectrometry and its pharmacokinetic study.

    Science.gov (United States)

    Zhang, Dujuan; Teng, Yanni; Chen, Keguang; Liu, Sha; Wei, Chunmin; Wang, Benjie; Yuan, Guiyan; Zhang, Rui; Liu, Xiaoyan; Guo, Ruichen

    2012-10-01

    A sensitive and selective liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of salbutamol in human plasma and urine, and successfully applied to the pharmacokinetic study of salbutamol in Chinese healthy volunteers after inhalation of salbutamol sulfate aerosol. Salbutamol and the internal standard (IS) acetaminophen in plasma and urine were extracted with ethyl acetate, separated on a C(18) reversed-phase column, eluted with mobile phase of acetonitrile-ammonium acetate (5 m m; 30:70, v/v), ionized by positive ion pneumatically assisted electrospray and detected in the multi-reaction monitoring mode using precursor → product ions of m/z 240.2 → 148.1 for salbutamol and 152 → 110 for the IS. The lower limits of quantitation of salbutamol in human plasma and urine by this method were 0.02 and 1 ng/mL, respectively. The specificity, matrix effect, recovery, sensitivity, linearity, accuracy, precision and several stabilities were validated for salbutamol in human plasma and urine. In conclusion, the validation results showed that this method is robust, specific and sensitive, and can successfully fulfill the requirement of clinical pharmacokinetic study of salbutamol in healthy Chinese volunteers.

  7. Development and validation of a liquid chromatography with tandem mass spectrometry method for the determination of nitroimidazole residues in beeswax.

    Science.gov (United States)

    Mitrowska, Kamila; Antczak, Maja

    2017-03-01

    In this study, a new method for the determination of 12 nitroimidazoles and their hydroxymetabolites (metronidazole, hydroxymetronidazole, dimetridazole, ronidazole, hydroxydimetridazole, ipronidazole, hydroxyipronidazole, carnidazole, ornidazole, secnidazole, ternidazole, tinidazole) in beeswax has been developed and validated. The optimized sample preparation procedure included melting and dilution of beeswax in a mixture of n-hexane and isopropanol followed by extraction with 2% acetic acid. The extracts were purified on strong cation exchange based solid-phase extraction cartridges and evaporated in a vacuum system with vortex motion. The separation and detection of the nitroimidazoles in the beeswax extracts were achieved within 12 min by liquid chromatography tandem mass spectrometry using a pentafluorophenyl analytical column and applying a gradient elution with acetonitrile and 0.01% acetic acid as mobile phases. The method performance characteristics were evaluated at three concentration levels (1, 2, and 5 μg/kg) and the method was found to be suitable for determination of all tested nitroimidazoles. The limits of detection and quantification were 0.2-0.5 and 0.5-1 μg/kg, respectively. The recoveries varied from 71.2 to 104.9% while the relative standard deviations were less than 13.8% under the intermediate precision conditions.

  8. Determination of Flavonoids and Anthocyanins in Nitraria tangutorum by High Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry.

    Science.gov (United States)

    Zhe, Gao; Ying-Chun, Wang; Yan-Xu, Chang

    2016-01-01

    Using high-performance liquid chromatography coupled with diode array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-MSn) method, qualitative and quantitative analysis of flavonoids of stems, leaves, fruits and seeds, and anthocyanidin of fresh fruits in Nitraria tangutorum were performed. A total of 14 flavonoid components were identified from the seeds of N. tangutorum including three quercetin derivatives, three kaempferol derivatives, and eight isorhamnetin derivatives. A total of 12, 10, and 7 flavonoid components were identified from leaves, stems, and fruits of N. tangutorum, respectively; all were present in seeds also. The total content of flavonoids in leaves was the highest, up to 42.43 mg/g·dry weight. A total of 12 anthocyanidin components were identified from the fresh fruits of N. tangutorum, belonging to five anthocyanidin. The total content of anthocyanidin in fresh fruits was up to 45.83 mg/100 g· fresh weight, of which the acylated anthocyanidin accounted for 65.7%. The HPLC-DAD-MS(n) method can be operated easily, rapidly, and accurately, and is feasible for qualitative and quantitative analysis of flavone glycosides in N. tangutorum.

  9. Determination of L-ephedrine, pseudoephedrine, and caffeine in rat plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cooper, Stephen D; Fletcher, Brenda L; Silinski, Melanie A Rehder; Brown, Sherri S; Lodge, Jon W; Fernando, Reshan A; Collins, Bradley J

    2011-07-01

    A rapid and simple liquid chromatography tandem mass spectrometry method was developed and validated for the simultaneous determination of L-ephedrine, pseudoephedrine, and caffeine in male Fisher-344 rat plasma at nanogram-per-milliliter concentrations for use in support of toxicology studies. Only 25 μL of plasma is required, and extraction is performed using a simple, single-step protein precipitation. The method was validated over a range of 2.09 to 5460 ng/mL for L-ephedrine, 2.09 to 5050 ng/mL for pseudoephedrine and 2.03 to 5340 ng/mL for caffeine. A binary gradient elution at 0.3 mL/min was used with a Waters XBridge Phenyl (2.1 × 150 mm, 3.5 μm) column and a Waters XBridge Phenyl 2.1- × 10-mm guard column at ambient temperature. The mobile phase consisted of 10 mM ammonium acetate in water (pH 5.0) and methanol. Caffeine trimethyl-(13)C(3) was used as the internal standard. The method was evaluated for linearity, recovery, precision, accuracy, and stability, and it was successfully applied in toxicokinetic studies of ephedrine, administered alone, in combination with caffeine, and in the herbal source Ma Huang.

  10. [Determination of 16 pesticide residues in fruits and vegetables by QuEChERS-liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Wu, Yan; Jiang, Bing; Xu, Yigang; Zhao, Wei; Meng, Xiangrui; Zhou, Yuan; Yu, Jiahui; Zu, Yuangang

    2015-03-01

    A sensitive and convenient liquid chromatography-tandem mass spectrometric method was developed for the determination of 16 pesticides such as imidacloprid, prochloraz, difenoconazole, azoxystrobin, and thiamethoxam in fruits and vegetables. After compared with methanol and acetone-cyclohexane (1:2, v/v), acetonitrile was chosen as the extraction solvent. The samples were extracted by acetonitrile in high-speed homogenization. The extraction solution was cleaned up by liquid-liquid extraction, and the supernatant was collected. In this work, QuEChERS exhibited much higher efficiency than Carbon-NH2 solid-phase extraction in purification. The pigments and organic acids were removed by purge line (150 mg primary secondary amine (PSA) sorbent and 900 mg absolute magnesium sulfate), leading to the decrease of the background interferences. The average recoveries of the 16 pesticides were almost in the range of 75%-111% at the three spiked levels, and the relative standard deviations were less than 16%. The qualitative analysis and quantitative analysis were investigated by LC-MS/MS and matrix-matched calibration curves. The results showed that the method of QuEChERS combined with LC-MS/MS is rapid, accurate and sensitive for the determination of the 16 pesticide residues in fruits and vegetables.

  11. Multiresidue analysis of atrazine, diuron and their degradation products in sewage sludge by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Ghanem, Aline; Bados, Philippe; Perreau, François; Benabdallah, Rachid; Plagellat, Cécile; de Alencastro, Luiz Felippe; Einhorn, Jacques

    2008-05-01

    A multiresidue method has been developed to analyze atrazine (ATZ), diuron (DIU), and their major degradation products, desethylatrazine (DEA), desisopropylatrazine (DIA), and dichlorophenylmethylurea in sewage sludge. Liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS-MS) allowed, in the multiple-reaction monitoring mode, the simultaneous analysis of these pesticides in only one run after their extraction with ethyl acetate-dichloromethane 90:10 (v/v) and a cleanup on a Florisil column. Stable isotopically labeled ATZ and DIU were used as internal standards to overcome matrix effects during the pesticide quantification. Using fortified samples, the method gave rise to 86-115% as mean recovery values depending on the analyte. Limits of detection (LODs) and of quantification (LOQs) ranging from 0.3 (DIA) to 1.5 (DEA) microg kg(-1) dw and from 0.4 (DIA) to 2.0 (DEA) microg kg(-1) dw, respectively, were sufficient to achieve the monitoring of these molecules in sludge from wastewater treatment plants of the Ile-de-France region.

  12. [Determination of virginiamycin M1, in feeds by ultra high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Huang, Yonghui

    2011-10-01

    A comprehensive analytical method based on ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of virginiamycin M1 in feeds. The sample was extracted twice by ultrasonic extraction with ace-tonitrile-0.2% (v/v) formic acid (8:2, v/v). The chromatographic separation was achieved with a BEH C18 column and acetonitrile-0. 3% (v/v) formic acid (35: 65, v/v) as the mobile phase. The identification and quantification of the analyte were carried out on electrospray ionization MS/MS in a multiple reaction monitoring (MRM) mode. The correlation coefficient (r) of virginiamycin M1 was 0. 999 5 in the linear range of 0. 3 -226. 6 microg/L. The detection limit (S/ N = 3) and quantification limit (S/N = 10) of virginiamycin M1 were 2 microg/kg and 7 microg/kg, respectively. The average spiked recoveries were in the range of 82. 6% to 102. 7% with the relative standard deviations (RSDs) of 0.9% - 10.5%. The results demonstrate that the proposed method is simple, sensitive, repeatable and suitable for the testing of virginiamycin M, in feeds.

  13. 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.

  14. 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.

  15. Large-scale profiling of diterpenoid glycosides from Stevia rebaudiana using ultrahigh performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Shafii, Behnaz; Vismeh, Ramin; Beaudry, Randy; Warner, Ryan; Jones, A Daniel

    2012-07-01

    The plant Stevia rebaudiana accumulates a suite of diterpenoid metabolites that are natural sweeteners finding increased use as sugar substitutes. To guide breeding of stevia plants that accumulate substances with desirable flavor in high yield, rapid and accurate methods are needed to profile these substances in plant populations. This report describes an 8-min ultrahigh performance liquid chromatography-tandem mass spectrometry method for separation and quantification of seven stevia glycosides including steviolbioside; stevioside; rebaudiosides A, B, and C; rubusoside; and dulcoside as well as aglycones steviol and isosteviol. This negative mode electrospray ionization/multiple reaction monitoring method yielded low limits of detection stevia glycosides. Stevioside and Reb A, B, and C were quantified in more than 1,100 extracts from stevia leaves as part of a large-scale profiling exercise. Leaf tissue levels in this population spanned about two orders of magnitude for stevioside (2-125 mg/g dry weight), Reb A (2.5-164 mg/g), Reb B (0.5-50 mg/g), and Reb C (1.5-125 mg/g), but levels of individual metabolites exhibited independent variation. The wide spread of metabolite levels highlights the utility and importance of performing targeted metabolic profiling for large plant populations.

  16. Gas chromatography/tandem mass spectrometry detection of extracellular kynurenine and related metabolites in normal and lesioned rat brain.

    Science.gov (United States)

    Notarangelo, Francesca M; Wu, Hui-Qiu; Macherone, Anthony; Graham, David R; Schwarcz, Robert

    2012-02-15

    We describe here a gas chromatography-tandem mass spectrometry (GC/MS/MS) method for the sensitive and concurrent determination of extracellular tryptophan and the kynurenine pathway metabolites kynurenine, 3-hydroxykynurenine (3-HK), and quinolinic acid (QUIN) in rat brain. This metabolic cascade is increasingly linked to the pathophysiology of several neurological and psychiatric diseases. Methodological refinements, including optimization of MS conditions and the addition of deuterated standards, resulted in assay linearity to the low nanomolar range. Measured in samples obtained by striatal microdialysis in vivo, basal levels of tryptophan, kynurenine, and QUIN were 415, 89, and 8 nM, respectively, but 3-HK levels were below the limit of detection (<2 nM). Systemic injection of kynurenine (100 mg/kg, i.p.) did not affect extracellular tryptophan but produced detectable levels of extracellular 3-HK (peak after 2-3 h: ~50 nM) and raised extracellular QUIN levels (peak after 2h: ~105 nM). The effect of this treatment on QUIN, but not on 3-HK, was potentiated in the N-methyl-D-aspartate (NMDA)-lesioned striatum. Our results indicate that the novel methodology, which allowed the measurement of extracellular kynurenine and 3-HK in the brain in vivo, will facilitate studies of brain kynurenines and of the interplay between peripheral and central kynurenine pathway functions under physiological and pathological conditions.

  17. High throughput liquid chromatography-tandem mass spectrometry assay for mercapturic acids of acrolein and crotonaldehyde in cigarette smokers' urine.

    Science.gov (United States)

    Carmella, Steven G; Chen, Menglan; Zarth, Adam; Hecht, Stephen S

    2013-09-15

    3-Hydroxypropylmercapturic acid (3-HPMA) and 3-hydroxy-1-methylpropylmercapturic acid (HMPMA) are urinary metabolites of the toxicants acrolein and crotonaldehyde, respectively. Virtually all human urine samples contain these metabolites, resulting from the action of glutathione-S-transferases on acrolein and crotonaldehyde, which are lipid peroxidation products, environmental and dietary contaminants, and constituents of cigarette smoke. We have developed a high throughput liquid chromatography-tandem mass spectrometry method for quantitative analysis of 3-HPMA and HMPMA in large numbers of small urine samples, as would be required in molecular epidemiology and clinical studies relating levels of these metabolites to cancer risk. Solid-phase extraction on mixed mode reverse phase-anion exchange 96-well plates provided sufficient purification for LC-MS/MS analysis, which was performed by auto-injection using a 96-well format, and resulted in clean, readily interpretable chromatograms, with detection limits of 4.5pmol/mL urine for 3-HPMA and 3.5pmol/mL urine for HMPMA. Accuracy was 92% for 3-HPMA and 97% for HMPMA while inter-day precision was 9.1% (coefficient of variation) for 3-HPMA and 11.0% for HMPMA. The method was applied to more than 2600 urine samples from smokers; mean levels of 3-HPMA and HMPMA were 4800±5358 (S.D.)pmol/mL and 3302±3341pmol/mL, respectively.

  18. Detection and determination of reticuline and N-methylcoculaurine in the Annonaceae family using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kotake, Yaichiro; Okuda, Katsuhiro; Kamizono, Machiko; Matsumoto, Naoki; Tanahashi, Takao; Hara, Hiroshi; Caparros-Lefebvre, Dominique; Ohta, Shigeru

    2004-06-25

    In Guadeloupe, the French West Indies, there is a high incidence of atypical parkinsonism or progressive supranuclear palsy, and all of the investigated patients had taken herbal tea or tropical fruits of the Annonaceae family. Local inhabitants consume the fruits, and also drink tea made from the leaves. In the present study, we used liquid chromatography-tandem mass spectrometry (LC/MS/MS) with multiple reaction monitoring (MRM) to detect low-molecular-weight neurotoxic benzylisoquinoline derivatives in the Annonaceae family. We detected reticuline and N-methylcoculaurine in every Annona muricata sample examined, except for pulp and seed. They were not detected in sweetsop fruits. Norreticuline was not detected in any sample. These three compounds were toxic to SH-SY5Y neuroblastoma cells and inhibited mitochondrial respiratory complex I. It is possible that uptake of the benzylisoquinoline derivatives reticuline and N-methylcoculaurine and their accumulation in the brain may be related to the pathogenesis of the local endemic disease.

  19. Determination and Pharmacokinetics of Di-(2-ethylhexyl Phthalate in Rats by Ultra Performance Liquid Chromatography with Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Tung-Hu Tsai

    2013-09-01

    Full Text Available Di-(2-ethylhexyl phthalate (DEHP is used to increase the flexibility of plastics for industrial products. However, the illegal use of the plasticizer DEHP in food and drinks has been reported in Taiwan in 2011. In order to assess the exact extent of the absorption of DEHP via the oral route, the aim of this study is to develop a reliable and validated ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS method to evaluate the oral bioavailability of DEHP in rats. The optimal chromatographic separation of DEHP and butyl benzyl phthalate (BBP; used as internal standard were achieved on a C18 column. The mobile phase was consisted of 5 mM ammonium acetate-methanol (11:89, v/v with a flow rate of 0.25 mL/min. The monitoring ion transitions were m/z 391.4 → 149.0 for DEHP and m/z 313.3 → 149.0 for BBP. The mean matrix effects of DEHP at low, medium and high concentrations were 94.5 ± 5.7% and 100.1 ± 2.3% in plasma and feces homogenate samples, respectively. In conclusion, the validated UPLC-MS/MS method is suitable for analyzing the rat plasma sample of DEHP and the oral bioavailability of DEHP was about 7% in rats.

  20. Minimization of carryover for high-throughput liquid chromatography with tandem mass spectrometry analysis of 14 mycotoxins in corn grits.

    Science.gov (United States)

    Tamura, Masayoshi; Matsumoto, Keiko; Watanabe, Jun; Iida, Junko; Nagatomi, Yasushi; Mochizuki, Naoki

    2014-07-01

    A method for the simultaneous analysis of 14 mycotoxins with the minimization of carryover was developed. Our verification experiments suggested that the carryover occurred due to the chelation of fumonisins with the metal. To wash the fumonisins from the metal, the inner surface of the injection needle was rinsed with 10 mM trisodium citrate and 1% formic acid in water/methanol/acetonitrile/isopropanol after each injection, and the analysis was performed on a metal-free Mastro C18 column. This approach remarkably minimized the carryover of fumonisins. Fourteen mycotoxins in samples were extracted with 2% acetic acid in water/acetonitrile and a quick, easy, cheap, effective, rugged, and safe extraction kit, purified on a MultiSep 229 Ochra, and then quantified by liquid chromatography with tandem mass spectrometry. Determinations performed using this method produced a linearity greater than 0.99 and recoveries ranging from 72.6 to 117.4%, with good intraday precision from 4.0 to 12.4%, and interday precision from 6.5 to 17.0%. The limits of detection ranged from 0.01 to 0.71 μg/kg, demonstrating that a highly sensitive method for the simultaneous analysis of mycotoxins over a wide range of concentrations was achieved with minimal carryover. When 12 samples of commercially available corn grits were analyzed with this method, deoxynivalenol, fumonisin B1, fumonisin B2, fumonisin B3, and zearalenone were present most frequently.

  1. Determining mycotoxins in baby foods and animal feeds using stable isotope dilution and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Kai; Wong, Jon W; Krynitsky, Alexander J; Trucksess, Mary W

    2014-09-10

    We developed a stable isotope dilution assay with liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine multiple mycotoxins in baby foods and animal feeds. Samples were fortified with [(13)C]-uniformly labeled mycotoxins as internal standards ([(13)C]-IS) and prepared by solvent extraction (50% acetonitrile in water) and filtration, followed by LC-MS/MS analysis. Mycotoxins in each sample were quantitated with the corresponding [(13)C]-IS. In general, recoveries of aflatoxins (2-100 ng/g), deoxynivalenol, fumonisins (50-2000 ng/g), ochratoxin A (20-1000 ng/kg), T-2 toxin, and zearalenone (40-2000 ng/g) in tested matrices (grain/rice/oatmeal-based formula, animal feed, dry cat/dog food) ranged from 70 to 120% with relative standard deviations (RSDs) <20%. The method provides sufficient selectivity, sensitivity, accuracy, and reproducibility to screen for aflatoxins at ng/g concentrations and deoxynivalenol and fumonisins at low μg/g concentrations in baby foods and animal feeds, without using conventional standard addition or matrix-matched calibration standards to correct for matrix effects.

  2. A rapid liquid chromatography tandem mass spectrometry-based method for measuring propranolol on dried blood spots.

    Science.gov (United States)

    Della Bona, Maria Luisa; Malvagia, Sabrina; Villanelli, Fabio; Giocaliere, Elisa; Ombrone, Daniela; Funghini, Silvia; Filippi, Luca; Cavallaro, Giacomo; Bagnoli, Paola; Guerrini, Renzo; la Marca, Giancarlo

    2013-05-05

    Propranolol, a non-selective beta blocker drug, is used in young infants and newborns for treating several heart diseases; its pharmacokinetics has been extensively evaluated in adult patients using extrapolation to treat pediatric population. The purpose of the present study was to develop and validate a method to measure propranolol levels in dried blood spots. The analysis was performed by using liquid chromatography/tandem mass spectrometry operating in multiple reaction monitoring mode. The calibration curve in matrix was linear in the concentration range of 2.5-200 μg/L with correlation coefficient r=0.9996. Intra-day and inter-day precisions and biases were less than 8.0% (n=10) and 11.5% (n=10) respectively. The recoveries ranged from 94 to 100% and the matrix effect did not result in a severe signal suppression. Propranolol on dried blood spot showed a good stability at three different temperatures for one month. This paper describes a micromethod for measuring propranolol levels on dried blood spot, which determines a great advantage in neonates or young infants during pharmacokinetic studies because of less invasive sampling and small blood volume required.

  3. A new liquid chromatography-tandem mass spectrometry method for determination of parabens in human placental tissue samples.

    Science.gov (United States)

    Jiménez-Díaz, I; Vela-Soria, F; Zafra-Gómez, A; Navalón, A; Ballesteros, O; Navea, N; Fernández, M F; Olea, N; Vílchez, J L

    2011-05-15

    Endocrine disruptors are a group of organic compounds widely used, which are ubiquitous in the environment and in biological samples. The main effect of these compounds is associated with their ability to mimic or block the action of natural hormones in living organisms, including humans. Parabens (esters of p-hydroxybenzoic acid) belong to this group of compounds. In this work, we propose a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to asses the presence of parabens most commonly used in industrial applications (methyl-, ethyl-, propyl- and butyl-paraben) in samples of human placental tissue. The method involves the extraction of the analytes from the samples using ethyl acetate, followed by a clean-up step using centrifugation prior to their quantification by LC-MS/MS using an atmospheric pressure chemical ionization (APCI) interface in the negative mode. Deuterated bisphenol A (BPA-d(16)) was used as surrogate. Found detection limits (LOD) ranged from 0.03 to 0.06 ng g(-1) and quantification limits (LOQ) from 0.1 to 0.2 ng g(-1), while inter- and intra-day variability was under 13.8%. The method was validated using standard addition calibration and a spike recovery assay. Recovery rates for spiked samples ranged from 82% to 108%. This method was satisfactorily applied for the determination of parabens in 50 placental tissue samples collected from women who live in the province of Granada (Spain).

  4. 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.

  5. 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.

  6. 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.

  7. Liquid chromatographytandem mass spectrometry method for the determination of ten tetracycline residues in muscle samples

    Directory of Open Access Journals (Sweden)

    Gajda Anna

    2015-09-01

    Full Text Available A liquid chromatographytandem mass spectrometry (LC-MS/MS method for the determination of oxytetracycline (OTC, 4-epi oxytetracycline (4-epi OTC, tetracycline (TC, 4-epi tetracycline (4-epi TC, chlortetracycline (CTC, 4-epi chlortetracycline (4-epi CTC, doxycycline (DC, minocycline (MINO, methacycline (META and rolitetracycline (ROLI residues in muscles was developed. The procedure consisted of an oxalic acid extraction followed by protein removal with trichloroacetic acid. Further solid phase clean-up on polymeric (Strata X reversed phase columns was performed to obtain an extract suitable for LC-MS/MS analysis. The tetracyclines were separated on a C 18 analytical column with mobile phase consisting of 0.01% formic acid in acetonitrile and 0.01% formic acid in water in gradient mode. The method was validated according to the Commission Decision 2002/657/EC. The recoveries of all target compounds were 91.8% – 103.6%. The decision limits were from 109.0 to 119.8 μg/kg and detection capability varied within the range of 122.2 to 137.6 μg/kg, depending on the analyte.

  8. Accurate determination of ochratoxin A in Korean fermented soybean paste by isotope dilution-liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Ahn, Seonghee; Lee, Suyoung; Lee, Joonhee; Kim, Byungjoo

    2016-01-01

    Ochratoxin A (OTA), a naturally occurring mycotoxin, has been frequently detected in doenjang, a traditional fermented soybean paste, when it is fermented under improper conditions. Reliable screening of OTA in traditional fermented soybean paste (doenjang) is a special food-safety issue in Korea. Our laboratory, the National Metrology Institute of Korea, established an isotope dilution-liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method as a higher-order reference method to be used for SI-traceable value-assignment of OTA in certified reference materials (CRMs). (13)C20-OTA was used as an internal standard. Sample preparation conditions and LC/MS measurement parameters were optimised for this purpose. The analytical method was validated by measuring samples fortified with OTA at various levels. Repeatability and reproducibility studies showed that the ID-LC/MS/MS method is reliable and reproducible within 2% relative standard deviation. The analytical method was applied to determine OTA in various commercial doenjang products and home-made doenjang products.

  9. Simultaneous determination of seven bisphenols in environmental water and solid samples by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Yang, Yunjia; Lu, Libin; Zhang, Jing; Yang, Yi; Wu, Yongning; Shao, Bing

    2014-02-01

    This article presents a simple and universal analytical method for the simultaneous analysis of bisphenol S (BPS), bisphenol F (BPF), bisphenol A (BPA), bisphenol B (BPB), bisphenol AF (BPAF), tetrachlorobisphenol A (TCBPA), and tetrabromobisphenol A (TBBPA) in environmental water (river water, sewage) and solid samples (sediment, sludge) based on liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS). Analytes were extracted from water samples using hydrophilic lipophilic balanced (HLB) solid-phase extraction (SPE) cartridges, and the extracts were further purified using MAX SPE cartridges. For the solid samples, a combination of ultrasonic extraction with the same SPE clean-up procedures used for the water samples was employed. The absolute recoveries for all analytes in the water and solid samples ranged from 57.1 to 114.3%. Good method reproducibility was achieved in terms of intra- and inter-day precision, yielding relative standard deviations (RSDs) less than 16.9 and 18.1%, respectively. The method limits of quantitation (MLOQ) for the seven compounds in environmental water and solid samples ranged from 0.05 to 4.35ng/L and from 0.06 to 2.83ng/g (dry weight, d.w.), respectively. Finally, this method was successfully applied to real environmental sample analysis, which revealed that all of the tested BPs were present, with the exception of BPB.

  10. A liquid chromatography-tandem mass spectrometry-based method for the simultaneous determination of hydroxy sterols and bile acids.

    Science.gov (United States)

    John, Clara; Werner, Philipp; Worthmann, Anna; Wegner, Katrin; Tödter, Klaus; Scheja, Ludger; Rohn, Sascha; Heeren, Joerg; Fischer, Markus

    2014-12-01

    Recently, hydroxy sterols and bile acids have gained growing interest as they are important regulators of energy homoeostasis and inflammation. The high number of different hydroxy sterols and bile acid species requires powerful analytical tools to quantify these structurally and chemically similar analytes. Here, we introduce a liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method for rapid quantification of 34 sterols (hydroxy sterols, primary, secondary bile acids as well as their taurine and glycine conjugates). Chromatographic baseline separation of isomeric hydroxy sterols and bile acids is obtained using a rugged amide embedded C18 (polar embedded) stationary phase. The current method features a simple extraction protocol validated for blood plasma, urine, gall bladder, liver, feces, and adipose tissue avoiding solid phase extraction as well as derivatization procedures. The total extraction recovery for representative analytes ranged between 58-86% in plasma, 85% in urine, 79-92% in liver, 76-98% in adipose tissue, 93-104% in feces and 62-79% in gall bladder. The validation procedure demonstrated that the calibration curves were linear over the selected concentration ranges for 97% of the analytes, with calculated coefficients of determination (R2) of greater than 0.99. A feeding study in wild type mice with a standard chow and a cholesterol-enriched Western type diet illustrated that the protocol described here provides a powerful tool to simultaneously quantify cholesterol derivatives and bile acids in metabolically active tissues and to follow the enterohepatic circulation.

  11. Simultaneous determination of buprenorphine, norbuprenorphine and naloxone in human plasma by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Liu, Yongzhen; Li, Xiaohua; Xu, Allan; Nasser, Azmi F; Heidbreder, Christian

    2016-02-20

    A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for simultaneous quantification of naloxone, buprenorphine and its metabolite norbuprenorphine in human plasma. Human plasma samples were extracted using a single step liquid-liquid extraction, and then separated on an Imtakt Unison UK-C18 column (2.1×50mm, 3μm) using alkaline mobile phases with gradient elution. All of the analytes were detected in positive ion mode using multiple reaction monitoring (MRM). The method was validated and the specificity, linearity, lower limit of quantitation, precision, accuracy, recoveries and stability were determined. The linear range was 20-10000pg/mL for buprenorphine and norbuprenorphine; and 1-500pg/mL for naloxone. The correlation coefficient (R(2)) values for all three analytes were ≥0.995. The precision and accuracy for intra-day and inter-day were 63% and matrix effects were tracked by the deuterated internal standards (IS) with the IS-normalized matrix factor ranging from 0.96 to 1.33 for all three analytes. The validated method was successfully applied in a clinical pharmacokinetic study with low dose administration of sublingual buprenorphine and naloxone.

  12. 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.

  13. [Determination of glufosinate residue in tea by liquid chromatography-tandem mass spectrometry coupled with precolumn derivatization].

    Science.gov (United States)

    Lin, Yonghui; Liu, Zhengcai; Yang, Fang; Qiu, Yuanjin; Liu, Suzhen; Su, Zhijiao; Zhang, Qiong; Xue, Zhimin; Fang, Yu

    2012-12-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the determination of glufosinate (GLUF) residue in tea. The GLUF was extracted with water for 30 min under ultrasonication, and cleaned-up using a C18 solid phase extraction cartridge, then derived using fluorenylmethylchloroformate (FMOC-Cl) in borate buffer for 2 h. The separation was performed on a Kinetex C18 column with the mobile phases of acetonitrile and 5 mmol/L ammonium acetate aqueous solution (containing 0.2% (v/v) formic acid) in a gradient elution mode. The identification and quantification of the GLUF were carried out by MS/MS in negative electrospray ionization (ESI(-)) and multiple reaction monitoring (MRM) mode, the quantification analysis was performed by external standard method. The calibration curve showed good linearity in the range of 2.5 - 50.0 microg/L with the correlation coefficient r2 > 0.999. The limit of quantification (LOQ) was 0.10 mg/kg. The average recoveries of GLUF spiked at 0.10, 0.50 and 1.00 mg/kg levels in tea were between 61.6% and 81.4%, and the relative standard deviations (RSDs) were between 3.2% and 8.4%. The method is simple, rapid, sensitive, accurate and suitable for the confirmation and quantification of GLUF in tea.

  14. Comprehensive proteomic analysis of mineral nanoparticles derived from human body fluids and analyzed by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Martel, Jan; Young, David; Young, Andrew; Wu, Cheng-Yeu; Chen, Chi-De; Yu, Jau-Song; Young, John D

    2011-11-01

    Mineralo-protein nanoparticles (NPs) formed spontaneously in the body have been associated with ectopic calcifications seen in atherosclerosis, chronic degenerative diseases, and kidney stone formation. Synthetic NPs are also known to become coated with proteins when they come in contact with body fluids. Identifying the proteins found in NPs should help unravel how NPs are formed in the body and how NPs in general, be they synthetic or naturally formed, interact within the body. Here, we developed a proteomic approach based on liquid chromatography (LC) and tandem mass spectrometry (MS/MS) to determine the protein composition of carbonate-apatite NPs derived from human body fluids (serum, urine, cerebrospinal fluid, ascites, pleural effusion, and synovial fluid). LC-MS/MS provided not only an efficient and comprehensive determination of the protein constituents, but also a semiquantitative ranking of the identified proteins. Notably, the identified NP proteins mirrored the protein composition of the contacting body fluids, with albumin, fetuin-A, complement C3, α-1-antitrypsin, prothrombin, and apolipoproteins A1 and B-100 being consistently associated with the particles. Since several coagulation factors, calcification inhibitors, complement proteins, immune regulators, protease inhibitors, and lipid/molecule carriers can all become NP constituents, our results suggest that mineralo-protein complexes may interface with distinct biochemical pathways in the body depending on their protein composition. We propose that LC-MS/MS be used to characterize proteins found in both synthetic and natural NPs.

  15. 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.

  16. Screening for new psychoactive substances in hair by ultrahigh performance liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Strano-Rossi, Sabina; Odoardi, Sara; Fisichella, Marco; Anzillotti, Luca; Gottardo, Rossella; Tagliaro, Franco

    2014-11-06

    In the latest years, many new psychoactive substances (NPS) from several drug classes have appeared in the illicit drug market. Their rapid, sensitive and specific identification in biological fluids is hence of great concern for clinical and forensic toxicologists. Here is described a multi-analyte method for the determination of NPS, pertaining to different chemical classes (synthetic cannabinoids, synthetic cathinones, ketamine, piperazines and amphetamine-type substances-ATS) in human hair using ultrahigh performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) in electrospray ionization mode. We focused on a sample preparation able to extract the different classes of NPS. About 30mg of hair was decontaminated and incubated overnight under sonication in different conditions depending on the type of analytes to be extracted: (a) with 300μL of HCOOH 0.1% for cathinones, piperazines and ATS; (b) with 300μL of MeOH for synthetic cannabinoids. Ten microliter of the extracts were then injected in UHPLC-ESI-MS/MS in MRM mode. The LODs varied from 2pg/mg to 20pg/mg. The method was linear in the range from the LOQ to 500pg/mg and showed acceptable precision (%RSD<15) and accuracy (%E<15) for all the analytes. The method was finally applied on 50 samples from real forensic cases (driving license re-granting, postmortem toxicological analyses, workplace drug testing). In three samples we detected synthetic cannabinoids, in four samples cathinones or ephedrines, in two samples ketamine.

  17. Determination of hepatotoxic indospicine in Australian camel meat by ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Tan, Eddie T T; Fletcher, Mary T; Yong, Ken W L; D'Arcy, Bruce R; Al Jassim, Rafat

    2014-02-26

    Indospicine is a hepatotoxic amino acid found in Indigofera plant spp. and is unusual in that it is not incorporated into protein but accumulates as the free amino acid in the tissues (including muscle) of animals consuming these plants. Dogs are particularly sensitive to indospicine, and secondary poisoning of dogs has occurred from the ingestion of indospicine-contaminated horse meat and more recently camel meat. In central Australia, feral camels are known to consume native Indigofera species, but the prevalence of indospicine residues in their tissues has not previously been investigated. In this study, a method was developed and validated with the use of ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to determine the level of indospicine in camel meat samples using isotopically labeled indospicine as an internal standard. UPLC-MS/MS analysis showed that the method is reproducible, with high recovery efficiency and a quantitation limit of 0.1 mg/kg. Camel meat samples from the Simpson Desert were largely contaminated (≈50%) by indospicine with levels up to 3.73 mg/kg (fresh weight) determined. However, the majority of samples (95%) contained less than 1 mg/kg indospicine.

  18. Simultaneous quantitation of acetylsalicylic acid and clopidogrel along with their metabolites in human plasma using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Chhonker, Yashpal S; Pandey, Chandra P; Chandasana, Hardik; Laxman, Tulsankar Sachin; Prasad, Yarra Durga; Narain, V S; Dikshit, Madhu; Bhatta, Rabi S

    2016-03-01

    The interest in therapeutic drug monitoring has increased over the last few years. Inter- and intra-patient variability in pharmacokinetics, plasma concentration related toxicity and success of therapy have stressed the need of frequent therapeutic drug monitoring of the drugs. A sensitive, selective and rapid liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantification of acetylsalicylic acid (aspirin), salicylic acid, clopidogrel and carboxylic acid metabolite of clopidogrel in human plasma. The chromatographic separations were achieved on Waters Symmetry Shield(TM) C18 column (150 × 4.6 mm, 5 µm) using 3.5 mm ammonium acetate (pH 3.5)-acetonitrile (10:90, v/v) as mobile phase at a flow rate of 0.75 mL/min. The present method was successfully applied for therapeutic drug monitoring of aspirin and clopidogrel in 67 patients with coronary artery disease.

  19. [Simultaneous determination of penicillin G and its major metabolites in blood using ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Chen, Cong; Yan, Hui; Shen, Baohua; Zhuo, Xianyi

    2012-05-01

    A fast method for the quantitative determination of penicillin G (PEN G) , penicilloic acid and penilloic acid in blood with ultra performance liquid chromatography-electrospray tandem mass spectrometry was developed. A simple deproteinization of the blood was used with a mixed solution of acetonitrile and water (4:1, v/v) as extraction solvent. The blood extract was directly injected onto an LC column. The chromatographic separation of the components was performed on a BEH C18 column (50 mm x 2.1 mm, 1.7 microm) using acetonitrile and water containing 0.1% formic acid. The mass spectrometer was operated in positive electrospray ion mode. Finally, the analysis was carried out with multiple reaction monitoring (MRM) mode. The limits of detection (LODs) for these three compounds were in the range of 0.1 to 2.0 ng/mL and the limits of quantification (LOQs) in the range of 0.5 to 5.0 ng/mL. Within the linear range, the correlation coefficients (r) of PEN G and its metabolites were all more than 0.9974. Accuracies for these targeted compounds were ranged from 92.3% to 105.5%, and the within-day precisions were less than 10%. The stabilities of the components were evaluated in the temperature range from 18 to 80 degrees C, and the mass concentration of penicillin G was decreased significantly with the extensions of storage temperature and storage time. Biological samples of the rats medicated with PEN G were analyzed using the developed method. The results show that PEN G can just be detected at 0.5 h after administration. However, the detection time limitation of penicilloic acid can be extended to 36 h. The established method has been further expanded for the applicability of forensic identification, and has a reference value for the detection of penicillin G residue in food.

  20. [Determination of imidaclothiz in tea by QuEChERS cleanup and liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Liu, Songnan; Zhao, Xinying; Dong, Xiaoqian; Xu, Wenwen; Zhao, Rong

    2015-11-01

    The method for the determination of imidaclothiz residue in tea by liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed. The imidaclothiz in tea was extracted by acetonitrile and purified by QuEChERS with PSA (primary secondary amine), C18, GCB (graphitized carbon black) as the adsorbents. The purified solution was centrifuged and the supernatant was diluted with water of equal volume. The separation was performed on a C18 column with a gradient elution program of acetonitrile (containing 0.1% (v/v) formic acid) and water at a flow rate of 0.30 mL/min. The mass spectrometer was carried out with electrospray ion source in the positive mode (ESI+) and selective reaction monitoring (SRM), quantified by external standard solution. The results showed that the mass concentration of imidaclothiz in the range of 1 to 500 μg/L was linearly correlated with the peak area, and the correlation coefficient (r) was 0.999 9. The limit of quantification (LOQ, S/N ≥ 10) was 0.01 mg/kg. The recoveries in oolong tea and green tea at three spiked levels (0.01, 0.3 and 3 mg/kg) varied from 87.0%-101.0% and the relative standard deviations (RSDs, n = 7) were between 2.1% and 13.1%. The real sample tests showed that the method is simple, cheap, accurate, specific, rapid, and suitable for the qualitative and quantitative confirmation of imidaclothiz residue in tea.

  1. Quantitative profiling of retinyl esters in milk from different ruminant species by using high performance liquid chromatography-diode array detection-tandem mass spectrometry.

    Science.gov (United States)

    Rocchi, Silvia; Caretti, Fulvia; Gentili, Alessandra; Curini, Roberta; Perret, Daniela; Pérez-Fernández, Virginia

    2016-11-15

    An effective high performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS/MS) analytical approach was developed for retinoid profiling in raw milk samples (cow, buffalo, ewe, and goat). The analytes were isolated by means of liquid-liquid extraction, including a "lipid freezing" step, with yields exceeding 66%. Since the positive atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) detection is not completely selective, a reliable identification has been accomplished by fully separating the analytes on a tandem C18/C30 column system under non-aqueous reversed phase (NARP) chromatography conditions. After validation, different milk varieties obtained from pasture-fed animals were analysed, providing, for the first time, the retinoid composition of both buffalo's and ewe's milk. According to the literature, retinyl palmitate has been found to be the most abundant vitamin A vitamer, but retinyl oleate is the prevalent form in the caprine milk.

  2. Application of a liquid chromatographytandem mass spectrometry (LC/MS/MS) method to the pharmacokinetics of ON01910 in brain tumor-bearing mice

    OpenAIRE

    Nuthalapati, Silpa; Guo, Ping; Zhou, Qingyu; Ramana Reddy, M. V.; Reddy, E. Premkumar; Gallo, James M.

    2011-01-01

    ON01910 is a small molecular weight benzyl styryl sulfone currently under investigation as a novel anticancer agent. The purpose of the investigation was to develop a sensitive and reproducible liquid chromatography-tandem mass spectrometry (LC/MS/MS) method to quantitate levels of ON01910 in small amounts of five biological matrices; mouse plasma, feces, urine, normal brain and brain tumor. For all matrices, protein precipitation sample preparation was used that led to linear calibration cur...

  3. In-Cell Clean-Up Pressurised Liquid Extraction Method to Determine Pesticides in Mushroom Compost by Gas Chromatography-Tandem Mass Spectrometry

    OpenAIRE

    María Teresa Tena; María Pilar Martínez-Moral; Patricia Labarta

    2012-01-01

    A fast, simple, and easily automated method for the determination of two insecticides, diazinon and deltamethrin, and two fungicides, iprodione and prochloraz, in mushroom cultivation compost samples, based on selective pressurised liquid extraction (SPLE) and gas chromatography coupled to tandem mass spectrometry, is presented. The proposed method integrates extraction and clean-up processes in one single step, by adding a clean-up sorbent into the extraction cell. SPLE variables were thorou...

  4. Sensitive analysis of anti-HIV drugs, efavirenz, lopinavir and ritonavir, in human hair by liquid chromatography coupled with tandem mass spectrometry

    OpenAIRE

    Yong HUANG; Gandhi, Monica; Greenblatt, Ruth M.; Gee, Winnie; Lin, Emil T.; Messenkoff, Nicholas

    2008-01-01

    A highly sensitive and selective method using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) was developed and validated for the measurement of three antiretroviral agents, efavirenz, lopinavir and ritonavir, in human hair. Hair samples from adherent HIV-infected patients on antiretroviral therapies were cut into about 1 mm length segments and drugs were extracted by first shaking the samples with methanol in a 37°C water bath overnight (>14 h), followed by methyl tert...

  5. 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...

  6. Simultaneous enantioselective determination of triadimefon and its metabolite triadimenol in edible vegetable oil by gel permeation chromatography and ultraperformance convergence chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Yao, Zhoulin; Li, Xiaoge; Miao, Yelong; Lin, Mei; Xu, Mingfei; Wang, Qiang; Zhang, Hu

    2015-11-01

    A novel, sensitive, and efficient enantioselective method for the determination of triadimefon and its metabolite triadimenol in edible vegetable oil, was developed by gel permeation chromatography and ultraperformance convergence chromatography/tandem triple quadrupole mass spectrometry. After the vegetable oil samples were prepared using gel permeation chromatography, the eluent was collected, evaporated, and dried with nitrogen gas. The residue was redissolved by adding methanol up to a final volume of 1 mL. The analytes of six enantiomers were analyzed on Chiralpak IA-3 column (150 × 4.6 mm) using compressed liquid CO2-mixed 14 % co-solvents, comprising methanol/acetonitrile/isopropanol = 20/20/60 (v/v/v) in the mobile phase at 30 °C, and the total separation time was less than 4 min at a flow rate of 2 mL/min. Quantification was achieved using matrix-matched standard calibration curves. The overall mean recoveries for six enantiomers from vegetable oil were 90.1-97.3 %, with relative standard deviations of 0.8-5.4 % intra-day and 2.3-5.0 % inter-day at 0.5, 5, and 50 μg/kg levels. The limits of quantification were 0.5 μg/kg for all enantiomers based on five replicate extractions at the lowest fortified level in vegetable oil. Moreover, the absolute configuration of six enantiomers had been determined based on comparisons of the vibrational circular dichroism experimental spectra with the theoretical curve obtained by density functional theory calculations. Application of the proposed method to the 40 authentic vegetable oil samples from local markets suggests its potential use in enantioselective determination of triadimefon and triadimenol enantiomers. Graphical Abstract Chemical structures and UPC(2)-MS/MS separation chromatograms of triadimefon and triadimenol.

  7. Profiling of drug binding proteins by monolithic affinity chromatography in combination with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Xuepei; Wang, Tongdan; Zhang, Hanzhi; Han, Bing; Wang, Lishun; Kang, Jingwu

    2014-09-12

    A new approach for proteome-wide profiling drug binding proteins by using monolithic capillary affinity chromatography in combination with HPLC-MS/MS is reported. Two immunosuppresive drugs, namely FK506 and cyclosporin A, were utilized as the experimental models for proof-of-concept. The monolithic capillary affinity columns were prepared through a single-step copolymerization of the drug derivatives with glycidyl methacrylate and ethylene dimethacrylate. The capillary chromatography with the affinity monolithic column facilitates the purification of the drug binding proteins from the cell lysate. By combining the capillary affinity column purification and the shot-gun proteomic analysis, totally 33 FK506- and 32 CsA-binding proteins including all the literature reported target proteins of these two drugs were identified. Among them, two proteins, namely voltage-dependent anion-selective channel protein 1 and serine/threonine-protein phosphatase PGAM5 were verified by using the recombinant proteins. The result supports that the monolithic capillary affinity chromatography is likely to become a valuable tool for profiling of binding proteins of small molecular drugs as well as bioactive compounds.

  8. High-performance liquid chromatography coupled with tandem mass spectrometry technology in the analysis of Chinese Medicine Formulas: A bibliometric analysis (1997-2015).

    Science.gov (United States)

    He, Xi-Ran; Li, Chun-Guang; Zhu, Xiao-Shu; Li, Yuan-Qing; Jarouche, Mariam; Bensoussan, Alan; Li, Ping-Ping

    2017-01-01

    There is a recognized challenge in analyzing traditional Chinese medicine formulas because of their complex chemical compositions. The application of modern analytical techniques such as high-performance liquid chromatography coupled with a tandem mass spectrometry has improved the characterization of various compounds from traditional Chinese medicine formulas significantly. This study aims to conduct a bibliometric analysis to recognize the overall trend of high-performance liquid chromatography coupled with tandem mass spectrometry approaches in the analysis of traditional Chinese medicine formulas, its significance and possible underlying interactions between individual herbs in these formulas. Electronic databases were searched systematically, and the identified studies were collected and analyzed using Microsoft Access 2010, Graph Pad 5.0 software and Ucinet software package. 338 publications between 1997 and 2015 were identified, and analyzed in terms of annual growth and accumulated publications, top journals, forms of traditional Chinese medicine preparations and highly studied formulas and single herbs, as well as social network analysis of single herbs. There is a significant increase trend in using high-performance liquid chromatography coupled with tandem mass spectrometry related techniques in analysis of commonly used forms of traditional Chinese medicine formulas in the last 3 years. Stringent quality control is of great significance for the modernization and globalization of traditional Chinese medicine, and this bibliometric analysis provided the first and comprehensive summary within this field.

  9. Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.

    Science.gov (United States)

    Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie

    2014-11-01

    A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices.

  10. Quantification of miltefosine in peripheral blood mononuclear cells by high-performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Kip, A.E.; Rosing, H.; Hillebrand, M.J.X.; Castro, M.M.; Gomez, M.A.; Schellens, J.H.M.; Beijnen, J.H.; Dorlo, T.P.C.

    2015-01-01

    Phagocytes, the physiological compartment in which Leishmania parasites reside, are the main site of action of the drug miltefosine, but the intracellular pharmacokinetics of miltefosine remain unexplored. We developed a bioanalytical method to quantify miltefosine in human peripheral blood mononuclear cells (PBMCs), expanding from an existing high performance liquid chromatography-tandem mass spectrometry method for the quantification of miltefosine in plasma. The method introduced deuterated miltefosine as an internal standard. Miltefosine was extracted from PBMC pellets by addition of 62.5% methanol. Supernatant was collected, evaporated and reconstituted in plasma. Chromatographic separation was performed on a reversed phase C18 column and detection with a triple-quadrupole mass spectrometer. Miltefosine was quantified using plasma calibration standards ranging from 4 to 1000 ng/mL. This method was validated with respect to its PBMC matrix effect, selectivity, recovery and stability. No matrix effect could be observed from the PBMC content (ranging from 0.17 to 26.3 × 106 PBMCs) reconstituted in plasma, as quality control samples were within 3.0% of the nominal concentration (precision less than 7.7%). At the lower limit of quantitation of 4 ng/mL plasma, corresponding to 0.12 ng/106 PBMCs in a typical clinical sample, measured concentrations were within 8.6% of the nominal value. Recovery showed to be reproducible as adding additional pre-treatment steps did not increase the recovery with more than 9%. This method was successfully applied to measure intracellular miltefosine concentrations in PBMC samples from six cutaneous leishmaniasis patients up to one month post-treatment. PMID:26160472

  11. Confirmatory determination of six penicillins in honey by liquid chromatography/electrospray ionization-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Jian

    2004-01-01

    A confirmatory method for 6 penicillin antibiotics (amoxicillin, ampicillin, penicillin G, oxacillin, cloxacillin, and dicloxacillin) in honey is presented that allows determination and confirmation of identity of the antibiotics at trace levels. The method includes the use of a stable isotope-labeled internal standard benzyl (d7-phenyl) penicillate and removal of sugar and other substances by solvent and solid-phase extraction. The honey extracts are then analyzed for penicillin residues by liquid chromatography/electrospray ionization-tandem mass spectrometry. Mass spectral acquisition was achieved in an electrospray positive ion mode by applying multiple reaction monitoring of 2 or 3 fragment ion transitions to provide a high degree of sensitivity and specificity. Typical recoveries of 6 penicillins at fortification levels of 6, 16, 40, and 80 microg/kg ranged from 51.4 to 132.9%. The recoveries varied with the individual penicillins and were affected by different honey matrixes. The ion ratios were consistent and could be used for confirmation of identity of the penicillins. The method limits of detection (microg/kg) were 0.25 for amoxicillin, 0.19 for ampicillin, 0.068 for penicillin G, 0.028 for oxacillin, 0.052 for cloxacillin, and 0.085 for dicloxacillin. The method limits of confirmation (microg/kg) were 0.44 for amoxicillin, 0.52 for ampicillin, 0.23 for penicillin G, 0.14 for oxacillin, 0.14 for cloxacillin, and 0.15 for dicloxacillin when a sample size of 5 g honey was used.

  12. Pharmacokinetics and tissue distribution study of schisandrin B in rats by ultra-fast liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Zhu, Heyun; Zhang, Xiurong; Guan, Jiao; Cui, Baiji; Zhao, Longshan; Zhao, Xu

    2013-05-05

    A rapid, sensitive and high throughput ultra-fast liquid chromatography with tandem mass spectrometry (UFLC-MS/MS) method was established and validated for the determination of schisandrin B in rat plasma and various tissues (including heart, liver, spleen, lung, and kidney). The biological samples were prepared by protein precipitation, and the separation was achieved on a shim-pack XR-ODS C18 column (75 mm × 3.0 mm, 2.2 μm) with a mobile phase consisting of methanol-0.1% formic acid water (85:15, v/v) at a flow rate of 0.4 mL/min. The MS/MS detection was performed on an API 3200 QTRAP mass spectrometry equipped with electrospray ionization (ESI) source using multiple reactions monitoring (MRM) mode by monitoring the fragmentation of m/z 401.2→300.2 for schisandrin B and m/z 271.2→203.1 for imperatorin (internal standard, IS). The calibration curve was linear in the range of 1-500 ng/mL for plasma and tissue homogenates (r ≥ 0.9927). The lower limit of quantification (LLOQ) was 1 ng/mL. The validated method was successfully applied to the pharmacokinetics and tissue distribution study of schisandrin B after oral administration to rats. The pharmacokinetic curve showed double peaks after oral administration, which demonstrated that a hepatoenteral circulation may exist. Tissue distribution showed the highest level was observed in liver, then in kidney, which indicated schisandrin B was mainly accumulated in liver and renal excretion might be a main elimination route.

  13. Quantification and confirmation of flunixin in equine plasma by liquid chromatography-quadrupole time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Luo, Yi; Rudy, Jeffrey A; Uboh, Cornelius E; Soma, Lawrence R; Guan, Fuyu; Enright, James M; Tsang, Deborah S

    2004-03-05

    The method describes quantification and confirmation of flunixin in equine plasma by liquid chromatography-quadrupole time-of-flight mass spectrometry (LC/Q-TOF/MS/MS). Samples were screened by enzyme-linked immunosorbent assay (ELISA) and only those samples presumptively declared positive were subjected to quantification and confirmation for the presence of flunixin by this method. The method is also readily adaptable to instrumental screening for the analyte. Flunixin was recovered from plasma by liquid-liquid extraction (LLE). The sample was diluted with 2 ml saturated phosphate buffer (pH 3.10) prior to LLE. The dried extract was reconstituted in acetonitrile:water:formic acid (50:50:0.1, v/v/v) and subsequently analyzed on a Q-TOF tandem mass spectrometer (Micromass) operated under electrospray ionization positive ion mode. The concentration of flunixin was determined by the internal standard (IS) calibration method using the peak area ratio with clonixin as the IS. The limits of detection (LOD) and quantification (LOQ) for flunixin in equine plasma were 0.1 and 1 ng/ml, respectively, whereas the limit of confirmation (LOC) was 2.5 ng/ml. The qualifying ions for the identification of flunixin were m/z 297 [M+H](+), 279 (BP), 264, 259, 239 and those for clonixin (IS) were m/z 263 [M+H](+), 245 (BP) and 210. The measurement uncertainty about the result was 8.7%. The method is simple, sensitive, robust and reliably fast in the quantification and confirmation of flunixin in equine plasma. Application of this method will assist racing authorities in the enforcement of tolerance plasma concentration of flunixin in the racehorse on race day.

  14. Validated ultra-performance liquid chromatography tandem mass spectrometry method for the determination of pramipexole in human plasma.

    Science.gov (United States)

    Yadav, Manish; Rao, Rajasekhar; Kurani, Hemal; Rathod, Jaysukh; Patel, Rakesh; Singhal, Puran; Shrivastav, Pranav S

    2010-11-01

    A sensitive and high throughput ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method has been developed for the determination of pramipexole, a dopamine agonist, in human plasma. Sample preparation involved liquid-liquid extraction of pramipexole and ranitidine as the internal standard (IS) in ethyl acetate from 100 μL human plasma. The chromatographic separation is achieved on a Waters Acquity UPLC BEH C18 (100 mm × 2.1 mm, 1.7 μm) analytical column using an isocratic mobile phase, consisting of 10 mM ammonium formate (pH 7.50)-acetonitrile (15:85, v/v), at a flow-rate of 0.5 mL/min. The precursor → product ion transition for pramipexole (m/z 212.1 → 153.0) and IS (m/z 315.0 → 176.1) were monitored on a triple quadrupole mass spectrometer, operating in the multiple reaction monitoring (MRM) and positive ion mode. The method was validated over a wide dynamic concentration range of 20-4020 pg/mL. Matrix effect is assessed by post-column infusion experiment and the process efficiency were 91.9% and 85.7% for pramipexole and IS, respectively. The method is rugged and rapid with a total run time of 1.5 min and is applied to a bioequivalence study of 0.25 mg PPX tablet formulation in 30 healthy Indian male subjects under fasting condition.

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

    Science.gov (United States)

    Karbiwnyk, Christine M; Andersen, Wendy C; Turnipseed, Sherri B; Storey, Joseph M; Madson, Mark R; Miller, Keith E; Gieseker, Charles M; Miller, Ron A; Rummel, Nathan G; Reimschuessel, Renate

    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](-)m/z 128 ion resulting in the product ions m/z 85 and 42. Recoveries from catfish, tilapia and trout fortified with 10-100 microgkg(-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 microgkg(-1). An internal standard, (13)C(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 microgkg(-1). Average recovery of CYA from shrimp was 85% (R.S.D.=10%, n=13) with an MDL of 3.5 microgkg(-1).

  16. Simultaneous determination of seventeen mycotoxins residues in Puerariae lobatae radix by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Shufang; Cheng, Ling; Ji, Shen; Wang, Ke

    2014-09-01

    This work reported an efficient and accurate liquid chromatography tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of seventeen mycotoxins in Puerariae lobatae radix, a frequently used traditional Chinese medicine (TCM). The effects of four different clean-up methods, including TC-M160, TC-T220, Mycosep 227, and QuEChERS method, on the recoveries of mycotoxins were investigated and compared. Finally, TC-M160 was chosen for better recovery and repeatability for mycotoxins analysis. The analytes were separated on an Agilent ZORBAX SB C18 column (4.6mm×250mm, 5μm particle size), and eluted with a mobile phase consisting of (A) water containing 0.1% formic acid and (B) acetonitrile containing 0.1% formic acid at a flow rate of 0.6mL/min. The separated compounds were detected by a triple quadrupole mass spectrometer operating in positive electrospray ionization with multiple reaction monitoring (MRM) mode. The results of method validation accorded with the requirement of analytical method for mycotoxins in COMMISSION REGULATION (EC) No 401/2006. The developed method was successfully applied for determination of mycotoxins in seventeen batches of Puerariae lobatae radix collected from different provinces of China. Three batches of them were found with contamination of mycotoxins AFB1 at (0.751±0.176)μg/kg, T-2 at (1.10±0.01)μg/kg, and T-2 at (0.853±0.044)μg/kg, respectively. The results demonstrated that the proposed method was suitable for monitoring mycotoxins residues in Puerariae lobatae radix.

  17. Quantification of clenbuterol at trace level in human urine by ultra-high pressure liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nicoli, Raul; Petrou, Michael; Badoud, Flavia; Dvorak, Jiri; Saugy, Martial; Baume, Norbert

    2013-05-31

    Clenbuterol is a β2 agonist agent with anabolic properties given by the increase in the muscular mass in parallel to the decrease of the body fat. For this reason, the use of clenbuterol is forbidden by the World Anti-Doping Agency (WADA) in the practice of sport. This compound is of particular interest for anti-doping authorities and WADA-accredited laboratories due to the recent reporting of risk of unintentional doping following the eating of meat contaminated with traces of clenbuterol in some countries. In this work, the development and the validation of an ultra-high pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method for the quantification of clenbuterol in human urine is described. The analyte was extracted from urine samples by liquid-liquid extraction (LLE) in basic conditions using tert butyl-methyl ether (TBME) and analyzed by UHPLC-MS/MS with a linear gradient of acetonitrile in 9min only. The simple and rapid method presented here was validated in compliance with authority guidelines and showed a limit of quantification at 5pg/mL and a linearity range from 5pg/mL to 300pg/mL. Good trueness (85.8-105%), repeatability (5.7-10.6% RSD) and intermediate precision (5.9-14.9% RSD) results were obtained. The method was then applied to real samples from eighteen volunteers collecting urines after single oral doses administration (1, 5 and 10μg) of clenbuterol-enriched yogurts.

  18. Determination of endocrine-disrupting compounds in drinking waters by fast liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Magi, Emanuele; Scapolla, Carlo; Di Carro, Marina; Liscio, Camilla

    2010-09-01

    Growing attention has been recently paid to safety of food and drinking water, making necessary the adoption of policies for water sources protection and the development of sensitive and rapid analytical methods to identify micropollutants. Endocrine-disrupting compounds (EDCs) have emerged as a major issue as they alter the functioning of the endocrine system. Since ingestion of EDCs via food is considered the major exposure route, there is a growing interest in understanding EDC fate during drinking water treatment and in monitoring potential contamination of surface waters and groundwaters. In this work, a fast liquid chromatography-electrospray ionization-tandem mass spectrometry method was developed for the determination of 4-n-nonylphenol (NP), bisphenol A (BPA), estrone (E1), 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in drinking waters. In the literature analytical articles seldom provide details regarding fragmentation pathways. In this paper spectra of the five EDCs in negative ESI were interpreted with the support of accurate mass spectra acquired by a quadrupole time-of-flight instrument; fragmentation pathways were also proposed. The chromatographic separation of EDCs was optimized on a Pinnacle DB Biphenylic column with a water-acetonitrile gradient. Quantitative analysis was performed in multiple reaction monitoring (MRM) mode using bisphenol A-d(16) (BPA-d(16)) as internal standard; calibration curves showed good correlation coefficients (0.9989-0.9997). All figures of merit of the method were satisfactory; limits of detection were in the range 0.2-0.4 ng/ml. The method was applied to the determination of the analytes in waters sampled by polar organic chemical integrative samplers in a drinking water treatment plant. Rather low concentration of BPA, NP and E1 were measured in the inlet, while none of the considered EDCs was detected in the outlet.

  19. Analysis of 19-nortestosterone residue in animal tissues by ion-trap gas chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    Jin-qing JIANG; Lei ZHANG; Guang-ling LI; Hai-tang ZHANG; Xue-feng YANG; Jun-wei LIU; Ren-feng LI; Zi-liang WANG; Jian-hua WANG

    2011-01-01

    A rapid sample treatment procedure for the gas chromatography-tandem mass spectrometry (GC-MS) determination of 19-nortestosterone (19-NT) in animal tissues has been developed. In our optimized procedures, enzymatic hydrolysis with p-glucuronidase from Escherichia coli was performed in an acetate buffer (pH 5.2,0.2 mol/L). Next, the homogenate was mixed with methanol and heated at 60 掳C for 15 min, then placed in an ice-bath at -18 掳C for 2 h. After liquid-liquid extraction with n-hexane, the analytes were subjected to a normal-phase solid phase extraction (SPE) C18 cartridge for clean-up. The dried organic extracts were derivatized with heptafluorobutyric anhydride (HFBA), and then the products were injected into GC-MS. Using electron impact mass spectrometry (EI-MS) with positive chemical ionization (PCI), four diagnostic ions (mlz 666, 453, 318, and 306) were determined. A standard calibration curve over the concentration range of 1-20 ng/g was reached, with Y=467084X-68354 (R2=0.9997) for 19-NT, and the detection limit was 0.3 ng. When applied to spiked samples collected from bovine and ovine, the recoveries ranged from 63% to 101% with relative standard deviation (RSD) between 2.7% and 8.9%. The procedure is a highly efficient, sensitive, and more economical method which offers considerable potential to resolve cases of suspected nandrolone doping in husbandry animals.

  20. Applying 'Sequential Windowed Acquisition of All Theoretical Fragment Ion Mass Spectra' (SWATH) for systematic toxicological analysis with liquid chromatography-high-resolution tandem mass spectrometry.

    Science.gov (United States)

    Arnhard, Kathrin; Gottschall, Anna; Pitterl, Florian; Oberacher, Herbert

    2015-01-01

    Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become an indispensable analytical technique in clinical and forensic toxicology for detection and identification of potentially toxic or harmful compounds. Particularly, non-target LC-MS/MS assays enable extensive and universal screening requested in systematic toxicological analysis. An integral part of the identification process is the generation of information-rich product ion spectra which can be searched against libraries of reference mass spectra. Usually, 'data-dependent acquisition' (DDA) strategies are applied for automated data acquisition. In this study, the 'data-independent acquisition' (DIA) method 'Sequential Windowed Acquisition of All Theoretical Fragment Ion Mass Spectra' (SWATH) was combined with LC-MS/MS on a quadrupole-quadrupole-time-of-flight (QqTOF) instrument for acquiring informative high-resolution tandem mass spectra. SWATH performs data-independent fragmentation of all precursor ions entering the mass spectrometer in 21m/z isolation windows. The whole m/z range of interest is covered by continuous stepping of the isolation window. This allows numerous repeat analyses of each window during the elution of a single chromatographic peak and results in a complete fragment ion map of the sample. Compounds and samples typically encountered in forensic casework were used to assess performance characteristics of LC-MS/MS with SWATH. Our experiments clearly revealed that SWATH is a sensitive and specific identification technique. SWATH is capable of identifying more compounds at lower concentration levels than DDA does. The dynamic range of SWATH was estimated to be three orders of magnitude. Furthermore, the >600,000 SWATH spectra matched led to only 408 incorrect calls (false positive rate = 0.06 %). Deconvolution of generated ion maps was found to be essential for unravelling the full identification power of LC-MS/MS with SWATH. With the available software, however, only semi

  1. Simultaneous analysis of multiple neurotransmitters by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Tufi, Sara; Lamoree, Marja; de Boer, Jacob; Leonards, Pim

    2015-05-22

    Neurotransmitters are endogenous metabolites that allow the signal transmission across neuronal synapses. Their biological role is crucial for many physiological functions and their levels can be changed by several diseases. Because of their high polarity, hydrophilic interaction liquid chromatography (HILIC) is a promising tool for neurotransmitter analysis. Due to the large number of HILIC stationary phases available, an evaluation of the column performances and retention behaviors has been performed on five different commercial HILIC packing materials (silica, amino, amide and two zwitterionic stationary phases). Several parameters like the linear correlation between retention and the distribution coefficient (logD), the separation factor k and the column resolution Rs have been investigated and the column performances have been visualized with a heat map and hierarchical clustering analysis. An optimized and validated HILIC-MS/MS method based on the ZIC-cHILIC column is proposed for the simultaneous detection and quantification of twenty compounds consisting of neurotransmitters, precursors and metabolites: 3-methoxytyramine (3-MT), 5-hydroxyindoleacetic acid (5-HIAA), 5-hydroxy-L-tripthophan, acetylcholine, choline, L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine, epinephrine, γ-aminobutyric acid (GABA), glutamate, glutamine, histamine, histidine, L-tryptophan, L-tyrosine, norepinephrine, normetanephrine, phenylalanine, serotonin and tyramine. The method was applied to neuronal metabolite profiling of the central nervous system of the freshwater snail Lymnaea stagnalis. This method is suitable to explore neuronal metabolism and its alteration in different biological matrices.

  2. Stereoselective Determination of Tebuconazole in Water and Zebrafish by Supercritical Fluid Chromatography Tandem Mass Spectrometry.

    Science.gov (United States)

    Liu, Na; Dong, Fengshou; Xu, Jun; Liu, Xingang; Chen, Zenglong; Tao, Yan; Pan, Xinglu; Chen, XiXi; Zheng, Yongquan

    2015-07-22

    A simple and sensitive method for the enantioselective determination of tebuconazole enantiomers in water and zebrafish has been established using supercritical fluid chromatography (SFC)-MS/MS. The effects of the chiral stationary phases, mobile phase, auto back pressure regulator (ABPR) pressure, column temperature, flow rate of the mobile phase, and compensation pump solvent were evaluated. Finally, the optimal SFC-MS/MS working conditions were determined to include a CO2/MeOH mobile phase (87:13, v/v), 2.0 mL/min flow rate, 2200 psi ABPR, and 30 °C column temperature using a Chiralpak IA-3 chiral column under electrospray ionization positive mode. The modified QuEChERS method was applied to water and zebrafish samples. The mean recoveries for the tebuconazole enantiomers were 79.8-108.4% with RSDs ≤ 7.0% in both matrices. The LOQs ranged from 0.24 to 1.20 μg/kg. The developed analytical method was further validated by application to the analysis of authentic samples.

  3. Rapid detection of economic adulterants in fresh milk by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Abernethy, Grant; Higgs, Kerianne

    2013-05-03

    A method to aid in the detection of the economically driven adulteration of fresh milk with a range of small, nitrogen containing compounds, including melamine, ammeline, ammelide, cyanuric acid, allantoin, thiourea, urea, biuret, triuret, semicarbazide, aminotriazine, 3- and 4-aminotriazole, cyanamide, dicyandiamide, guanidine, choline, hydroxyproline, nitrate, and a range of amino acids, has been developed. (15)N2-Urea is used as an internal standard. The adulteration of milk with exogenous urea has previously been difficult to detect because of the variation in the naturally occurring levels of urea in milk. However, by monitoring the contaminants biuret and triuret, which comprise up to 1% of synthetic urea, the adulteration of milk with urea-based fertilizer can be detected. We estimate that to be economically viable, adulteration of the order of 90-4000ppm of the above adulterants would need to be added to fresh milk. For most of the compounds, an arbitrary detection threshold of 2ppm is therefore more than sufficient. For biuret, a lower detection threshold, better than 0.5ppm, is desirable and the sensitivity for biuret and triuret can be improved by the post-column addition of lithium to create lithium adducts under electrospray ionisation. Sample handling involves a two-step solvent precipitation method that is deployed in a 96-well plate format, and the hydrophilic interaction liquid chromatography uses a rapid gradient (1.2min). Three separate injections, to detect the positively charged compounds, the negatively charged compounds and amino acids and finally the lithium adducts, are used. This rapid and qualitative survey method may be deployed as a second tier screening method to quickly reduce sample numbers indicated as irregular by an FTIR based screening system, and to direct analysis to appropriate quantification methods.

  4. Determination of polar organophosphorus pesticides in vegetables and fruits using liquid chromatography with tandem mass spectrometry: Selection of extraction solvent

    NARCIS (Netherlands)

    Mol, H.G.J.; Dam, R.C.J. van; Steijger, O.M.

    2003-01-01

    A method based on liquid chromatography (LC)-mass spectrometry (MS)/MS was developed for sensitive determination of a number of less gas chromatography (GC)-amenable organophosphorus pesticides (OPs; acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl and vamidothion) in cabbage and

  5. Rapid and Sensitive Liquid Chromatography-Tandem Mass Spectrometry for Quantification of Glycyrrhctic Acid in Human Plasma

    Institute of Scientific and Technical Information of China (English)

    TIAN Li; GAO Xiao-li; CHEN Xiao-yan; ZHONG Da-fang; ZHANG Yi-fan; DAI Xiao-jian

    2011-01-01

    A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry(LC-MS/MS) for the determination of glycyrrhetic acid in human plasma with ginsenoside Rh2 as internal standard was developed and validated. The plasma samples were prepared via liquid-liquid extraction with ethyl acetate. Chromatographic separation was accomplished on a Venusil MP-C1s(50 mm×2.1 mm, 5 μm i.d.) column at 25 ℃. The mobile phase consisted of acetonitrile/5 mmol·L-1 ammonium acetate(10:90, volume ratio) at a flow rate of 0.4 mL/min. Negative electrospray ionization was utilized as the ionization source. Glycyrrhetic acid and internal standard were determined via the mutiple reaction monitoring of precursor→production ion transitions at m/z 469→425, 409 and m/z 621→ 161,respectively. Each sample was chromatographed within 2.5 min. The lower limit of quantification was 0.50 ng/mL for 200 μL of plasma sample and the linear range was from 0.50 ng/mL to 800 ng/mL. The intra- and inter-day precisions were less than 8.76% in terms of relative standard deviation(RSD), and the accuracy was within a range of -3.25% -1.32% in terms of relative error(RE). The method was successfully applied to the pharmacokinetic studies of glycyrrhetic acid in healthy male Chinese volunteers after a single oral administration of 75 mg of glycyrrhizin.

  6. Pediatric Reference Intervals for Free Thyroxine and Free Triiodothyronine by Equilibrium Dialysis-Liquid Chromatography-Tandem Mass Spectrometry

    Science.gov (United States)

    La’ulu, Sonia L.; Rasmussen, Kyle J.; Straseski, Joely A.

    2016-01-01

    Objective: Thyroid hormone concentrations fluctuate during growth and development. To accurately diagnose thyroid disease in pediatric patients, reference intervals (RIs) should be established with appropriate age groups from an adequate number of healthy subjects using the most exact methods possible. Obtaining statistically useful numbers of healthy patients is particularly challenging for pediatric populations. The objective of this study was to determine non-parametric RIs for free thyroxine (fT4) and free triiodothyronine (fT3) using equilibrium dialysis-high performance liquid chromatography-tandem mass spectrometry with over 2200 healthy children 6 months-17 years of age. Methods: Subjects were negative for both thyroglobulin and thyroid peroxidase autoantibodies and had normal thyrotropin concentrations. The study included 2213 children (1129 boys and 1084 girls), with at least 120 subjects (average of 125) from each year of life, except for the 6 month to 1 year age group (n=96). Results: Non-parametric RIs (95th percentile) for fT4 were: 18.0-34.7 pmol/L (boys and girls, 6 months-6 years) and 14.2-25.7 pmol/L (boys and girls, 7-17 years). RIs for fT3 were: 5.8-13.1 pmol/L (girls, 6 months-6 years); 5.7-11.8 pmol/L (boys, 6 months-6 years); 5.7-10.0 pmol/L (boys and girls, 7-12 years); 4.5-8.6 pmol/L (girls, 13-17 years); and 5.2-9.4 pmol/L (boys, 13-17 years). Conclusion: Numerous significant differences were observed between pediatric age groups and previously established adult ranges. This emphasizes the need for well-characterized RIs for thyroid hormones in the pediatric population. PMID:26758817

  7. Multiresidue determination of veterinary drugs in aquaculture fish samples by ultra high performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Lopes, Renata Pereira; Reyes, Rocío Cazorla; Romero-González, Roberto; Vidal, José Luis Martínez; Frenich, Antonia Garrido

    2012-05-01

    A simple, selective and fast multiresidue method was developed for the determination of 32 veterinary drug residues belonging to several families, in gilthead sea bream (Sparus aurata) by ultra high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The extraction was based on modified QuEChERS (quick, easy, cheap, effective, rugged and safe) procedure, using as extraction solution a mixture of acetonitrile and methanol (75:25, v/v), and it reduces sample handling, increasing sample throughput in relation to current methodologies. The developed method was validated and mean recovery ranged from 69% to 125% (at 10, 25, 50 and 100 μg/kg). Intra and interday precision, estimated as the same levels and expressed as relative standard deviation, RSD, were lower than 20% and 30%, respectively. Limits of detection (LODs) and quantification (LOQs) were lower than 7.5 and 25 μg/kg, respectively, except for danofloxacin, oxytetracycline and tetracycline (LOD and LOQ of 15.0 and 50 μg/kg, respectively). Decision limit (CC(α)) and detection capability (CC(β)) were also calculated and ranged from 16.7 μg/kg (levamisole) to 605.0 (flumequine) μg/kg and from 23.5 μg/kg (levamisole) to 611.5 μg/kg (flumequine), respectively. The expanded uncertainty, U, was also evaluated ant it was below 25% at 100 μg/kg level, except for tetracycline (28%). Finally, the method was applied to ten samples obtained from local supermarkets in Almería (Spain) and traces of some compounds were detected.

  8. [Simultaneous determination of ethyl carbamate and chloropropanols in flavorings by gas chromatography-triple quadrupole tandem mass spectrometry].

    Science.gov (United States)

    Xu, Xiaomin; He, Huali; Ruan, Yudi; Huang, Baifen; Zhang, Jingshun; Cai, Zengxuan; Ren, Yiping

    2013-11-01

    A simultaneous determination method for ethyl carbamate (EC) and chloropropanols (3-monochloropropane-1, 2-diol (3-MCPD) and 2-monochloropropane-1, 3-diol (2-MCPD)) in flavorings was developed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). After spiked with internal standard, the sample was extracted by matrix solid-phase dispersion extraction technique with an Extrelut NT column. Hexane was used to wash the fat soluble matrix interferences and then an ethyl acetate-ethyl ether (20: 80, v/v) mixture was added to elute the analytes. The concentrated extract was detected by GC-MS/MS in multiple reaction monitoring (MRM) mode. The limits of detection (LODs) were 2, 5 and 5 microg/kg for EC, 3-MCPD and 2-MCPD, respectively. The linear ranges were 5 - 1 000 microg/kg (r = 0.9997), 10-1000 microg/kg (r = 0.999 1) and 10-1000 microg/kg (r = 0.999 5) for EC, 3-MCPD and 2-MCPD, respectively. In soy sauce, yellow rice wine, salami sauce and flavoring of instant noodle matrices, the recoveries (RSDs, n = 7) in MRM mode at the levels of 20, 100 and 400 microg/kg were 87.7%-104% (4.3%-10.7%), 90.1%-109% (2.6%-10.2%), and 90.9%-103% (3.0%-9.5%), respectively. EC, 3-MCPD and 2-MCPD were found in some real samples of the soy sauce, wine and flavoring of instant noodle. EC or 3-MCPD was found in some of the salami samples. The method is accurate, fast and suitable for the simultaneous determination of EC, 3-MCPD and 2-MCPD in flavorings.

  9. Quantification of Warfarin in Dried Rat Plasma Spots by High-Performance Liquid Chromatography with Tandem Mass Spectrometry

    Science.gov (United States)

    2016-01-01

    This paper presents the development and validation of a novel method for quantification of the oral anticoagulant drug warfarin in dried plasma spots (DPS) by high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS). Blood plasma was chosen as a biological fluid to preclude the influence of the hematocrit on the results of the analysis. A 30 μL sample of rat plasma was placed onto Whatman 903 Protein Saver Card and was allowed to dry. A single DPS is sufficient for preparing eight 3.2 mm discs, each containing approximately 1.5–1.6 μL of plasma. Warfarin extraction from one 3.2 mm disc was carried out by adding 200 μL of the acetonitrile : water mixture (1 : 1, v/v) containing 10 mM NH4COOH (pH 4.0), with incubation on a shaker at 1000 rpm for 1 h at 25°C. After chromatographic separation, warfarin and coumachlor (an internal standard) were measured using negative-ion multiple-reaction monitoring with ion transitions m/z 307 → 161 for warfarin and m/z 341 → 161 for the internal standard. The working range of this method is 10–10,000 ng/mL. Within this range, intra- and interday variability of precision and accuracy was <13% and recovery was 82–99%. The results indicate that the new method requires only small plasma samples and may be useful for pharmacokinetic research on warfarin. PMID:28058133

  10. Liquid Chromatography Tandem Mass Spectrometry Method for Quantification of Solifenacin in Human Plasma and its Application to Bioequivalence Study

    Directory of Open Access Journals (Sweden)

    Nishant Paliwal

    2013-06-01

    Full Text Available A hasty, specific and robust assay based on liquid-liquid extraction and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS-MS has been developed and validated for the quantitative analysis of Solifenacin ( a drug used for urinary incontinence in human plasma using Solifenacin D5 as internal standard (ISTD. The precursor to product ion transitions of m/z 363.20/110.10 and m/z 368.14/110.20 were used to measure the analyte and the ISTD, respectively. The method was validated in terms of selectivity, matrix effect, sensitivity, linearity, precision and accuracy, various stabilities (standard stock solution stability in refrigerator and at room temperature, stock dilution stability at refrigerator and room temperature, auto sampler stability, freeze thaw stability, long term stability- 65 o C ± 10o C & long term stability- 22 o C ± 5°C, reagent stability, bench top stability, dry extract stability, wet extract stability in refrigerator, effect of potentially interfering drugs, dilution integrity, recovery, lon suppression through infusion, and blood Stability. The mean percentage recovery of Solifenacin and the internal standard was 65.39 ± 3.646% and 66.24 ± 2.209% respectively. The assay exhibited a linear dynamic range of 0.200 to 30.361 ng mL-1. The RSD % of intra-day and inter-day assay was ≤15%. The application of this assay was demonstrated in a bioequivalence study and will be ideal for clinical pharmacokinetic studies in study population with as lower as 0.200 ng mL-1 analytical sensitivity and as little as 300 μL plasma sample.

  11. On-line liquid chromatography/tandem mass spectrometry simultaneous determination of opiates, cocainics and amphetamines in dried blood spots.

    Science.gov (United States)

    Saussereau, E; Lacroix, C; Gaulier, J M; Goulle, J P

    2012-02-15

    A novel approach has been developed for the illicit drugs quantitative determination using dried blood spots (DBS) on filter paper. The illicit drugs tested were opiates (morphine and its 3- and 6-glucuronide metabolites, codeine, 6-monoacetylmorphine), cocainics (ecgonine methylester, benzoylecgonine, cocaine, cocaethylene) and amphetamines (amphetamine, methamphetamine, MDA, MDMA, MDEA). The described method, requiring a small blood volume, is based on high performance liquid chromatography coupled to tandem mass spectrometry using on-line extraction. A Whatman card 903 was spotted with 30μL of whole blood and left overnight to dry at room temperature. A 3-mm diameter disk was removed using a manual punch, suspended in 150μL of water for 10min with ultrasonication, and then 100μL was injected in the on-line LC-MS/MS system. An Oasis HLB was used as an extraction column and a C18 Atlantis as an analytical column. The chromatographic cycle was performed with 20mM ammonium formate buffer (pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 16min. Detection was performed in positive electrospray ionization mode (ESI+) with a Quattro Micro (Waters). Recoveries of all analytes were up to 80%. DBS were stored in duplicate at 4°C and -20°C for up to 6 months. Illicit drugs seemed to be much more stabled at -20°C. Furthermore, it was tested whether analysis of DBS may be as reliable as that of whole blood investigating authentic samples; significant correlations were obtained. This DBS assay has potential as rapid, sensitive and inexpensive option for the illicit drugs determination in small blood volumes, which seems of great interest in suspected cases of driving under the influence of drugs.

  12. Simultaneous determination of opiates, methadone, buprenorphine and metabolites in human urine by superficially porous liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lin, Huei-Ru; Chen, Chin-Lun; Huang, Chieh-Liang; Chen, Shao-Tsu; Lua, Ahai-Chuang

    2013-04-15

    For monitoring compliance of methadone or buprenorphine maintenance patient, a method for the simultaneous determination of methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), buprenorphine, norbuprenorphine, opiates (morphine, codeine, 6-monoacetylmorphine) in urine by superficially porous liquid chromatography tandem mass spectrometry was developed and validated. After enzyme digestion and liquid-liquid extraction, reverse-phase separation was achieved in 5.2 min and quantification was performed by multiple reaction monitoring. Chromatographic separation was performed at 40 °C on a reversed phase Poroshell column with gradient elution. The mobile phase consisted of water and methanol, each containing 0.1% formic acid, at a flow rate of 0.32 mL/min. Intra-day and inter-day precision were less than 12.1% and accuracy was between -9.8% and 13.7%. Extraction efficiencies were more than 68%. Although ion suppression was detected, deuterated internal standards compensated for these effects. Carryover was minimal, less than 0.20%. All analytes were stable at room temperature for 16 h, 4 °C for 72 h, and after three freeze-thaw cycles. The assay also fulfilled compound identification criteria in accordance with the European Commission Decision 2002/657/EC. We analyzed 62 urine samples from patients received maintenance therapy and found that 54.8% of the patient samples tested were detected for morphine, codeine, or 6-monoacetylmorphine. This method provides a reliable and simultaneous quantification of opiates, maintenance drugs, and their metabolites in urine samples. It facilitates the routine monitoring in individuals prescribed the drug to ensure compliance and help therapeutic process.

  13. Effect of D-allose on prostate cancer cell lines: phospholipid profiling by nanoflow liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jeong, Rae Ung; Lim, Sangsoo; Kim, Myoung Ok; Moon, Myeong Hee

    2011-08-01

    D-Allose, a rare, naturally occurring monosaccharide, is known to exert anti-proliferative effects on cancer cells. The effects of D-allose on the cellular membranes of hormone-refractory prostate cancer cell line (DU145), hormone-sensitive prostate cancer cell line (LNCaP), and normal prostate epithelial cells (PrEC) were studied at the molecular level by phospholipid (PL) profiling using a shotgun lipidomic method. The molecular structures of 85 PL species including 23 phosphatidylcholines, 12 phosphatidylethanolamines (PEs), 11 phosphatidylserines (PSs), 16 phosphatidylinositols, 9 phosphatidic acids (PAs), and 14 phosphatidylglycerols (PGs) were identified by data-dependent collision-induced dissociation of nanoflow liquid chromatography-tandem mass spectrometry, and the PL amounts were quantified. The addition of D-allose to prostate cancer cell lines during their growth phases had negligible or decreased effects on the relative regulation of PL species, but several new PS molecules (two for DU145 and three for LNCaP) emerged. In contrast, experiments on the PrEC cell line revealed that some high abundant species (14:0/14:0-PE, 16:2/16:0-PG, and 20:6/18:1-PA) showed significant increases in concentration. These findings support a mechanism for the anti-proliferative effect of D-allose on prostate cancer cell lines that involves the induction of programmed cell death since PS molecules are known to induce apoptosis. Principal component analysis was carried out to examine differences in PL distributions among the three cell lines promoted by D-allose.

  14. Determination of resveratrol and piceid in beer matrices by solid-phase extraction and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Chiva-Blanch, Gemma; Urpi-Sarda, Mireia; Rotchés-Ribalta, Maria; Zamora-Ros, Raul; Llorach, Rafael; Lamuela-Raventós, Rosa Maria; Estruch, Ramon; Andrés-Lacueva, Cristina

    2011-02-04

    Beer is one of the most commonly consumed undistilled alcoholic beverages in many countries. In recent studies, the stilbenes resveratrol and piceid have been found in some hop varieties which are used in the production of beer. Therefore, they could be transferred to beer. The aim of the present work was to validate a method to study the potential content of trans- and cis-resveratrol and piceid in 110 commercial beers from around the world. The resveratrol and piceid contents of 110 beers were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after a solid-phase extraction (SPE) using optimized and validated procedures for the beer matrix. The beer matrix effect was also studied. Stilbenes were found in quantifiable amounts in 92 beers, while concentrations below the limit of quantification (LOQ) were found in 18 beers. Resveratrol was found in the range of 1.34-77.0μg/L in 79% of the beers analyzed, and piceid was found in the range of 1.80-27.3μg/L in only 33% of them. The mean of total resveratrol in all the beers was 14.7±20.5μg/L. The content of resveratrol has been compared with other resveratrol containing foods. A serving of beer contains similar amounts of stilbenes as berries, less than chocolate and grape products but more than pistachios, peanuts or tomatoes. Overall, beer is one of the products with the lowest levels of total resveratrol (μg/L), and despite its high consumption it should not be considered as a representative source of resveratrol.

  15. On-line derivatization gas chromatography with furan chemical ionization tandem mass spectrometry for screening of amphetamines in urine.

    Science.gov (United States)

    Tzing, Shin-Hwa; Ghule, Anil; Liu, Jen-Yu; Ling, Yong-Chien

    2006-12-22

    A simple alternative method with minimal sample pretreatment is investigated for screening of amphetamines in small volume (using only 20 microL) of urine sample. The method is sensitive and selective. The method uses gas chromatography (GC) direct sample introduction (DSI) for on-line derivatization (acylation) of amphetamines to improve sensitivity. Furan as chemical ionization (CI) reagent in conjunction with tandem mass spectrometry (MS/MS) is used to improve selectivity. Low background with sharp protonated molecular ion peaks of analytes is the evidence of improvement in sensitivity and selectivity. Blank urine samples spiked with known amounts of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine and 3,4-methylenedioxyethylamphetamine is analyzed. Selected ion monitoring of the characteristic product ions (m/z 119+136+150+163) using furan CI-MS/MS in positive ion mode is used for quantification. Limits of detection (LOD) between 0.4 and 1.0 ng mL(-1) and limits of quantitation (LOQ) between 1.0 and 2.0 ng mL(-1) are established. Linear response over the range of 1-1000 ng mL(-1) (r(2)>0.997) is observed for all analytes, except for methamphetamine (2.0-1000 ng mL(-1)). Good accuracy between 86 and 113% and precision ranging from 4 to 18% is obtained. The method is also tested on real samples of urine from suspected drug abusers. This method could be used for screening and determination of amphetamines in urine samples, however needs additional work for full validation.

  16. Identification and quantitation of amphetamines, cocaine, opiates, and phencyclidine in oral fluid by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Fritch, Dean; Blum, Kristen; Nonnemacher, Sheena; Haggerty, Brenda J; Sullivan, Matthew P; Cone, Edward J

    2009-01-01

    Analytical methods for measuring multiple licit and illicit drugs and metabolites in oral fluid require high sensitivity, specificity, and accuracy. With the limited volume available for testing, comprehensive methodology is needed for simultaneous measurement of multiple analytes in a single aliquot. This report describes the validation of a semi-automated method for the simultaneous extraction, identification, and quantitation of 21 analytes in a single oral fluid aliquot. The target compounds included are amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxy-amphetamine, 3,4-methylenedioxyethylamphetamine, pseudoephedrine, cocaine, benzoylecgonine, codeine, norcodeine, 6-acetylcodeine, morphine, 6-acetylmorphine, hydrocodone, norhydrocodone, dihydrocodeine, hydromorphone, oxycodone, noroxycodone, oxymorphone, and phencyclidine. Oral fluid specimens were collected with the Intercept device and extracted by solid-phase extraction (SPE). Drug recovery from the Intercept device averaged 84.3%, and SPE extraction efficiency averaged 91.2% for the 21 analytes. Drug analysis was performed by liquid chromatography-tandem mass spectrometry in the positive electrospray mode using ratios of qualifying product ions within +/-25% of calibration standards. Matrix ion suppression ranged from -57 to 8%. The limit of quantitation ranged from 0.4 to 5 ng/mL using 0.2 mL of diluted oral fluid sample. Application of the method was demonstrated by testing oral fluid specimens from drug abuse treatment patients. Thirty-nine patients tested positive for various combinations of licit and illicit drugs and metabolites. In conclusion, this validated method is suitable for simultaneous measurement of 21 licit and illicit drugs and metabolites in oral fluid.

  17. 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 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.

  18. Multi-class mycotoxins analysis in Angelica sinensis by ultra fast liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Liu, Qiutao; Kong, Weijun; Guo, Weiying; Yang, Meihua

    2015-04-15

    An ultra fast liquid chromatography coupled with tandem mass spectrometry (UFLC-MS/MS) method was developed and validated for simultaneous analysis of multi-class mycotoxins including aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), fumonisins (FB1 and FB2) and zearalanone (ZEN) in 20 batches of Angelica sinensis samples collected from different markets and stores in China. The eight mycotoxins were extracted and cleaned up by using QuEChERS-based procedure, and then were quantified under the multiple reaction monitoring (MRM) together with positive and negative ionization modes. Focusing on the optimization of extraction and clean-up conditions, as well as UFLC separation and MS/MS parameters of targeted analytes, the developed method expressed good linearity for the eight mycotoxins within their respective linear ranges with correlation coefficients all higher than 0.9974. The limits of detection (LODs) and quantification (LOQs) ranged from 0.005 to 0.125 μg/kg and from 0.0625 to 0.25 μg/kg, respectively. Recoveries for spiked A. sinensis sample at three different levels were all above 78.9% with relative standard deviations (RSDs) below 6.36% for all analytes. Analysis of real samples demonstrated that two visibly moldy A. sinensis samples were detected with AFB1 of 2.07 and 2.92 μg/kg, and AFG1 of 2.84 and 1.53 μg/kg. The proposed quantitative method with significant advantages including simple pretreatment, rapid determination and high sensitivity would be the preferred candidate for the determination and quantification of multi-class mycotoxin contaminants in complex matrixes, which well fulfilled the maximum residue limits (MRLs) from various countries.

  19. Simultaneous determination of eugenol, isoeugenol and methyleugenol in fish fillet using gas chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Ke, Changliang; Liu, Qi; Li, Liudong; Chen, Jiewen; Wang, Xunuo; Huang, Ke

    2016-09-15

    Gas chromatography (GC) coupled with triple quadrupole tandem mass spectrometry (MS/MS) operated in electron ionization mode (EI) has been shown to have advantages in the trace analysis of chemical compounds. Employing the instrument, a method has been built to simultaneously determine eugenol, isoeugenol' and methyleugenol, which have been widely used as fish anesthetic, in the fish fillet. Procedure for the sample preparation was achieved by using hexane extraction followed by phenyl solid phase extraction (SPE) cleanup, which was free of such steps as rotary evaporation and nitrogen blowing by taking the volatility of eugenol and its isomers into consideration. The method was validated by conducting recovery studies on fortified fish fillet samples at four concentrations. The linearity in the range of 5-500μg·L(-1) was forced through the origin giving a coefficient of determination (r(2)) greater than 0.9982. Limits of detection (LODs) for eugenol, isoeugenol' and methyleugenol were 0.4, 1.2' and 0.2μg·kg(-1), respectively. The limits of quantification (LOQs) were 1.2, 4' and 0.7μg·kg(-1) for eugenol, isoeugenol' and methyleugenol, respectively. The recoveries for eugenol and its isomers ranged from 76.4 to 99.9% with relative standard deviations (RSD) in a range from 2.18 to 15.5%. This method is quick, simple and suitable for determining the residues of eugenol, isoeugenol and methyleugenol simultaneously in batch samples of fish fillet.

  20. Determination of levetiracetam in human plasma by liquid chromatography/electrospray tandem mass spectrometry and its application to bioequivalence studies.

    Science.gov (United States)

    Jain, Deepak S; Subbaiah, Gunta; Sanyal, Mallika; Pal, Usha; Shrivastav, Pranav S

    2006-01-01

    The first liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of levetiracetam, an antiepileptic drug, in human plasma is described. The plasma filtrate obtained after solid-phase extraction (SPE), using a polymer-based, hydrophilic-lipophilic balanced (HLB) cartridge, was submitted directly to a short column LC/MS/MS assay. There was no significant matrix effect on the analysis. For validation of the method, the recovery of the free analytes was compared to that from an optimized extraction method, and the analyte stability was examined under conditions mimicking sample storage, handling, and analytical procedures. The extraction procedure yielded extremely clean extracts with a recovery of 79.95% and 89.02% for levetiracetam and the internal standard (IS), respectively. The intra-assay and inter-assay precision for the samples at the lower limit of quantitation (LLOQ) were 6.33 and 6.82%, respectively. The calibration curves were linear for the dynamic range of 0.5 to 50 microg/mL with a correlation coefficient r >/= 0.9971. The intra-assay accuracy at LLOQ, LQC, MQC, and HQC levels ranged from 81.60 to 95.40, 93.00 to 103.47, 95.97 to 104.09, and 91.15 to 95.18%, respectively, while the inter-assay accuracy at LLOQ, LQC, MQC and HQC levels varied from 80.20 to 95.40, 88.53 to 107.53, 95.97 to 108.45, and 91.15 to 112.70%, respectively. The method is rugged and fast with a total instrumental run time of 2 min. The method was successfully applied for bioequivalence studies in human subject samples after oral administration of 1000 mg immediate release (IR) formulations.

  1. Determination of paroxetine in plasma by liquid chromatography coupled to tandem mass spectrometry for pharmacokinetic and bioequivalence studies.

    Science.gov (United States)

    Jhee, Ok Hwa; Seo, Hee Kyoung; Lee, Min Ho; Jeon, Yong Cheol; Shaw, Leslie M; Lee, Seung Hoon; Hur, Yeon; Kim, Kwang-Hyun; Lee, Heon-Soo; Lee, Seo Eun; Kang, Ju Seop

    2007-01-01

    A rapid and validated liquid chromatography coupled to tandem mass spectrometric method (LC-MS-MS) has been developed and applied to pharmacokinetic and bioequivalence studies in 24 healthy male Korean volunteers. The procedure involves a liquid-liquid extraction of paroxetine (CAS 61869-08-7) and fluoxetine (internal standard, CAS 54910-89-3) with ether/methyl chloride (7:3, v/v) and separated by LC equipped with C18 column using acetonitrile: 5 mmol/L ammonium formate (4:3, v/v) as mobile phase. Detection is carried out on an API 2000 MS system by multiple reactions monitoring mode. The ionization was optimized using ESI(+) and selectivity was achieved by MS-MS analysis, mlz 330.0-->192.0 and m/ z 310-->148 for paroxetine and fluoxetine, respectively. The method has a total run time of 1.5 min and was linear over a working range of 0.05-20 ng/mL and the lower limit of quantification was 0.05 ng/ mL. No endogenous compounds were found to interfere with the analysis. The inter-day and intra-day accuracy was in the ranges of 102.69-107.79% and 102.07-109.57%, respectively and precision of inter-day and intra-day expressed as relative standard deviation were 1.86-9.99% and 1.52-6.28%, respectively. The validation of this method on linearity, specificity, accuracy, precision as well as applicability to pharmacokinetic and bioequivalence studies by analysis of blood samples taken up to 72 h after oral administration of 20 mg of paroxetine in 24 healthy volunteers were found to be good performance.

  2. Quantitative trace analysis of eight chloramphenicol isomers in urine by chiral liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Berendsen, Bjorn J A; Essers, Martien L; Stolker, Linda A A M; Nielen, Michel W F

    2011-10-14

    Chloramphenicol is a broad-spectrum antibiotic with, apart from its human medicinal use, veterinary abuse in all major food-producing animals. Chloramphenicol occurs in four stereoisomers (all para-nitro substituted) and furthermore four meta-nitro analogs of chloramphenicol exist. In this paper these are referred to as eight chloramphenicol isomers. According to EU regulations an analytical method should be able to discriminate the analyte from interfering substances that might be present in the sample, including isomers. For the first time a quantitative method for the analysis of trace levels of eight chloramphenicol isomers in urine by chiral liquid chromatography in combination with tandem mass spectrometric detection is reported. The separation of the isomers on the analytical column, the clean-up of urine and the selectivity of the monitored product ions turned out to be critical parameters. To obtain reproducible retention isocratic elution on a chiral AGP column was applied. For urine samples matrix compounds present in the final extract caused decreased retention of the isomers on the chiral stationary phase and a lack of chromatographic resolution. Therefore an extended clean-up procedure that combines solid phase extraction and liquid-liquid extraction had to be developed. The final method was fully validated and showed satisfactory performance for all isomers with decision limits (CCα) ranging from 0.005 to 0.03 μg L(-1) and within-laboratory reproducibility of all isomers below 20% at the minimum required performance limit level of 0.3 μg L(-1).

  3. Rapid methods to determine procyanidins, anthocyanins, theobromine and caffeine in rat tissues by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Serra, Aida; Macià, Alba; Romero, Maria-Paz; Piñol, Carme; Motilva, Maria-José

    2011-06-01

    Rapid, selective and sensitive methods were developed and validated to determine procyanidins, anthocyanins and alkaloids in different biological tissues, such as liver, brain, the aorta vein and adipose tissue. For this purpose, standards of procyanidins (catechin, epicatechin, and dimer B(2)), anthocyanins (cyanidin-3-glucoside and malvidin-3-glucoside) and alkaloids (theobromine, caffeine and theophylline) were used. The methods included the extraction of homogenized tissues by off-line liquid-solid extraction, and then solid-phase extraction to analyze alkaloids, or microelution solid-phase extraction plate for the analysis of procyanidins and anthocyanins. The eluted extracts were then analyzed by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, using a triple quadrupole as the analyzer. The optimum extraction solution was water/methanol/phosphoric acid 4% (94/4.5/1.5, v/v/v). The extraction recoveries were higher than 81% for all the studied compounds in all the tissues, except the anthocyanins, which were between 50 and 65% in the liver and brain. In order to show the applicability of the developed methods, different rat tissues were analyzed to determine the procyanidins, anthocyanins and alkaloids and their generated metabolites. The rats had previously consumed 1g of a grape pomace extract (to analyze procyanidins and anthocyanins) or a cocoa extract (to analyze alkaloids) per kilogram of body weight. Different tissues were extracted 4h after administration of the respective extracts. The analysis of the metabolites revealed a hepatic metabolism of procyanidins. The liver was the tissue which produced a greater accumulation of these metabolites.

  4. Stable isotope labeling assisted liquid chromatography-electrospray tandem mass spectrometry for quantitative analysis of endogenous gibberellins.

    Science.gov (United States)

    Hao, Yan-Hong; Zhang, Zheng; Wang, Lu; Liu, Chao; Lei, Ai-Wen; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-11-01

    In the current study, we developed a stable isotope labeling strategy for the absolute quantification of gibberellins (GAs) by high performance liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS/MS). N,N-dimethyl ethylenediamine (DMED) and its deuterated counterpart d(4)-DMED were used to derivatize GAs extracted from plant tissue samples and GA standards respectively. The both derivatives of GAs were mixed and then subjected to HPLC-ESI-MS/MS analysis. The absolute quantification of GAs in plant tissues could be achieved by calculating the peak area ratios of DMED labeled GAs/d(4)-DMED labeled GAs. In the proposed strategy, the derivatization reaction of the labeling reagents with GAs could be completed rapidly (within 5 min) with high efficiency (>99%) under mild conditions. The resulting derivatives could produce specific fragments in collision induced dissociation (CID), leading to high selectivity in multiple-reaction monitoring (MRM) mode, thus enhanced the reliability of the LC-MS/MS method. Furthermore, the limits of quantitation (LOQs) of GAs were considerably decreased (2-32 folds) due to incorporating easily ionized moieties into GAs, and the quantification of GAs in plant tissue could be achieved without isotopically labeled GA standards. Good linearity was obtained with correlation coefficients R(2) values of >0.99. The limits of detection (LODs) and quantitation (LOQs) ranged from 0.02 to 0.74 pg and 0.07 to 2.45 pg, respectively. Eleven GAs could be successfully determined in spiked sample with 72-128% recoveries and the relative standard deviations (RSDs) were between 1.0% and 13.9%. Finally, the developed method was successfully applied for the detection of GAs in 50mg (fresh weight) Oryza sativa leaves.

  5. Stable Isotope Dilution Analysis of Gibberellin Residues in Tomato Paste by Liquid Chromatography-Tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    SUN Li; ZHAO Yan-sheng; NIE Xue-mei; LING Yun; CHU Xiao-gang; SHANG De-jun; DONG Ying

    2012-01-01

    An accurate and sensitive method for the simultaneous determination of gibberellic acid(GA3),gibberellin A4(GA4) and gibberellin A7(GA7) residues in tomato paste was developed by coupling solid phase extraction to high performance liquid chromatography-tandem mass spectrometry(LC-MS/MS) with electrospray ionization based stable isotope dilution analysis(SIDA).The isotope labeled internal standard can compensate for the losses during the extraction and cleanup steps and for discrimination due to ion suppression.After extraction from methanol,hydrophile lipophilic balance(HLB) solid phase extraction(SPE) column was tested for the capacity of the cleanup of the tomato paste in compared with C18 SPE column which is the common way to the detection of GAs,and the former gained better result.Spiked experiments were performed in the non-contaminated tomato pastes and the recoveries of GA3,GA4 and GA7 were 42.6%-75.0% in external standard method(ESM) and 91.1%-103.8% in internal standard method(ISM) respectively.The validities of this method were investigated and good analytical performance for the three GAs was obtained,including low limits of method detection(2 ng/g for GA3 and GA4,0.3 ng/g for GA7),excellent linear dynamic ranges(5-500 ng/g for GA3 and GA4,1-100 ng/g for GAy) and good relative standard deviation ranges(4.8%-9.4% for the intra-day test and 3.5%-11.9% for the inter-day test).

  6. Robust analysis of underivatized free amino acids in soil by hydrophilic interaction liquid chromatography coupled with electrospray tandem mass spectrometry.

    Science.gov (United States)

    Gao, Jiajia; Helmus, Rick; Cerli, Chiara; Jansen, Boris; Wang, Xiang; Kalbitz, Karsten

    2016-06-03

    Amino acids are an important and highly dynamic fraction of organic N in soils and their determination in soil without derivatization is challenging due to the difficulties in separation and detection of trace amounts of these polar analytes. In the present work, we developed an analytical method to quantify 20 free amino acids in aqueous soil extracts without derivatization. The method employed hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) technique combined with a cation exchange solid phase extraction (SPE). Four stable isotope labelled amino acids were used as internal standards to improve the method performance. Good separation of 20 underivatized amino acids was achieved within 12min. The limit of detection (LODs) and limit of quantification (LOQs) were in the range of 13-384ngg(-1) and 43-1267ngg(-1) (dry soil basis), respectively. The results showed that overall recoveries with high precision were obtained for the extracted free amino acids from ten different soils. The overall recoveries of 18 amino acids were similar for the ten soils used, which differed substantially in organic C content and in other properties as soil texture and pH. For most of the amino acids, the average recoveries from soil extracts were between 74% and 117%, with the exception of Met (31%), Pro (52%) and Arg (68%). Variability was within acceptable limits (relative standard deviations were between 4% and 13%), with the exception of Met (relative standard deviation=90%) and Arg (relative standard deviation=53%). Thus the proposed method with high throughout and high analyte specificity shows great promise for consistent analysis of free amino acids extracted from soils and offers new horizons for the analysis of amino acids in terrestrial and aquatic ecosystem.

  7. [Simultaneous determination of four mercapturic acids in human urine using solid phase extraction and liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Hou, Hongwei; Xiong, Wei; Gao, Na; Song, Dongkui; Tang, Gangling; Hu, Qingyuan

    2011-01-01

    A method was developed for the simultaneous extraction and determination of four mercapturic acids (MAs), N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA), N-acetyl-S-(3-hydroxypropyl)-L-cysteine (3-HPMA), N-acetyl-S-(2-carboxyethyl)-L-cysteine ( CEMA) and S-phenylmercapturic acid (SPMA), in human urine using solid phase extraction and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Frozen urine samples were thawed at room temperature, and centrifuged to remove any settled precipitate. The supernatant was then purified and concentrated by a C18 solid phase extraction column, and analyzed by HPLC-MS/MS in the multiple reaction monitoring (MRM) mode for the quantitative analysis. The ranges of recovery for DHBMA, 3-HPMA, CEMA and SPMA spiked in human urine matrix at three concentration levels were 105.6%-124.4%, 102.7%-106.5%, 103.2%-103.9% and 101.7%-104.3%, respectively, with the relative standard deviations of 2.6%-7.7%. The limits of detection (LOD, S/N > or = 3) were 0. 062, 0. 031, 0. 020 and 0. 003 microg/L for DHBMA, 3-HPMA, CEMA and SPMA, respectively. The method was successfully used to detect 4 MAs in 37 human urine samples from smokers and non-smokers. It was found that the contents of 3-HPMA, CEMA and SPMA in the urines from cigarette smokers were about three to six-fold more than those in the urines from the non-smokers.

  8. Simultaneous quantitation of urinary cotinine and acrylonitrile-derived mercapturic acids with ultraperformance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wu, Chia-Fang; Uang, Shi-Nian; Chiang, Su-Yin; Shih, Wei-Chung; Huang, Yu-Fang; Wu, Kuen-Yuh

    2012-02-01

    Acrylonitrile (AN), a widely used industrial chemical also found in tobacco smoke, has been classified as a possible human carcinogen (group 2B) by the International Agency for Research on Cancer. AN can be detoxified by glutathione S-transferase (GST) to form glutathione (GSH) conjugates in vivo. It can be metabolically activated by cytochrome P450 2E1 to form 2-cyanoethylene oxide, which can also be detoxified by GST to generate GSH conjugates. The GSH conjugates can be further metabolized to mercapturic acids (MAs), namely, N-acetyl-S-(2-cyanoethyl)cysteine (CEMA), N-acetyl-S-(2-hydroxyethyl)cysteine (HEMA), and N-acetyl-S-(1-cyano-2-hydroxyethyl)cysteine (CHEMA). This study developed an ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) method to quantitatively profile the major AN urinary metabolites (CEMA, HEMA, and CHEMA) to assess AN exposure, as well as analyze urinary cotinine (COT) as an indicator for tobacco smoke exposure. The limits of quantitation were 0.1, 0.1, 1.0, and 0.05 μg/L for HEMA, CEMA, CHEMA, and COT, respectively. This method was applied to analyze the three AN-derived MAs in 36 volunteers with no prior occupational AN exposure. Data analysis showed significant correlations between the level of COT and the levels of these MAs, suggesting them as biomarkers for exposure to low levels of AN. The results demonstrate that a highly specific and sensitive UPLC-MS/MS method has been successfully developed to quantitatively profile the major urinary metabolites of AN in humans to assess low AN exposure.

  9. 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.

  10. 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.

  11. Simple and rapid screening procedure for 143 new psychoactive substances by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Adamowicz, Piotr; Tokarczyk, Bogdan

    2016-07-01

    In recent years, many new psychoactive substances (NPS) from several drug classes have appeared on the drug market. These substances, also known as 'legal highs', belong to different chemical classes. Despite the increasing number of NPS, there are few comprehensive screening methods for their detection in biological specimens. In this context, the purpose of this study was to develop a fast and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening procedure for NPS in blood. The elaborated method allows the simultaneous screening of 143 compounds from different groups (number of compounds): cathinones (36), phenethylamines (26), tryptamines (18), piperazines (9), piperidines (2), synthetic cannabinoids (34), arylalkylamines (7), arylcyclohexylamines (3), aminoindanes (2), and other drugs (6). Blood samples (0.2 mL) were precipitated with acetonitrile (0.6 mL). The separation was achieved with gradient mobile phase of 0.1% formic acid in acetonitrile and 0.1% formic acid in water in 14 min. Detection of all compounds was based on multiple reaction monitoring (MRM) transitions. The total number of transitions monitored in dynamic mode was 432. The whole procedure was rapid and simple. The limits of detection (LODs) estimated for 104 compounds were in the range 0.01-3.09 ng/mL. The extraction recoveries determined for 32 compounds were from 1.8 to 133%. The procedure was successfully applied to the analysis of forensic blood samples in routine casework. The developed method should have wide applicability for rapid screening of new drugs of abuse in forensic or clinical samples. The procedure can be easily expanded for more substances. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Clinical and forensic examinations of glycaemic marker methylglyoxal by means of high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Hess, Cornelius; Stratmann, Bernd; Quester, Wulf; Tschoepe, Diethelm; Madea, Burkhard; Musshoff, Frank

    2013-03-01

    The postmortem determination of hyperglycaemic coma is quite difficult because of the lack of morphological findings and the difficult interpretation of biochemical parameters. Methylglyoxal (MG) is a reactive oxoaldehyde, which is mainly derived from glycolysis. An electrospray ionisation liquid chromatography-tandem mass spectrometric procedure for the determination of methylglyoxal in human serum and postmortem blood was developed. It involves protein precipitation with perchloric acid and a derivatisation step with 2,3-diaminonaphthalene. The assay was validated according to international guidelines. Serum samples from diabetics obtained at a diabetes clinic and from non-diabetics were used to assess data about reference concentrations in human serum. The assay showed linearity within the physiological concentrations in serum (5-500 ng/ml). Intraday imprecision at three concentrations was 10.3, 9.2 and 8.3 %, and interday imprecision was 15.3, 14.2 and 9.4 %; the limit of detection was 1.3 ng/ml, and limit of quantification, 3.2 ng/ml. One hundred and eighteen clinical (100 diabetics, 18 non-diabetics) and 98 forensic samples (84 non-diabetics, 14 in a status of hyperglycaemic coma) were measured. During life, diabetics showed significantly (p < 0.001) higher serum concentrations of MG than non-diabetics. After death, concentrations of MG increased significantly (p < 0.001). However, there was no correlation between the sum formula of Traub in vitreous humour and MG femoral blood concentrations (R = 0.237). This indicates that MG concentrations in the deceased cannot distinguish deaths due to a hyperglycaemic coma from other causes of death.

  13. 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.

  14. Generic solid phase extraction-liquid chromatography-tandem mass spectrometry method for fast determination of drugs in biological fluids

    NARCIS (Netherlands)

    Schellen, A.; Ooms, B.; Lagemaat, D. van de; Vreeken, R.; Dongen, W.D. van

    2003-01-01

    A generic method was developed for the fast determination of a wide range of drugs in serum or plasma. The methodology comprises generic solid-phase extraction, on-line coupled to gradient HPLC with tandem mass spectrometric detection (SPE-LC-MS/MS). The individual components of the SPE-LC-MS/MS sys

  15. Large pore dermal microdialysis and liquid chromatography-tandem mass spectroscopy shotgun proteomic analysis: a feasibility study

    DEFF Research Database (Denmark)

    Petersen, Lars J.; Sorensen, Mette A.; Codrea, Marius C.

    2013-01-01

    HPLC systems, followed by tandem mass spectrometry (MS/MS) on a Quadrupole-TOF hybrid instrument. The MS/MS spectra were merged and mapped to a human target protein database to achieve peptide identification and protein inference. ResultsResults showed variation in protein amounts and profiles for each...

  16. Quantitation of α-Lactalbumin by Liquid Chromatography Tandem Mass Spectrometry in Medicinal Adjuvant Lactose

    Directory of Open Access Journals (Sweden)

    Rui Yan

    2014-01-01

    Full Text Available Lactose is a widely used pharmaceutical excipient, sometimes irreplaceable. Traces of residual proteins left during production of lactose are potential allergen to body. The present paper describes a sensitive and specific LC-MS method for the determination of α-lactalbumin (α-La in lactose samples. Chromatographic separation was performed on an Acquity UPLC BEH300 C18 column (2.1×150 mm, 1.7 μm with an isocratic mobile phase consisting of water containing 0.1% TFA and acetonitrile containing 0.1% TFA (80 : 20, v/v. Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an ESI interface operating in positive ionization mode. Quantitation was performed using selected ion monitoring of m/z 2364 for α-La. The calibration curve was linear from 0.2 to 10 µg/mL. The intra- and interday precisions were less than 7.6% and the accuracy ranged from 96.4 to 104.5%. The limit of quantification (LOQ was 0.15 µg/mL and the limit of detection (LOD was 0.05 µg/mL. This method was then successfully applied to investigate 6 different lactose samples. The application can provide technical preparation for the development of specification of lactose.

  17. Collaborative trial validation study of two methods, one based on high performance liquid chromatography-tandem mass spectrometry and on gas chromatography-mass spectrometry for the determination of acrylamide in bakery and potato products.

    Science.gov (United States)

    Wenzl, Thomas; Karasek, Lubomir; Rosen, Johan; Hellenaes, Karl-Erik; Crews, Colin; Castle, Laurence; Anklam, Elke

    2006-11-03

    A European inter-laboratory study was conducted to validate two analytical procedures for the determination of acrylamide in bakery ware (crispbreads, biscuits) and potato products (chips), within a concentration range from about 20 microg/kg to about 9000 microgg/kg. The methods are based on gas chromatography-mass spectrometry (GC-MS) of the derivatised analyte and on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) of native acrylamide. Isotope dilution with isotopically labelled acrylamide was an integral part of both methods. The study was evaluated according to internationally accepted guidelines. The performance of the HPLC-MS/MS method was found to be superior to that of the GC-MS method and to be fit-for-the-purpose.

  18. [Qualitative and quantitative analysis of the amino acids in Rhizoma Arisaematis by ultra high performance liquid chromatography-tandem mass spectrometry and high performance liquid chromatography].

    Science.gov (United States)

    Wang, Xing; Chi, Yumei; Kang, An

    2014-12-01

    A method for the identification and determination of the polar amino components without ultraviolet activity in traditional Chinese medicines was developed. With Rhizoma Arisaematis as the object of this study, using pre-column derivatization with phenyl isothiocyanate (PITC) as the derivatization reagent, compounds were separated and identified on a C18 column (100 mm x 2.1 mm, 3.5 µm) by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A total of 20 components, including 18 amino acids and 2 amine compounds were identified. Furthermore, after the optimization of the derivatization conditions, 15 amino acids were determined by high performance liquid chromatography (HPLC) on Diamonsil C18 column (250 mm x 4.6 mm, 5 µm), detected at 254 nm and gradiently eluted by acetonitrile and 0. 05 mol/L ammonium acetate-acetic acid (pH 6. 5) as the mobile phases. The results of methodological study demonstrated that the method can meet the requirements of the determination. All calibration curves expressed good linearity: Glu, Try in the range of 2-100 mg/L, Arg in the range of 6-300 mg/L, others in the range of 0. 8-40 µg/L, with the correlation coefficients ≥ 0. 999 5. The average recovery of this method was among 95%-105% and the RSD was less than 3%. The developed method was successfully applied to quantitative determination of amino compounds in 12 batches of Rhizoma Arisaematis samples. The method is simple, sensitive, accurate, and can be used for rapid identification and determination of amino components in traditional Chinese medicines.

  19. Comparison of liquid chromatography-ultraviolet and chromatography-tandem mass spectrometry for the determination of indapamide in human whole blood and their applications in bioequivalence studies.

    Science.gov (United States)

    Zhao, Libo; Gu, Shifen; Xu, Rong; Cui, Xiaoyu; Gan, Fangliang; Chen, Hui

    2010-01-01

    The aim of this study was to compare two methods which were based on liquid chromatography with ultraviolet detection (LC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS), respectively, to determine indapamide (CAS 26807-65-8) and to apply them to bioequivalence studies. The universal parameters, including selectivity, linearity, precision, and quantification limit, served as gold standard for the comparison of the two methods. As a result, the two methods were both very consistent and reliable. Furthermore, the LC-MS/MS method required only one-fifth the blood volume needed by the other method and was approximately 25 times more sensitive than the other method. The total run time of the LC-MS/MS method was 3.5 min per sample as opposed to 11 min for the other method. Forty healthy male Chinese volunteers were selected as subjects. One half were orally administrered 2.5 mg indapamide immediate release tablets while the other half were orally administered 1.5 mg indapamide sus-tained release coated tablets. The collected blood samples were determined with the two methods described above. The pharmacokinetic parameters were determined using a noncompartmental method. For the bioequivalence studies, the pharmacokinetic parameters acquired here were in line with the literature and parameters met the criteria set by the State Food and Drug Administration of China (SFDA) for bioequivalence study, indicating that generic drugs are bioequivalent to branded drugs. The present study suggests that the two methods based on LC-UV and LC-MS/MS were suitable for bioavailability studies of indapamide with different pharmaceutical formulations. Consequently, it can be believed that the criterion that each individual expected concentration range would need a given bioassay with the requested sensitivity is not absolutely right. In practice, most of the time, the highest sensitivity allows to bioassay concentrations in a higher range.

  20. Simultaneous quantification of isoniazid, rifampicin, ethambutol and pyrazinamide by liquid chromatography/tandem mass spectrometry

    DEFF Research Database (Denmark)

    Prahl, Julie B; Lundqvist, Marika; Bahl, Justyna M C

    2016-01-01

    A remediable cause of poor treatment response in drug-susceptible tuberculosis (TB) patients may be low plasma levels of one or more of the first-line anti-TB drugs. The aim of this work was to develop an accurate and precise LC-MS/MS method for simultaneous quantification of all four first......-line anti-TB drugs in plasma suitable for therapeutic drug monitoring (TDM). To adjust for degradation and losses during sample preparation, isotopically labeled compounds were used as internal standards. Plasma samples spiked with internal standards were extracted using protein precipitation with methanol...... and acetonitrile. Simultaneous separation of all four drugs was accomplished with a Chromolith Reversed-Phase column and mobile phases consisting of water, methanol, ammonium acetate and formic acid with subsequent mass spectrometric quantification. The linear range of the calibration curve for isoniazid was 0...

  1. 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.

  2. Multiresidue analysis of multiclass plant growth regulators in grapes by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Oulkar, Dasharath P; Banerjee, Kaushik; Ghaste, Manoj S; Ramteke, Sahadeo D; Naik, Dattatraya G; Patil, Shubhangi B; Jadhav, Manjusha R; Adsule, Pandurang G

    2011-01-01

    A selective and rapid multiresidue analysis method is presented for simultaneous estimation of 12 plant growth regulators (PGRs), namely, auxins (indol-3-acetic acid, indol-3-butyric acid, and naphthyl acetic acid), cytokinins (kinetin, zeatin, and 6-benzyladenine), gibberellic acid (GA3), abscisic acid, and synthetic compounds, namely, forchlorfenuron, paclobutrazole, isoprothiolane, and 2,4-dichlorophenoxy acetic acid (2,4-D) in bud sprouts and grape berries at the development stages of 2-3 and 6-8 mm diameters, which are the critical phases when exogenous application of PGRs may be necessary to achieve desired grape quality and yield. The sample preparation method involved extraction of plant material with acidified methanol (50%) by homogenization for 2 min at 15000 rpm. The pH of the extract was enhanced up to 6 by adding ammonium acetate, followed by homogenization and centrifugation. The supernatant extract was cleaned by SPE on an Oasis HLB cartridge (200 mg, 6 cc). The final extract was measured directly by LC/MS/MS with electrospray ionization in positive mode, except for 2,4-D, GA3, and abscisic acid extracts, which required analysis in negative mode. Quantification by multiple reaction monitoring (MRM) was supported with full-scan mass spectrometric confirmation using "information-dependent acquisition" triggered with MRM to "enhanced product ionization" mode of the hybrid quadrupole-ion trap mass analyzer. The LOQ of the test analytes varied between 1 and 10 ng/g with associated recoveries of 80-120% and precision RSD <25% (n = 8). Significant matrix-induced signal suppression was recorded when the responses for pre- and postextraction spikes of analytes were compared; this could be resolved by using matrix-matched calibration standards. The method could successfully be applied in analyzing incurred residue samples and would, therefore, be useful in precisely deciding the necessity and dose of exogenous applications of PGRs on the basis of measured

  3. Targeted High Performance Liquid Chromatography Tandem Mass Spectrometry-based Metabolomics differentiates metabolic syndrome from obesity.

    Science.gov (United States)

    Zhong, Fanyi; Xu, Mengyang; Bruno, Richard S; Ballard, Kevin D; Zhu, Jiangjiang

    2017-04-01

    Both obesity and the metabolic syndrome are risk factors for type 2 diabetes and cardiovascular disease. Identification of novel biomarkers are needed to distinguish metabolic syndrome from equally obese individuals in order to direct them to early interventions that reduce their risk of developing further health problems. We utilized mass spectrometry-based targeted metabolic profiling of 221 metabolites to evaluate the associations between metabolite profiles and established metabolic syndrome criteria (i.e. elevated waist circumference, hypertension, elevated fasting glucose, elevated triglycerides, and low high-density lipoprotein cholesterol) in plasma samples from obese men ( n = 29; BMI = 35.5 ± 5.2 kg/m(2)) and women ( n = 40; 34.9 ± 6.7 kg/m(2)), of which 26 met the criteria for metabolic syndrome (17 men and 9 women). Compared to obese individuals without metabolic syndrome, univariate statistical analysis and partial least squares discriminant analysis showed that a specific group of metabolites from multiple metabolic pathways (i.e. purine metabolism, valine, leucine and isoleucine degradation, and tryptophan metabolism) were associated with the presence of metabolic syndrome. Receiver operating characteristic curves generated based on the PLS-DA models showed excellent areas under the curve (0.85 and 0.96, for metabolites only model and enhanced metabolites model, respectively), high specificities (0.86 and 0.93), and good sensitivities (0.71 and 0.91). Moreover, principal component analysis revealed that metabolic profiles can be used to further differentiate metabolic syndrome with 3 versus 4-5 metabolic syndrome criteria. Collectively, these findings support targeted metabolomics approaches to distinguish metabolic syndrome from obesity alone, and to stratify metabolic syndrome status based on the number of criteria met. Impact statement We utilized mass spectrometry-based targeted metabolic profiling of 221 metabolites to

  4. Characterization of intact protein conjugates and biopharmaceuticals using ion-exchange chromatography with online detection by native electrospray ionization mass spectrometry and top-down tandem mass spectrometry.

    Science.gov (United States)

    Muneeruddin, Khaja; Nazzaro, Mark; Kaltashov, Igor A

    2015-10-06

    Characterization of biopharmaceutical products is a challenging task, which needs to be carried out at several different levels (including both primary structure and conformation). An additional difficulty frequently arises due to the structural heterogeneity inherent to many protein-based therapeutics (e.g., extensive glycosylation or "designer" modifications such as chemical conjugation) or introduced postproduction as a result of stress (e.g., oxidation and deamidation). A combination of ion-exchange chromatography (IXC) with online detection by native electrospray ionization mass spectrometry (ESI MS) allows characterization of complex and heterogeneous therapeutic proteins and protein conjugates to be accomplished at a variety of levels without compromising their conformational integrity. The IXC/ESI MS measurements allow protein conjugates to be profiled by analyzing conjugation stoichiometry and the presence of multiple positional isomers, as well as to establish the effect of chemical modifications on the conformational integrity of each species. While mass profiling alone is not sufficient for identification of nonenzymatic post-translational modifications (PTMs) that result in a very small mass change of the eluting species (e.g., deamidation), this task can be completed using online top-down structural analysis, as demonstrated using stressed interferon-β as an example. The wealth of information that can be provided by IXC/native ESI MS and tandem mass spectrometry (MS/MS) on protein-based therapeutics will undoubtedly make it a very valuable addition to the experimental toolbox of biopharmaceutical analysis.

  5. Control of levamisole residues in milk using a validated liquid chromatography-tandem mass spectrometry method

    Directory of Open Access Journals (Sweden)

    Nina Bilandžić

    2016-03-01

    Full Text Available Concentrations of the anthelmintic agent levamisole were measured in a total of 85 raw cow milk samples collected during 2014 from dairy farms across Croatia. The liquid chromatographytandem mass spectrometry (LC-MS/MS method used for levamisole quantification was validated according to the criteria set by Commission Decision 2002/657/EC. The following validation parameters were determined: limit of decision (CCα 0.55 μg kg-1, detection of capability (CCβ 0.59 μg kg-1, limit of detection (LOD 0.06 μg kg-1, limit of quantification (LOQ 0.22 μg kg-1, precision and accuracy (expressed as recovery 97.3-100 %, intra-laboratory reproducibility (RSD 4.2-5.6 %. Levamisole levels for 45 of the total of 85 samples were below the LOD value (0.06 µg kg-1. In the remaining 40 milk samples, levamisole was measured in the range from 0.061 to 0.142 µg kg-1 and the mean value was 0.092 µg kg-1. Accordingly, all concentrations analysed were below the LOQ value (0.22 µg kg-1 and limit of decision (CCα of the method used.

  6. Simultaneous quantitation of amphetamines and opiates in human hair by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Liu, Hsiu-Chuan; Liu, Ray H; Lin, Dong-Liang

    2015-04-01

    In this study, an incubation, solid-phase extraction (SPE) and LC-MS-MS procedure was developed, validated and used for simultaneous analysis of amphetamine (AP), methamphetamine (MA), morphine (MOR), codeine (COD), 6-acetylmorphine (6-AM) and 6-acetylcodeine (6-AC) in hair. Hair samples were initially cut into sections, washed with dichloromethane, then sonicated in a methanol-trifluoroacetic acid mixture. The resulting solutions were processed with a SPE procedure before undergoing LC-MS-MS analysis. Mass spectrometric analysis was performed in positive-ion, multiple reactions monitoring (MRM) mode, using appropriate collision energy for each selected precursor ion. The overall protocol, when applied to the analysis of hair (50 mg) samples fortified with 100-10,000 pg/mg of the analytes, was found to achieve 55.5-74.6% recovery of the six analytes with the following analytical parameters: (i) intra- and interday precision/accuracy data for the six analytes in the 1.6-7.6%/-6.0-12.8% and 1.3-6.6%/-6.9-9.3% ranges, respectively; (ii) r(2) > 0.998 for all six analytes and (iii) LOD 2 pg/mg for AP and MA, and 8 pg/mg for MOR, COD, 6-AM and 6-AC; LOQ 10 pg/mg for all six analytes. This method was then utilized to (i) analyze hair samples collected from 86 self-reported drug users and (ii) evaluate the deposition pattern of drugs in head hairs from four female MA and heroin users in a rehabilitation facility. This relatively simple protocol was found superior over the GC-MS methods we have previously developed and utilized in our laboratory for the analysis of these six analytes.

  7. Liquid chromatography tandem mass spectrometric quantitation of sulfamethazine and its metabolites: direct analysis of swine urine by triple quadrupole and by ion trap mass spectrometry.

    Science.gov (United States)

    Bartolucci, G; Pieraccini, G; Villanelli, F; Moneti, G; Triolo, A

    2000-01-01

    This work describes a new method for the quantitation of trace amounts of sulfamethazine (SMZ) and its main metabolite, N4-acetylsulfamethazine (Ac-SMZ), in swine urine, using high-performance liquid chromatography (HPLC) tandem mass spectrometric analysis of crude urine after addition of internal standard and simple dilution with water. The aim was to determine whether residues of this sulfamidic drug, normally administered to swine in order to prevent infectious diseases, were present in urine at levels lower than those permitted by regulatory authorities before human consumption (EU Project SMT, contract number CT 96-2092). A 10 microL volume of diluted urine was injected into a very short, narrow-bore chromatographic column (Zorbax SB-C18 2.1 i. d. x30 mm length, 3.5 microm pore size). Elution of the analytes of interest was achieved in less than seven minutes using a rapid gradient (from 20 to 80% methanol in 3 minutes). Either a PE Sciex API 365 triple quadrupole (QqQ), operated in the selected reaction monitoring (SRM) mode, or a Finnigan LCQ ion trap (IT) mass spectrometer, operated in narrow-range product ion scan, was used as the final detector. Electrospray (ESI) was used as the ionization technique. A comparison of the two tandem mass spectrometers was performed by analyzing the same set of test samples, at three concentration levels, on three different days. Linearity of responses of the calibration standards, intra- and inter-assay precision of the samples, specificity and limits of detection were evaluated for both systems. Both the QqQ and the IT instrument was suitable for rapid, sensitive and specific determination of the analytes, although the overall performance of the QqQ was slightly superior in terms of linearity, precision and sensitivity.

  8. Stress degradation study and structure characterization of oxidation degradation product of dexlansoprazole using liquid chromatography-mass spectrometry/time of flight, liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance

    Institute of Scientific and Technical Information of China (English)

    Lakkireddy PRAKASH; M HIMAJA

    2016-01-01

    The present study deals with the forced degradation behavior of dexlansoprazole under International Conference on Harmonisation( ICH)prescribed stress conditions. The drug was found to be more labile under acid,base,neutral,oxidative hydrolysis and thermal stress,while it was moderately stable under photolytic conditions. The known and unknown degradation products were separated on a C-18 column using a stability-indicating method. Liquid chromatography-mass spectrometry( LC-MS)analysis was performed for all the deg-radation studies. Isolation and structure characterization of oxidation degradation products were executed using sophisticated tools,viz. preparative high performance liquid chromatography( HPLC),liquid chromatography-mass spectrometry/time of flight( LC-MS/TOF),liquid chromatography-tandem mass spectrometry( LC-MS/MS),and nuclear magnetic resonance( NMR). This study demonstrates an ample methodology of degradation studies and structure elucidation of unknown degradation products of dexlansoprazole,which helps in the development and stability study of active pharmaceutical ingredients and formulated products.

  9. Quantitation of the Oral Anticoagulants Dabigatran, Rivaroxaban, Apixaban, and Warfarin in Plasma Using Ultra-Performance Liquid Chromatography with Tandem Mass Spectrometry (UPLC-MS/MS).

    Science.gov (United States)

    Noguez, Jaime H; Ritchie, James C

    2016-01-01

    This chapter describes a method to measure the oral anticoagulants dabigatran, rivaroxaban, apixaban, and warfarin in plasma samples using ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-MS/MS). The instrument is operated in multiple reaction monitoring (MRM) mode with an electrospray ionization (ESI) source in positive ionization mode. Samples are extracted with a 90:10 methanol/0.1 N hydrochloric acid solution containing stable isotope-labeled internal standards for each analyte. After centrifugation the supernatant is transferred to a mass spectrometry vial, injected onto the UPLC-ESI-MS/MS, and quantified using an eight-point calibration curve.

  10. Construction of an Ultrahigh Pressure Liquid Chromatography-Tandem Mass Spectral Library of Plant Natural Products and Comparative Spectral Analyses.

    Science.gov (United States)

    Lei, Zhentian; Jing, Li; Qiu, Feng; Zhang, Hua; Huhman, David; Zhou, Zhiqin; Sumner, Lloyd W

    2015-07-21

    A plant natural product tandem mass spectral library has been constructed using authentic standards and purified compounds. Currently, the library contains 1734 tandem mass spectra for 289 compounds, with the majority (76%) of the compounds being plant phenolics such as flavonoids, isoflavonoids, and phenylpropanoids. Tandem mass spectra and chromatographic retention data were acquired on a triple quadrupole mass spectrometer coupled to an ultrahigh pressure liquid chromatograph using six different collision energies (CEs) (10-60 eV). Comparative analyses of the tandem mass spectral data revealed that the loss of ring substituents preceded the C-ring opening during the fragmentation of flavonoids and isoflavonoids. At lower CE (i.e., 10 and 20 eV), the flavonoids and isoflavonoid central ring structures typically remained intact, and fragmentation was characterized by the loss of the substituents (i.e., methyl and glycosyl groups). At higher CE, the flavonoid and isoflavonoid core ring systems underwent C-ring cleavage and/or rearrangement depending on the structure, particularly hydroxylation patterns. In-source electrochemical oxidation was observed for phenolics that had ortho-diphenol moieties (i.e., vicinal hydroxyl groups on the aromatic rings). The ortho-diphenols were oxidized to ortho-quinones, yielding an intensive and, in most cases, a base ion peak corresponding to a [(M - 2H) - H](-) ion in their mass spectra. The library also contains reverse-phase retention times, allowing for the construction, validation, and testing of an artificial neural network retention prediction of other flavonoids and isoflavonoids not contained within the library. The library is freely available for nonprofit, academic use and it can be downloaded at http://www.noble.org/apps/Scientific/WebDownloadManager/DownloadArea.aspx.

  11. 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}.

  12. Ultra high performance liquid chromatography tandem mass spectrometry determination and profiling of prohibited steroids in human biological matrices. A review.

    Science.gov (United States)

    Gosetti, Fabio; Mazzucco, Eleonora; Gennaro, Maria Carla; Marengo, Emilio

    2013-05-15

    list of the prohibited substances of the World Anti-Doping Agency (WADA). In WADA list steroids figure in three main classes, namely anabolic steroids, corticosteroids and substances with anti-estrogenic properties. It must be strongly reminded that assumption of doping agents not only leads to athletes the possible failing of doping tests but causes important health risk and WADA prohibited list establishes criteria to highlight the alteration of the natural steroid profile caused by exogenous administration. Doping control analyses are generally performed in urine, a matrix that provides a prolonged detection time window, and less often in blood, serum, plasma, hair, saliva, and nails. To identify the chemical structures of anabolic steroids the use of mass spectrometry detection is very advantageous. Gas chromatography-mass spectrometry (GC-MS) techniques allowed for the development of comprehensive screening methods. GC-MS methods are sensitive and robust but present the disadvantages of time-consuming sample pretreatment, that is often based on hydrolysis and derivatisation reactions. Liquid chromatography-mass spectrometry (LC-MS) methods have been successfully used to identify and determinate steroids in different matrices, as well as to study their metabolisms. Nowadays, automatic rapid ultra high performance liquid chromatography (UHPLC) tandem mass spectrometry has become the technique of choice for steroid analysis. Due to its generally higher speed, sensitivity, reproducibility and specificity with respect to HPLC, it can be used to simultaneously separate and determinate multi component steroid mixtures. The technique is of huge interest to separate conjugates anabolic androgenic steroids, as it allows efficiency enhancement due to the small particle (sub-2μm) column packing, which provides high peak capacity within analysis times even 5-10 fold shorter than conventional HPLC methods. Modern multiplex instruments can analyze thousands of samples per month

  13. Simultaneous detection of five one-carbon metabolites in plasma using stable isotope dilution liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Adaikalakoteswari, Antonysunil; Webster, Craig; Goljan, Ilona; Saravanan, Ponnusamy

    2016-02-15

    Disturbance in one-carbon (1-C) cycle occurs due to nutritional deficiencies (vitamin B12/folate) or specific genetic polymorphisms. This leads to altered levels of key 1-C metabolites such as SAM (s-adenosyl methionine), SAH (s-adenosyl homocysteine), methionine, homocysteine and MMA (methyl malonic acid). These 1-C metabolites are determinants of cellular methylation potential and epigenetic modifications of DNA which impairs metabolic pathways in several pathological diseases and developmental programming. Though methods were able to measure these analytes only independently, none of the methods detect simultaneously. Therefore we developed a method to measure these five 1-C metabolites in a single run using liquid chromatography tandem mass spectrometry (LC-MS/MS). We used stable isotopes dilution LC-MS/MS to measure the 1-C metabolites in human plasma. Blood samples were collected from pregnant women (n=30) at early gestation in the ongoing, multicentre, prospective PRiDE study. Linearity exhibited across the calibration range for all the analytes with the limit of detection (LOD) of 1.005nmol/l for SAM, 0.081nmol/l for SAH, 0.002μmol/l for methionine, 0.046μmol/l for homocysteine and 3.920nmol/l for MMA. The average recovery for SAM was 108%, SAH-110%, methionine-97%, homocysteine-91% and MMA-102%. The inter-assay CV for SAM was 7.3, SAH-5.6%, methionine-3.5%, homocysteine-7.0% and MMA-4.0%. The intra-assay CV for SAM was 8.7%, SAH-4.7%, methionine-5.4%, homocysteine-8.1% and MMA-6.1%. Pregnant women at early gestation with low B12 levels had significantly higher homocysteine, MMA, lower levels of methionine, SAM and SAM:SAH ratio and higher triglycerides. We developed a simple and rapid method to simultaneously quantify 1-C metabolites such as SAM, SAH, methionine, homocysteine and MMA in plasma by stable isotope dilution LC-MS/MS which would be useful to elucidate the epigenetic mechanisms related in the gene-nutrient interactions.

  14. Determination of pesticide residues in olives by liquid extraction surface analysis followed by liquid chromatography/tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Gómez-Almenar, M. C.

    2015-06-01

    Full Text Available Nowadays, pesticides are essential in modern agriculture for crop protection, however, this use supposes a potential risk for human health and the environment. Traditional techniques of pesticide determination require the use of laborious and complex extraction methods to separate pesticides from the matrix, above all in fatty matrices like olives. For this reason, a new simple, rapid, cheap and selective method for the extraction and quantification of the most frequently used pesticides in olive growing has been developed. Pesticide determination was carried out by ultra-performance liquid chromatography (UPLC coupled with triple-quadrupole tandem mass spectrometry (MS/MS. Mean recoveries were found in a range between 73 and 114% with relative standard deviations lower than 20% in most pesticides evaluated and the limits of detection (LODs and quantification (LOQs were lower than 4 μg· kg-1 and 8 μg· kg-1, respectively. Finally, this method was applied to the analysis of 25 olive samples where Dimethoate and Terbuthylazine were detected in some cases, but their results were lower than 15 μg· kg-1.Hoy en día los pesticidas son esenciales en la agricultura moderna para la protección de los cultivos pero su uso supone un riesgo para la salud y el medio ambiente. Las técnicas tradicionales de determinación de pesticidas requieren el uso de métodos de extracción complejos a fin de separar los pesticidas de la matriz, sobre todo en matrices grasas como las aceitunas. Por ello, se ha desarrollado un nuevo método simple, rápido, barato y selectivo para la extracción y cuantificación de los pesticidas más frecuentemente utilizados en el cultivo del olivo, empleando cromatografía líquida de ultra-resolución (UPLC acoplada a espectrometría de masas (MS/MS. Las recuperaciones alcanzadas variaron entre el 73 y 114% obteniendo desviaciones estándar relativas inferiores al 20%. Los límites de detección (LD y cuantificación (LQ fueron

  15. 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

  16. Determination of perfluorinated compounds in mollusks by matrix solid-phase dispersion and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Villaverde-de-Sáa, Eugenia; Quintana, José Benito; Rodil, Rosario; Ferrero-Refojos, Raúl; Rubí, Elisa; Cela, Rafael

    2012-01-01

    Perfluorinated compounds (PFCs) have been used for over 40 years in different commercial and industrial applications mainly as surfactants and surface protectors and have become an important class of marine emerging pollutants. This study presents the development and validation of a new analytical method to determine the simultaneous presence of eight PFCs in different kinds of mollusks using matrix solid-phase dispersion (MSPD) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simplicity of the analytical procedure, low volume of solvent and quantity of sample required, low global price, and integration of extraction and clean-up into a single step, are the most important advantages of the developed methodology. Solvent, solid support (dispersing agent), clean-up sorbent, and their amounts were optimized by means of an experimental design. In the final method, 0.5 g of sample are dispersed with 0.2 g of diatomaceous earth and transferred into a polypropylene syringe containing 4 g of silica as clean-up sorbent. Then, analytes are eluted with 20 mL of acetonitrile. The extract is finally concentrated to a final volume of 0.5 mL in methanol, avoiding extract dryness in order to prevent evaporation losses and injected in the LC-MS/MS. The combination of this MSPD protocol with LC-MS/MS afforded detection limits from 0.05 to 0.3 ng g(-1). Also, a good linearity was established for the eight PFCs in the range from limit of quantification (LOQ) to 500 ng mL(-1) with R(2) > 0.9917. The recovery of the method was studied with three types of spiked mollusk and was in the 64-126% range. Moreover, a mussel sample was spiked and aged for more than 1 month and analyzed by the developed method and a reference method, ion-pair extraction, for comparison, producing both methods statistically equal concentration values. The method was finally applied to the determination of PFCs in different kinds of mollusks revealing concentrations up to 8.3 ng g(-1) for

  17. Rapid and simple extraction of lipids from blood plasma and urine for liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Bang, Dae Young; Byeon, Seul Kee; Moon, Myeong Hee

    2014-02-28

    A simple and fast lipid extraction method from human blood plasma and urine is introduced in this study. The effective lipid extraction from biological systems with a minimization of the matrix effect is important for the successful qualitative and quantitative analysis of lipids in liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). The method described here is based on the modification of the quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction method, which was originally developed for pesticide residue analysis in food, for the purpose of isolating lipids from biological fluids. Applicability of QuEChERS method for lipids was evaluated by varying organic solvents for the extraction/partitioning of lipids in MgSO4/CH3COONa for the removal of water and by varying sorbents (primary secondary amines, graphitized carbon black, silica, strong anion exchange resins and C18 particles) for the dispersive solid-phase extraction (dSPE) step. This study shows that 2:1 (v/v) CHCl3/CH3OH is effective in the extraction/partitioning step and that 50mg of C18 particles (for 0.1mL plasma and 1mL of urine) are more suitable for sample cleanup for the dSPE step of the QuEChERS method. Matrix effects were calculated by comparing the recovery values of lipid standards spiked to both plasma and urine samples after extraction with those of the same standards in a neat solution using nanoflow LC-ESI-MS/MS, resulting in improved MS signals due to the decrease of the ion suppression compared to the conventional Folch method. The modified QuEChERS method was applied to lipid extracts from both human urine and plasma samples, demonstrating that it can be powerfully utilized for high-speed (lipids compared to the Folch method, with equivalent or slightly improved results in lipid identification using nLC-ESI-MS/MS.

  18. Rapid determination of benzodiazepines, zolpidem and their metabolites in urine using direct injection liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jeong, Yu-Dong; Kim, Min Kyung; Suh, Sung Ill; In, Moon Kyo; Kim, Jin Young; Paeng, Ki-Jung

    2015-12-01

    Benzodiazepines and zolpidem are generally prescribed as sedative, hypnotics, anxiolytics or anticonvulsants. These drugs, however, are frequently misused in drug-facilitated crime. Therefore, a rapid and simple liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for identification and quantification of benzodiazepines, zolpidem and their metabolites in urine using deuterium labeled internal standards (IS). Urine samples (120 μL) mixed with 80 μL of the IS solution were centrifuged. An aliquot (5 μL) of the sample solution was directly injected into the LC-MS/MS system for analysis. The mobile phases consisted of water and acetonitrile containing 2mM ammonium trifluoroacetate and 0.2% acetic acid. The analytical column was a Zorbax SB-C18 (100 mm × 2.1 mm i.d., 3.5 μm, Agilent). The separation and detection of 18 analytes were achieved within 10 min. Calibration curves were linear over the concentration ranges of 0.5-20 ng/mL (zolpidem), 1.0-40 ng/mL (flurazepam and temazepam), 2.5-100 ng/mL (7-aminoclonazepam, 1-hydroxymidazolam, midazolam, flunitrazepam and alprazolam), 5.0-200 ng/mL (zolpidem phenyl-4-carboxylic acid, α-hydroxyalprazolam, oxazepam, nordiazepam, triazolam, diazepam and α-hydroxytriazolam), 10-400 ng/mL (lorazepam and desalkylflurazepam) and 10-100 ng/mL (N-desmethylflunitrazepam) with the coefficients of determination (r(2)) above 0.9971. The dilution integrity of the analytes was examined for supplementation of short linear range. Dilution precision and accuracy were tested using two, four and ten-folds dilutions and they ranged from 3.7 to 14.4% and -12.8 to 12.5%, respectively. The process efficiency for this method was 63.0-104.6%. Intra- and inter-day precisions were less than 11.8% and 9.1%, while intra- and inter-day accuracies were less than -10.0 to 8.2%, respectively. The lower limits of quantification were lower than 10 ng/mL for each analyte. The applicability of the developed method was successfully

  19. Rapid analysis of pharmaceuticals and personal care products in fish plasma micro-aliquots using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Chen, Fangfang; Gong, Zhiyuan; Kelly, Barry C

    2015-02-27

    A sensitive analytical method based on liquid-liquid extraction (LLE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for rapid analysis of 11 pharmaceuticals and personal care products (PPCPs) in fish plasma micro-aliquots (∼20μL). Target PPCPs included, bisphenol A, carbamazepine, diclofenac, fluoxetine, gemfibrozil, ibuprofen, naproxen, risperidone, sertraline, simvastatin and triclosan. A relatively quicker and cheaper LLE procedure exhibited comparable analyte recoveries with solid-phase extraction. Rapid separation and analysis of target compounds in fish plasma extracts was achieved by employing a high efficiency C-18 HPLC column (Agilent Poroshell 120 SB-C18, 2.1mm×50mm, 2.7μm) and fast polarity switching, enabling effective monitoring of positive and negative ions in a single 9min run. With the exception of bisphenol A, which exhibited relatively high background contamination, method detection limits of individual PPCPs ranged between 0.15 and 0.69pg/μL, while method quantification limits were between 0.05 and 2.3pg/μL. Mean matrix effect (ME) values ranged between 65 and 156% for the various target analytes. Isotope dilution quantification using isotopically labelled internal surrogates was utilized to correct for signal suppression or enhancement and analyte losses during sample preparation. The method was evaluated by analysis of 20μL plasma micro-aliquots collected from zebrafish (Danio rerio) from a laboratory bioaccumulation study, which included control group fish (no exposure), as well as fish exposed to environmentally relevant concentrations of PPCPs. Using the developed LC-MS/MS based method, concentrations of the studied PPCPs were consistently detected in the low pg/μL (ppb) range. The method may be useful for investigations requiring fast, reliable concentration measurements of PPCPs in fish plasma. In particular, the method may be applicable for in situ contaminant biomonitoring, as well as

  20. Cyclic pentapeptide analogs based on endomorphin-2 structure: cyclization studies using liquid chromatography combined with on-line mass spectrometry and tandem mass spectrometry.

    Science.gov (United States)

    Piekielna, Justyna; Kluczyk, Alicja; Perlikowska, Renata; Janecka, Anna

    2014-05-01

    The cyclization of linear analogs based on endomorphin-2 structure, Tyr/Dmt-d-Lys-Phe-Phe-Asp-NH2 and Tyr/Dmt-d-Cys-Phe-Phe-Cys-NH2 (where Dmt=2',6'-dimethyltyrosine), resulting in obtaining lactam or disulfide derivatives, was studied using liquid chromatography combined with on-line mass spectrometry (LC-MS) and tandem mass spectrometry (LC-MS/MS). In case of cyclization via an amide bond, the formation of the cyclic monomers, cyclic but not linear dimers and even traces of cyclic trimers was observed. Disulfide bridge containing peptides was obtained by the solid-phase synthesis of the linear sequences, followed by either in-solution or on-resin cyclization. In case of the in-solution cyclization, the expected cyclic monomers were the only products. When oxidation of the cysteine residues was performed when the peptides were still on the resin, cyclic monomer and two cyclodimers, parallel and antiparallel, were found. Digestion of the isolated cyclodimers with α-chymotrypsin allowed for their unambiguous identification. The comparison of the cyclic monomer/dimer ratios for analogs with Tyr versus Dmt in position 1 revealed that the presence of the exocyclic Dmt favored formation of the cyclic monomer, most likely due to the increased steric bulk of this amino acid side-chain as compared with Tyr.

  1. Classification of the medicinal plants of the genus Atractylodes using high-performance liquid chromatography with diode array and tandem mass spectrometry detection combined with multivariate statistical analysis.

    Science.gov (United States)

    Cho, Hyun-Deok; Kim, Unyong; Suh, Joon Hyuk; Eom, Han Young; Kim, Junghyun; Lee, Seul Gi; Choi, Yong Seok; Han, Sang Beom

    2016-04-01

    Analytical methods using high-performance liquid chromatography with diode array and tandem mass spectrometry detection were developed for the discrimination of the rhizomes of four Atractylodes medicinal plants: A. japonica, A. macrocephala, A. chinensis, and A. lancea. A quantitative study was performed, selecting five bioactive components, including atractylenolide I, II, III, eudesma-4(14),7(11)-dien-8-one and atractylodin, on twenty-six Atractylodes samples of various origins. Sample extraction was optimized to sonication with 80% methanol for 40 min at room temperature. High-performance liquid chromatography with diode array detection was established using a C18 column with a water/acetonitrile gradient system at a flow rate of 1.0 mL/min, and the detection wavelength was set at 236 nm. Liquid chromatography with tandem mass spectrometry was applied to certify the reliability of the quantitative results. The developed methods were validated by ensuring specificity, linearity, limit of quantification, accuracy, precision, recovery, robustness, and stability. Results showed that cangzhu contained higher amounts of atractylenolide I and atractylodin than baizhu, and especially atractylodin contents showed the greatest variation between baizhu and cangzhu. Multivariate statistical analysis, such as principal component analysis and hierarchical cluster analysis, were also employed for further classification of the Atractylodes plants. The established method was suitable for quality control of the Atractylodes plants.

  2. Liquid chromatography coupled to tandem mass spectrometry for the residue determination of ethylenethiourea (ETU) and propylenethiourea (PTU) in water.

    Science.gov (United States)

    Ripollés, Cristina; Sancho, Juan V; López, Francisco J; Hernández, Félix

    2012-06-22

    Ethylenethiourea (ETU) and propylenethiourea (PTU) are the main degradation products of dithiocarbamates fungicides, which are widely used in agriculture from several years ago. Their determination in water at low concentrations (e.g. sub-ppb levels) is highly problematic due to their polar character and low molecular size. In the present study, two analytical methodologies have been developed and compared for the selective and sensitive determination of ETU and PTU in various types of waters. Both approaches are based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with electrospray ionization, using triple quadrupole analyzer. Whereas the first methodology used an on-line solid-phase extraction (SPE) step in order to reach the adequate sensitivity, the second one avoided sample treatment and was based on direct injection into an ultra high performance liquid chromatography (UHPLC-MS/MS) system, making use of a new-generation instrument in order to reach sub-ppb analyte levels in water. Strong matrix effects (typically leading to signal enhancement) were observed for most of the evaluated waters, especially when applying the on-line SPE method, surely due to the higher amount of sample injected into the system. The use of the own analyte (ETU-d₄)) as isotope-labelled internal standard (ILIS) allowed to compensate these effects and to achieve an accurate ETU quantification at low concentrations. Moreover, three simultaneous transitions, operating in selected reaction monitoring mode, were acquired for both ETU and ETU-d₄. This fact together with the evaluation of their relative intensity ratios assured the reliable identification of the analyte in the water samples. The two optimized methodologies were validated by analysis of six different samples (two drinking water, two groundwater and two surface water), spiked at two levels (0.1 and 1.0 μg/L), and analyzed each in quintuplicate. Satisfactory accuracy and precision, with recoveries

  3. Determination of 19 drugs of abuse and metabolites in whole blood by high-performance liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Bjørk, Marie Kjaergaard; Nielsen, Marie K K; Markussen, Lotte Ø

    2010-01-01

    A high-performance liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method has been developed and validated for the determination of 19 drugs of abuse and metabolites and used in whole blood. The following compounds were included: amphetamine, methylenedioxyamphetamine...... frequent drugs of abuse and their metabolites in whole blood. The quantification by LC-MS/MS was successfully applied to 412 forensic cases from October 2008 to mid February 2009, where 267 cases were related to zero-tolerance traffic legislation....

  4. Determination of pazopanib (GW-786034) in mouse plasma and brain tissue by liquid chromatography-tandem mass spectrometry (LC/MS-MS)

    OpenAIRE

    Minocha, Mukul; Khurana, Varun; Mitra, Ashim K.

    2012-01-01

    A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric (LC/MS-MS) method has been developed and validated for the quantitative determination of pazopanib in mouse plasma and brain tissue homogenate. Single liquid-liquid extraction step with ethyl acetate was employed for analysis of pazopanib and the internal standard (IS); vandetanib. HPLC separation was performed on an XTerra® MS C18 column 50 × 4.6mm, 5.0 μm. The mobile phase consisted of 70% acetonitrile and 30% wat...

  5. Quantitation of Cotinine and its Metabolites in Rat Plasma and Brain Tissue by Hydrophilic Interaction Chromatography Tandem Mass Spectrometry (HILIC-MS/MS)

    OpenAIRE

    Li, Pei; Beck, Wayne D.; Callahan, Patrick M.; Terry, Alvin V.; Bartlett, Michael G

    2012-01-01

    In this work, we developed a sensitive method to quantify cotinine (COT), norcotinine (NCOT), trans-3′-hydroxycotinine (OHCOT) and cotinine-N-oxide (COTNO) in rat plasma and brain tissue, using solid phase extraction (SPE), hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry (MS/MS). The linear range was 1–100 ng/ml for each analyte in rat plasma and brain homogenate (3–300 ng/g brain tissue). The method was validated with precision within 15% relative standard ...

  6. Fast analysis of 29 polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs with ultra-high performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry

    OpenAIRE

    Shih-Chun Candice Lung; Chun-Hu Liu

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs are ubiquitous in the environment. Some of them are probable carcinogens and some are source markers. This work presents an ultra-high performance liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry (UHPLC-APPI-MS/MS) method for simultaneous analysis of 20 PAHs and nine nitro-PAHs. These compounds are separated in 15 minutes in the positive mode and 11 minutes in the negative mode, one half of GC/MS analysi...

  7. Comparison of High Performance Liquid Chromatography with Fluorescence Detector and with Tandem Mass Spectrometry methods for detection and quantification of Ochratoxin A in green and roasted coffee beans

    Directory of Open Access Journals (Sweden)

    Raquel Duarte da Costa Cunha Bandeira

    2013-12-01

    Full Text Available Two analytical methods for the determination and confirmation of ochratoxin A (OTA in green and roasted coffee samples were compared. Sample extraction and clean-up were based on liquid-liquid phase extraction and immunoaffinity column. The detection of OTA was carried out with the high performance liquid chromatography (HPLC combined either with fluorescence detection (FLD, or positive electrospray ionization (ESI+ coupled with tandem mass spectrometry (MS-MS. The results obtained with the LC-ESI-MS/MS were specific and more sensitive, with the advantages in terms of unambiguous analyte identification, when compared with the HPLC-FLD.

  8. 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.

  9. Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Determination of ε-Acetamidocaproic Acid in Rat Plasma

    OpenAIRE

    Kim, Tae Hyun; Choi1, Yong Seok; Choi, Young Hee; Kim, Yoon Gyoon

    2013-01-01

    A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ε-acetamidocaproic acid (AACA), the primary metabolite of zinc acexamate (ZAC), in rat plasma by using normetanephrine as an internal standard. Sample preparation involved protein precipitation using methanol. Separation was achieved on a Gemini-NX C18 column (150 mm × 2.0 mm, i.d., 3 μm particle size) using a mixture of 0.1% formic acid-water : acetonitril...

  10. The use of ultra-high pressure liquid chromatography with tandem mass spectrometric detection in the analysis of agrochemical residues and mycotoxins in food - challenges and applications.

    Science.gov (United States)

    O'Mahony, John; Clarke, Lesa; Whelan, Michelle; O'Kennedy, Richard; Lehotay, Steven J; Danaher, Martin

    2013-05-31

    In the field of food contaminant analysis, the most significant development of recent years has been the integration of ultra-high pressure liquid chromatography (UHPLC), coupled to tandem quadrupole mass spectrometry (MS/MS), into analytical applications. In this review, we describe the emergence of UHPLC through technological advances. The implications of this new chromatographic technology for MS detection are discussed, as well as some of the remaining challenges in exploiting it for chemical residue applications. Finally, a comprehensive overview of published applications of UHPLC-MS in food contaminant analysis is presented, with a particular focus on veterinary drug residues.

  11. 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 extensi

  12. A strategy for identification and structural characterization of compounds from Gardenia jasminoides by integrating macroporous resin column chromatography and liquid chromatography-tandem mass spectrometry combined with ion-mobility spectrometry.

    Science.gov (United States)

    Wang, Lu; Liu, Shu; Zhang, Xueju; Xing, Junpeng; Liu, Zhiqiang; Song, Fengrui

    2016-06-24

    In this paper, an analysis strategy integrating macroporous resin (AB-8) column chromatography and high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) combined with ion mobility spectrometry (IMS) was proposed and applied for identification and structural characterization of compounds from the fruits of Gardenia jasminoides. The extracts of G. jasminoides were separated by AB-8 resin column chromatography combined with reversed phase liquid chromatography (C18 column) and detected by electrospray ionization tandem mass spectrometry. Additionally, ion mobility spectrometry (IMS) was employed as a supplementary separation technique to discover previously undetected isomers from the fruits of G. jasminoides. A total of 71 compounds, including iridoids, flavonoids, triterpenes, monoterpenoids, carotenoids and phenolic acids were identified by the characteristic high resolution mass spectrometry and the ESI-MS/MS fragmentations. In conclusion, the IMS-MS technique achieved the separation of isomers in crocin-3 and crocin-4 according to their acquired mobility drift times differing from classical analysis by mass spectrometry. The proposed strategy can be used as a highly sensitive and efficient procedure for identification and separation isomeric components in extracts of herbal medicines.

  13. Liquid chromatography-tandem mass spectrometry determination of synthetic cathinones and phenethylamines in influent wastewater of eight European cities

    DEFF Research Database (Denmark)

    Bade, Richard; Bijlsma, Lubertus; Sancho, Juan V.

    2017-01-01

    (SPE) with Oasis MCX cartridges. Isotopically labelled internal standards were used to correct for matrix effects and potential SPE losses. Following chromatographic separation on a C18 column within 6 min, the compounds were measured by tandem mass spectrometry in positive ionization mode. The method...... relatively stable for up to 7 days. The method was then applied to influent wastewater samples from eight European countries, in which mephedrone, methylone and MDPV were detected. This work reveals that although NPS use is not as extensive as for classic illicit drugs, the application of a highly sensitive...

  14. Diagnosis of glutaric aciduria type 1 by measuring 3-hydroxyglutaric acid in dried urine spots by liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Al-Dirbashi, Osama Y; Kölker, Stefan; Ng, Dione;

    2011-01-01

    on stable isotope dilution gas chromatography mass spectrometry (GC-MS) and require extensive sample preparation. Here we describe a simple liquid chromatography tandem MS (LC-MS/MS) method to quantify this important metabolite in dried urine spots (DUS). This method is based on derivatization with 4-[2-(N...... for 45 min, and 5 μl of the reaction solution was analyzed by LC-MS/MS. Reference ranges obtained were in excellent agreement with the literature. The method was applied retrospectively for the analysis of DUS samples from established low- and high-excreter GA1 patients as well as controls (n = 100......). Comparison of results obtained versus those obtained by GC-MS was satisfactory (n = 14). In populations with a high risk of GA1, this approach will be useful as a primary screening method for high- or low-excreter variants. In these populations, however, DUS analysis should not be implemented before...

  15. Determination of metformin and other biguanides in forensic whole blood samples by hydrophilic interaction liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Sørensen, Lambert K

    2012-01-01

    Metformin is an anti-diabetic drug in the biguanide class which also includes phenformin and buformin. Because of the potential adverse effects of the biguanides, a reliable liquid chromatography-tandem mass spectrometry method using pneumatically assisted electrospray ionization was developed for the quantification of the drugs in both live and post-mortem human whole blood. The blood proteins were precipitated by the addition of a mixture of methanol and acetonitrile, and the extract was cleaned up by cation-exchange solid-phase extraction to eliminate ion suppression effects. The separation was performed by hydrophilic interaction liquid chromatography. Matrix-matched calibrants combined with isotope dilution of metformin were used for calibration. The detection limits were 0.01 mg/L for metformin and phenformin and the relative intra-laboratory reproducibility standard deviations were less than 6% at concentrations of 1-10 mg/L. The mean true recoveries were greater than 86%.

  16. Integrating qualitative and quantitative characterization of traditional Chinese medicine injection by high-performance liquid chromatography with diode array detection and tandem mass spectrometry.

    Science.gov (United States)

    Xie, Yuan-yuan; Xiao, Xue; Luo, Juan-min; Fu, Chan; Wang, Qiao-wei; Wang, Yi-ming; Liang, Qiong-lin; Luo, Guo-an

    2014-06-01

    The present study aims to describe and exemplify an integrated strategy of the combination of qualitative and quantitative characterization of a multicomponent mixture for the quality control of traditional Chinese medicine injections with the example of Danhong injection (DHI). The standardized chemical profile of DHI has been established based on liquid chromatography with diode array detection. High-performance liquid chromatography coupled with time-of-flight mass spectrometry and high-performance liquid chromatography with electrospray multistage tandem ion-trap mass spectrometry have been developed to identify the major constituents in DHI. The structures of 26 compounds including nucleotides, phenolic acids, and flavonoid glycosides were identified or tentatively characterized. Meanwhile, the simultaneous determination of seven marker constituents, including uridine, adenosine, danshensu, protocatechuic aldehyde, p-coumaric acid, rosmarinic acid, and salvianolic acid B, in DHI was performed by multiwavelength detection based on high-performance liquid chromatography with diode array detection. The integrated qualitative and quantitative characterization strategy provided an effective and reliable pattern for the comprehensive and systematic characterization of the complex traditional Chinese medicine system.

  17. Diclofenac in municipal wastewater treatment plant: quantification using laser diode thermal desorption--atmospheric pressure chemical ionization--tandem mass spectrometry approach in comparison with an established liquid chromatography-electrospray ionization-tandem mass spectrometry method.

    Science.gov (United States)

    Lonappan, Linson; Pulicharla, Rama; Rouissi, Tarek; Brar, Satinder K; Verma, Mausam; Surampalli, Rao Y; Valero, José R

    2016-02-12

    Diclofenac (DCF), a prevalent non-steroidal anti-inflammatory drug (NSAID) is often detected in wastewater and surface water. Analysis of the pharmaceuticals in complex matrices is often laden with challenges. In this study a reliable, rapid and sensitive method based on laser diode thermal desorption/atmospheric pressure chemical ionization (LDTD/APCI) coupled with tandem mass spectrometry (MS/MS) has been developed for the quantification of DCF in wastewater and wastewater sludge. An established conventional LC-ESI-MS/MS (liquid chromatography-electrospray ionization-tandem mass spectrometry) method was compared with LDTD-APCI-MS/MS approach. The newly developed LDTD-APCI-MS/MS method reduced the analysis time to 12s in lieu of 12 min for LC-ESI-MS/MS method. The method detection limits for LDTD-APCI-MS/MS method were found to be 270 ng L(-1) (LOD) and 1000 ng L(-1) (LOQ). Furthermore, two extraction procedures, ultrasonic assisted extraction (USE) and accelerated solvent extraction (ASE) for the extraction of DCF from wastewater sludge were compared and ASE with 95.6 ± 7% recovery was effective over USE with 86 ± 4% recovery. The fate and partitioning of DCF in wastewater (WW) and wastewater sludge (WWS) in wastewater treatment plant was also monitored at various stages of treatment in Quebec Urban community wastewater treatment plant. DCF exhibited affinity towards WW than WWS with a presence about 60% of DCF in WW in contrary with theoretical prediction (LogKow=4.51).

  18. Quantification of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate using stable isotope dilution liquid chromatography with atmospheric-pressure photoionization tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Xiaotao; Hou, Hongwei; Chen, Huan; Liu, Yong; Wang, An; Hu, Qingyuan

    2015-09-17

    A stable isotope dilution liquid chromatography with tandem mass spectrometry method for the analysis of 16 polycyclic aromatic hydrocarbons in cigarette smoke condensate was developed and validated. Compared with previously reported methods, this method has lower limits of detection (0.04-1.35 ng/cig). Additionally, the proposed method saves time, reduces the number of separation steps, and reduces the quantity of solvent needed. The new method was applied to evaluate polycyclic aromatic hydrocarbon content in 213 commercially available cigarettes in China, under the International Standardization Organization smoking regime and the Health Canadian intense smoking regime. The results showed that the total polycyclic aromatic hydrocarbon content was more than two times higher in samples from the Health Canadian intense smoking regime than in samples from the International Standardization Organization smoking regime (1189.23 vs. 2859.50 ng/cig, ppolycyclic aromatic hydrocarbons (and total polycyclic aromatic hydrocarbons) increased with labeled tar content in both of the tested smoking regimes. There was a positive correlation between total polycyclic aromatic hydrocarbons under the International Standardization Organization smoking regime with that under the Health Canadian intense smoking regime. The proposed liquid chromatography with tandem mass spectrometry method is satisfactory for the rapid, sensitive, and accurately quantitative evaluation of polycyclic aromatic hydrocarbon content in cigarette smoke condensate, and it can be applied to assess potential health risks from smoking. This article is protected by copyright. All rights reserved.

  19. Determination of tetracycline antibiotics in fatty food samples by selective pressurized liquid extraction coupled with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Jiao, Zhe; Zhang, Suling; Chen, Hongwei

    2015-01-01

    For the determination of trace residues of tetracycline antibiotics in fatty food samples, selective pressurized liquid extraction coupled with high-performance liquid chromatography and tandem mass spectrometry was applied in this study. Copper(II) isonicotinate was first used as online cleanup adsorbent in the selective pressurized liquid extraction process. The adsorbent to sample ratio, extraction temperature, extraction time, and recycle times, etc. were optimized. The tetracyclines in food samples of pork, chicken meat, and clam meat were detected by liquid chromatography with tandem mass spectrometry. Tetracycline was found at levels of 0.32 and 0.53 μg/g and oxytetracycline was found at 0.14 and 0.21 μg/g in chicken meat and clam meat, respectively, while chlorotetracycline and deoxytetracycline were below the detection limit. The detection limit (S/N = 3) for these four tetracyclines were from 0.2 to 3.3 ng/g, the recoveries were from 75.8 to 110.5%, and relative standard deviations were from 5.5 to 13.6%. Copper(II) isonicotinate showed a higher purification capacity than other cleanup adsorbents for extraction of antibiotics in fatty food and the recovery showed predominance compared with a pressurized liquid extraction method without adsorbent. The study demonstrated that copper(II) isonicotinate would be a promising cleanup adsorbent in pressurized liquid extraction for the analysis of trace organic pollutants in complicated samples.

  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.

  1. Rapid simultaneous analysis of 17 haloacetic acids and related halogenated water contaminants by high-performance ion chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Xue, Runmiao; Donovan, Ariel; Shi, Honglan; Yang, John; Hua, Bin; Inniss, Enos; Eichholz, Todd

    2016-09-01

    Haloacetic acids (HAAs), which include chloroacetic acids, bromoacetic acids, and emerging iodoacetic acids, are toxic water disinfection byproducts. General screening methodology is lacking for simultaneously monitoring chloro-, bromo-, and iodoacetic acids. In this study, a rapid and sensitive high-performance ion chromatography-tandem mass spectrometry method for simultaneous determination of chloro-, bromo-, and iodo- acetic acids and related halogenated contaminants including bromate, bromide, iodate, and iodide was developed to directly analyze water samples after filtration, eliminating the need for preconcentration, and chemical derivatization. The resulting method was validated in both untreated and treated water matrices including tap water, bottled water, swimming pool water, and both source water and drinking water from a drinking water treatment facility to demonstrate application potential. Satisfactory accuracies and precisions were obtained for all types of tested samples. The detection limits of this newly developed method were lower or comparable with similar techniques without the need for extensive sample treatment requirement and it includes all HAAs and other halogenated compounds. This provides a powerful methodology to water facilities for routine water quality monitoring and related water research, especially for the emerging iodoacetic acids. Graphical abstract High performance ion chromatography-tandem mass spectrometry method for detection of haloacetic acids in water.

  2. A quick, easy, cheap, effective, rugged, and safe sample pretreatment and liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of 33 mycotoxins in Lentinula edodes.

    Science.gov (United States)

    Han, Zheng; Feng, Zhihong; Shi, Wen; Zhao, Zhihui; Wu, Yongjiang; Wu, Aibo

    2014-08-01

    Lentinula edodes, one of the most cultivated edible fungi in the world, are usually neglected for mycotoxins contamination due to the initial thinking of its resistance to mycotoxingenic molds. In the present study, a sensitive and reliable liquid chromatography with tandem mass spectrometry method was developed for the simultaneous quantification of 33 mycotoxins in L. edodes. Targeted mycotoxins were extracted using a quick, easy, cheap, effective, rugged, and safe procedure without any further clean-up step, and analyzed by liquid chromatography with tandem mass spectrometry on an Agilent Poroshell 120 EC-C18 column (100 × 3 mm, 2.7 μm) with a linear gradient elution program using water containing 5 mM ammonium acetate and methanol as the mobile phase. After validation by determining linearity (R(2) > 0.99), sensitivity (LOQ ≤ 20 ng/kg), recovery (73.6-117.9%), and precision (0.8-19.5%), the established method has been successfully applied to reveal the contamination states of various mycotoxins in L. edodes. Among the 30 tested samples, 22 were contaminated by various mycotoxins with the concentration levels ranging from 3.3-28,850.7 μg/kg, predicting that the edible fungus could be infected by the mycotoxins-producing fungi. To the best of our knowledge, this is the first report about real mycotoxins contamination in L. edodes.

  3. 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.

  4. Sensitive analysis of anti-HIV drugs, efavirenz, lopinavir and ritonavir, in human hair by liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Huang, Yong; Gandhi, Monica; Greenblatt, Ruth M; Gee, Winnie; Lin, Emil T; Messenkoff, Nicholas

    2008-11-01

    A highly sensitive and selective method using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) was developed and validated for the measurement of three antiretroviral agents, efavirenz, lopinavir and ritonavir, in human hair. Hair samples from adherent HIV-infected patients on antiretroviral therapies were cut into about 1 mm length segments and drugs were extracted by first shaking the samples with methanol in a 37 degrees C water bath overnight (>14 h), followed by methyl tert-butyl ether/ethyl acetate (1:1) extraction under weak alkaline conditions. The extracted lopinavir and ritonavir were separated by reversed-phase chromatography and detected by tandem mass spectrometry in electrospray positive ionization mode with multiple reaction monitoring (MRM), while efavirenz was monitored in negative ionization MRM mode. This method was validated from 0.01 to 4.0 ng/mg hair for ritonavir and 0.05-20 ng/mg hair for lopinavir and efavirenz by using 2 mg of a human hair sample. The interday and intraday assay precision (coefficients of variation, CV) for spiked quality control (QC) samples at low, medium and high concentrations were within 15% and accuracy ranged from 89% to 110%. Assay reproducibility was also demonstrated by analysis of incurred hair QC samples (CV hair samples of HIV-infected women on antiretroviral therapy in an observational study using small amounts of hair.

  5. Development and validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of nine corticosteroid residues in bovine liver samples

    Energy Technology Data Exchange (ETDEWEB)

    Dusi, Guglielmo, E-mail: guglielmo.dusi@izsler.it [Istituto Zooprofilattico Sperimentale della Lombardia e dell' Emilia Romagna, ' B. Ubertini' , Via Bianchi 9, 25124 Brescia (Italy); Gasparini, Mara; Curatolo, Michele; Assini, Walter; Bozzoni, Eros; Tognoli, Nadia; Ferretti, Enrica [Istituto Zooprofilattico Sperimentale della Lombardia e dell' Emilia Romagna, ' B. Ubertini' , Via Bianchi 9, 25124 Brescia (Italy)

    2011-08-26

    A liquid chromatography tandem mass spectrometry (LC-MS/MS) confirmatory method for the simultaneous determination of nine corticosteroids in liver, including the four MRL compounds listed in Council Regulation 37/2010, was developed. After an enzymatic deconjugation and a solvent extraction of the liver tissue, the resulting solution was cleaned up through an SPE Oasis HLB cartridge. The analytes were then detected by liquid chromatography-negative-ion electrospray tandem mass spectrometry, using deuterium-labelled internal standards. The procedure was validated as a quantitative confirmatory method according to the Commission Decision 2002/657/EC criteria. The results showed that the method was suitable for statutory residue testing regarding the following performance characteristics: instrumental linearity, specificity, precision (repeatability and intra-laboratory reproducibility), recovery, decision limit (CC{alpha}), detection capability (CC{beta}) and ruggedness. All the corticosteroids can be detected at a concentration around 1 {mu}g kg{sup -1}; the recoveries were above 62% for all the analytes. Repeatability and reproducibility (within-laboratory reproducibility) for all the analytes were below 7.65% and 15.5%, respectively.

  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. [Comparison of the performances of gas chromatography-quadrupole time of flight mass spectrometry and gas chromatography-tandem mass spectrometry in rapid screening and confirmation of 208 pesticide residues in fruits and vegetables].

    Science.gov (United States)

    Cao, Xinyue; Pang, Guofang; Jin, Linghe; Kang, Jian; Hu, Xueyan; Chang, Qiaoying; Wang, Minglin; Fan, Chunlin

    2015-04-01

    The performances of gas chromatography-tandem mass spectrometry (GC-MS/MS) and gas chromatography quadrupole time of flight mass spectrometry (GC-QTOF/MS) for the determination of 208 pesticide residues in fruit and vegetable samples, including apple, orange, tomato and cucumber, were compared comprehensively. Based on the differences of the two instruments, their respective characteristics and scopes of application in the detection of the pesticide residues were presented, which provided the reference for the analysis of pesticide residues. The performance parameters of the two instruments, such as overall recoveries, precisions, limits of detection, linear ranges, identification points and matrix effects, were evaluated according to a designed experiment. At three spiked levels (5.0, 10.0 and 20.0 µg/kg), the average recoveries for the majority of pesticides (93.0%) ranged from 70% to 120% in the four matrices with relative standard deviations below 20%. The limits of detection for most of the pesticides by GC-MS/MS and GC-Q-TOF/MS were less than 5.0 µg/kg. Compared with GC-QTOF/MS, GC-MS/MS showed relatively lower limits of detection and wider linear ranges, and its performance was more satisfactory in accurate quantitative analysis due to its superior sensitivity. On the other hand, GC-QTOF/MS provided accurate mass measurement, which was proved to be an efficient analytical tool on the rapid screening and confirmation of a large number of pesticides and non-target compounds.

  8. Online coupling of high-resolution chromatography with extreme UV photon activation tandem mass spectrometry: Application to the structural investigation of complex glycans by dissociative photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Ropartz, David, E-mail: David.Ropartz@nantes.inra.fr [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Giuliani, Alexandre [Synchrotron SOLEIL, L' Orme des Merisiers, F-91190 Gif-sur-Yvette (France); UAR 1008 CEPIA, INRA, F-44316 Nantes (France); Fanuel, Mathieu [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France); Hervé, Cécile; Czjzek, Mirjam [Sorbonne Universités, Université Pierre et Marie Curie, Paris VI, CNRS, Integrative Biology of Marine Models, UMR 8227, Station Biologique, Place George Teissier, F29688 Roscoff Cedex (France); Rogniaux, Hélène [INRA, UR1268 Biopolymers Interactions Assemblies F-44316 Nantes (France)

    2016-08-24

    The activation of ions by extreme-energy photons (XUV) produced by a synchrotron radiation beamline is a powerful method for characterizing complex glycans using tandem mass spectrometry (MS). As previously described, this activation method leads to rich fragmentation spectra with many structurally valuable cross-ring cleavages while maintaining labile modifications on the glycan structures. However, until now, the tandem MS event was too long to be compatible with liquid chromatography elution times. In this work, the duty cycle of the activation and detection of fragments was shortened, and the background signal on the spectra was drastically reduced. Both improvements allowed, for the first time, the successful coupling of a UHPLC system to XUV-activated tandem MS. The approach was used to characterize a complex mixture of oligo-porphyrans, which are a class of highly sulfated oligosaccharides, in a fully automated way. Due to an enhanced dynamic range and an increased sensitivity, some hypothetical structures of low abundance have been unequivocally confirmed in this study and others have been revised. Some previously undescribed species of oligo-porphyrans that exhibit lateral branching have been fully resolved. This work contributes to the scarce knowledge of the structure of porphyrans in red algae and pushes the current capacities of XUV-activation tandem MS by demonstrating the possibility of a direct coupling with UHPLC. This study will considerably broaden the applicability and practicality of this method in many fields of analytical biology. - Highlights: • For the first time, XUV photon activation tandem MS was coupled to UHPLC. • The approach was used to characterize a complex mixture of biomolecules. • The MSMS duty cycle was compatible with elution times of UHPLC without compromised. • Minor species were characterized with an enhanced sensitivity and dynamic range. • These results broaden the application of the technique in many field of

  9. Simultaneous analysis of polychlorinated biphenyls and organochlorine pesticides in seawater samples by membrane-assisted solvent extraction combined with gas chromatography-electron capture detector and gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Shi, Xizhi; Tang, Zigang; Sun, Aili; Zhou, Lei; Zhao, Jian; Li, Dexiang; Chen, Jiong; Pan, Daodong

    2014-12-01

    A highly efficient and environment-friendly membrane-assisted solvent extraction system combined with gas chromatography-electron capture detector was applied in the simultaneous determination of 17 polychlorinated biphenyls and organochlorine pesticides in seawater samples. Variables affecting extraction efficiency, including extraction solvent used, stirring rate, extraction time, and temperature, were optimized extensively. Under optimal extraction conditions, recoveries between 76.9% and 104.6% in seawater samples were achieved, and relative standard deviation values below 10% were obtained. The limit of detection (signal-to-noise ratio=3) and limit of quantification (signal-to-noise ratio=10) of 17 polychlorinated biphenyls and organochlorine pesticides in seawater ranged from 0.14ngL(-1) to 0.36ngL(-1) and 0.46ngL(-1) to 1.19ngL(-1), respectively. Matrix effects on extraction efficiency were evaluated by comparing with the results obtained using tap water. The extraction effect of developed membrane-assisted solvent extraction method was further demonstrated by gas chromatography-tandem mass spectrometry which can provide structural information of the analytes for more accurate identification, and results identical to those produced by gas chromatography-electron capture detector were obtained. These findings demonstrate the applicability of the developed membrane-assisted solvent extraction determination method for coupling to gas chromatography-electron capture detector or tandem mass spectrometry for determining polychlorinated biphenyls and organochlorine pesticides in seawater samples.

  10. 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.

  11. Structural characterisation of degradation products formed upon di-n-butyl phthalate radiolysis by high-performance liquid chromatography electro-spray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tintaru, A.; Charles, L. [Univ Aix Marseille 1, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Univ Aix Marseille 2, CNRS, Lab Chim Provence Spectrometries Appl Chim Struct, UMR 6264, F-13397 Marseille (France); Labed, V. [CEA Marcoule, DTCD SPDE L2ED, F-30207 Bagnols Sur Ceze (France)

    2010-07-01

    Complete text of publication follows: Structural characterisation of 15 degradation products, formed upon di-n-butyl phthalate (DBP) radiolysis, has been achieved using a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) coupling. The dissociation behaviour of protonated DBP was first established to be further used to characterise structural deviation in the degradation products. Based on accurate mass measurements, compounds shown by HPLC-MS analysis were all found to be DBP oxidation products, amongst which various sets of isomers could be distinguished. Collision-induced dissociation experiments performed on each electro-sprayed molecule first allowed unambiguous definition of the location of the additional oxygen atoms; that is, in the alkyl branch or on the aromatic ring. Although location of the oxygen atom in the alkyl branches could not always be precisely determined, relative abundances of some product ions allowed oxygenated functions to be identified

  12. Multi-component quantitation of loratadine, pseudoephedrine and paracetamol in plasma and pharmaceutical formulations with liquid chromatography-tandem mass spectrometry utilizing a monolithic column

    Directory of Open Access Journals (Sweden)

    Kamran Abro

    2012-01-01

    Full Text Available The purpose of this study was to develop a rapid, simple and sensitive quantitation method for pseudoephedrine (PSE, paracetamol (PAR and loratadine (LOR in plasma and pharmaceuticals using liquid chromatography-tandem mass spectrometry with a monolithic column. Separation was achieved using a gradient composition of methanol-0.1% formic acid at a flow rate of 1.0 mL min-1. Mass spectral transitions were recorded in SRM mode. System validation was evaluated for precision, specificity and linearity. Limit of detection for pseudoephedrine, paracetamol, and loratadine were determined to be 3.14, 1.86 and 1.44 ng mL-1, respectively, allowing easy determination in plasma with % recovery of 93.12 to 101.56%.

  13. Characterization of in vitro metabolites of deoxypodophyllotoxin in human and rat liver microsomes using liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Lee, Sang Kyu; Jun, In Hye; Yoo, Hye Hyun; Kim, Ju Hyun; Seo, Young Min; Kang, Mi Jeong; Lee, Seung Ho; Jeong, Tae Cheon; Kim, Dong Hyun

    2008-01-01

    The in vitro metabolism of deoxypodophyllotoxin (DPT), a medicinal herbal product isolated from Anthriscus sylvestris (Apiaceae), was investigated in rats and human microsomes and human recombinant cDNA-expressed CYPs. The incubation of DPT with pooled human microsomes in the presence of NADPH generated five metabolites while its incubation with dexamethasone (Dex)-induced rat liver resulted in seven metabolites (M1-M7) with major metabolic reactions including mono-hydroxylation, O-demethylation and demethylenation. Reasonable structures of the seven metabolites of DPT could be proposed, based on the electrospray tandem mass spectra. Chemical inhibition by ketoconazole and metabolism studies with human recombinant cDNA-expressed CYPs indicated that CYP 3A4 and 2C19 are the major CYP isozymes in the metabolism of DPT in human liver microsomes.

  14. Simultaneous targeted analysis of trimethylamine-N-oxide, choline, betaine, and carnitine by high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Liu, Jia; Zhao, Mingming; Zhou, Juntuo; Liu, Changjie; Zheng, Lemin; Yin, Yuxin

    2016-11-01

    Trimethylamine-N-oxide (TMAO) is a metabolite generated from choline, betaine and carnitine in a gut microbiota-dependent way. This molecule is associated with development of atherosclerosis and cardiovascular events. A sensitive liquid chromatographic electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) has been developed and validated for the simultaneous determination of TMAO related molecules including TMAO, betaine, choline, and carnitine in mouse plasma. Analytes are extracted after protein precipitation by methanol and subjected to LC-ESI-MS/MS without preliminary derivatization. Separation of analytes was achieved on an amide column with acetonitrile-water as the mobile phase. This method has been fully validated in this study in terms of selectivity, linearity, sensitivity, precision, accuracy, and carryover effect, and the stability of the analyte under various conditions has been confirmed. This developed method has successfully been applied to plasma samples of our mouse model.

  15. An evaluation of sucrose as a possible contaminant in e-liquids for electronic cigarettes by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kubica, Paweł; Wasik, Andrzej; Kot-Wasik, Agata; Namieśnik, Jacek

    2014-05-01

    The influence of sucrose combustion products on smoking and nicotine addiction is still controversial because the presence of the sucrose may be treated as a source of aldehydes and organic acids. In e-liquids used as refills for electronic cigarettes, which are made primarily of poly(propylene glycol), glycerine and ethanol, sucrose may be present at trace levels, and its impact on mainstream smoke formation, and hence on human health and smoking/nicotine addiction is unknown. An analytical method was developed where high-performance liquid chromatography in hydrophilic interaction liquid chromatography mode and tandem mass spectrometry were used for fast and simple determination of sucrose and other saccharides in e-liquids for electronic cigarettes. Minimal effort was required in the sample preparation step, and satisfactory results were obtained, and the sample matrix had an insignificant impact. The chromatographic separation was done using an Ascentis Express OH5 column (150 mm × 2.1 mm, 2.7 μm). The coefficients of variation for within-day precision for three concentrations were 2.4 %, 1.6 % and 2.3 %, and the between-day coefficients of variation for a single concentration were 2.1 %, 2.5 % and 1.7 % measured on the next 3 days. The detection limit was 0.73 μg/g, and the sucrose content in e-liquids ranged from 0.76 to 72.93 μg/g among 37 samples. Moreover, with the method presented it is possible to determine the presence of other saccharides such as fructose, glucose, maltose and lactose. However, only sucrose was found in all samples of e-liquids. The proposed method is rapid, simple and reliable in terms of high-performance liquid chromatography coupled with tandem mass spectrometry.

  16. Sensitive, automatic method for the determination of diazepam and its five metabolites in human oral fluid by online solid-phase extraction and liquid chromatography with tandem mass spectrometry

    DEFF Research Database (Denmark)

    Jiang, Fengli; Rao, Yulan; Wang, Rong;

    2016-01-01

    A novel and simple online solid-phase extraction liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of diazepam and its five metabolites including nordazepam, oxazepam, temazepam, oxazepam glucuronide, and temazepam glucuronide...... in human oral fluid. Human oral fluid was obtained using the Salivette(®) collection device, and 100 μL of oral fluid samples were loaded onto HySphere Resin GP cartridge for extraction. Analytes were separated on a Waters Xterra C18 column and quantified by liquid chromatography with tandem mass...

  17. Determination of Clarithromycin in Human Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Validation and Application in Clinical Pharmacokinetic Study

    Institute of Scientific and Technical Information of China (English)

    ZHANGXiang-rong; CHENXiao-yan; LIXiao-yan; ZHONGDa-fang

    2004-01-01

    Aim To develop a liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method to determine clarithromycin in human plasma. Methods The analyte and internal standard roxithromycin were extracted from plasma samples by n-nexane-dichloromethane-isopropanel (300:150:15, V/V/V) and chromatographed on a C18 column. The mobile phase consisted of methanol-water-formic acid (80:20:1, V/V/V). Detection was performed on a triple quadrupole tandem mass spectrometer via electrospray ionization source (ESI) in the positive mode. Results The method had a lower limit of quantification of 10.0 ng·mL-1 when 0.2 mL plasma was used. The linear calibration curves were obtained in the concentration range of 10.0-5000 ng·mL-1. The intra-and inter-rum precisions were lower than 3.3% in terms of relative standard deviation (RSD), and the accuracy ranged±0.7% in terms of relative error (RE). Tmax, Cmax, T1/2 and AUC0-24h values were found to be (3.1±2.7)h, (8 750±4 734)ng·mL-1, (5.3±2.2)h, and (5932±2 449)ng·mL-1, respectively, after a single oral dose of 250 mg clarithromycin tablet to 18 volunteers. Conclusion This validated method was successful in the evaluation of pharmacokinetic profiles of clarithromycin tablets administered to 18 healthy male volubteers.

  18. Simultaneous measurement of aldosterone and cortisol by high-performance liquid chromatography-tandem mass spectrometry: application to dehydration-rehydration studies.

    Science.gov (United States)

    Taylor, Paul J; van Rosendal, Simon P; Coombes, Jeff S; Gordon, Richard D; Stowasser, Michael

    2010-05-01

    Aldosterone and cortisol are useful biomarkers of dehydration and stress, respectively. The aim of this study was to develop an HPLC-tandem mass spectrometric method for the simultaneous measurement of aldosterone and cortisol in human plasma that could be applied to the study of athletes undergoing exercise and rehydration. Samples were prepared and analysed using an on-line sample preparation/HPLC system coupled to a triple quadrupole tandem-mass spectrometer. Samples (200 microL) were pre-treated and extracted on Hysphere C18 HD cartridges (7 microm, Spark Holland). Chromatography was performed on a Sunfire C18 analytical column (50 mm x 3.0 mm, 3 microm, Waters) under isocratic conditions at a flow rate of 0.3 mL/min. The mobile phase consisted of 35% acetonitrile/water. Mass spectrometric detection was by selected reaction monitoring using negative electrospray ionization conditions. The assay had an analytical range of 25-500 pg/mL and 25-500 ng/mL for aldosterone and cortisol, respectively (r(2)>0.992, n=22). Inter-day accuracy and imprecision for quality control samples was 99.4-106% and dehydration, rehydration and exercise when measured by this method. The reported method is suitable to facilitate the study of athletes undergoing dehydration and rehydration protocols.

  19. Screening and identification of unknown contaminants in water with liquid chromatography and quadrupole-orthogonal acceleration-time-of-flight tandem mass spectrometry.

    Science.gov (United States)

    Bobeldijk, I; Vissers, J P; Kearney, G; Major, H; Van Leerdam, J A

    2001-09-21

    In order to assess and maintain the quality of surface waters, target compound monitoring is often not sufficient. Many unknown micro-contaminants are present in water, originating in municipal, industrial or agricultural effluents. Some of these might pose a risk to drinking water production and consequently to human health. The possibilities of screening surface water and identification of these non-target water pollutants with modern data acquisition possibilities of hybrid quadrupole-orthogonal acceleration time of flight mass spectrometers (Q-TOF), such as data-dependent MS to MS/MS switching were investigated. Using model compounds, a procedure for the liquid chromatography-tandem mass spectrometry (LC-MS/MS) screening of water extracts was developed, enabling the detection and identification of compounds at levels < or = 0.25 microg/l in surface water. Based on the accurate mass the elemental compositions for the precursor and product ions are calculated. The calculated chemical formulae are searched against the Merck index, the NIST library, an own database containing about 2,500 water pollutants (pesticides and other contaminants) as well as a CI-CID library containing tandem MS spectra of about 100 water contaminants. The developed approach was applied for the identification of unknown compounds, present in native surface water extract. For three of these compounds, structures were proposed. Confirmation of the proposed structures with standards was beyond the scope of this study.

  20. Simple quantitative determination of potent thiols at ultratrace levels in wine by derivatization and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis.

    Science.gov (United States)

    Capone, Dimitra L; Ristic, Renata; Pardon, Kevin H; Jeffery, David W

    2015-01-20

    Volatile sulfur compounds contribute characteristic aromas to foods and beverages and are widely studied, because of their impact on sensory properties. Certain thiols are particularly important to the aromas of roasted coffee, cooked meat, passion fruit, grapefruit, and guava. These same thiols enhance the aroma profiles of different wine styles, imparting pleasant aromas reminiscent of citrus and tropical fruits (due to 3-mercaptohexan-1-ol, 3-mercaptohexyl acetate, 4-mercapto-4-methylpentan-2-one), roasted coffee (2-furfurylthiol), and struck flint (benzyl mercaptan), at nanogram-per-liter levels. In contrast to the usual gas chromatography (GC) approaches, a simple and unique high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for routine analysis of five wine thiols, using 4,4'-dithiodipyridine (DTDP) as a derivatizing agent and polydeuterated internal standards for maximum accuracy and precision. DTDP reacted rapidly with thiols at wine pH and provided stable derivatives, which were enriched by solid-phase extraction (SPE) prior to analysis by HPLC-MS/MS. All steps were optimized and the method was validated in different wine matrices, with method performance being comparable to a well-optimized but more cumbersome gas chromatography-mass spectrometry (GC-MS) method. A range of commercial wines was analyzed with the new method, revealing the distribution of the five thiols in white, red, rosé, and sparkling wine styles.

  1. Quantification of urinary o,o'-dityrosine, a biomarker for oxidative damage to proteins, by high performance liquid chromatography with triple quadrupole tandem mass spectrometry. A comparison with ion-trap tandem mass spectrometry.

    Science.gov (United States)

    Orhan, Hilmi; Coolen, Stefan; Meerman, John H N

    2005-11-15

    We recently described an isotope dilution reversed-phase liquid chromatography-atmospheric pressure chemical ionization-ion-trap-tandem mass spectrometry (HPLC-APCI-MS/MS) method for the quantitative determination of oxidized amino acids in human urine, including o,o'-dityrosine, a specific marker of protein oxidation. In the present study, we investigated the possibility to use a triple quadrupole instrument for the analysis of this biomarker in urine. The two instruments were compared in terms of sensitivity, specificity and reproducibility. Results showed that the triple quadrupole instrument reaches 2.5-fold higher sensitivity (LOD=0.01 microM) compared to the previously used ion-trap instrument. Precision of the present assay is as follows: in-day variation is 4.6% and inter-day variation is 17%. The currently developed method was applied to a group of smoker urine samples. The mean urinary o,o'-dityrosine concentration was 0.08+/-0.01 microM. Expressed per urinary creatinine concentration, this corresponds to 10.1+/-0.4 micromol/mol creatinine. This is comparable to the previously reported values of 5.8+/-0.3 micromol/mol creatinine in non-smokers night-time urines, and 12.3+/-5 micromol/mol creatinine in day-time urines measured by the ion-trap instrument.

  2. Characterization of lemon (Citrus limon) polar extract by liquid chromatography-tandem mass spectrometry in high resolution mode.

    Science.gov (United States)

    Ledesma-Escobar, C A; Priego-Capote, F; Luque de Castro, M D

    2015-11-01

    Eighty four metabolites (32 flavonoids, 15 amino acids, nine carboxylic acids, six coumarins, six sugars, five phenolic acids and 11 unclassified compounds) have been tentatively identified in a polar extract from lemon, without reference standards, based on their liquid chromatography-quadrupole-time-of-flight MS/MS spectra and the comparison with databases. Despite information in databases for some families of plant compounds is poor, tentative identification based on MS/MS information (mass of the precursor ion and their fragments, together with neutral mass loss) was possible with the help of known fragmentation patterns for the given families of compounds. Both positive and negative ionization modes and at least two collision energies were always applied to obtain as much information as possible from each molecular entity, thus helping for identification. As the tentatively identified metabolites are the same regardless of the organism they belong, their fragmentation patterns are useful for identification with independence of the sample nature.

  3. Discovering Mercury Protein Modifications in Whole Proteomes Using Natural Isotope Distributions Observed in Liquid Chromatography-Tandem Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Polacco, Benjamin J.; Purvine, Samuel O.; Zink, Erika M.; LaVoie, Stephen P.; Lipton, Mary S.; Summers, Anne O.; Miller, Susan M.

    2011-08-01

    The identification of peptides that result from post-translational modifications is critical for understanding normal pathways of cellular regulation as well as identifying damage from, or exposures to xenobiotics, i.e. the exposome. However, because of their low abundance in proteomes, effective detection of modified peptides by mass spectrometry (MS) typically requires enrichment to eliminate false identifications. We present a new method for confidently identifying peptides with mercury (Hg)-containing adducts that is based on the influence of mercury’s seven stable isotopes on peptide isotope distributions detected by high-resolution MS. Using a pure protein and E. coli cultures exposed to phenyl mercuric acetate, we show the pattern of peak heights in isotope distributions from primary MS single scans efficiently identified Hg adducts in data from chromatographic separation coupled with tandem mass spectrometry with sensitivity and specificity greater than 90%. Isotope distributions are independent of peptide identifications based on peptide fragmentation (e.g. by SEQUEST), so both methods can be combined to eliminate false positives. Summing peptide isotope distributions across multiple scans improved specificity to 99.4% and sensitivity above 95%, affording identification of an unexpected Hg modification. We also illustrate the theoretical applicability of the method for detection of several less common elements including the essential element, selenium, as selenocysteine in peptides.

  4. Quantification of Photocyanine in Human Serum by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and Its Application in a Pharmacokinetic Study

    Directory of Open Access Journals (Sweden)

    Bing-Tian Bi

    2014-01-01

    Full Text Available Photocyanine is a novel anticancer drug. Its pharmacokinetic study in cancer patients is therefore very important for choosing doses, and dosing intervals in clinical application. A rapid, selective and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS method was developed and validated for the determination of photocyanine in patient serum. Sample preparation involved one-step protein precipitation by adding methanol and N,N-dimethyl formamide to 0.1 mL serum. The detection was performed on a triple quadrupole tandem mass spectrometer operating in multiple reaction-monitoring (MRM mode. Each sample was chromatographed within 7 min. Linear calibration curves were obtained for photocyanine at a concentration range of 20–2000 ng/mL (r>0.995, with the lower limit of quantification (LLOQ being 20 ng/mL. The intrabatch accuracy ranged from 101.98% to 107.54%, and the interbatch accuracy varied from 100.52% to 105.62%. Stability tests showed that photocyanine was stable throughout the analytical procedure. This study is the first to utilize the HPLC-MS/MS method for the pharmacokinetic study of photocyanine in six cancer patients who had received a single dose of photocyanine (0.1 mg/kg administered intravenously.

  5. Systematic screening and characterization of glycosides in tobacco leaves by liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry using neutral loss scan and product ion scan.

    Science.gov (United States)

    Ding, Li; Wang, Xiaoyu; Wang, Sheng; Yu, Jingjing; Qin, Yaqiong; Zhang, Xiaobing; Xie, Fuwei

    2015-12-01

    Glycosides in tobacco leaves are highly important aromatic precursors. It is necessary to reveal glycosides in tobacco leaves to improve tobacco planting and processing. This study describes a method for the systematic screening of glycosides in tobacco leaves by liquid chromatography with tandem mass spectrometry. Although glycosides contain numerous aglycones, the number of glycans is limited. Based on a screening table of glycans designed for neutral loss scan, glycosides with different aglycones were systematically screened out. Then, the MS(2) fragment spectra of scanned glycosides were further obtained using product ion scan. By comparison with the spectra in online tandem mass spectral databases, reported references, and verification by commercial standards, 64 glycosides were detected, including 39 glycosides linked with monosaccharides, 18 glycosides linked with disaccharides and 7 glycosides linked with trisaccharides. It is noteworthy that glycosides linked with trisaccharides have previously been rarely reported in tobacco. This method appears to be a useful tool for the systematic screening and characterization of glycosides in tobacco and can potentially be applied to other plants.

  6. Simultaneous quantification of two canthinone alkaloids of Picrasma quassioides in rat plasma by liquid chromatography-tandem mass spectrometry and its application to a rat pharmacokinetic study.

    Science.gov (United States)

    Shi, Yuanyuan; Hong, Chunyan; Xu, Jian; Yang, Xiaoling; Xie, Ning; Feng, Feng; Liu, Wenyuan

    2015-04-01

    Picrasma quassioides (D. Don) Benn. is used in traditional Chinese medicine for the treatment of inflammation. Characteristic components of the medicinal extract are canthinone alkaloids. In this study, a sensitive and rapid liquid chromatography with tandem mass spectrometry method has been developed for simultaneous quantification of two major canthinone alkaloids, 5-hydroxy-4-methoxycanthin-6-one and 4,5-dimethoxycanthin-6-one, in rat plasma after oral administration of P. quassioides extract (200 mg/kg). The chromatographic separation was performed on a C18 column using acetonitrile-aqueous 0.1% formic acid (90:10, v/v) as the mobile phase. Plasma samples were prepared for analysis using a simple liquid-liquid extraction with ethyl acetate. Analytes were detected using tandem mass spectrometry in positive multiple reaction monitoring mode. Method validation revealed excellent linearity over the range 1.25-900 ng/mL for 5-hydroxy-4-methoxycanthin-6-one and 0.5-800 ng/mL for 4,5-dimethoxycanthin-6-one with satisfactory intra- and inter-day precision, accuracy and recovery. Samples were stable under the conditions tested. The pharmacokinetic profiles of the analytes in rats showed that both canthinones were rapidly absorbed and that 4,5-dimethoxycanthin-6-one was eliminated faster than 5-hydroxy-4-methoxycanthin-6-one.

  7. Simultaneous determination of polycyclic musks in blood and urine by solid supported liquid-liquid extraction and gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Liu, Hongtao; Huang, Liping; Chen, Yuxin; Guo, Liman; Li, Limin; Zhou, Haiyun; Luan, Tiangang

    2015-06-15

    A rapid, precise and accurate method for the simultaneous determination of 5 polycyclic musks (PCMs) in biological fluids was developed by solid supported liquid-liquid extraction (SLE) coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS). All parameters influencing SLE-GC-MS performance, including electron energy of electron-impact ionization source, collision energy for tandem mass spectrometer when operated in selected-reaction monitoring (SRM) mode, type and volume of elution reagent, nitrogen evaporation time, pH and salinity of sample have been carefully optimized. Eight milliliter of n-hexane was finally chosen as elution reagent. Blood and urine sample could be loaded into SLE cartridge without adjusting pH and salinity. Deuterated tonalide (AHTN-d3) was chosen as internal standard. The correlation coefficient (r(2)) of the calibration curves of target compounds ranged from 0.9996 to 0.9998. The dynamic range spanned over two orders of magnitude. The limit of detection (LOD) of target compounds in blood and urine ranged from 0.008 to 0.105μgL(-1) and 0.005 to 0.075μgL(-1), respectively. The developed procedure was successfully applied to the analysis of PCMs in human blood and urine obtaining satisfying recoveries on low, medium and high levels. The method was compared with SLE-GC-MS and shown one to two orders of magnitude improvement in sensitivity.

  8. [Simultaneous determination of 11 quinolones in hotpot ingredients by dispersive solid-phase extraction and ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Cao, Peng; Mou, Yan; Gao, Fei; Geng, Jinpei; Zhang, Xiqing; Sui, Tao; Liang, Junni; Sha, Meilan; Guan, Lili

    2013-09-01

    A method for the simultaneous determination of the residues of 11 quinolones in hotpot ingredients by quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction and ultra performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was established. The sample was extracted with acetonitrile (containing 5% formic acid) and followed by stratifying with a salting-out agent. Clean-up of the extracts was processed by C18 and PSA, a modified QuEChERS procedure. The analytes were then separated on a Poroshell 120 EC-C18 column, and finally detected by tandem mass spectrometry in positive ESI mode. The linearity of all the 11 quinolones in the range from 1.0 to 100.0 microg/kg had correlation coefficients greater than 0.998. The limits of detection (LOD) of the method were from 1.8 to 3.1 microg/kg and the limits of quantification (LOQ) were from 6.0 to 10.3 microg/kg. The average recoveries of the 11 quinolones were in the range from 70.1% to 100.3%, with relative standard deviations from 2.42% to 10.88%. The established method is sensitive and of good recoveries. It can be applied as a rapid and reliable method for the determination of the 11 quinolones in hotpot ingredients.

  9. Determination of a dipeptidyl peptidase IV agonist, β-aminoacyl containing thiazolidine derivatives (KR-66223) in rat plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kim, Min-Sun; Park, Jong-Shik; Jang, Su-Min; Lee, Byung Hoi; Ahn, Sung-Hoon; Ahn, Jin Hee; Yoo, Sung Eun; Song, Im-Sook; Silinski, Peter; Schneider, Stephen Edward; Bae, Myung Ae

    2011-07-15

    A sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for a novel dipeptidyl peptidase IV agonist (DDP-IV) agonist, KR-66223, in rat plasma. It involves liquid-liquid extraction (LLE) followed by HPLC separation and electrospray ionization tandem mass spectrometry. KR-66223 and imipramine (IS) was separated on Gemini-NX C18 column with mixture of acetonitrile-ammonium formate (10mM) (90:10, v/v) as mobile phase. The ion transitions monitored were m/z 553.2→206.2 for KR-66223, m/z 281.3→86.1 for imipramine in multiple reaction monitoring (MRM) mode. The linear ranges of the assay were 0.003-10μg/ml with a correlation coefficient (R(2)) greater than 0.99 and the lower limit of quantification was 3ng/ml. The average recovery was 78.9% and 87.1% from rat plasma for KR-66223 and imipramine, respectively. The coefficients of variation of intra- and inter-assay were 3.9-14.4% and the relative error was 0.8-11.5%. The method was validated and successfully applied to the pharmacokinetic study of KR-66223 in rat.

  10. Determination of parabens in urine samples by microextraction using packed sorbent and ultra-performance liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Cristina Jardim, Valeria; de Paula Melo, Lidervan; Soares Domingues, Diego; Costa Queiroz, Maria Eugênia

    2015-01-01

    A simple, sensitive, and selective method using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) was developed and validated for simultaneous determination of parabens [methyl paraben (MeP), ethyl paraben (EtP), propyl paraben (PrP), butyl paraben (BuP), and benzyl paraben (BzP)] in human urine samples. After microextraction by packed sorbent (MEPS) using a C18 phase, the parabens were separated on a Kinetex C18 column (100 mm × 2.1 mm × 1.7 μm) within 4.6 min using isocratic elution. These compounds were detected on a triple quadrupole tandem mass spectrometer using the multiple reactions monitoring (MRM) mode via an electrospray ionization source operating in the negative ionization mode. Important factors that influence MEPS performance were evaluated, such as the sample pH, draw-eject sample volume, clean-up step, and desorption conditions. The proposed MEPS/UPLC-MS/MS method presented a linear range from 0.5 ng mL(-1) (limit of quantification - LOQ) to 50 ng mL(-1), and interassay precision with coefficients of variation lower than 15%, and relative standard error values of the accuracy ranged from -8.8% to 15%. The MEPS/UPLC-MS/MS method was applied successfully to determine parabens in urine samples from 30 postpartum volunteers, enabling assessment of human exposure to these compounds.

  11. Analysis of drugs in plasma samples from schizophrenic patients by column-switching liquid chromatography-tandem mass spectrometry with organic-inorganic hybrid cyanopropyl monolithic column.

    Science.gov (United States)

    Domingues, Diego Soares; Souza, Israel Donizeti de; Queiroz, Maria Eugênia Costa

    2015-07-01

    This study reports on the development of a rapid, selective, and sensitive column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze sixteen drugs (antidepressants, anticonvulsants, anxiolytics, and antipsychotics) in plasma samples from schizophrenic patients. The developed organic-inorganic hybrid monolithic column with cyanopropyl groups was used for the first dimension of the column-switching arrangement. This arrangement enabled online pre-concentration of the drugs (monolithic column) and their subsequent analytical separation on an XSelect SCH C18 column. The drugs were detected on a triple quadrupole tandem mass spectrometer (multiple reactions monitoring mode) with an electrospray ionization source in the positive ion mode. The developed method afforded adequate linearity for the sixteen target drugs; the coefficients of determination (R(2)) lay above 0.9932, the interassay precision had coefficients of variation lower than 6.5%, and the relative standard error values of the accuracy ranged from -14.0 to 11.8%. The lower limits of quantification in plasma samples ranged from 63 to 1250pgmL(-1). The developed method successfully analyzed the target drugs in plasma samples from schizophrenic patients for therapeutic drug monitoring (TDM).

  12. Single-step multiresidue determination of ten multiclass veterinary drugs in pork, milk, and eggs using liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Park, Jin-A; Zhang, Dan; Kim, Dong-Soon; Kim, Seong-Kwan; Cho, Kyeong-Su; Jeong, Dana; Shim, Jae-Han; Kim, Jin-Suk; Abd El-Aty, A M; Shin, Ho-Chul

    2015-08-01

    A multiclass, multiresidue determination method is reported for the detection of ten veterinary drugs, including scopolamine, metoclopramide, acriflavine, berberine, tripelennamine, diphenhydramine, acrinol, triamcinolone, loperamide, and roxithromycin in pork, milk, and eggs. The method involves a simple extraction using 0.1% formic acid in acetonitrile, followed by defatting with n-hexane, centrifugation, and filtration prior to liquid chromatography with tandem mass spectrometric analysis. As ion suppression and enhancement effects are reported, matrix-matched calibrations are used for quantification, with determination coefficients ≥0.9765. For the majority of the tested analytes, the intra- and interday accuracy (expressed as recovery %) range from 70.6 to 94.6% and from 70.1 to 93.3%, respectively, and the precision (expressed as relative standard deviation) ranges from 0.5 to 19.8% and from 2.8 to 18.4% in all matrices. The limits of quantification range between 0.5 and 10 ng/g. The validated tandem mass spectrometry method is successfully applied to market samples; the target analytes are not detected in any of the tested samples. In terms of accuracy, no extract cleanup is deemed necessary. The developed method is feasible for the simultaneous detection of the tested analytes in pork, milk, and eggs.

  13. Functionalized graphene quantum dots loaded with free radicals combined with liquid chromatography and tandem mass spectrometry to screen radical scavenging natural antioxidants from Licorice and Scutellariae.

    Science.gov (United States)

    Wang, Guoying; Niu, XiuLi; Shi, Gaofeng; Chen, Xuefu; Yao, Ruixing; Chen, Fuwen

    2014-12-01

    A novel screening method was developed for the detection and identification of radical scavenging natural antioxidants based on a free radical reaction combined with liquid chromatography with tandem mass spectrometry. Functionalized graphene quantum dots were prepared for loading free radicals in the complex screening system. The detection was performed with and without a preliminary exposure of the samples to specific free radicals on the functionalized graphene quantum dots, which can facilitate charge transfer between free radicals and antioxidants. The difference in chromatographic peak areas was used to identify potential antioxidants. This is a novel approach to simultaneously evaluate the antioxidant power of a component versus a free radical, and to identify it in a vegetal matrix. The structures of the antioxidants in the samples were identified using tandem mass spectrometry and comparison with standards. Fourteen compounds were found to possess potential antioxidant activity, and their free radical scavenging capacities were investigated. The order of scavenging capacity of 14 compounds was compared according to their free radical scavenging rate. 4',5,6,7-Tetrahydroxyflavone (radical scavenging rate: 0.05253 mL mg(-1) s(-1) ) showed the strongest capability for scavenging free radicals.

  14. Determination of alprostadil in rat plasma by ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry after intravenous administration.

    Science.gov (United States)

    Lin, Xia; Zhang, Yu; Cui, Yue; Wang, Lin; Wang, Jing; Tang, Xing

    2009-05-01

    A rapid, highly selective ultra performance liquid chromatography-electrospray ionisation-tandem mass spectrometry method (UPLC-ESI-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of alprostadil in rat plasma. After a simple sample preparation procedure involving a one-step liquid-liquid extraction, alprostadil and the internal standard, diphenhydramine, were chromatographed on an ACQUITY UPLC BEH C(18) column with gradient elution using a mobile phase consisting of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.25 mL min(-1). The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode via an electrospray ionization (ESI) source. The calibration curve was linear (r(2)=0.99) over the concentration range 0.4-250.0 ng mL(-1), with a lower limit of quantification of 0.4 ng mL(-1) for alprostadil. The inter- and intra-day precision (%R.S.D.) was less than 8.5% and 2.4%, respectively, and the accuracy (RE%) was between 9.3% and 1.0% (n=6). Alprostadil in rat plasma was stable when stored at room temperature for 0.5h and at -20 degrees C for two weeks. The method was very rapid, simple and reliable, and was employed for the first time for the pharmacokinetic studies of alprostadil in rats after a single intravenous administration of 50 microg kg(-1).

  15. Rapid and sensitive hormonal profiling of complex plant samples by liquid chromatography coupled to electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Müller Maren

    2011-11-01

    Full Text Available Abstract Background Plant hormones play a pivotal role in several physiological processes during a plant's life cycle, from germination to senescence, and the determination of endogenous concentrations of hormones is essential to elucidate the role of a particular hormone in any physiological process. Availability of a sensitive and rapid method to quantify multiple classes of hormones simultaneously will greatly facilitate the investigation of signaling networks in controlling specific developmental pathways and physiological responses. Due to the presence of hormones at very low concentrations in plant tissues (10-9 M to 10-6 M and their different chemistries, the development of a high-throughput and comprehensive method for the determination of hormones is challenging. Results The present work reports a rapid, specific and sensitive method using ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UPLC/ESI-MS/MS to analyze quantitatively the major hormones found in plant tissues within six minutes, including auxins, cytokinins, gibberellins, abscisic acid, 1-amino-cyclopropane-1-carboxyic acid (the ethylene precursor, jasmonic acid and salicylic acid. Sample preparation, extraction procedures and UPLC-MS/MS conditions were optimized for the determination of all plant hormones and are summarized in a schematic extraction diagram for the analysis of small amounts of plant material without time-consuming additional steps such as purification, sample drying or re-suspension. Conclusions This new method is applicable to the analysis of dynamic changes in endogenous concentrations of hormones to study plant developmental processes or plant responses to biotic and abiotic stresses in complex tissues. An example is shown in which a hormone profiling is obtained from leaves of plants exposed to salt stress in the aromatic plant, Rosmarinus officinalis.

  16. Quantification of achiral and chiral methylsulfonyl polychlorinated biphenyl metabolites by column-switching liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry.

    Science.gov (United States)

    Cooper, Victoria I; Letcher, Robert J; Dietz, Rune; Sonne, Christian; Wong, Charles S

    2012-12-14

    An enantioselective heart-cut column-switching liquid chromatography-atmospheric pressure photoionization-tandem mass spectrometry method was developed for the analysis of 25 methylsulfonyl polychlorinated biphenyl metabolites in tissue extracts. Use of a pyrenyl-ethyl silica column in the first dimension enabled separation of all but two pairs of isobaric analytes. Enantioseparation was achieved for 9 out of the 10 atropisomeric analytes using a Chiralpak AD-H amylose-based column within 93 min, resulting in greater chromatographic resolution of enantioseparation over shorter analysis time by up to a factor of three, compared to previous one-dimensional and multi-dimensional gas chromatography-based methods. Precision for concentration and enantiomer fraction measurements was within 11% and 3% relative standard deviation, respectively. Limits of detection ranged from 0.01 to 1.73 ng on-column. Meta-congeners had poorer sensitivity (i.e., ng on-column), consistent with existing gas chromatography-based methods. Despite this limitation, the method was successfully applied to the analysis of Greenland sledge dog adipose tissue extracts, which had highly non-racemic residues of 4-methylsulfonyl-2,2',3,5',6-pentachlorobiphenyl and 4'-methylsulfonyl-2,2',3,3',4,6'-hexachlorobiphenyl, consistent with past reports in Arctic mammals.

  17. Quantification of biopharmaceuticals and biomarkers in complex biological matrices: a comparison of liquid chromatography coupled to tandem mass spectrometry and ligand binding assays.

    Science.gov (United States)

    Bults, Peter; van de Merbel, Nico C; Bischoff, Rainer

    2015-08-01

    The quantification of proteins (biopharmaceuticals or biomarkers) in complex biological samples such as blood plasma requires exquisite sensitivity and selectivity, as all biological matrices contain myriads of proteins that are all made of the same 20 proteinogenic amino acids, notwithstanding post-translational modifications. This review describes and compares the two main approaches, namely, ligand binding assays (LBAs) and liquid chromatography coupled to tandem mass spectrometry in the selected reaction monitoring (SRM) mode. While LBAs remain the most widely used approach, SRM assays are gaining interest due to their generally better analytical performance (precision and accuracy) and their capacity for multiplex analyses. This article focuses on the possible reasons for the discrepancies between results obtained by LBAs and SRM assays.

  18. Determination of sedative hypnotics in sewage sludge by pressurized liquid extraction with high-performance liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Arbeláez, Paula; Granados, Judith; Borrull, Francesc; Marcé, Rosa Maria; Pocurull, Eva

    2014-12-01

    This paper describes a method for the determination of eight sedative hypnotics (benzodiazepines and barbiturates) in sewage sludge using pressurized liquid extraction and liquid chromatography with tandem mass spectrometry. Pressurized liquid extraction operating conditions were optimized and maximum recoveries were reached using methanol under the following operational conditions: 100ºC, 1500 psi, extraction time of 5 min, one extraction cycle, flush volume of 60% and purge time of 120 s. Pressurized liquid extraction recoveries were higher than 88% for all the compounds except for carbamazepine (55%). The repeatability and reproducibility between days, expressed as relative standard deviation (n = 5), were lower than 6 and 10%, respectively. The detection limits for all compounds were lower than 12.5 μg/kg of dry weight. The method was applied to determine benzodiazepines and barbiturates in sewage sludge from urban sewage treatment plants, and carbamazepine showed the highest concentration (7.9-18.9 μg/kg dry weight).

  19. Quantitation of Cotinine and its Metabolites in Rat Plasma and Brain Tissue by Hydrophilic Interaction Chromatography Tandem Mass Spectrometry (HILIC-MS/MS)

    Science.gov (United States)

    Li, Pei; Beck, Wayne D.; Callahan, Patrick M.; Terry, Alvin V.; Bartlett, Michael G.

    2014-01-01

    In this work, we developed a sensitive method to quantify cotinine (COT), norcotinine (NCOT), trans-3′-hydroxycotinine (OHCOT) and cotinine-N-oxide (COTNO) in rat plasma and brain tissue, using solid phase extraction (SPE), hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry (MS/MS). The linear range was 1–100 ng/ml for each analyte in rat plasma and brain homogenate (3–300 ng/g brain tissue). The method was validated with precision within 15% relative standard deviation (RSD) and accuracy within 15% relative error (RE). Stable isotope-labeled internal standards (IS) were used for all the analytes to achieve good reproducibility, minimizing the influence of recovery and matrix effects. This method can be used in future studies to simultaneously determine the concentrations of COT and three major metabolites in rat plasma and brain tissue. PMID:23022114

  20. Determination of benzothiazole and benzotriazole derivates in tire and clothing textile samples by high performance liquid chromatography-electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Avagyan, Rozanna; Sadiktsis, Ioannis; Thorsén, Gunnar; Östman, Conny; Westerholm, Roger

    2013-09-13

    A high performance liquid chromatography-tandem mass spectrometry method utilizing electrospray ionization in positive and negative mode has been developed for the separation and detection of benzothiazole and benzotriazole derivates. Ultra-sonication assisted solvent extraction of these compounds has also been developed and the overall method demonstrated on a selected clothing textile and an automobile tire sample. Matrix effects and extraction recoveries, as well as linearity and limits of detection have been evaluated. The calibration curves spanned over more than two orders of magnitude with coefficients of correlation R(2)>0.99 and the limits of detection and the limits of quantification were in the range 1.7-58pg injected and 18-140pg/g, respectively. The extraction recoveries ranged between 69% and 102% and the matrix effects between 75% and 101%. Benzothiazole and benzotriazole derivates were determined in the textile sample and benzothiazole derivatives determined in the tire sample with good analytical performance.

  1. Ultrasound-assisted emulsification microextraction for determination of 2,4,6-trichloroanisole in wine samples by gas chromatography tandem mass spectrometry.

    Science.gov (United States)

    Fontana, Ariel R; Patil, Sangram H; Banerjee, Kaushik; Altamirano, Jorgelina C

    2010-04-28

    A fast and effective microextraction technique is proposed for preconcentration of 2,4,6-trichloroanisole (2,4,6-TCA) from wine samples prior gas chromatography tandem mass spectrometric (GC-MS/MS) analysis. The proposed technique is based on ultrasonication (US) for favoring the emulsification phenomenon during the extraction stage. Several variables influencing the relative response of the target analyte were studied and optimized. Under optimal experimental conditions, 2,4,6-TCA was quantitatively extracted achieving enhancement factors (EF) > or = 400 and limits of detection (LODs) 0.6-0.7 ng L(-1) with relative standard deviations (RSDs) or = 0.9995. Validation of the methodology was carried out by standard addition method at two concentrations (10 and 50 ng L(-1)) achieving recoveries >80% indicating satisfactory robustness of the method. The methodology was successfully applied for determination of 2,4,6-TCA in different wine samples.

  2. 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...... methylphenidate was not determined to be related to the cause of death, the femoral blood concentration of d-methylphenidate ranged from 5 to 58 ng/g, and from undetected to 48 ng/g for l-methylphenidate (median d/l-ratio 5.9). Ritalinic acid was present at concentrations 10–20 times higher with roughly equal...... amounts of the d- and l-forms. In blood from 10 living subjects that were not suspected of being intoxicated by methylphenidate, the concentration ranges and patterns were similar to those of the postmortem cases. Thus, methylphenidate does not appear to undergo significant postmortem redistribution....

  3. [Analysis of proteins in the extracts of Physalis alkekengi L. var. franchetii (Mast.) Makino using nanoflow reversed-phase liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Yu, Haiyang; Yan, Jiaze; Guo, Ming; Jin, Yan

    2013-04-01

    The protein was extracted from Physalis alkekengi L. var. franchetii (Mast.) Makino fruit by using water extraction and acid precipitation methods, and it consisted of 188 mg/g of protein on dry basis of the extract. Among 18 amino acids, eight essential amino acids for human account for 31% were found in this extract. Based on shotgun proteomics method, the protein extracted from Physalis fruit was analysed by nanoflow reversed-phase liquid chromatography-tandem mass spectrometry (nano-RPLC-MS/MS) system. Combined with database searches and bioinformatics analysis, the protein species and six molecular functions were identified, including with catalytic activity, antioxidant activity, enzyme regular activity, nutrient reservoir activity, transporter activity and binding activity. And three antioxidant activity-related proteins were identified. These results may lay the foundation for further study of the functional properties of the proteins in Physalis fruit.

  4. Simultaneous enantioselective quantification of fluoxetine and norfluoxetine in human milk by direct sample injection using 2-dimensional liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Alvim-Jr, Joel; Lopes, Bianca Rebelo; Cass, Quezia Bezerra

    2016-06-17

    A two-dimensional liquid chromatography system coupled to triple quadrupole tandem mass spectrometer (2D LC-MS/MS) was employed for the simultaneously quantification of fluoxetine (FLX) and norfluoxetine (NFLX) enantiomers in human milk by direct injection of samples. A restricted access media of bovine serum albumin octadecyl column (RAM-BSAC18) was used in the first dimension for the milk proteins depletion, while an antibiotic-based chiral column was used in the second dimension. The results herein described show good selectivity, extraction efficiency, accuracy, and precision with limits of quantification in the order of 7.5ngmL(-1)for the FLX enantiomers and 10.0ngmL(-1) for NFLX enantiomers. Furthermore, it represents a practical tool in terms of sustainability for the sample preparation of such a difficult matrix.

  5. Phenolic Compounds of Pinus brutia Ten.: Chemical Investigation and Quantitative Analysis Using an Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry with Electrospray Ionization Source

    Directory of Open Access Journals (Sweden)

    İbrahim Kıvrak

    2013-08-01

    Full Text Available In this study, phenolic content of Pinus brutia ’s bark was examined using an ultra-performance liquid chromatography tandem mass spectrometry with electrospray ionization source (UPLC-ESI-MS/MS working in multiple reaction monitoring mode. U ltrasonic extraction method with 50% ethanol solution was used for the extraction of bark. The bark of Pinus brutia consisted of 15 compounds: gallic acid, gentisic acid, protocatechuic acid, 4-hydroxy benzoic acid, catechin hydrate, vanillic acid, caffeic acid, vanillin, p-coumaric acid, ferulic acid, myricetin, resveratrol, luteolin, naringenin, kaempferol. Major compound detected was catechin hydrate (28.305 mg 100 g -1 extract. The phenolic compounds of Pinus brutia extract and pycnogenol were compared, and it is shown that both of them consisted of considerable amount of phenolic compounds.

  6. 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 chicken, respectively. This method can be used for rapid and easy multiresidue screening of antibiotics for three meats (pork, beef, and chicken).

  7. Ultra-performance liquid chromatography electrospray ionization-tandem mass spectrometry method for the simultaneous determination of itraconazole and hydroxy itraconazole in human plasma

    Institute of Scientific and Technical Information of China (English)

    Ashish Dwivedi; Bhupinder Singh; Sandeep Sharma; R.S. Lokhandae; Naveen Dubey

    2014-01-01

    A highly sensitive, selective, and precise ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous quantification of itraconazole and hydroxy itraconazole in human plasma by a single liquid-liquid extraction step. The precursor to product ion transitions of m/z 705.3/392.3, m/z 721.2/408.3 and m/z 708.2/435.4 were used to detect and quantify itraconazole, hydroxy itraconazole and itraconazole-d3 respectively. The lower limit of quantitation was found to be 0.500 ng/mL for itraconazole and 1.00 ng/mL for hydroxy itraconazole. The mean recoveries for itraconazole and hydroxy itraconazole were found to be 100.045% and 100.021%, respectively. This developed method with a chromatographic run time of 2.0 min was successfully applied to a bioequivalence study of 100 mg itraconazole capsule.

  8. Structural elucidation of metabolites of ginkgolic acid in rat liver microsomes by ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry and hydrogen/deuterium exchange.

    Science.gov (United States)

    Liu, Z H; Chen, J; Yu, L S; Jiang, H D; Yao, T W; Zeng, S

    2009-07-01

    Ginkgolic acids have been shown to possess allergenic as well as genotoxic and cytotoxic properties. The question arises whether the metabolism of ginkgolic acids in the liver could decrease or increase their toxicity. In this study, the in vitro metabolism of ginkgolic acid (15:1, GA), one component of ginkgo acids, was investigated as a model compound in Sprague-Dawley rat liver microsomes. The metabolites were analyzed by ultra-performance liquid chromatography coupled with photodiode array detector/negative-ion electrospray ionization tandem mass spectrometry (UPLC-PDA/ESI-MS/MS) and hydrogen/deuterium (H/D) exchange. The result showed that the benzene ring remained unchanged and the oxidations occurred at the side alkyl chain in rat liver microsomes. At least eight metabolites were found. Among them, six phase I metabolites were tentatively identified. This study might be useful for the investigation of toxicological mechanism of ginkgolic acids.

  9. Determination of (fluoro)quinolone antibiotic residues in pig kidney using liquid chromatography-tandem mass spectrometry. Part II: intercomparison exercise.

    Science.gov (United States)

    Toussaint, B; Chedin, M; Vincent, U; Bordin, G; Rodriguez, A R

    2005-09-23

    A recently in-house validated method for the liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of eleven (fluoro)quinolone antibiotics (FQs) in pig kidney has been fully validated through an intercomparison exercise. This ring trial involved eight European laboratories and was based on the Commission Decision 2002/657/CE for validation of method and on the IUPAC protocol for method-performances studies. The laboratories data were submitted to a one-way analysis of variance. Satisfactory results were obtained for each FQ with regards to within- and between-laboratory reproducibility and accuracy. The method was validated for the simultaneous qualitative and quantitative determination of the eleven FQs in pig kidney around their maximum residue limit (MRL) as defined in the European Council Regulation 2377/90/EEC.

  10. Extraction and Analysis of Disperse Dyes from Colored Polyester Single Fibers Using Liquid Chromatography/Linear Ion Trap Tandem Mass Spectrometry.

    Science.gov (United States)

    Kato, Takao; Suzuki, Yasuhiro; Handa, Makoto

    2016-01-01

    Nine disperse dyes extracted from colored polyester threads and single fibers of manufactory-supplied textiles by using centrifugal filtration were analyzed using liquid chromatography/linear ion trap tandem mass spectrometry (LC/LIT-MS(n)). Based on diode array detector data, dimethylformamide (DMF) was found to be a more effective extraction solvent than acetonitrile/water (4:3, v/v) or methanol/water (1:1, v/v) mixtures. The precursor, [M+H](+) ions, were detected for the dyes extracted using DMF. The MS(2) and MS(3) spectra also matched those of the standard disperse dyes. Without relying on comparison clothes, disperse dyes extracted from the single fibers (5 mm in length) were successfully identified by LC/LIT-MS(n) and the custom-built database.

  11. 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.

  12. Comprehensive metabolite profiling of Plantaginis Semen using ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry coupled with elevated energy technique.

    Science.gov (United States)

    Wang, Dandan; Qi, Meng; Yang, Qiming; Tong, Renchao; Wang, Rui; Bligh, S W Annie; Yang, Li; Wang, Zhengtao

    2016-05-01

    Plantaginis Semen is commonly used in traditional medicine to treat edema, hypertension, and diabetes. The commercially available Plantaginis Semen in China mainly comes from three species. To clarify the chemical composition and distinct different species of Plantaginis Semen, we established a metabolite profiling method based on ultra high performance liquid chromatography with electrospray ionization quadrupole time-of-flight tandem mass spectrometry coupled with elevated energy technique. A total of 108 compounds, including phenylethanoid glycosides, flavonoids, guanidine derivatives, terpenoids, organic acids, and fatty acids, were identified from Plantago asiatica L., P. depressa Willd., and P. major L. Results showed significant differences in chemical components among the three species, particularly flavonoids. This study is the first to provide a comprehensive chemical profile of Plantaginis Semen, which could be involved into the quality control, medication guide, and developing new drug of Plantago seeds.

  13. Tentative identification of polar and mid-polar compounds in extracts from wine lees by liquid chromatography-tandem mass spectrometry in high-resolution mode.

    Science.gov (United States)

    Delgado de la Torre, M P; Priego-Capote, F; Luque de Castro, M D

    2015-06-01

    Sustainable agriculture has a pending goal in the revalorization of agrofood residues. Wine lees are an abundant residue in the oenological industry. This residue, so far, has been used to obtain tartaric acid or pigments but not for being qualitatively characterized as a source of polar and mid-polar compounds such as flavonoids, phenols and essential amino acids. Lees extracts from 11 Spanish wineries have been analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in high resolution mode. The high-resolution power of LC-MS/MS has led to the tentative identification of the most representative compounds present in wine lees, comprising primary amino acids, anthocyans, flavanols, flavonols, flavones and non-flavonoid phenolic compounds, among others. Attending to the profile and content of polar and mid-polar compounds in wine lees, this study underlines the potential of wine lees as an exploitable source to isolate interesting compounds.

  14. Refined methodology for the determination of neonicotinoid pesticides and their metabolites in honey bees and bee products by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    Science.gov (United States)

    Kamel, Alaa

    2010-05-26

    An analytical method was refined for the extraction and determination of neonicotinoid pesticide residues and their metabolites in honey bees and bee products. Samples were extracted with 2% triethylamine (TEA) in acetonitrile (ACN) followed by salting out, solid phase extraction (SPE) cleanup, and detection using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated in triplicate at three fortification concentrations in each matrix. Good recoveries were observed for most analytes and ranged between 70 and 120% with relative standard deviations between replicates of pesticides and ranged between 0.2 and 15 ng/g for the neonicotinoid metabolites. This refined method provides lower detection limits and improved recovery of neonicotinoids and their metabolites, which will help researchers evaluate subchronic effects of these pesticides, address data gaps related to colony collapse disorder (CCD), and determine the role of pesticides in pollinator decline.

  15. 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).

  16. Determination of sulfadiazine in phosphate- and DOC-rich agricultural drainage water using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry

    DEFF Research Database (Denmark)

    Bouyou, P.A. Léon; Weisser, Johan Juhl; Strobel, Bjarne W.

    2014-01-01

    Trace levels of the veterinary antibiotic compound sulfadiazine (SDZ) can be determined in agricultural drainage water samples with this new method. Optimized sample pretreatment and solid-phase extraction was combined with liquid chromatography coupled to tandem mass spectrometry (SPE LC...... obtained ranged from 104 to 109 % (relative standard deviation 2.8–5.2 %). The new methods enable determination of the veterinary antibiotic compound SDZ in agricultural drainage water from field experiments and monitoring schemes for phosphate- and dissolved organic carbon (DOC)-rich water samples......-MS/MS) using positive electrospray ionization. The linear dynamic range for the LC-MS/MS was assessed from 5 μg/L to 25 mg/L with a 15-point calibration curve displaying a coefficient of correlation r 2 = 0.9915. Agricultural drainage water spiked at a concentration of 25 ng/L gave recoveries between 63 and 98...

  17. Comparative pharmacokinetics of a proliposome formulation of Ginkgo biloba extract and Ginaton in rats by a sensitive ultra performance liquid chromatography-tandem mass spectrometry method.

    Science.gov (United States)

    Zheng, Bin; Xing, Gaoyang; Bi, Ye; Yan, Guodong; Wang, Jing; Cheng, Yingkun; Liu, Yan; Ashraf, Muhammad Aqeel; Xie, Jing

    2016-01-01

    As a novel oral drug delivery system, proliposome was applied to improve the solubility of active components of Ginkgo biloba extract (GbE). There are currently few reports focusing on the pharmacokinetic characteristics of proliposome of GbE (GbP). A rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous quantification of active components of GbP and a commercial tablet product (Ginaton) in rat plasma was developed and successfully validated. The method was applied to the comparative pharmacokinetic evaluation of GbP and Ginaton in rat plasma. The results indicated that GbP has a significant effect on absorption, elimination and bioavailability of flavonoids and terpenoid lactones in comparison with Ginaton. The obtained results would be helpful for evaluating the absorption mechanism in the gastrointestinal tract in pharmacokinetic level and guiding the development of the novel oral drug delivery system.

  18. Determination of VX-G analogue in red blood cells via gas chromatography-tandem mass spectrometry following an accidental exposure to VX.

    Science.gov (United States)

    McGuire, Jeffrey M; Taylor, James T; Byers, Christopher E; Jakubowski, Edward M; Thomson, Sandra M

    2008-01-01

    A sensitive method for determining exposure to the chemical warfare agent VX is described in which the biomarker ethyl methylphosphonofluoridate (VX-G) is measured in red blood cells (RBCs) following treatment with fluoride ion using isotope-dilution gas chromatography-tandem mass spectrometry. The analyte was isolated via solid-phase extraction and detected using ammonia chemical ionization in the multiple reaction monitoring mode. A good linear relationship was obtained in the quantitative concentration range of 4 ng/mL to 1000 ng/mL with an absolute detection limit of VX vapor. Detection and quantitation of VX-G were possible in samples taken as late as 27 days following exposure.

  19. Validated Method for the Quantification of Baclofen in Human Plasma Using Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Nahar, Limon Khatun; Cordero, Rosa Elena; Nutt, David; Lingford-Hughes, Anne; Turton, Samuel; Durant, Claire; Wilson, Sue; Paterson, Sue

    2016-03-01

    A highly sensitive and fully validated method was developed for the quantification of baclofen in human plasma. After adjusting the pH of the plasma samples using a phosphate buffer solution (pH 4), baclofen was purified using mixed mode (C8/cation exchange) solid-phase extraction (SPE) cartridges. Endogenous water-soluble compounds and lipids were removed from the cartridges before the samples were eluted and concentrated. The samples were analyzed using triple-quadrupole liquid chromatography-tandem mass spectrometry (LC-MS-MS) with triggered dynamic multiple reaction monitoring mode for simultaneous quantification and confirmation. The assay was linear from 25 to 1,000 ng/mL (r(2) > 0.999; n = 6). Intraday (n = 6) and interday (n = 15) imprecisions (% relative standard deviation) were baclofen (10 and 60 mg) on nonconsecutive days were analyzed to demonstrate method applicability.

  20. 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.

  1. Vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction for the determination of carbamates in juices by micellar electrokinetic chromatography tandem mass spectrometry.

    Science.gov (United States)

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

    2015-07-01

    A new method based on vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction has been developed for the extraction of carbamate pesticides in juice samples prior to their determination by micellar electrokinetic chromatography coupled to tandem mass spectrometry. This sample treatment allowed the satisfactory extraction and the extract clean-up of 25 carbamates from different fruit and vegetal juices (banana, tomato, and peach). In this study, the addition of ammonium perfluorooctanoate in the aqueous sample in combination with vortex agitation, provided very clean extracts with short extraction times. Under optimized conditions, recoveries of the proposed method for these pesticides from fortified juice samples ranged from 81% to 104%, with relative standard deviations lower than 15%. Limits of quantification were between 2.3µgkg(-)(1) and 4.7µgkg(-)(1), showing the high sensitivity of this fast and simple method.

  2. Determination of acrylamide in food by solid-phase microextraction coupled to gas chromatography-positive chemical ionization tandem mass spectrometry.

    Science.gov (United States)

    Lee, Maw-Rong; Chang, Li-Yo; Dou, Jianpeng

    2007-01-16

    A method has been developed to determine acrylamide in aqueous matrices by using direct immersion solid-phase microextraction (SPME) coupled to gas chromatography-positive chemical ionization tandem mass spectrometry (GC-PCI-MS-MS) in the selected reaction monitoring (SRM) mode. The optimized SPME experimental procedures to extract acrylamide in water solutions were: use of a carbowax/divinylbenzene (CW/DVB)-coated fiber at pH 7, extraction time of 20 min and analyte desorption at 210 degrees C for 3 min. A detection limit of 0.1 microg L(-1) was obtained. The linear range was 1-1000 microg L(-1). The relative standard deviation was 10.64% (n=7). The proposed analytical method was successfully used for the quantification of trace acrylamide in foodstuffs such as French fries (1.2 microg g(-1)) and potato crisps (2.2 microg g(-1)).

  3. Development and validation of a multiclass method for the quantification of veterinary drug residues in honey and royal jelly by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jin, Yue; Zhang, Jinzhen; Zhao, Wen; Zhang, Wenwen; Wang, Lin; Zhou, Jinhui; Li, Yi

    2017-04-15

    The aim of this study was to develop an analytical method for the analysis of a wide range of veterinary drugs in honey and royal jelly. A modified sample preparation procedure based on the quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed, followed by liquid chromatography tandem mass spectrometry determination. Use of the single sample preparation method for analysis of 42 veterinary drugs becomes more valuable because honey and royal jelly belong to completely different complex matrices. Another main advantage of the proposed method is its ability to identify and quantify 42 veterinary drugs with higher sensitivity than reference methods of China. This work has shown that the reported method was demonstrated to be convenient and reliable for the quick monitoring of veterinary drugs in honey and royal jelly samples.

  4. Multi-residue and multi-class method for the determination of antibiotics in bovine muscle by ultra-high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Freitas, Andreia; Barbosa, Jorge; Ramos, Fernando

    2014-09-01

    A multi-residue quantitative screening method covering 41 antibiotics from 7 different families, by ultra-high-performance-liquid-chromatography tandem mass spectrometry (UHPLC-MS/MS), is described. Sulfonamides, trimethoprim, tetracyclines, macrolides, quinolones, penicillins and chloramphenicol are simultaneously detected after a simple sample preparation of bovine muscle optimized to achieve the best recovery for all compounds. A simple sample treatment was developed consisting in an extraction with a mixture of acetonitrile and ethylenediaminetetraacetic acid (EDTA), followed by a defatting step with n-hexane. The methodology was validated, in accordance with Decision 2002/657/EC by evaluating the required parameters: decision limit (CCα), detection capability (CCβ), specificity, repeatability and reproducibility. Precision in terms of relative standard deviation was under 20% for all compounds and the recoveries between 91% and 119%. CCα and CCβ were determined according the maximum residue limit (MRL) or the minimum required performance limit (MRPL), when required.

  5. Silymarin in liposomes and ethosomes: pharmacokinetics and tissue distribution in free-moving rats by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Chang, Li-Wen; Hou, Mei-Ling; Tsai, Tung-Hu

    2014-12-03

    The aim of this study was to prepare silymarin formulations (silymarin entrapped in liposomes and ethosomes, formulations referred to as LSM and ESM, respectively) to improve oral bioavailability of silymarin and evaluate its tissue distribution by liquid chromatography with tandem mass spectrometry (LC-MS/MS) in free-moving rats. Silibinin is the major active constituent of silymarin, which is the main component to be analyzed. A rapid, sensitive, and repeatable LC-MS/MS method was developed and validated in terms of precision, accuracy, and extraction recovery. Furthermore, the established method was applied to study the pharmacokinetics and tissue distribution of silymarin in rats. The size, ζ potential, and drug release of the formulations were characterized. These results showed that the LSM and ESM encapsulated formulations of silymarin may provide more efficient tissue distribution and increased oral bioavailability, thus improving its therapeutic bioactive properties in the body.

  6. Simultaneous Determination of Melamine, Ammelide, Ammeline, and Cyanuric Acid in Milk and Milk Products by Gas Chromatography-tandem Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    HONG MIAO; SAI FAN; YONG-NING WU; LEI ZHANG; PING-PING ZHOU; JING-GUANG LI; HUI-JING CHEN; YUN-FENG ZHAO

    2009-01-01

    Objective To develop an analytical method for simultaneously qualitative and quantitative determination of melamine and triazine-related by-products including ammelide, ammeline, and cyanuric acid in milk and milk products by gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods Melamine and triazine-related by-products namely ammelide, ammeline and cyanuric acid in the samples were extracted in a solvent mixture of diethylamine, water, and acetonitrile (10:40:50, V/V/V). After centrifugation, an aliquot of the supernatant was evaporated to dryness under a gentle stream of nitrogen gas, and then melamine and triazine-related by-products were derivatized using BSTFA with 1% TMCS. The derivatives of melamine and its analogues were determined by gas chromatography/ tandem mass spectrometry using multiple reactional monitoring (MRM) with 2, 6-Diamino-4-chloropyrimidine (DACP) being used as an internal standard. Results The linear detectable ranges were from 0.004 mg/kg to 1.6 mg/kg for melamine, ammelide, ammeline, and cyanuric acid with a correlation coefficient no less than 0.999. The recovery rates of the four compounds in spiked blank milk powder at concentrations 0.5, 1, 2 mg/kg were between 61.4%-117.2%, and the relative standard deviation was no more than 11.5% (n=6). The detection limits of melamine, ammelide, ammeline and cyanuric acid in milk powder were 0.002 mg/kg with a ratio of signal to noise of 3. Conclusion This GC-MS/MS method for simultaneous determination of melamine, ammelide, ammeline, and cyanuric acid in milk and milk products is sensitive and specific.

  7. [Determination of eight bisphenol diglycidyl ethers in water by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Haijing; Lin, Shaobin

    2014-07-01

    A solid phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS) method was developed for the determination of eight bisphenol diglycidyl ethers, including bisphenol A diglycidyl ether (BADGE), bisphenol A (3-chloro-2-hydroxypropyl) glycidyl ether (BADGE x HCl), bisphenol A bis (3-chloro-2-hydroxypropyl) ether (BADGE x 2HCl), bisphenol A (2, 3-dihydroxypropyl) glycidyl ether (BADGE x H2O), bisphenol A bis(2,3-dihydroxypropyl) ether (BADGE x 2H2O), bisphenol A (3-chloro-2-hydroxypropyl) (2,3-dihydroxypropyl) ether (BADGE x HCl x H2O), bisphenol F diglycidyl ether (BFDGE) and bisphenol F bis (3-chloro-2-hydroxypropyl) ether (BFDGE 2HCl) in water. A total of ten samples were collected from the leaching of the coatings for drinking water supply system. Then, 200 mL exposure water was preconcentrated on C18 solid-phase extraction cartridge. The eight compounds were analyzed by liquid chromatography-tandem mass spectrometry method on a C18 column by the gradient elution with methanol, water and 5 mmol/L ammonium acetate as mobile phases in the multiple reaction monitoring (MRM) scan mode. The external matrix standard solutions were used for the quantitative determination and the calibration curves of the eight compounds showed good linearity in the range of 0.007-5.00 microg/L with the correlation coefficients more than 0.999 0. The limits of quantification (LOQs) of the method were 7-91 ng/L. The spiked recoveries ranged from 79.1% to 101% with the relative standard deviations of 4.0% - 12%. The method is sensitive and accurate, and is applicable to the determination of bisphenol diglycidyl ethers in water.

  8. Rapid determination of six carcinogenic primary aromatic amines in mainstream cigarette smoke by two-dimensional online solid phase extraction combined with liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Bie, Zhenying; Lu, Wei; Zhu, You; Chen, Yusong; Ren, Hubo; Ji, Lishun

    2017-01-27

    A fully automated, rapid, and reliable method for simultaneous determination of six carcinogenic primary aromatic amines (AAs), including o-toluidine (o-TOL), 2, 6-dimethylaniline (2, 6-DMA), o-anisidine (o-ASD), 1-naphthylamine (1-ANP), 2-naphthylamine (2-ANP), and 4-aminobiphenyl (4-ABP), in mainstream cigarette smoke was established. The proposed method was based on two-dimensional online solid phase extraction combined with liquid chromatography tandem mass spectrometry (SPE/LC-MS/MS). The particulate phase of the mainstream cigarette smoke was collected on a Cambridge filter pad and pretreated via ultrasonic extraction with 2% formic acid (FA), while the gas phase was trapped by 2% FA without pretreatment for determination. The two-dimensional online SPE comprised of two cartridges with different absorption characteristics was applied for sample pretreatment. Analysis was performed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) under multiple reaction monitoring mode. Each sample required about 0.5h for solid phase extraction and analysis. The limit of detections (LODs) for six AAs ranged from 0.04 to 0.58ng/cig and recoveries were within 84.5%-122.9%. The relative standard deviations of intra- and inter-day tests for 3R4F reference cigarette were less than 6% and 7%, respectively, while no more than 7% and 8% separately for a type of Virginia cigarette. The proposed method enabled minimum sample pretreatment, full automation, and high throughput with high selectivity, sensitivity, and accuracy. As a part of the validation procedure, fifteen brands of cigarettes were tested by the designed method.

  9. Multi-residue method for the determination of pesticides and pesticide metabolites in honeybees by liquid and gas chromatography coupled with tandem mass spectrometry--Honeybee poisoning incidents.

    Science.gov (United States)

    Kiljanek, Tomasz; Niewiadowska, Alicja; Semeniuk, Stanisław; Gaweł, Marta; Borzęcka, Milena; Posyniak, Andrzej

    2016-02-26

    A method for the determination of 200 pesticides and pesticide metabolites in honeybee samples has been developed and validated. Almost 98% of compounds included in this method are approved to use within European Union, as active substances of plant protection products or veterinary medicinal products used by beekeepers to control mites Varroa destructor in hives. Many significant metabolites, like metabolites of imidacloprid, thiacloprid, fipronil, methiocarb and amitraz, are also possible to detect. The sample preparation was based on the buffered QuEChERS method. Samples of bees were extracted with acetonitrile containing 1% acetic acid and then subjected to clean-up by dispersive solid phase extraction (dSPE) using a new Z-Sep+ sorbent and PSA. The majority of pesticides, including neonicotionoids and their metabolites, were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) but some of pesticides, especially pyrethroid insecticides, were analyzed by gas chromatography tandem mass spectrometry (GC-MS/MS). The procedure was validated according to the Guidance document SANCO/12571/2013 at four concentration levels: 1, 5, 10 and 100 ng/g bees and verified in the international proficiency test. The analysis of bee samples spiked at the limit of quantification (LOQ) showed about 98% mean recovery value (trueness) and 97% of analytes showed recovery in the required range of 70-120% and RSDr (precision) below 20%. Linearity and matrix effects were also established. The LOQs of pesticides were in the range of 1-100 ng/g. The developed method allows determination of insecticides at concentrations of 10 ng/g or less, except abamectin and tebufenozide. LOQ values are lower than the median lethal doses LD50 for bees. The method was used to investigate more than 70 honeybee poisoning incidents. Data about detected pesticides and their metabolites are included.

  10. Development of a Supercritical Fluid Chromatography-Tandem Mass Spectrometry Method for the Determination of Azacitidine in Rat Plasma and Its Application to a Bioavailability Study

    Directory of Open Access Journals (Sweden)

    Dongpo Li

    2013-12-01

    Full Text Available Azacitidine is widely used for the treatment of myelodysplastic syndromes (MDS and acute myelogenous leukaemia (AML. The analysis of azacitidine in biological samples is subject to interference by endogenous compounds. Previously reported high-performance liquid chromatography/tandem mass spectrometric (HPLC-MS/MS bioanalytical assays for azacitidine suffer from expensive sample preparation procedures or from long separation times to achieve the required selectivity. Herein, supercritical fluid chromatography with tandem mass spectrometry (SFC-MS/MS was explored as a more promising technique for the selective analysis of structure-like or chiral drugs in biological matrices. In this study, a simple, rapid and specific SFC/MS/MS analytical method was developed for the determination of azacitidine levels in rat plasma. Azacitidine was completely separated from the endogenous compounds on an ACQUITY UPLC™ BEH C18 column (100 mm × 3.0 mm, 1.7 μm; Waters Corp., Milford, MA, USA using isocratic elution with CO2/methanol as the mobile phase. The single-run analysis time was as short as 3.5 min. The sample preparation for protein removal was accomplished using a simple methanol precipitation method. The lower limit of quantification (LLOQ of azacitidine was 20 ng/mL. The intra-day and inter-day precisions were less than 15%, and the relative error (RE was within ±15% for the medium- and high-concentration quality control (QC samples and within ±20% for the low-concentration QC samples. Finally, the developed method was successfully applied to a pharmacokinetic study in rats following the intravenous administration of azacitidine.

  11. Degradation Behavior of Moroxydine Hydrochloride in Rice Plant and Field Water Using High Performance Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    ZHAO Lin

    2014-10-01

    Full Text Available Through field experiments, which were conducted in Zhaodong County of Heilongjiang Province, Zhulou County of Henan Province and Jurong County of Jiangsu Province, the degradation dynamics of moroxydine hydrochloride in rice plant and field water were investigated.The detection was performed by tandem mass spectrometry with electrospray ionization in positive mode(ESI+. The results showed that the average recoveries of rice plant and field water at three spiked levels (0.005, 0.05, 0.5 mg·kg -1were found in the range of 92.50%-109.20% with RSD 6.10%-6.90% and 86.40%-107.2% with RSD 0.73%-3.10%, respectively. Limits of detection(LODof plant and water were 0.005 mg·kg -1. The degradation kinetic equation showed that the half-life of moroxydine hydrochloride in rice plant and field water was 1.2-4.7 d,1.0-3.5 d, respectively. The moroxydine hydrochloride was proved to be an easily degradable pesticide.

  12. Simultaneous determination of fluoroquinolones in environmental water by liquid chromatography-tandem mass spectrometry with direct injection: A green approach.

    Science.gov (United States)

    Denadai, Marina; Cass, Quezia Bezerra

    2015-10-30

    This work describes an on-line multi-residue method for simultaneous quantification of ciprofloxacin, enrofloxacin, gemifloxacin, moxifloxacin, norfloxacin and ofloxacin in superficial and wastewater samples. For that, an octyl restricted-access media bovine serum albumin column (RAM-BSA C8) was used for sample clean-up, enrichment and analysis with quantitation carried out by tandem mass spectrometry. For water samples volumes of only 500μL the method provided good selectivity, extraction efficiency, accuracy, and precision with quantification limits in the order of 20-150ngL(-1). Out of the six fluoroquinolones only ciprofloxacin (195ngL(-1)) and norfloxacin (270ngL(-1)) were quantified in an influent sample of the wastewater treatment plant (WWTP) of São Carlos (SP, Brazil). None were found in the superficial water samples analyzed. The capability of injecting native sample in an automated mode provides high productivity and represents a greener approach in environmental sample analysis.

  13. Determination of Aromatic Amines Released from Azo Dyes in Paper Packaging by Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Yang, Fei; Bian, Zhaoyang; Li, Zhonghao; Fan, Ziyan; Wang, Ying; Liu, ShanShan; Deng, Huimin; Tang, Gangling

    2016-09-01

    An LC-tandem MS (LC-MS/MS) method for the determination of 21 kinds of carcinogenic aromatic amines released from azo dyes in food wrappers was used in this research. Sodium dithionite was added to a citric acid buffer medium to reduce and decompose possible azo dyes. The extract was analyzed after liquid-liquid extraction (LLE) and dispersive SPE (d-SPE). The conditions for chromatographic separation, mass spectrum, LLE, and d-SPE were optimized. Under optimal conditions, the LOD was in the range of 0.13-0.35 mg/kg and LOQ in the range of 0.38-1.05 mg/kg, with the addition of standard recoveries of most aromatic amines being ≥80% and RSDs ≤10%. The recoveries for 2,4-diaminotoluene and 2,4-diaminoanisole were significantly lower, being ≤40%. The method was successfully used to analyze 30 practical samples, and the results showed that it is user-friendly, with high sensitivity, rapid control, and low matrix interference.

  14. Rapid assay of rufinamide in dried blood spots by a new liquid chromatography-tandem mass spectrometric method.

    Science.gov (United States)

    la Marca, Giancarlo; Malvagia, Sabrina; Filippi, Luca; Innocenti, Marzia; Rosati, Anna; Falchi, Melania; Pellacani, Simona; Moneti, Gloriano; Guerrini, Renzo

    2011-01-05

    Rufinamide (RUF) is a new antiepileptic drug with efficacy in several types of seizures. The aim of this study was to evaluate the use of dried blood spot (DBS) specimens to determinate RUF levels during treatment. Therapeutic drug monitoring of RUF could be useful in routine clinical practice. Advantages of DBS include short collection time, low invasiveness, ease and low cost of sample collection, transport and storage. The analysis was performed in selected reaction monitoring (SRM) mode. The calibration curve in matrix was linear in the concentration range of 0.008-0.8 mg/L (0.48-47.60 mg/L in DBS) of rufinamide with correlation coefficient value of 0.996. In the concentration range of 0.48-47.6 mg/L, the coefficients of variation in DBS were in the range 1.58-4.67% and the accuracy ranged from 89.73% to 107.32%. The sensitivity and specificity of tandem mass spectrometry allow now high throughput rufinamide analysis. This new assay has favourable characteristics being highly precise and accurate. The published HPLC-UV methods also proved to be precise and accurate, but required not less than 0.2-0.5 mL of plasma and are therefore unsuitable for sample collection in neonates in whom obtaining larger blood samples is not convenient or possible.

  15. Determination of cocaine and benzoylecgonine in nails by liquid chromatography-electrospray ionization-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Marzena Sykutera

    2015-02-01

    Full Text Available Nails and hair are a biological matrix which can be analyzed to confirm the use of a xenobiotic even several months after intake. Results of nail analysis can be used, for example, as evidence in civil and criminal law cases in which a history of drug use can influence the court’s decision. The paper presents results of analysis of a nail sample taken from a man who was suspected of trafficking cocaine. The suspect pleaded guilty to the possession of the drug for his own use because, as he claimed, he was addicted to cocaine. A nail sample was taken. Detection and quantification were carried out using liquid chromatography-mass spectrometry (LC-ESI-MS. The concentration of cocaine in nails was found to be 47 ng/mg, and benzoylecgonine – 14 ng/mg.

  16. Quantification of levoglucosan and its isomers by High Performance Liquid Chromatography - Electrospray Ionization tandem Mass Spectrometry and its applications to atmospheric and soil samples

    Science.gov (United States)

    Piot, C.; Jaffrezo, J.-L.; Cozic, J.; Pissot, N.; El Haddad, I.; Marchand, N.; Besombes, J.-L.

    2012-01-01

    The determination of atmospheric concentrations of levoglucosan and its two isomers, unambiguous tracers of biomass burning emissions, became even more important with the development of wood as renewable energy for domestic heating. Many researches demonstrated the increase during recent years of atmospheric particulate matter load due to domestic biomass combustion in developed countries. Analysis of biomass burning tracers is traditionally performed with Gas Chromatography-Mass Spectrometry (GC-MS) technique after derivatization and requires an organic solvent extraction. A simpler and faster technique using Liquid Chromatography - Electrospray Ionisation - tandem Mass Spectrometry (LC-ESI-MS/MS) was optimized for the analysis of levoglucosan, mannosan and galactosan isomers after an aqueous extraction. This technique allows a good separation between the three compounds in a very reduced time (runtime ~5 min). LOD and LOQ of this method are 30 μg l-1 and 100 μg l-1 respectively, allowing the use of filters from low-volume sampler (as commonly used in routine campaigns). A comparison of simultaneous levoglucosan measurements by GC-MS and LC-ESI-MS/MS for about 50 samples coming from different types of sampling sites and seasons was realized and shows very good agreement between the two methods. Therefore LC-ESI-MS/MS method can be used as an alternative to GC-MS particularly for measurement campaigns in routine where analysis time is important and detection limit is reduced. This paper shows that this method is also applicable to other environmental sample types like soil.

  17. Liquid chromatography/high resolution tandem mass spectrometry - Tool for the study of polyphenol profile changes during micro-scale biogas digestion of grape marcs.

    Science.gov (United States)

    Kučera, Lukáš; Kurka, Ondřej; Barták, Petr; Bednář, Petr

    2017-01-01

    A microscale discontinuous fermenter was used for anaerobic digestion of wine waste - a hardly gasifiable feedstock material. Efficiency of biogas production, i.e. changes in content of nitrogen, oxygen, carbon dioxide and methane in gas phase, was monitored by gas chromatography/mass spectrometry. Liquid chromatography/high resolution tandem mass spectrometry in combination with principal component analysis and orthogonal projection to latent structures was used to reveal main chemical differences of gasified wine waste mixture from commonly used ones in agricultural biogas plants. Compounds with particular polyphenolic structures appeared among the most distinctive markers. Analysis of samples collected during acidogenic phase and unstabilized methanogenesis indicates formation of certain dihydro-flavonoids in early stages of the process and their consequent degradation. Due to formerly described higher toxicity of some dihydroflavonoids (e.g. taxifolin) compared to their more common counterparts (e.g. quercetin, malvidin etc.), unstabilized digestate would represent a potential environmental risk when used as a fertilizer deserving a proper control.

  18. Liquid chromatography tandem mass spectrometry determination of chemical markers and principal component analysis of Vitex agnus-castus L. fruits (Verbenaceae) and derived food supplements.

    Science.gov (United States)

    Mari, Angela; Montoro, Paola; Pizza, Cosimo; Piacente, Sonia

    2012-11-01

    A validated analytical method for the quantitative determination of seven chemical markers occurring in a hydroalcoholic extract of Vitex agnus-castus fruits by liquid chromatography electrospray triple quadrupole tandem mass spectrometry (LC/ESI/(QqQ)MSMS) is reported. To carry out a comparative study, five commercial food supplements corresponding to hydroalcoholic extracts of V. agnus-castus fruits were analysed under the same chromatographic conditions of the crude extract. Principal component analysis (PCA), based only on the variation of the amount of the seven chemical markers, was applied in order to find similarities between the hydroalcoholic extract and the food supplements. A second PCA analysis was carried out considering the whole spectroscopic data deriving from liquid chromatography electrospray linear ion trap mass spectrometry (LC/ESI/(LIT)MS) analysis. High similarity between the two PCA was observed, showing the possibility to select one of these two approaches for future applications in the field of comparative analysis of food supplements and quality control procedures.

  19. Suitability of selective pressurized liquid extraction combined with gas chromatography-ion-trap tandem mass spectrometry for the analysis of polybrominated diphenyl ethers.

    Science.gov (United States)

    Losada, S; Parera, J; Abalos, M; Abad, E; Santos, F J; Galceran, M T

    2010-09-23

    A one-step extraction and clean-up method using pressurized liquid extraction (PLE) (selective PLE) combined with gas chromatography-ion-trap tandem mass spectrometry (GC-ITMS-MS) was evaluated for the analysis of polybrominated diphenyl ethers (from tri- to hepta-PBDEs) at low concentrations in fish and shellfish samples. To this end, the performance of an on-line PLE extraction/clean-up method and of a classical Soxhlet extraction and clean-up method using a multi-layer modified silica column were compared. The two sample treatment methods provided similar results, although an important reduction in the sample treatment time (40 min per sample) was achieved using the selective PLE method. In addition, the suitability of the PLE combined with GC-ITMS-MS method was evaluated by comparing the results obtained in the analysis of fish samples with those obtained by gas chromatography-high resolution mass spectrometry (GC-HRMS). Good agreement between both techniques was obtained with differences between the mean values of less than 16%. The selective PLE method coupled to GC-ITMS-MS produced accurate results for PBDE determination with low limits of detection (1.0-16.8 pg g(-1) wet weight) and quantification (3.1-51 pg g(-1) wet weight) as well as good precision (RSD<16%). This method has been applied to the analysis of PBDEs in fish and shellfish samples collected at fish markets in Catalonia (NE Spain).

  20. Confirmatory analysis method for zeranol, its metabolites and related mycotoxins in urine by liquid chromatography-negative ion electrospray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bennekom, E.O. van; Brouwer, L.; Laurant, E.H.M.; Hooijerink, H.; Nielen, M.W.F

    2002-11-25

    The determination of the banned anabolic substance zeranol and the metabolites taleranol and zearalanone in bovine urine is complicated by the occurrence of the structurally-related mycotoxin zearalenone and the corresponding {alpha}- and {beta}-zearalenol metabolites which possess similar estrogenic properties. A liquid chromatography-negative ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of all six resorcylic acid lactones ('zeranols') in urine samples using deuterium-labelled internal standards. The method was validated as a confirmatory method for bovine urine samples according to new draft EU guidelines and showed good precision and linearity, and CC{alpha} and CC{beta} values of 0.02-0.30 and <1.0 ng ml{sup -1}, respectively. The applicability was demonstrated by comparing the results of an incurred sample with previous results on the same sample obtained by gas chromatography high resolution mass spectrometry. Preliminary data show that following a simple matrix solid phase dispersion clean-up, liver samples from poultry will be amenable to this method as well.

  1. Simultaneous determination of trimethylamine and trimethylamine N-oxide in mouse plasma samples by hydrophilic interaction liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Mi, Si; Zhao, Yuan-Yuan; Jacobs, René L; Curtis, Jonathan M

    2017-02-01

    A method was developed that applies hydrophilic interaction liquid chromatography with tandem mass spectrometry in the multiple reaction monitoring mode to separate and accurately quantify trimethylamine and trimethylamine N-oxide in a single chromatographic run. This was achieved by converting trimethylamine to ethyl betaine, which is less volatile and hence results in greatly improved quantitation. Ethyl betaine also gives a similar response to trimethylamine N-oxide using positive-ion electrospray ionization mass spectrometry. It is readily separated from trimethylamine N-oxide by hydrophilic liquid chromatography in a 5 min run and with improved peak shape compared to underivatized trimethylamine. Validation of the method yielded a limit of detection (S/N ≥ 3) of 0.5 ng/mL for trimethylamine and 0.25 ng/mL for trimethylamine N-oxide. Method accuracies of 91.4-105.3% with precisions of 0.4-5.5% were obtained for standard mixtures over the range of 2.5-500 ng/mL. Recoveries measured for the extraction of trimethylamine and trimethylamine N-oxide spikes into mouse plasma were both >90%. The method, which simultaneously measures trimethylamine and trimethylamine N-oxide, was successfully applied to mouse plasma samples and could be adapted for use with other biological fluids.

  2. Simultaneous determination of gamma-Hydroxybutyrate (GHB) and its analogues (GBL, 1.4-BD, GVL) in whole blood and urine by liquid chromatography coupled to tandem mass spectrometry

    DEFF Research Database (Denmark)

    Johansen, Sys Stybe; Windberg, Charlotte Norup

    2011-01-01

    A simple liquid chromatography-tandem mass spectrometry (LC-MS-MS) method has been developed and validated for simultaneous identification and quantification of ¿-hydroxybutyrate (GHB), ¿-butyrolactone (GBL), 1.4-butanediol (1.4-BD), and ¿-valerolactone (GVL) in whole blood from forensic cases...

  3. The evaluation of the applicability of a high pH mobile phase in ultrahigh performance liquid chromatography tandem mass spectrometry analysis of benzodiazepines and benzodiazepine-like hypnotics in urine and blood

    OpenAIRE

    2012-01-01

    A sensitive liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous detection of benzodiazepines, benzodiazepine-like hypnotics and some metabolites (7-aminoflunitrazepam, alprazolam, bromazepam, brotizolam, chlordiazepoxide, chlornordiazepam, clobazam, clonazepam, clotiazepam, cloxazolam, diazepam, ethylloflazepate, flunitrazepam, flurazepam, loprazolam, lorazepam, lormetazepam, midazolam, N-desmethylflunitrazepam, nitrazepam, N-methylclonazepam (in...

  4. Automated mini-column solid-phase extraction cleanup for high-throughput analysis of chemical contaminants in foods by low-pressure gas chromatographytandem mass spectrometry

    Science.gov (United States)

    This study demonstrated the application of an automated high-throughput mini-cartridge solid-phase extraction (mini-SPE) cleanup for the rapid low-pressure gas chromatographytandem mass spectrometry (LPGC-MS/MS) analysis of pesticides and environmental contaminants in QuEChERS extracts of foods. ...

  5. Characterization of Proanthocyanidins from Parkia biglobosa (Jacq. G. Don. (Fabaceae by Flow Injection Analysis — Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Wagner Vilegas

    2013-03-01

    Full Text Available The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae roots and barks by Liquid Chromatography - Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

  6. Characterization of proanthocyanidins from Parkia biglobosa (Jacq.) G. Don. (Fabaceae) by Flow Injection Analysis-Electrospray Ionization Ion Trap Tandem Mass Spectrometry and Liquid Chromatography/Electrospray Ionization Mass Spectrometry.

    Science.gov (United States)

    Tala, Viviane Raïssa Sipowo; Candida da Silva, Viviane; Rodrigues, Clenilson Martins; Nkengfack, Augustin Ephrem; dos Santos, Lourdes Campaner; Vilegas, Wagner

    2013-03-01

    The present study investigates the chemical composition of the African plant Parkia biglobosa (Fabaceae) roots and barks by Liquid Chromatography-Electrospray Ionization and Direct Injection Tandem Mass Spectrometry analysis. Mass spectral data indicated that B-type oligomers are present, namely procyanidins and prodelphinidins, with their gallate and glucuronide derivatives, some of them in different isomeric forms. The analysis evidenced the presence of up to 40 proanthocyanidins, some of which are reported for the first time. In this study, the antiradical activity of extracts of roots and barks from Parkia biglobosa was evaluated using DPPH method and they showed satisfactory activities.

  7. Identification of oxidative degradates of the thrombin inhibitor, 3-(2-phenethylamino)-6-methyl-1-(2-amino-6-methyl-5-methyleneca rboxamidomethylpyridinyl)pyrazinone, using liquid chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Wu, Y; Chen, X; Gier, L; Almarsson, O; Ostovic, D; Loper, A E

    1999-07-01

    Liquid chromatography/mass spectrometry was used to identify reaction products from a solution of 3-(2-phenethylamino)-6-methyl-1-(2-amino-6-methyl-5-methyleneca rboxamidomethylpyridinyl)pyrazinone (L-375,378) and hydrogen peroxide, a system that generates high levels of the oxidative degradates which form in the tablets and intravenous (i.v.) solutions of L-375,378. Two major hydrogen peroxide reaction products of L-375,378 (m/z 407) with m/z values of 369 and 370 were separated and identified. Both compounds were products of ring opening with elimination of three carbon atoms from the center pyrazinone ring. The structural assignments for these two products were alpha-amidinoamide and alpha-diamide compounds, respectively. In addition, five products (m/z 423) with a molecular weight 16 Da greater than that for L-375,378 were separated. Further liquid chromatography/tandem mass spectrometry experiments indicated that three of these M + 16 products were phenolic derivatives of L-375,378. Among them, the para-hydroxy compound has been verified using an authentic standard. The other two phenolic compounds were believed to be the meta- and ortho-hydroxy derivatives of L-375,378. The fourth M + 16 product was derived from hydroxylation of the methyl group on the center pyrazinone ring. The fifth M + 16 product was derived from oxidation on the aminopyridine moiety, most likely N-oxide of the pyridine ring. Other minor hydrogen peroxide reaction products were not studied in detail because they did not appear in tablets or i.v. formulations.

  8. High-resolution high-performance liquid chromatography with electrospray ionization mass spectrometry and tandem mass spectrometry characterization of a new isoform of human salivary acidic proline-rich proteins named Roma-Boston Ser22(Phos) → Phe variant

    Science.gov (United States)

    Iavarone, Federica; D’Alessandro, Alfredo; Tian, Na; Cabras, Tiziana; Messana, Irene; Helmerhorst, Eva J.; Oppenheim, Frank G.; Castagnola, Massimo

    2015-01-01

    During a survey of human saliva by a top-down reversed-phase high-performance liquid chromatography with electrospray ionization mass spectrometry approach, two proteins eluting at 27.4 and 28.4 min, with average masses of 15 494 ± 1 and 11 142 ± 1 Da, were detected in a subject from Boston. The Δmass value (4352 Da) of the two proteins was similar to the difference in mass values between intact (150 amino acids, [a.a.]) and truncated acidic proline-rich proteins (aPRPs; 106 a.a.) suggesting an a.a. substitution in the first 106 residues resulting in a strong reduction in polarity, since under the same experimental conditions aPRPs eluted at ~22.5 min (intact) and 23.5 min (truncated forms). Manual inspection of the high-resolution high-performance liquid chromatography with electrospray ionization tandem mass spectra of the truncated isoform showed the replacement of the phosphorylated Ser-22 in PRP-3 with a Phe residue. Inspection of the tandem mass spectra of the intact isoform confirmed the substitution, which is allowed by the code transition TCT→TTT and is in agreement with the dramatic increase in elution time. The isoform was also detected in two other subjects, one from Boston (unrelated to the previous) and one from Rome. For this reason we propose to name this variant PRP-1 (PRP-3) RB (Roma-Boston) Ser22(phos)→Phe. PMID:24771659

  9. Quantitative comparison of lipoprotein fractions derived from human plasma and serum by liquid chromatography-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Collins Lisamarie A

    2010-07-01

    Full Text Available Abstract Background Lipoproteins are complex, globular molecules which play essential roles in the transport and metabolism of cholesterol. Their implication in the development of cardiovascular diseases, such as atherosclerosis, has sustained a great deal of interest in these particles. Their various functions, and their contribution to the development of atherosclerosis, are often attributed to their protein constituents, which vary greatly among the different lipoprotein classes. Recent advances in the field of mass spectrometry have provided insight into the array of proteins associated with low-density lipoproteins (LDLs and, even more so, with high-density lipoproteins (HDLs. Plasma and serum are the most commonly used samples for the analysis of lipoproteins. Although these lipoprotein sources are unique, it was our goal to determine whether or not their inherent differences would ultimately affect a quantitative analysis of the LDL and HDL proteomes. To this end, we isolated LDL and HDL fractions with fast protein liquid chromatography-size exclusion chromatography (FPLC-SEC from both human plasma and serum samples from the same individuals. After delipidating these samples, we performed a quantitative proteomic analysis to compare the lipoprotein-associated proteins derived from both plasma and serum. Results Although the primary differences between the samples are found in fibrinogen proteins which are removed from serum, it of interest to note that, with respect to LDL-associated proteins, apolipoproteinB-100 was found at significantly higher levels in serum samples. Complement component 3 was found at significantly higher levels in serum-derived HDL fractions. Both of these proteins are known LDL- and HDL-associated proteins, respectively. Conclusion Overall, the results from our study indicate that both plasma and serum samples are equally suited for proteomic studies, and provide similar results. These findings are particularly

  10. A Liquid Chromatography Tandem Mass Spectrometry based method for the Simultaneous Determination of Irbesartan and Hydrochlorothiazide in Human Plasma

    Directory of Open Access Journals (Sweden)

    Peeyush Jain

    2014-09-01

    Full Text Available The aim of current study was to develop and validate a rapid, explicit and vigorous assay based on solid phase extraction and liquid chromatographyelectrospray ionization tandem mass spectrometry (LC-ESI MS-MS for the simultaneous quantitative analysis of Irbesartan and Hydrochlorothiazide in human plasma using Losartan and Hydroflumethiazide as internal standards (IS. The precursor to product ion transitions of m/z 427.3/ 193.0 and m/z 295.8/ 205.1 were used to measure the Irbesartan and Hydrochlorothiazide respectively. The method was validated over a concentration range of 99.9 to 6274.0 ng mL-1 for Irbesartan and 3.18 to 500.45 ng mL-1 for Hydrochlorothiazide. The method was validated over the parameters like selectivity, matrix effect, sensitivity, linearity, precision and accuracy various stabilities (bench top stability, standard stock solution stability, stock dilution stability, auto sampler stability, freeze thaw stability, long term stability, effect of potentially interfering drugs, dilution integrity, recovery and reinjection reproducibility. The mean % recovery of Irbesartan, Hydrochlorothiazide, Losartan and Hydroflumethiazide were 89.03 %, 83.15 %, 88.89 % and 84.89 % with a precision of 9.39 %, 2.79 %, 4.36 % and 2.12 % respectively. The RSD % of intra-day and inter-day assay was ≤15%. The application of this assay was demonstrated in a bioequivalence study after an oral administration of a tablet containing higher dose of Hydrochlorothiazide and Irbesartan in healthy volunteers.

  11. Validation of analysis of amphetamines, opiates, phencyclidine, cocaine, and benzoylecgonine in oral fluids by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kala, Subbarao V; Harris, Steve E; Freijo, Tom D; Gerlich, Stan

    2008-10-01

    The aim of the present study was to develop and validate a method for the detection and quantitation of drugs of abuse in oral fluids. Fortified oral fluid samples (made in-house) and samples from donors collected with Quantasil oral fluid collection kits from Immunalysis were screened on an Olympus 5400 using reagents purchased from Immunalysis. Amphetamines (AMPs), opiates, phencyclidine (PCP), and cocaine and its metabolite benzoylecgonine (BE) in oral fluids were quantitated by an Applied Biosystems 3200 QTRAP liquid chromatograph-tandem mass spectrometer (LC-MS-MS). AMPs, opiates, PCP, cocaine, and BE were extracted from samples using liquid-liquid or solid-phase extractions and the extracts were separated on a Shimadzu high-performance liquid chromatograph prior to the MS-MS analysis. For each drug, two multiple reaction mode transitions were monitored using positive electrospray ionization coupled to an MS-MS detector. Corresponding d3, d5, d6, and d11 internal standards were used to quantitate the results. The limit of detection/quantitation for AMPs, opiates, PCP, cocaine, and its metabolite BE were 10, 10, 2, 2, and 2 ng/mL of oral fluid, respectively, on a signal-to-noise ratio > 4. This corresponded to 25, 25, 5, 5, and 5 pg on column. The method was verified by participating in the North America Oral Fluid Proficiency Testing administered by Research Triangle Institute and by analyzing real samples from donors. In conclusion, LC-MS-MS provided a simple way to analyze and quantitate drugs of abuse in oral fluids.

  12. Development of a liquid chromatography tandem mass spectrometry method for the simultaneous measurement of voriconazole, posaconazole and itraconazole.

    Science.gov (United States)

    Wadsworth, John M; Milan, Anna M; Anson, James; Davison, Andrew S

    2017-01-01

    Background Azole-based antifungals are the first-line therapy for some of the most common mycoses and are now also being used prophylactically to protect immunocompromised patients. However, due to variability in both their metabolism and bioavailability, therapeutic drug monitoring is essential to avoid toxicity but still gain maximum efficacy. Methods Following protein precipitation of serum with acetonitrile, 20  µL of extract was injected onto a 2.1 × 50 mm Waters Atlantis dC18 3  µm column. Detection was via a Waters Quattro Premier XE tandem mass spectrometer operating in ESI-positive mode. Multiple reaction monitoring (MRM) detected two product ions for each compound and one for each isotopically labelled internal standard. Ion suppression, linearity, stability, matrix effects, recovery, imprecision, lower limits of measuring interval and detection were all assessed. Results Optimal chromatographic separation was achieved using gradient elution over 8 minutes. Voriconazole, posaconazole and itraconazole eluted at 1.71, 2.73 and 3.41 min, respectively. The lower limits of measuring interval for all three compounds was 0.1 mg/L. The assay was linear to 10 mg/L for voriconazole (R(2 )= 0.995) and 5 mg/L for posaconazole (R(2 )= 0.990) and itraconazole (R(2 )= 0.991). The assay was both highly accurate and precise with % bias of voriconazole, posaconazole and itraconazole, respectively, when compared with previous NEQAS samples. The intra-assay precision (CV%) was 1.6%, 2.5% and 1.9% for voriconazole, posaconazole and itraconazole, respectively, across the linear range. Conclusion A simple and robust method has been validated for azole antifungal therapeutic drug monitoring. This new assay will result in a greatly improved sample turnaround time and will therefore vastly increase the clinical utility of azole antifungal drug monitoring.

  13. Simultaneous quantification of protein phosphorylation sites using liquid chromatography-tandem mass spectrometry-based targeted proteomics: a linear algebra approach for isobaric phosphopeptides.

    Science.gov (United States)

    Xu, Feifei; Yang, Ting; Sheng, Yuan; Zhong, Ting; Yang, Mi; Chen, Yun

    2014-12-05

    As one of the most studied post-translational modifications (PTM), protein phosphorylation plays an essential role in almost all cellular processes. Current methods are able to predict and determine thousands of phosphorylation sites, whereas stoichiometric quantification of these sites is still challenging. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS)-based targeted proteomics is emerging as a promising technique for site-specific quantification of protein phosphorylation using proteolytic peptides as surrogates of proteins. However, several issues may limit its application, one of which relates to the phosphopeptides with different phosphorylation sites and the same mass (i.e., isobaric phosphopeptides). While employment of site-specific product ions allows for these isobaric phosphopeptides to be distinguished and quantified, site-specific product ions are often absent or weak in tandem mass spectra. In this study, linear algebra algorithms were employed as an add-on to targeted proteomics to retrieve information on individual phosphopeptides from their common spectra. To achieve this simultaneous quantification, a LC-MS/MS-based targeted proteomics assay was first developed and validated for each phosphopeptide. Given the slope and intercept of calibration curves of phosphopeptides in each transition, linear algebraic equations were developed. Using a series of mock mixtures prepared with varying concentrations of each phosphopeptide, the reliability of the approach to quantify isobaric phosphopeptides containing multiple phosphorylation sites (≥ 2) was discussed. Finally, we applied this approach to determine the phosphorylation stoichiometry of heat shock protein 27 (HSP27) at Ser78 and Ser82 in breast cancer cells and tissue samples.

  14. Liquid chromatography-tandem mass spectrometry (LC/APCI-MS/MS) methods for the quantification of captan and folpet phthalimide metabolites in human plasma and urine.

    Science.gov (United States)

    Berthet, Aurélie; Bouchard, Michèle; Schüpfer, Patrick; Vernez, David; Danuser, Brigitta; Huynh, Cong Khanh

    2011-02-01

    Captan and folpet are fungicides largely used in agriculture. They have similar chemical structures, except that folpet has an aromatic ring unlike captan. Their half-lives in blood are very short, given that they are readily broken down to tetrahydrophthalimide (THPI) and phthalimide (PI), respectively. Few authors measured these biomarkers in plasma or urine, and analysis was conducted either by gas chromatography coupled to mass spectrometry or liquid chromatography with UV detection. The objective of this study was thus to develop simple, sensitive and specific liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry (LC/APCI-MS/MS) methods to quantify both THPI and PI in human plasma and urine. Briefly, deuterated THPI was added as an internal standard and purification was performed by solid-phase extraction followed by LC/APCI-MS/MS analysis in negative ion mode for both compounds. Validation of the methods was conducted using spiked blank plasma and urine samples at concentrations ranging from 1 to 250 μg/L and 1 to 50 μg/L, respectively, along with samples of volunteers and workers exposed to captan or folpet. The methods showed a good linearity (R (2) > 0.99), recovery (on average 90% for THPI and 75% for PI), intra- and inter-day precision (RSD, <15%) and accuracy (<20%), and stability. The limit of detection was 0.58 μg/L in urine and 1.47 μg/L in plasma for THPI and 1.14 and 2.17 μg/L, respectively, for PI. The described methods proved to be accurate and suitable to determine the toxicokinetics of both metabolites in human plasma and urine.

  15. Simultaneous determination of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Yuanyuan; Li, Xiaowei; Zhang, Zhiwen; Ding, Shuangyang; Jiang, Haiyang; Li, Jiancheng; Shen, Jianzhong; Xia, Xi

    2016-02-01

    A sensitive, confirmatory ultra-high performance liquid chromatography-tandem mass spectrometric method was developed and validated to detect 23 veterinary drugs and metabolites (nitroimidazoles, benzimidazoles, and chloramphenicol components) in bovine milk. Compounds of interest were sequentially extracted from milk with acetonitrile and basified acetonitrile using sodium chloride to induce liquid-liquid partition. The extract was purified on a mixed mode solid-phase extraction cartridge. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged analytes in a 9 min chromatography run time. Recoveries based on matrix-matched calibrations and isotope labeled internal standards for milk ranged from 51.7% to 101.8%. The detection limits and quantitation limits of the analytical method were found to be within the range of 2-20 ng/kg and 5-50 ng/kg, respectively. The recommended method is simple, specific, and reliable for the routine monitoring of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk samples.

  16. Determination of torasemide in human plasma and its bioequivalence study by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2016-04-01

    Full Text Available A sensitive and selective method using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC–ESI–MS to determine the concentration of torasemide in human plasma samples was developed and validated. Tolbutamide was chosen as the internal standard (IS. The chromatography was performed on a Gl Sciences Inertsil ODS-3 column (100 mm×2.1 mm i.d., 5.0 µm within 5 min, using methanol with 10 mM ammonium formate (60:40, v/v as mobile phase at a flow rate of 0.2 mL/min. The targeted compound was detected in negative ionization at m/z 347.00 for torasemide and 269.00 for IS. The linearity range of this method was found to be within the concentration range of 1–2500 ng/mL (r=0.9984 for torasemide in human plasma. The accuracy of this measurement was between 94.05% and 103.86%. The extracted recovery efficiency was from 84.20% to 86.47% at three concentration levels. This method was also successfully applied in pharmacokinetics and bioequivalence studies in Chinese volunteers.

  17. Determination of the neurotoxin BMAA (beta-N-methylamino-L-alanine) in cycad seed and cyanobacteria by LC-MS/MS (liquid chromatography tandem mass spectrometry).

    Science.gov (United States)

    Rosén, Johan; Hellenäs, Karl-Erik

    2008-12-01

    A highly specific method for the analysis of beta-N-methylamino-L-alanine (BMAA) by LC-MS/MS (liquid chromatography tandem mass spectrometry) has been developed and applied for cycad seeds and cyanobacteria. BMAA was analysed as a free fraction or as total BMAA after acidic hydrolysis to release any protein-bound BMAA. Deuterium labelled BMAA was synthesised and used as internal standard. The method comprises HILIC (hydrophilic interaction chromatography) and positive electrospray ionisation of the native compound, i.e. no derivatisation was used. For safe identification five specific product ions (m/z 102, 88, 76, 73 and 44), all derived from a precursor ion of m/z 119 and originating from different parts of the molecule, were detected (typical relative abundance 100%, 16%, 14%, 12% and 22% respectively). Cyanobacteria or muscle tissue was spiked with BMAA (10 to 1000 microg g(-1)) to validate the method (accuracy 95% to 109%, relative standard deviation 1% to 6%). The detection limit for free and total BMAA in tissue was cycad seeds, whereas previously reported findings of BMAA in samples of cyanobacteria could not be confirmed. Instead, the presence of alpha-,gamma-diamino butyric acid (DAB), an isomer of BMAA, was confirmed in one sample. The possible implications of this finding are discussed.

  18. Simultaneous determination of 13 phytohormones in oilseed rape tissues by liquid chromatography-electrospray tandem mass spectrometry and the evaluation of the matrix effect.

    Science.gov (United States)

    Fan, Sufang; Wang, Xiupin; Li, Peiwu; Zhang, Qi; Zhang, Wen

    2011-03-01

    In the experiment, a high-performance liquid chromatography and electrospray ionization-tandem mass spectrometry with selected reaction monitoring was used to simultaneously determine various classes of phytohormones, including indole-3-acetic acid, α-naphthaleneacetic acid, 2-chlorobenzoic acid, 4-chlorobenzoic acid, indole-3-butyric acid, gibberellic acid, 2,4-dichlorophenoxyacetic acid, 2-naphthoxyacetic acid, abscisic acid, 2,3,5-triiodobenzoic acid, uniconazole, paclobutrazol and 2,4-epibassinolide in rape tissues. The analyses were separated by an HPLC equipped with a reversed-phase column using a binary solvent system composed of methanol and water, both containing 0.1% of formic acid. The matrix effect was also considered and determined. The technology was applied to analyze rape tissues, including roots, stems, leaves, flowers, immature pods and rape seeds. The rape tissues were subjected to ultrasound-assisted extraction and purified by dispersive solid-phase extraction, and then transferred into the liquid chromatography system. The detection limit for each plant hormone was defined by the ratio of signal/background noise (S/N) of 3. The results showed perfect linearity (R(2) values of 0.9987-1.0000) and reproducibility of elution times (relative standard deviations, RSDs,<1%) and peak areas (RSDs,<7%) for all target compounds.

  19. Determination of torasemide in human plasma and its bioequivalence study by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry$

    Institute of Scientific and Technical Information of China (English)

    Lin Zhang; Rulin Wang; Yuan Tian; Zunjian Zhang

    2016-01-01

    A sensitive and selective method using high-performance liquid chromatography coupled with elec-trospray ionization tandem mass spectrometry (HPLC–ESI–MS) to determine the concentration of tor-asemide in human plasma samples was developed and validated. Tolbutamide was chosen as the internal standard (IS). The chromatography was performed on a Gl Sciences Inertsil ODS-3 column (100 mm ? 2.1 mm i.d., 5.0 mm) within 5 min, using methanol with 10 mM ammonium formate (60:40, v/v) as mobile phase at a flow rate of 0.2 mL/min. The targeted compound was detected in negative io-nization at m/z 347.00 for torasemide and 269.00 for IS. The linearity range of this method was found to be within the concentration range of 1–2500 ng/mL (r¼0.9984) for torasemide in human plasma. The accuracy of this measurement was between 94.05%and 103.86%. The extracted recovery efficiency was from 84.20% to 86.47% at three concentration levels. This method was also successfully applied in pharmacokinetics and bioequivalence studies in Chinese volunteers.

  20. Liquid Chromatography with Electrospray Ionization and Tandem Mass Spectrometry Applied in the Quantitative Analysis of Chitin-Derived Glucosamine for a Rapid Estimation of Fungal Biomass in Soil

    Directory of Open Access Journals (Sweden)

    Madelen A. Olofsson

    2016-01-01

    Full Text Available This method employs liquid chromatography-tandem mass spectrometry to rapidly quantify chitin-derived glucosamine for estimating fungal biomass. Analyte retention was achieved using hydrophilic interaction liquid chromatography, with a zwitter-ionic stationary phase (ZIC-HILIC, and isocratic elution using 60% 5 mM ammonium formate buffer (pH 3.0 and 40% ACN. Inclusion of muramic acid and its chromatographic separation from glucosamine enabled calculation of the bacterial contribution to the latter. Galactosamine, an isobaric isomer to glucosamine, found in significant amounts in soil samples, was also investigated. The two isomers form the same precursor and product ions and could not be chromatographically separated using this rapid method. Instead, glucosamine and galactosamine were distinguished mathematically, using the linear relationships describing the differences in product ion intensities for the two analytes. The m/z transitions of 180 → 72 and 180 → 84 were applied for the detection of glucosamine and galactosamine and that of 252 → 126 for muramic acid. Limits of detection were in the nanomolar range for all included analytes. The total analysis time was 6 min, providing a high sample throughput method.

  1. Determination of therapeutic γ-aminobutyric acid analogs in forensic whole blood by hydrophilic interaction liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Sørensen, Lambert K; Hasselstrøm, Jørgen B

    2014-05-01

    Vigabatrin, pregabalin, gabapentin and baclofen are γ-aminobutyric acid analogs that are used in the treatment of epileptic seizures (vigabatrin, pregabalin and gabapentin) and spasticity (baclofen). The intake of these drugs may induce adverse reactions and impair the ability of an individual to drive a vehicle. There have also been reports of cases of intoxication and fatalities from overdoses. For rapid and accurate quantification of these drugs in forensic cases, an ultraperformance liquid chromatography tandem mass spectrometry method using pneumatically assisted electrospray ionization has been developed. The technique has been validated on both ante- and postmortem human whole blood. The protein in the blood samples was removed by the addition of a mixture of methanol and acetonitrile, and the extract was ultrafiltered and diluted with acetonitrile. The separation was performed by hydrophilic interaction liquid chromatography. Calibration of the system was achieved through use of matrix-matched calibrants combined with isotope dilution. The lower limits of quantification were 0.02-0.04 mg/L, and the relative intra-laboratory reproducibility standard deviations were 89%. The trueness expressed as the relative bias of the test results was within ±7% at concentrations of 1-40 mg/L for vigabatrin, pregabalin and gabapentin and of 0.1-4 mg/L for baclofen.

  2. Environmentally friendly method for the determination of acrylamide and trimethylolpropane in paper packaging materials by liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Yang, Fei; Li, Zhonghao; Bian, Zhaoyang; Tang, Gangling; Fan, Ziyan; Wang, Ying; Liu, ShanShan; Zhang, Hongfei

    2014-12-01

    A simple, rapid, and environmentally friendly method was developed for the determination of acrylamide and trimethylolpropane in paper packaging materials. No organic solvent was used and the matrix effect was investigated. The extract was directly analyzed by liquid chromatography with tandem mass chromatography for quantification and confirmation. The chromatographic separations were performed on a ZORBAX HILIC Plus (2.1 mm × 150 mm, 3μm; Agilent, USA) column with only one mobile phase (100% water). Calibration curves for acrylamide and trimethylopropane were achieved with concentrations ranging from 0.4 to 20 mg/kg and the corresponding r(2) values were 0.998 and 0.999, respectively. The recoveries were >85% with relative standard deviations paper packages. The concentrations of acrylamide and trimethylolpropane ranged from 0.41 to 7.5 and 0.50 to 8.8 mg/kg, respectively. The results of this study revealed that this method could be used accurately and precisely.

  3. Robust method for the analysis of phytochelatins in rice by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry based on polymeric column materials.

    Science.gov (United States)

    Yu, Shasha; Bian, Yingfang; Zhou, Rong; Mou, Renxiang; Chen, Mingxue; Cao, Zhaoyun

    2015-12-01

    A sensitive and robust high-performance liquid chromatography coupled with electrospray tandem mass spectrometry method for the identification and quantification of glutathione and phytochelatins from rice was developed. Homogenized samples were extracted with water containing 100 mM dithiothreitol, and solid-phase extraction using polymer anion exchange resin was employed for sample purification. Chromatography was performed on a polymeric column with acetonitrile and water containing 0.1% formic acid as the mobile phase at the flow rate of 300 μL/min. The limit of quantitation was 6-100 nM. This assay showed excellent linearity for both glutathione and phytochelatins over physiological normal ranges, with correlation coefficients (r) > 0.9976. Recoveries for four biothiols were within the range of 76-118%, within relative standard deviations less than 15%. The intraday precision (n = 7) was 2.1-13.3%, and the interday precision over 15 days was 4.3-15.2%. The optimized method was applied to analyze tissue samples from rice grown using nutrient solutions with three different cadmium concentrations (0, 50, and 100 μM). With increasing cadmium concentrations, the content of phytochelatin 2 and phytochelatin 3 in rice roots increased, in contrast to most phytochelatins, and the content of glutathione in rice stems and roots decreased significantly.

  4. Liquid chromatography--tandem mass spectrometry method for simultaneous determination of albendazole and albendazole sulfoxide in human plasma for bioequivalence studies

    Directory of Open Access Journals (Sweden)

    Dhiraj M. Rathod

    2016-08-01

    Full Text Available An improved high performance liquid chromatography--tandem mass spectrometry (LC–MS/MS method has been developed for sensitive and rapid determination of albendazole (ABZ and its active metabolite, albendazole sulfoxide (ABZSO, in the positive ionization mode. The method utilized solid phase extraction (SPE for sample preparation of the analytes and their deuterated internal standards (ISs from 100 µL human plasma. The chromatography was carried out on Hypurity C18 column using acetonitrile-2.0 mM ammonium acetate, pH 5.0 (80:20, v/v as the mobile phase. The assay exhibited a linear response over the concentration range of 0.200–50.0 ng/mL for ABZ and 3.00–600 ng/mL for ABZSO. The recoveries of the analytes and ISs ranged from 86.03%–89.66% and 89.85%–98.94%, respectively. Matrix effect, expressed as IS-normalized matrix factors, ranged from 0.985 to 1.042 for the both analytes. The method was successfully applied for two separate studies in healthy subjects using single dose of 400 mg conventional tablets and 400 mg chewable ABZ tablets, respectively.

  5. Confirmatory method for the determination of resorcylic acid lactones in urine sample using immunoaffinity cleanup and liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Dusi, Guglielmo [Istituto Zooprofilattico Sperimentale della Lombardia e dell' Emilia Romagna, ' B. Ubertini' , Via Bianchi 7, 25124 Brescia (Italy)], E-mail: guglielmo.dusi@bs.izs.it; Bozzoni, Eros; Assini, Walter; Tognoli, Nadia; Gasparini, Mara; Ferretti, Enrica [Istituto Zooprofilattico Sperimentale della Lombardia e dell' Emilia Romagna, ' B. Ubertini' , Via Bianchi 7, 25124 Brescia (Italy)

    2009-04-01

    The presence of zeranol ({alpha}-zearalanol) in urine samples due to natural contamination or illegal treatment is under debate within the European Union. The simultaneous determination of zeranol, its epimer taleranol ({beta}-zearalanol), zearalanone and the structurally related mycotoxin zearalenone with the corresponding {alpha}- and {beta}-zearalenol metabolites appears to be critical in deciding whether an illegal use has occurred. The aim of this study is to develop and validate a simple analytical procedure applicable to bovine and swine urine samples for the determination of all six resorcylic acid lactones. After an enzymatic deconjugation, the urine was subjected to a one-step cleanup on a commercially available immunoaffinity chromatography cartridge. The analytes were detected by liquid chromatography-negative-ion electrospray tandem mass spectrometry using deuterium-labelled internal standards. The method was validated as a quantitative confirmatory method according to European Commission Decision 2002/657/EC. The evaluated parameters were: linearity, specificity, precision (repeatability and intra-laboratory reproducibility), recovery, decision limit, detection capability and ruggedness. The decision limits (CC{alpha}) obtained, were between 0.56 and 0.68 {mu}g L{sup -1}; recovery above 66% for all the analytes. Repeatability was between 1.4 and 5.3% and within-laboratory reproducibility between 1.9 and 16.1% for the six resorcylic acid lactones.

  6. Efficient and sensitive detection of residues of nine coccidiostats in egg and muscle by liquid chromatography-electrospray tandem mass spectrometry.

    Science.gov (United States)

    Dubois, M; Pierret, G; Delahaut, Ph

    2004-12-25

    We present a method based on electrospray liquid chromatography tandem mass spectrometry (LC-MS/MS) for determining in muscle and eggs the following nine coccidiostats: halofuginone, diclazuril, dinitrocarbanilide (the main metabolite of nicarbazin), robenidine, monensin, lasalocid, narasin, salinomycin, and maduramicin. Dinitrocarbanilide-d8, nigericin, and diclazuril-bis were used as internal standards. The method uses extraction in acetonitrile followed by a clean-up on an SiOH solid-phase extraction column. High-performance liquid chromatography (HPLC) separation was performed on a Purospher C(18) column (125 mm x 3 mm i.d.) protected by a guard column, the mobile phase being a water-acetonitrile gradient (each gradient component containing 0.1% formic acid) at a flow rate of 1 ml min(-1). For unequivocal identification of each analyte, two ions were detected and chosen for multiple reaction monitoring (MRM). Validation was carried out on spiked muscle and egg samples. The method described meets all the criteria of Decision 2002/657/EC and is easy to use in routine analysis. Validation results are presented with the measured CCalpha and CCbeta values. This whole method allows extraction and analysis of up to 24 samples per day.

  7. Development and validation of a turbulent flow chromatography and tandem mass spectrometry method for the quantitation of methotrexate and its metabolites 7-hydroxy methotrexate and DAMPA in serum.

    Science.gov (United States)

    Schofield, Ryan C; Ramanathan, Lakshmi V; Murata, Kazunori; Grace, Marie; Fleisher, Martin; Pessin, Melissa S; Carlow, Dean C

    2015-10-01

    A rapid and simple turbulent flow liquid chromatography (TFC-LC) method implementing positive heated electrospray ionization (HESI) for the accurate and precise determination of methotrexate (MTX), 7-hydroxy methotrexate (7-OH MTX), and 4-amino-4-deoxy-N(10)-methylpteroic acid (DAMPA) concentrations in serum was developed. MTX was isolated from serum samples (100μL) after protein precipitation with methanol containing formic acid and internal standard (MTX-D3) followed by centrifugation. The supernatant was injected into the turbulent flow liquid chromatography which is followed by electrospray positive ionization tandem mass spectrometry (TFC-LC-MS/MS) and quantified using a six-point calibration curve. For MTX and DAMPA the assays were linear from 10 to 1000nmol/L and for 7-OH MTX from 20 to 2000nmol/L. Dilutions of 10, 100 and 1000-fold were validated giving a clinically reportable range of 10nmol/L to 5×10(5)nmol/L. Within-day and between-day precisions at concentrations spanning the analytical measurement ranges were less than 10% for all three analytes. MTX, DAMPA and 7-OH MTX were sufficiently stable under all relevant analytical conditions. No significant matrix effect was observed during the method validation. The TFC-LC-MS/MS MTX method was also compared with three other clinically validated MTX assays: a dihydrofolate reductase (DHFR) inhibition assay, an immunoassay based on fluorescence polarization and a previously developed LC-MS/MS assay.

  8. Determination of lansoprazole enantiomers in dog plasma by column-switching liquid chromatography with tandem mass spectrometry and its application to a preclinical pharmacokinetic study.

    Science.gov (United States)

    Wang, Hao; Sun, Yantong; Meng, Xiangjun; Yang, Bo; Wang, Jian; Yang, Yan; Gu, Jingkai

    2015-09-01

    Lansoprazole, a selective proton pump inhibitor, has a chiral benzimidazole sulfoxide structure and is used for the treatment of gastric acid hypersecretory related diseases. To investigate its stereoselective pharmacokinetics, a column-switching liquid chromatography with tandem mass spectrometry method was developed for the determination of lansoprazole enantiomers in dog plasma using (+)-pantoprazole as an internal standard. After a simple protein precipitation procedure with acetonitrile, matrix components left behind after sample preparation were further eliminated from the sample by reversed-phase chromatography on a C18 column. The fluent was fed to a chiral column for the separation of lansoprazole enantiomers. Baseline separation of lansoprazole enantiomers was achieved on a Chiralcel OZ-RH column using acetonitrile/0.1% formic acid in water (35:65, v/v) as the mobile phase at 40°C. The linearity of the calibration curves ranged from 3 to 800 ng/mL for each enantiomer. Intra- and inter-day precisions ranged from 2.1 to 7.3% with an accuracy of ±1.7% for (+)-lansoprazole, and from 1.6 to 6.9% with an accuracy of ±3.5% for (-)-lansoprazole, respectively. The validated method was successfully applied for the stereoselective pharmacokinetic study of lansoprazole in beagle dog after intravenous infusion.

  9. Automated liquid chromatography-tandem mass spectrometry method for the analysis of firocoxib in urine and plasma from horse and dog.

    Science.gov (United States)

    Letendre, Laura; Kvaternick, Valerie; Tecle, Berhane; Fischer, James

    2007-06-15

    A rugged, sensitive and efficient liquid chromatography-tandem mass spectrometry method was developed and validated for the quantitative analysis of firocoxib in urine from 5 to 3000 ng/mL and in plasma from 1 to 3000 ng/mL. The method requires 200 microL of either plasma or urine and includes sample preparation in 96-well solid phase extraction (SPE) plates using a BIOMEK 2000 Laboratory Automated Workstation. Chromatographic separation of firocoxib from matrix interferences was achieved using isocratic reversed phase chromatography on a PHENOMENEX LUNA Phenyl-Hexyl column. The mobile phase was 45% acetonitrile and 55% of a 2 mM ammonium formate buffer. The method was accurate (88-107%) and precise (CV93% were achieved and ionization efficiencies (due to matrix effects) were >72%. Extensive stability and ruggedness testing was also performed; therefore, the method can be used for pharmacokinetic studies as well as drug monitoring and screening. The data presented here is the first LC-MS/MS method for the quantitation of firocoxib in plasma (LLOQ of 1 ng/mL), a 25-fold improvement in sensitivity over the HPLC-UV method and the first quantitative method for firocoxib in urine (LLOQ of 5 ng/mL). Additionally the sample preparation process has been automated to improve efficiency.

  10. Identification and quantification of peptides and proteins secreted from prostate epithelial cells by unbiased liquid chromatography tandem mass spectrometry using goodness of fit and analysis of variance.

    Science.gov (United States)

    Florentinus, Angelica K; Bowden, Peter; Sardana, Girish; Diamandis, Eleftherios P; Marshall, John G

    2012-02-01

    The proteins secreted by prostate cancer cells (PC3(AR)6) were separated by strong anion exchange chromatography, digested with trypsin and analyzed by unbiased liquid chromatography tandem mass spectrometry with an ion trap. The spectra were matched to peptides within proteins using a goodness of fit algorithm that showed a low false positive rate. The parent ions for MS/MS were randomly and independently sampled from a log-normal population and therefore could be analyzed by ANOVA. Normal distribution analysis confirmed that the parent and fragment ion intensity distributions were sampled over 99.9% of their range that was above the background noise. Arranging the ion intensity data with the identified peptide and protein sequences in structured query language (SQL) permitted the quantification of ion intensity across treatments, proteins and peptides. The intensity of 101,905 fragment ions from 1421 peptide precursors of 583 peptides from 233 proteins separated over 11 sample treatments were computed together in one ANOVA model using the statistical analysis system (SAS) prior to Tukey-Kramer honestly significant difference (HSD) testing. Thus complex mixtures of proteins were identified and quantified with a high degree of confidence using an ion trap without isotopic labels, multivariate analysis or comparing chromatographic retention times.

  11. Ultra Performance Liquid Chromatography with Tandem Mass Spectrometry for the Quantitation of Seventeen Sedative Hypnotics in Six Common Toxicological Matrices.

    Science.gov (United States)

    Mata, Dani C; Davis, John F; Figueroa, Ariana K; Stanford, Mary June

    2016-01-01

    An ultra performance liquid chromatography triple quadrupole mass spectrometry (LC-MS-MS) method for the quantification of 14 benzodiazepines and three sedative hypnotics is presented. The fast and inexpensive assay was developed for California's Orange County Crime Lab for use in antemortem (AM) and postmortem casework. The drugs were rapidly cleaned up from AM blood, postmortem blood, urine, liver, brain and stomach contents using DPX(®) Weak Anion Exchange (DPX WAX) tips fitted on a pneumatic extractor, which can process up to 48 samples at one time. Assay performance was determined for validation based on recommendations by the Scientific Working Group for Forensic Toxicology for linearity, limit of quantitation, limit of detection, bias, precision (within run and between run), dilution integrity, carry-over, selectivity, recovery, ion suppression and extracted sample stability. Linearity was verified using the therapeutic and toxic ranges of all 17 analytes. Final verification of the method was confirmed by four analysts using 20 blind matrix matched samples. All results were within 20% of each other and the expected value.

  12. 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

    2017-03-18

    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.

  13. Characterization of eight terpenoids from tissue cultures of the Chinese herbal plant, Tripterygium wilfordii, by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry.

    Science.gov (United States)

    Su, Ping; Cheng, Qiqing; Wang, Xiujuan; Cheng, Xiaoqing; Zhang, Meng; Tong, Yuru; Li, Fei; Gao, Wei; Huang, Luqi

    2014-09-01

    In this study, a reliable method for analysis and identification of eight terpenoids in tissue cultures of Tripterygium wilfordii has been established using high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (HPLC-ESI-MS). Our study indicated that sterile seedlings, callus cultures and cell-suspension cultures can rapidly increase the amount of biological materials. HPLC-ESI-MS was used to identify terpenoids from the extracts of these tissue cultures. Triptolide, triptophenolide, celastrol and wilforlide A were unambiguously determined by comparing the retention times, UV spectral data, and mass fragmentation behaviors with those of the reference compounds. Another four compounds were tentatively identified as triptonoterpenol, triptonoterpene, 22β-hydroxy-3-oxoolean-12-en-29-oic acid and wilforlide B, based on their UV and mass spectrometry spectra. The quantitative analysis showed that all three materials contain triptolide, triptophenolide, celastrol, wilforlide A, and the contents of the four compounds in the cell-suspension cultures were 53.1, 240, 129 and 964 µg/g, respectively, which were at least 2.0-fold higher than these in the sterile seedlings and callus cultures. Considering the known pharmacological activity of triptolide and celastrol, we recommend the cell-suspension cultures as biological materials for future studies, such as clinical and toxicological studies. The developed method was validated by the evaluation of its precision, linearity, detection limits and recovery, and it was successfully used to identify and quantify the terpenoids in the tissue cultures.

  14. 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).

  15. Ultra-high-performance liquid chromatography electrospray ionization tandem mass spectrometry for accurate analysis of glycerophospholipids and sphingolipids in drug resistance tumor cells.

    Science.gov (United States)

    Li, Lin; Wang, Linlin; Shangguan, Dihua; Wei, Yanbo; Han, Juanjuan; Xiong, Shaoxiang; Zhao, Zhenwen

    2015-02-13

    Glycerophospholipids and sphingolipids are important signaling molecules which are involved in many physiological and pathological processes. Here we reported an effective method for accurate analysis of these lipids by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The methanol method was adopted for extraction of lipids due to its simplicity and high efficiency. It was found that two subclasses of sphingolipids, sulfatide (ST) and cerebroside (CB), were heat labile, so a decreased temperature in the ion source of MS might be necessary for these compounds analysis. In addition, it was found that the isobaric interferences were commonly existent, for example, the m/z of 16:0/18:1 PC containing two (13)C isotope being identical to that of 16:0/18:0 PC determined by a unit mass resolution mass spectrometer; therefore, a baseline separation of interferential species was required to maintain selectivity and accuracy of analysis. In this work, an ultra-high-performance liquid chromatography (UHPLC)-based method was developed for separation of interferential species. Moreover, in order to deal with the characteristics of different polarity and wide dynamic range of glycerophospholipids and sphingolipids in biological systems, three detecting conditions were combined together for comprehensive and rational analysis of glycerophospholipids and sphingolipids. The method was utilized to profile glycerophospholipids and sphingolipids in drug resistant tumor cells. Our results showed that many lipids were significantly changed in drug resistant tumor cells compared to paired drug sensitive tumor cells. This is a systematic report about the isobaric interferences and heat labile compounds interferences when analyzing glycerophospholipids and sphingolipids by ESI-MS/MS, which aids in ruling out one potential source of systematic error to ensure the accuracy of analysis.

  16. Simultaneous determination of amitraz, chlordimeform, formetanate and their main metabolites in human urine by high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Gao, Xue; Tan, Yanglan; Guo, Hao

    2017-03-11

    A rapid, simple and reliable high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous determination of amitraz, chlordimeform, formetanate and their main metabolites, N-(2,4-dimethylphenyl)-N-methyl-formamidine (DMPF), 2,4-dimethylformamidine (DMF), 2,4-dimethylaniline (DMA), 4-chloro-2-methylaniline and 3-hydroxyacetanilide in human urine. The urine samples were mixed with buffer solutions (pH 8) and subsequently cleaned up by solid supported liquid/liquid extraction (SLE). The target analytes were efficiently separated with a Waters Atlantis T3 column (150mm×4.6mm, 5μm), ionized with electrospray ion source in positive mode, and quantitatively determined by tandem mass spectrometry in the multiple reaction monitoring (MRM) mode. In order to minimize matrix effects, the matrix-matched calibration curves of eight analytes were adopted with correlation coefficients (R(2)) above 0.99. The method were further validated by determining the limits of detection (LODs, 0.3-0.6ng/mL), the limits of quantitation (LOQs, 1.0-2.0ng/mL) and recoveries (89.1%-108.4%) with intra-day and inter-day relative standard deviation (RSD, <11%). The established method was applied and demonstrated in a real case by assaying a urine sample from a female poisoned by formetanate. The achieved results proved this method to be rapid, sensitive and accurate for simultaneous quantitation of eight analytes in human urine for intended forensic cases of human poisoning.

  17. [Determination of perfluorooctane sulfonates in fire-fighting foam and other materials by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Chen, Huiming; Cheng, Yan; Chen, Wei; Yu, Wenlian; Li, Xi; Wang, Zheng

    2010-02-01

    A novel method based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for the determination of perfluorooctane sulfonates (PFOS) in the fire-fighting foam, detergents and fabric finishing agents. The PFOS residue was extracted with water at first by ultrasonic, then separated by high-speed centrifugation. The supernatant was purified by pre-conditioned solid phase extraction (SPE) micro-column, and the extract was filtrated through a membrane with 0.2 microm diameter. The filtrated liquid was analyzed by HPLC using acetonitrile-10 mmol/L ammonium acetate solution (80 : 20, v/v) as mobile phase. The PFOS was detected by using negative electrospray ionization (ESI) on a tandem mass spectrometer in multiple reaction monitoring (MRM) mode. The qualitative analysis of the PFOS can be performed by using the relative abundance of two daughter ions of PFOS, and the quantitative analysis was performed by external standard method. The linear calibration curve was obtained in the range of 0.002 - 0.1 mg/L with a linear correlation coefficient (r2 ) of 0.998. The spiked recoveries for PFOS in the fire-fighting foam, detergents and fabric finishing agents were 93.4% - 103%, 93.2% - 102% and 91.8% - 102% with the relative standard deviation of 0.48% - 3.52%, 0.78% - 1.79% and 0.47% - 3.47%, respectively. And the detection limit for PFOS was 2 mg/kg (S/N > or = 10), which can meet the requirement for the PFOS restriction in fire-fighting foam, detergents and fabric finishing agents in the EU directives. With high accuracy and sensitivity, the method is simple and rapid, and can be used for PFOS inspection in fire-fighting foam, detergents and fabric finishing agents.

  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, 3