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Sample records for rapid liquid chromatography-tandem

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

    Science.gov (United States)

    Liu, Hualiang; Wang, Yuan; Zhu, Baoli

    2015-11-01

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

  2. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. 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

  4. Rapid determination of fumonisins in corn-based products by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Li, Wei; Herrman, Timothy J; Dai, Susie Y

    2010-01-01

    A simple, fast, and robust method was developed for the determination of fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3) in corn-based human food and animal feed (cornmeal). The method involves a single extraction step followed by centrifugation and filtration before analysis by ultra-performance liquid chromatographylelectrospray ionization (UPLC/ESI)-MS/MS. The LC/MS/MS method developed here represents the fastest and simplest procedure (<30 min) among both conventional HPLC methods and other LC/MS methods using SPE cleanup. The potential for high throughput analysis makes the method particularly beneficial for regulatory agencies and analytical laboratories with a high sample volume. A single-laboratory validation was conducted by testing three different spiking levels (200, 500, and 1000 ng/g for FB1 and FB2; 100, 250, and 500 ng/g for FB3) for accuracy and precision. Recoveries of FB1 ranged from 93 to 98% with RSD values of 3-8%. Recoveries of FB2 ranged from 104 to 108%, with RSD values of 2-6%. Recoveries of FB3 ranged from 94 to 108%, with RSD values of 2-5%.

  5. 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

  6. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. 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.

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

    Science.gov (United States)

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

  9. Rapid determination of 9 aromatic amines in mainstream cigarette smoke by modified dispersive liquid liquid microextraction and ultraperformance convergence chromatography tandem mass spectrometry.

    Science.gov (United States)

    Deng, Huimin; Yang, Fei; Li, Zhonghao; Bian, Zhaoyang; Fan, Ziyan; Wang, Ying; Liu, Shanshan; Tang, Gangling

    2017-07-21

    Aromatic amines in mainstream cigarette smoke have long been monitored due to their carcinogenic toxicity. In this work, a reliable and rapid method was developed for the simultaneous determination of 9 aromatic amines in mainstream cigarette smoke by modified dispersive liquid liquid microextraction (DLLME) and ultraperformance convergence chromatography tandem mass spectrometry (UPC 2 -MS/MS). Briefly, the particulate phase of the cigarette smoke was captured by a Cambridge filter pad, and diluted hydrogen chloride aqueous solution is employed to extract the aromatic amines under mechanical shaking. After alkalization with sodium hydroxide solution, small amount of toluene was introduced to further extract and enrich aromatic amines by modified DLLME under vortexing. After centrifugation, toluene phase was purified by a universal QuEChERS cleanup kit and was finally analyzed by UPC 2 -MS/MS. Attributing to the superior performance of UPC 2 -MS/MS, this novel approach allowed the separation and determination of 9 aromatic amines within 5.0min with satisfactory resolution and sensitivity. The proposed method was finally validated using Kentucky reference cigarette 3R4F, and emission levels of targeted aromatic amines determined were comparable to previously reported methods At three different spiked levels, the recoveries of most analytes were ranged from 74.01% to 120.50% with relative standard deviation (RSD) less than 12%, except that the recovery of p-toluidine at low spiked level and 3-aminobiphenyl at medium spiked level was 62.77% and 69.37% respectively. Thus, this work provides a novel alternative method for the simultaneous analysis of 9 aromatic amines in mainstream cigarette smoke. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    OpenAIRE

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

    2013-01-01

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

  11. Rapid and precise measurement of serum branched-chain and aromatic amino acids by isotope dilution liquid chromatography tandem mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Ruiyue Yang

    Full Text Available BACKGROUND: Serum branched-chain and aromatic amino acids (BCAAs and AAAs have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. METHODS: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standards and the amino acids were extracted with acetonitrile, followed by analysis using LC/MS/MS. The LC separation was performed on a reversed-phase C18 column, and the MS/MS detection was performed via the positive electronic spray ionization in multiple reaction monitoring mode. RESULTS: Specific analysis of the amino acids was achieved within 2 min. Intra-run and total CVs for the amino acids were less than 2% and 4%, respectively, and the analytical recoveries ranged from 99.6 to 103.6%. CONCLUSION: A rapid and precise method for the measurement of serum BCAAs and AAAs was developed and may serve as a quick tool for screening serum BCAAs and AAAs in studies assessing diabetes risk.

  12. A simple and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry method to determine plasma biotin in hemodialysis patients.

    Science.gov (United States)

    Yagi, Shigeaki; Nishizawa, Manabu; Ando, Itiro; Oguma, Shiro; Sato, Emiko; Imai, Yutaka; Fujiwara, Masako

    2016-08-01

    A simple, rapid, and selective method for determination of plasma biotin was developed using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). After single-step protein precipitation with methanol, biotin and stable isotope-labeled biotin as an internal standard (IS) were chromatographed on a pentafluorophenyl stationary-phase column (2.1 × 100 mm, 2.7 μm) under isocratic conditions using 10 mm ammonium formate-acetonitrile (93:7, v/v) at a flow rate of 0.6 mL/min. The total chromatographic runtime was 5 min for each injection. Detection was performed in a positive electrospray ionization mode by monitoring selected ion transitions at m/z 245.1/227.0 and 249.1/231.0 for biotin and the IS, respectively. The calibration curve was linear in the range of 0.05-2 ng/mL using 300 μL of plasma. The intra- and inter-day precisions were all biotin concentrations in hemodialysis patients. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Determination of moxifloxacin in human plasma, plasma ultrafiltrate, and cerebrospinal fluid by a rapid and simple liquid chromatography- tandem mass spectrometry method.

    Science.gov (United States)

    Pranger, Arianna D; Alffenaar, Jan-Willem C; Wessels, A Mireille A; Greijdanus, Ben; Uges, Donald R A

    2010-04-01

    Moxifloxacin (MFX) is a useful agent in the treatment of multi-drug-resistant tuberculosis (MDR-TB). At Tuberculosis Centre Beatrixoord, a referral center for tuberculosis in the Netherlands, approximately 36% of the patients have received MFX as treatment. Based on the variability of MFX AUC, the variability of in vitro susceptibility to MFX of M. tuberculosis, and the variability of penetration into sanctuary sites, measuring the concentration of MFX in plasma and cerebrospinal fluid (CSF) could be recommended. Therefore, a rapid and validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) analyzing method with a simple pretreatment procedure was developed for therapeutic drug monitoring of MFX in human plasma and CSF. Because of the potential influence of protein binding on efficacy, we decided to determine both bound and unbound (ultrafiltrate) fraction of MFX. The calibration curves were linear in the therapeutic range of 0.05 to 5.0 mg/L plasma and CSF with CV in the range of -5.4% to 9.3%. MFX ultrafiltrate samples could be determined with the same method setup for analysis of MFX in CSF. The LC-MS-MS method developed in this study is suitable for monitoring MFX in human plasma, plasma ultrafiltrate, and CSF.

  14. Sequential determination of fat- and water-soluble vitamins in Rhodiola imbricata root from trans-Himalaya with rapid resolution liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Tayade, Amol B; Dhar, Priyanka; Kumar, Jatinder; Sharma, Manu; Chaurasia, Om P; Srivastava, Ravi B

    2013-07-30

    A rapid method was developed to determine both types of vitamins in Rhodiola imbricata root for the accurate quantification of free vitamin forms. Rapid resolution liquid chromatography/tandem mass spectrometry (RRLC-MS/MS) with electrospray ionization (ESI) source operating in multiple reactions monitoring (MRM) mode was optimized for the sequential analysis of nine water-soluble vitamins (B1, B2, two B3 vitamins, B5, B6, B7, B9, and B12) and six fat-soluble vitamins (A, E, D2, D3, K1, and K2). Both types of vitamins were separated by ion-suppression reversed-phase liquid chromatography with gradient elution within 30 min and detected in positive ion mode. Deviations in the intra- and inter-day precision were always below 0.6% and 0.3% for recoveries and retention time. Intra- and inter-day relative standard deviation (RSD) values of retention time for water- and fat-soluble vitamin were ranged between 0.02-0.20% and 0.01-0.15%, respectively. The mean recoveries were ranged between 88.95 and 107.07%. Sensitivity and specificity of this method allowed the limits of detection (LOD) and limits of quantitation (LOQ) of the analytes at ppb levels. The linear range was achieved for fat- and water-soluble vitamins at 100-1000 ppb and 10-100 ppb. Vitamin B-complex and vitamin E were detected as the principle vitamins in the root of this adaptogen which would be of great interest to develop novel foods from the Indian trans-Himalaya. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Application of a rapid and sensitive liquid chromatography-tandem mass spectrometry method for determination of bumetanide in human plasma for a bioequivalence study.

    Science.gov (United States)

    Patel, Dinesh S; Sharma, Naveen; Patel, Mukesh C; Patel, Bhavin N; Shrivastav, Pranav S; Sanyal, Mallika

    2012-07-01

    A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been proposed for the determination of bumetanide in human plasma using tamsulosin as internal standard (IS). The analyte and IS were extracted from 200 μL of human plasma via solid phase extraction and the chromatographic separation was achieved on Peerless Basic C18 (100 mm × 4.6 mm, 3 μm) column under isocratic conditions. Detection of bumetanide and IS was done by tandem mass spectrometry, operating in positive ionization and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for bumetanide and IS were m/z 365.2→240.2 and 409.2→228.2 respectively. The method was fully validated as per the US FDA guidelines. The limit of detection and lower limit of quantitation of the method were 0.03 and 0.30 ng/mL respectively with a linear dynamic range of 0.30-200.0 ng/mL for bumetanide. The intra-batch and inter-batch precision (% CV) was ≤6.9% while the mean extraction recovery was >90% across quality control levels. The method is selective in presence of four diuretic drugs and some commonly used medications by healthy volunteers. It was successfully applied to a bioequivalence study of 2mg bumetanide tablet formulation in 10 healthy Indian male subjects under fasting condition. The reproducibility in the measurement of study data was demonstrated by reanalysis of 42 incurred samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Rapid screening for cyclo-dopa and diketopiperazine alkaloids in crude extracts of Portulaca oleracea L. using liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Xing, Jie; Yang, Zijuan; Lv, Beibei; Xiang, Lan

    2008-05-01

    A simple and rapid qualitative liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed and validated for screening cyclo-dopa and diketopiperazine alkaloids in crude extracts of Portulaca oleracea L. at sub-ppm levels. An electrospray ionization orbitrap mass spectrometer, which provides accurate full scan MS and MS/MS data, was used in this study. After simple extraction with ethanol and purification by AB-8 resin, the extracts were subjected to LC/MS/MS analysis. A high mass tolerance (10 ppm) was used in the initial screening to filter the full scan MS data. The cyclo-dopa and diketopiperazine alkaloid standards gave limits of detection (LODs) at or below 5 ng/mL. The results also indicated that the method had an acceptable precision for day-to-day use in the identification of compounds. The alkaloids could be identified based on their MS/MS data, elemental compositions, and retention behavior. This system was used to assay trace amounts of cyclo-dopa and diketopiperazine alkaloids in crude extracts of Portulaca oleracea L., leading to the identification of 5/2 confirmed/unconfirmed cyclo-dopa and 7/6 confirmed/unconfirmed diketopiperazine alkaloids, respectively. The screening method considerably reduces the time and cost involved in the identification of cyclo-dopa and diketopiperazine alkaloids in Portulaca oleracea L., as well as being a simple and convenient approach to the identification of other structural families of natural products. Copyright (c) 2008 John Wiley & Sons, Ltd.

  19. A rapid method based on hot water extraction and liquid chromatography-tandem mass spectrometry for analyzing tetracycline antibiotic residues in cheese.

    Science.gov (United States)

    Bogialli, Sara; Coradazzi, Cristina; Di Corcia, Antonio; Lagana, Aldo; Sergi, Manuel

    2007-01-01

    A rapid, specific, and sensitive procedure for determining residues of 4 widely used tetracycline antibiotics and 3 of their 4-epimers in cheese is presented. The method is based on the matrix solid-phase dispersion (MSPD) technique followed by liquid chromatography/tandem mass spectrometry (LC/MS/MS). After dispersing samples of mozzarella, asiago, parmigiano, gruyere, emmenthal, and camembert on sand, target compounds were eluted from the MSPD column by passing through it 6 mL water heated at 70 degrees C. After acidification and filtration, 200 microL of the aqueous extract was directly injected into the LC column. For analyte identification and quantification, MS data acquisition was performed in the multireaction monitoring mode, selecting 2 precursor ion-to-product ion transitions for each target compound. Hot water appeared to be an efficient extractant, because absolute recoveries were no lower than 78%. Using demeclocycline as a surrogate analyte, recoveries of analyte added to the 6 types of cheeses at the 30 ng/g level were 96-117%, with relative standard deviation (RSD) not higher than 9%. Statistical analysis of the mean recovery data showed that the extraction efficiency was not dependent on the type of cheese analyzed. This result indicates that this method could be applied to other cheese types not considered here. At the lowest concentration considered, i.e., 10 ng/g, the accuracy of the method ranged between 90 and 107%, with RSDs not larger than 12%. Based on a signal-to-noise ratio of 10, limits of quantitation were estimated to be 1-2 ng/g.

  20. 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 (<15min) preparation of lipids compared to the Folch method, with equivalent or slightly improved results in lipid identification using nLC-ESI-MS/MS. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Ultra Performance Liquid Chromatography Tandem Mass ...

    African Journals Online (AJOL)

    NICOLAAS

    drugs alone.16. After a single oral dose of 120–800 mg of NTB in healthy sub- jects in a fasting state the peak plasma NTB concentration (tmax) was found to be 4–7 h, with a half-life of approximately 9–17 h.17 ... performance liquid chromatography mass spectrometry/mass .... to the likely biological plasma constituents.

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

    Science.gov (United States)

    Barbera, Giorgia La; Capriotti, Anna Laura; Cavaliere, Chiara; Foglia, Patrizia; Montone, Carmela Maria; Chiozzi, Riccardo Zenezini; Laganà, Aldo

    2017-04-21

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

  3. Rapid analysis of aminoglycoside antibiotics in bovine tissues using disposable pipette extraction and ultrahigh performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lehotay, Steven J; Mastovska, Katerina; Lightfield, Alan R; Nuñez, Alberto; Dutko, Terry; Ng, Chilton; Bluhm, Louis

    2013-10-25

    A high-throughput qualitative screening and identification method for 9 aminoglycosides of regulatory interest has been developed, validated, and implemented for bovine kidney, liver, and muscle tissues. The method involves extraction at previously validated conditions, cleanup using disposable pipette extraction, and analysis by a 3 min ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. The drug analytes include neomycin, streptomycin, dihydrosptreptomycin, and spectinomycin, which have residue tolerances in bovine in the US, and kanamicin, gentamicin, apramycin, amikacin, and hygromycin, which do not have US tolerances established in bovine tissues. Tobramycin was used as an internal standard. An additional drug, paromomycin also was validated in the method, but it was dropped during implementation due to conversion of neomycin into paromomycin. Proposed fragmentation patterns for the monitored ions of each analyte were elucidated with the aid of high resolution MS using a quadrupole-time-of-flight instrument. Recoveries from spiking experiments at regulatory levels of concern showed that all analytes averaged 70-120% recoveries in all tissues, except hygromycin averaged 61% recovery. Lowest calibrated levels were as low as 0.005 μg/g in matrix extracts, which approximately corresponded to the limit of detection for screening purposes. Drug identifications at levels advantages compared to the previous microbial inhibition screening assay, especially for distinguishing individual drugs from a mixture and improving identification of gentamicin in tissue samples. Published by Elsevier B.V.

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

    Directory of Open Access Journals (Sweden)

    Giorgia La Barbera

    2017-04-01

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

  5. Rapid analysis of diclofenac and some of its transformation products in the three-spined stickleback, Gasterosteus aculeatus, by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Daniele, Gaëlle; Fieu, Maëva; Joachim, Sandrine; Bado-Nilles, Anne; Baudoin, Patrick; Turies, Cyril; Porcher, Jean-Marc; Andres, Sandrine; Vulliet, Emmanuelle

    2016-06-01

    Pharmaceuticals are emerging organic contaminants ubiquitously present in the environment due to incessant input into the aquatic compartment mainly resulting from incomplete removal in wastewater treatment plants. One of the major preoccupations concerning pharmaceuticals released into surface waters is their potential for bioaccumulation in biota, possibly leading to deleterious effects on ecosystems especially as they could affect a broad variety of organisms living in or depending on the aquatic environment. Thus, the development of accurate and sensitive methods is necessary to detect these compounds in aquatic ecosystems. Considering this need, this study deals with the analytical development of a methodology to quantify traces of diclofenac together with some of its biotic and abiotic transformation products in whole-body tissue of three-spined stickleback. A simple and reliable extraction method based on a modified QuEChERS extraction is implemented on 200 mg of fish. The detection and quantification of the ten target compounds are performed using liquid chromatography-tandem mass spectrometry. The whole process was successfully validated regarding linearity, recovery, repeatability, and reproducibility. The method limits of detection and quantification do not exceed 1 ng/g. To reproduce environmental conditions, we measured the concentration of DCF and its transformation products in three-spined sticklebacks after a 6-month exposure in mesocosms at several levels of DCF ranging from 0.05 to 4.1 μg/L. The phase I metabolite 4'-hydroxydiclofenac was detected in fish samples exposed at the highest DCF concentration. Graphical abstract Analysis of diclofenac and some of its transformation products in the three-spined stickleback, Gasterosteus aculeatus, by QuEChERS extraction followed by LC-MS/MS.

  6. Rapid screening of anabolic steroids in horse urine with ultra-high-performance liquid chromatography/tandem mass spectrometry after chemical derivatisation.

    Science.gov (United States)

    Wong, Colton H F; Leung, David K K; Tang, Francis P W; Wong, Jenny K Y; Yu, Nola H; Wan, Terence S M

    2012-04-06

    Liquid chromatography/mass spectrometry (LC/MS) has been successfully applied to the detection of anabolic steroids in biological samples. However, the sensitive detection of saturated hydroxysteroids, such as androstanediols, by electrospray ionisation (ESI) is difficult because of their poor ability to ionise. In view of this, chemical derivatisation has been used to enhance the detection sensitivity of hydroxysteroids by LC/MS. This paper describes the development of a sensitive ultra-high-performance liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) method for the screening of anabolic steroids in horse urine by incorporating a chemical derivatisation step, using picolinic acid as the derivatisation reagent. The method involved solid-phase extraction (SPE) of both free and conjugated anabolic steroids in horse urine using a polymer-based SPE cartridge (Abs Elut Nexus). The conjugated steroids in the eluate were hydrolysed by methanolysis and the resulting extract was further cleaned up by liquid-liquid extraction. The resulting free steroids in the extract were derivatised with picolinic acid to form the corresponding picolinoyl esters and analysed by UHPLC/MS/MS in the positive ESI mode with selected-reaction-monitoring. Separation of the targeted steroids was performed on a C18 UHPLC column. The instrument turnaround time was 10.5 min inclusive of post-run equilibration. A total of thirty-three anabolic steroids (including 17β-estradiol, 5(10)-estrene-3β,17α-diol, 5α-estrane-3β,17α-diol, 17α-ethyl-5α-estran-3α,17β-diol, 17α-methyl-5α-androstan-3,17β-diols, androstanediols, nandrolone and testosterone) spiked in negative horse urine at the QC levels (ranging from 0.75 to 30 ng/mL) could be consistently detected. The intra-day and inter-day precisions (% RSD) for the peak area ratios were around 7-51% and around 1-72%, respectively. The intra-day and inter-day precisions (% RSD) for the relative retention times were both less than 1% for

  7. Development of an automated on-line pepsin digestion-liquid chromatography-tandem mass spectrometry configuration for the rapid analysis of protein adducts of chemical warfare agents

    NARCIS (Netherlands)

    Carol-Visser, J.; van der Schans, M.; Fidder, A.; Huist, A.G.; van Baar, B.L.M.; Irth, H.; Noort, D.

    2008-01-01

    Rapid monitoring and retrospective verification are key issues in protection against and non-proliferation of chemical warfare agents (CWA). Such monitoring and verification are adequately accomplished by the analysis of persistent protein adducts of these agents. Liquid chromatography-mass

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

    DEFF Research Database (Denmark)

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

    2014-01-01

    The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments...... of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14 days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose...

  9. Determination of anthelmintic drug residues in milk using ultra high performance liquid chromatography-tandem mass spectrometry with rapid polarity switching.

    Science.gov (United States)

    Whelan, Michelle; Kinsella, Brian; Furey, Ambrose; Moloney, Mary; Cantwell, Helen; Lehotay, Steven J; Danaher, Martin

    2010-07-02

    A new UHPLC-MS/MS (ultra high performance liquid chromatography coupled to tandem mass spectrometry) method was developed and validated to detect 38 anthelmintic drug residues, consisting of benzimidazoles, avermectins and flukicides. A modified QuEChERS-type extraction method was developed with an added concentration step to detect most of the analytes at keeper to ensure analytes remain in solution. Using rapid polarity switching in electrospray ionisation, a single injection was capable of detecting both positively and negatively charged ions in a 13 min run time. The method was validated at two levels: the unapproved use level and at the maximum residue level (MRL) according to Commission Decision (CD) 2002/657/EC criteria. The decision limit (CCalpha) of the method was in the range of 0.14-1.9 and 11-123 microg kg(-1) for drugs validated at unapproved and MRL levels, respectively. The performance of the method was successfully verified for benzimidazoles and levamisole by participating in a proficiency study.

  10. Development and validation of a rapid multi-biomarker liquid chromatography/tandem mass spectrometry method to assess human exposure to mycotoxins.

    Science.gov (United States)

    Warth, Benedikt; Sulyok, Michael; Fruhmann, Philipp; Mikula, Hannes; Berthiller, Franz; Schuhmacher, Rainer; Hametner, Christian; Abia, Wilfred Angie; Adam, Gerhard; Fröhlich, Johannes; Krska, Rudolf

    2012-07-15

    Mycotoxins regularly occur in food worldwide and pose serious health risks to consumers. Since individuals can be exposed to a variety of these toxic secondary metabolites of fungi at the same time, there is a demand for proper analytical methods to assess human exposure by suitable biomarkers. This study reports on the development of a liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method for the quantitative measurement of 15 mycotoxins and key metabolites in human urine using polarity switching. Deoxynivalenol (DON), DON-3-O-glucuronide, DON-15-O-glucuronide (D15GlcA), de-epoxy DON, nivalenol (NIV), T-2 toxin, HT-2 toxin, zearalenone, zearalenone-14-O-glucuronide, α- and β-zearalenol, fumonisins B(1) and B(2) (FB(1), FB(2)), ochratoxin A (OTA) and aflatoxin M(1) (AFM(1)) were determined without the need for any cleanup using a rapid and simple dilute and shoot approach. Validation was performed in the range of 0.005-40 µg L(-1) depending on the analyte and expected urinary concentration levels. Apparent recoveries between 78 and 119% and interday precisions of 2-17% relative standard deviation (RSD) were achieved. The applicability of the method was demonstrated by the analysis of urine samples obtained from Cameroon. In naturally contaminated urine samples up to six biomarkers of exposure (AFM(1), DON, D15GlcA, NIV, FB(1), and OTA) were detected simultaneously. We conclude that the developed LC/MS/MS method is well suited to quantify multiple mycotoxin biomarkers in human urine down to the sub-ppb range within 18 min and without any prior cleanup. The co-occurrence of several mycotoxins in the investigated samples clearly emphasizes the great potential and importance of this method to assess exposure of humans and animals to naturally occurring mycotoxins. Copyright © 2012 John Wiley & Sons, Ltd.

  11. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Rapid and sensitive liquid chromatography-tandem mass spectrometric method for the quantitative determination of potentially harmful substance 5,5'-oxydimethylenebis (2-furfural) in traditional Chinese medicine injections.

    Science.gov (United States)

    Zang, Qingce; Gao, Yang; Huang, Luojiao; He, Jiuming; Lin, Sheng; Jin, Hongtao; Zhang, Ruiping; Abliz, Zeper

    2018-03-01

    With the rapid development and wide application of traditional Chinese medicine injection (TCMI), a number of adverse events of some TCMIs have incessantly been reported and have drawn broad attention in recent years. Establishing effective and practical analytical methods for safety evaluation and quality control of TCMI can help to improve the safety of TCMIs in clinical applications. In this study, a sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed and validated for the quantitative determination of potentially harmful substance 5,5'-oxydimethylenebis (2-furfural, OMBF) in TCMI samples. Chromatographic separation was performed on a C18 reversed-phase column (150 mm × 2.1 mm, 5 µm) by gradient elution, using methanol-water containing 0.1% formic acid as mobile phase at the flow rate of 0.3 mL/min. MS/MS detection was performed on a triple quadrupole mass spectrometer with positive electrospray ionization in the multiple reaction-monitoring mode. The method was sensitive with a limit of quantification of 0.3 ng/mL and linear over the range of 0.3-30 ng/mL ( r =0.9998). Intra- and inter-day precision for analyte was <9.52% RSD with recoveries in the range 88.0-109.67% at three concentration levels. The validated method was successfully applied to quantitatively determine the compound OMBF in TCMIs and glucose injections. Our study indicates that this method is simple, sensitive, practicable and reliable, and could be applied for safety evaluation and quality control of TCMIs and glucose injections.

  13. Development and validation of a rapid and high-sensitivity liquid chromatography-tandem mass spectrometry assay for the determination of neostigmine in small-volume beagle dog plasma and its application to a pharmacokinetic study.

    Science.gov (United States)

    Cao, Di; Li, Wenxue; Zhao, Xin; Ye, Xiaolan; Sun, Fanlu; Li, Jinying; Song, Fenyun; Fan, Guorong

    2014-03-01

    A simple, rapid and high sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of neostigmine in small-volume beagle dog plasma was developed to assess the plasma pharmacokinetics of neostigmine. After protein precipitation in a Sirocco 96-well filtration plate, the filtrate was directly injected into the LC-MS/MS system. The analytes were separated on a Hanbon Hedera CN column (100 × 4.6 mm, 5 µm) with a mobile phase composed of methanol-water (60:40, v/v) and the water containing 0.01% formic acid at a flow rate of 0.6mL/min, with a split ratio of 1:1 flowing 300 μL into the mass spectrometer. The run time was 3 min. Detection was accomplished by electrospray ionization source in multiple reactions monitoring mode with the precursor-to-product ion transitions m/z 223.0 → 72.0 and 306.0 → 140.0 for neostigmine and anisodamine (internal standard), respectively. The method was sensitive with a lower limit of quantitation of 0.1 ng/mL, and good linearity in the range 0.1-100ng/mL for neostigmine (r ≥ 0.998). All the validation data, such as accuracy, intra-run and inter-run precision, were within the required limits. The method was successfully applied to pharmacokinetic study of neostigmine methylsulfate injection in beagle dogs. Copyright © 2013 John Wiley & Sons, Ltd.

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

    Science.gov (United States)

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

    2005-12-01

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

  15. 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...... 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...

  16. Liquid chromatography/tandem mass spectrometry method for quantitative estimation of solutol HS15 and its applications

    OpenAIRE

    Bhaskar, V. Vijaya; Middha, Anil; Srivastava, Pratima; Rajagopal, Sriram

    2015-01-01

    A rapid, sensitive and selective pseudoMRM (pMRM)-based method for the determination of solutol HS15 (SHS15) in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LCâMS/MS). The most abundant ions corresponding to SHS15 free polyethyleneglycol (PEG) oligomers at m/z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for pMRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using ...

  17. Liquid to liquid extraction and liquid chromatography-tandem mass spectrometry determination of hainanmycin in feed.

    Science.gov (United States)

    Wang, Ze Ping; Shen, Jian Zhong; Linhardt, Robert J; Jiang, Hui; Cheng, Lin Li

    2017-03-01

    Hainanmycin is a new veterinary polyether antibiotic and has few sensitive analytical method in present days. In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) relying on multiple reaction monitoring (MRM) detection was developed for analysis of hainanmycin in animal feed. Feed samples were extracted with ethyl acetate and purified by two steps of liquid-liquid extraction (LLE) to get rid of water solvable matrix and lipids one by one. The final simple was analyzed by LC-MS/MS. The LC mobile phase was composed of 0.1% aqueous formic acid and 0.1% formic acidified acetonitrile by gradient elution. Average recoveries ranged from 74.22% to 87.85%, as determined by spiking with 2.0 (LOQ) ∼2500μgkg -1 of hainanmycin. The inter-day and intra-day coefficient of variation was 9.21% to 11.77% and 7.67% to 13.49%, respectively. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.36μgkg -1 and 2.0μgkg -1 , respectively. Copyright © 2016. Published by Elsevier B.V.

  18. Determination of levofloxacin in human serum using liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Samiksha Ghimire

    2018-01-01

    Full Text Available A rapid liquid chromatography tandem-mass spectrometry method was developed for the determination of levofloxacin and its metabolite (desmethyl-levofloxacin in human serum. Sample preparation was done using protein precipitation technique. Our method had a run time of 2.5 min and retention times of 1.6 min for all analytes. The standard curves were linear within the concentration range of 0.10 to 5.00 mg/L for levofloxacin and 0.10 to 4.99 mg/L for desmethyl- levofloxacin; a correlation coefficient (R2 of 0.999 and 0.998 respectively. The lower limit of quantification for both analytes was 0.10 mg/L. Within-day precision ranged from 1.4% and 2.4% for levofloxacin, 1.5% to 5% for desmethyl-levofloxacin and between-day precision ranged from 3.6% to 4.1% for levofloxacin and 0.0% to 3.3% for desmethyl-levofloxacin; whereas, accuracy ranged from 0.1% to 12.7% for levofloxacin and 0.2% to 15.6% for desmethyl-levofloxacin. This method could be a useful asset for routine therapeutic drug monitoring of levofloxacin in multi-drug resistant tuberculosis patients.

  19. 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.

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

    Science.gov (United States)

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

    2011-01-15

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

  1. Determination and pharmacokinetic studies of arecoline in dog plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Li, Bing; Zhou, Xu-Zheng; Li, Jian-Yong; Yang, Ya-Jun; Niu, Jian-Rong; Wei, Xiao-Juan; Liu, Xi-Wang; Li, Jin-Shan; Zhang, Ji-Yu

    2014-10-15

    A rapid and sensitive high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of arecoline concentration in dog plasma. Plasma sample was prepared by protein precipitation using n-hexane (containing 1% isoamyl alcohol) with β-pinene as an internal standard. Chromatographic separation was achieved on an Agilent C18 column (4.6×75mm, 3.5μm) using methanol: 5mM ammonium acetate as the mobile phase with isocratic elution. Mass detection was carried out using positive electrospray ionization in multiple reaction monitoring mode. The calibration curve for arecoline was linear over a concentration range of 2-500ng/mL. The intra-day and inter-day accuracy and precision were within the acceptable limits of ±10% at all concentrations. In summary, the LC-MS/MS method described herein was fully validated and successfully applied to the pharmacokinetic study of arecoline hydrobromide tablets in dogs after oral administration. Copyright © 2014. Published by Elsevier B.V.

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

    Science.gov (United States)

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

    2007-10-15

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

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

    Science.gov (United States)

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

    2016-08-01

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

  4. 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.

  5. Liquid chromatography tandem mass spectrometry determination of total budesonide levels in dog plasma after inhalation exposure.

    Science.gov (United States)

    Berg, Seija; Melamies, Marika; Rajamäki, Minna; Vainio, Outi; Peltonen, Kimmo

    2012-01-01

    A sensitive and selective method to quantify budesonide in dog plasma samples was developed and fully validated. Liquid-liquid extraction was followed by solid-phase extraction and liquid chromatography-tandem mass spectrometry with electrospray ionization. After reconstitution of the analytes in the mobile phase, samples were analysed by reversed-phase liquid chromatography with isocratic elution. d8-Budesonide was used as an internal standard, and characteristic transitions of d8-budesonide and budesonide were used for quantification. The method was validated with respect to selectivity, specificity, linearity, recovery, repeatability, reproducibility and limits of detection and quantification. The validated method was successfully applied to monitor the plasma levels of budesonide in dogs exposed to clinical doses of inhaled and intravenous drug.

  6. 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.

  7. Simultaneous drug identification in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Lee, Hei Hwa; Chen, Suen Chi; Lee, Jong Feng; Lin, Hsin Yu; Chen, Bai Hsiun

    2018-01-01

    According to domestic and international epidemiological investigation, the proportion of substance involved sexual assault has the trend of ascent. In the past, laboratory methods that investigated urine sample of the sexual assault victims was to screen with enzyme immunoassay and then confirmed with mass spectrometry. The objective of the study is to simultaneously identify abused drugs in 126 decoded urine samples of sexual assault victims by liquid chromatography tandem mass spectrometry. The instrument was operated in multiple-reaction monitoring with an electro-spray positive ionization mode. Chromatograms were separated with ACE5 C18 column on a gradient of acetonitrile. After liquid-liquid extraction, samples were passed through a 0.22μm PVDF filter before injection into the system. The limits of quantitation ranged from 0.2 to 10ng/mL. The precision (CV) results were below 12.9% (intraday) and 15.0% (interday). The intraday accuracy ranged from 84.8 to 121.0%, interday accuracy ranged from 72.0 to 117.3%. We found that 29 (23.0%) were positive for drugs. The most common drug identified is flunitrazepam (11.1%), followed by nimetazepam and ketamine (7.9%), some new psychoactive substances, such as 2C-B, mephedrone, methylone, PMA and PMMA were also identified. We identified abused drugs, benzodiazepines, and new psychoactive substances in urine of sexual assault victims by using liquid chromatography tandem mass spectrometry. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    Science.gov (United States)

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

    2016-12-01

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

  10. 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.

  11. Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Gerssen, A.; McElhinney, M.; Mulder, P.P.J.; Bire, R.; Hess, P.; Boer, de J.

    2009-01-01

    The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC¿MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

  12. Solid phase extraction for removal of matrix effects in lipophilic marine toxin analysis by liquid chromatography-tandem mass spectrometry

    NARCIS (Netherlands)

    Gerssen, A.; McElhinney, A. M.; Mulder, P.P.J.; Bire, L.; Hess, P.; de Boer, J.

    2009-01-01

    The potential of solid phase extraction (SPE) clean-up has been assessed to reduce matrix effects (signal suppression or enhancement) in the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of lipophilic marine toxins. A large array of ion-exchange, silica-based, and mixed-function

  13. 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 ...

  14. 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

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

    Science.gov (United States)

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

    2010-03-01

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

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

    Science.gov (United States)

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

    2013-06-01

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

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

    Science.gov (United States)

    Schalk, Kathrin; Koehler, Peter

    2018-01-01

    Celiac disease (CD) is an inflammatory disorder of the upper small intestine caused by the ingestion of storage proteins (prolamins and glutelins) from wheat, barley, rye, and, in rare cases, oats. CD patients need to follow a gluten-free diet by consuming gluten-free products with gluten contents of less than 20 mg/kg. Currently, the recommended method for the quantitative determination of gluten is an enzyme-linked immunosorbent assay (ELISA) based on the R5 monoclonal antibody. Because the R5 ELISA mostly detects the prolamin fraction of gluten, a new independent method is required to detect prolamins as well as glutelins. This paper presents the development of a method to quantitate 16 wheat marker peptides derived from all wheat gluten protein types by liquid chromatography tandem mass spectrometry (LC-MS/MS) in the multiple reaction monitoring mode. The quantitation of each marker peptide in the chymotryptic digest of a defined amount of the respective reference wheat protein type resulted in peptide-specific yields. This enabled the conversion of peptide into protein type concentrations. Gluten contents were expressed as sum of all determined protein type concentrations. This new method was applied to quantitate gluten in wheat starches and compared to R5 ELISA and gel-permeation high-performance liquid chromatography with fluorescence detection (GP-HPLC-FLD), which resulted in a strong correlation between LC-MS/MS and the other two methods. PMID:29425234

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

    Directory of Open Access Journals (Sweden)

    Kathrin Schalk

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

  19. Simultaneous quantification of twenty Amadori products in soy sauce using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Katayama, Hiroshi; Tatemichi, Yuki; Nakajima, Ayako

    2017-08-01

    A liquid chromatography-tandem mass spectrometry method using a pentafluorophenylpropyl-bonded silica column was developed to simultaneously quantify twenty Amadori products (APs), including N-(1-Deoxy-d-fructosyl-1-yl)-l-isoleucine (Fru-Ile) and N-(1-Deoxy-d-fructosyl-1-yl)-l-leucine (Fru-Leu), in soy sauce, without the need for an ion-pairing reagent or sample derivatization. The method was applied to six types of soy sauce, to determine the total AP levels and the levels of individual APs. The level of total APs widely varied between the eight samples, from 358mg/L to 24347mg/L. The concentrations of N-ε-(1-deoxy-d-fructosyl-1-yl)-l-lysine (Fru-Lys) and N-(1-deoxy-d-fructosyl-1-yl)-l-pyroglutamic acid (Fru-pGlu) were the highest among the APs and the level of Fru-pGlu was similar to that of Fru-Lys. Furthermore, fermentation periods of up to six months greatly influenced AP levels in soy sauce but the levels remained constant thereafter. Thermal treatment of soy sauce had little effect on AP levels. Copyright © 2017. Published by Elsevier Ltd.

  20. Multi-detection of preservatives in cheeses by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Fuselli, Fabio; Guarino, Chiara; La Mantia, Alessandro; Longo, Lucia; Faberi, Angelo; Marianella, Rosa Maria

    2012-10-01

    The incorrect use of preservatives in cheeses may compromise food safety and damage consumers. According to the law, more than one preservative may be contemporarily used in cheeses. So a method for their contemporary detection may be useful for both manufacturers and control agencies quality control. In this research a liquid chromatography-tandem mass spectrometric with electrospray ionization method for the multi-determination of seven preservatives (benzoic acid, citric acid, hexamethylenetetramine, lysozyme, natamycin, nisin and sorbic acid) in cheese was developed. The preservatives were contemporarily extracted from cheese by a single procedure, and analyzed by RP-LC/ESI-MS/MS (Ion Trap) in positive ionization mode, with single reaction monitoring (SRM) acquisition. Three sample types (hard, pasta filata and fresh cheese) were used for method evaluation. Recoveries were mostly higher than 90%; MDLs ranged from 0.02 to 0.26 mgkg(-1), and MQLs were included between 0.07 and 0.88 mgkg(-1). Due to matrix effect, quantitation was performed by referring to a matrix matched calibration curve, for each cheese typology. This method was also applied to commercial cheese samples, with good results. It appears fast, reliable and suitable for both screening and confirmation of the presence and quantitation of the preservatives in a single, multi-detection analysis. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. 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.

  2. [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.

  3. EPA CRL MS014: Analysis of Aldicarb, Bromadiolone, Carbofuran, Oxamyl and Methomyl in Water by Multiple Reaction Monitoring Liquid Chromatography / Tandem Mass Spectrometry (LC/MS/MS)

    Science.gov (United States)

    Method MS014 describes procedures for solvent extraction of aldicarb, bromadiolone, carbofuran, oxamyl and methomyl from water samples, followed by analysis using liquid chromatography tandem mass spectrometry (LC-MS-MS).

  4. Analysis of vitamin K-1 in fruits and vegetables using accelerated solvent extraction and liquid chromatography tandem mass spectrometry with atmospheric pressure chemical ionization

    DEFF Research Database (Denmark)

    Jäpelt, Rie Bak; Jakobsen, Jette

    2016-01-01

    The objective of this study was to develop a rapid, sensitive, and specific analytical method to study vitamin K-1 in fruits and vegetables. Accelerated solvent extraction and solid phase extraction was used for sample preparation. Quantification was done by liquid chromatography tandem mass...... spectrometry with atmospheric pressure chemical ionization in selected reaction monitoring mode with deuterium-labeled vitamin K1 as an internal standard. The precision was estimated as the pooled estimate of three replicates performed on three different days for spinach, peas, apples, banana, and beetroot...

  5. 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

  6. Study on pharmacokinetics of 3,4-divanillyltetrahydrofuran in rats by ultra-fast liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Shan, Chen-Xiao; Cui, Xiao-Bing; Yu, Sheng; Chai, Chuan; Wen, Hong-Mei; Wang, Xin-Zhi; Sun, Xue

    2016-01-01

    3,4-Divanillyltetrahydrofuran is the main active ingredient of nettle root which can increase steroid hormones in the bloodstream for many of bodybuilders. To better understand its pharmacological activities, we need to determine its pharmacokinetic profiles. In this study, a rapid and sensitive ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method has been developed for the determination of 3,4-divanillyltetrahydrofuran in the plasma of rats. Chromatographic separation was performed on a C18 column at 40°C, with a gradient elution consisting of methanol and water containing 0.3% (v/v) formic acid at a flow rate of 0.8mL/min. The detection was performed using an electrospray triple-quadrupole MS/MS via positive ion multiple reaction monitoring mode. The lower limits-of-quantification determined were 0.5ng/mL. The intra- and inter-day precision (RSD%) was found to be within 15% and the accuracy (RE%) ranged from -4.0% to 7.0%. This simple yet sensitive method was fully validated and could be successfully applied to the study on pharmacokinetics of 3, 4-divanillyltetrahydrofuran. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. [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.

  8. 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.

  9. 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.

  10. Liquid chromatography/tandem mass spectrometry method for quantitative estimation of solutol HS15 and its applications

    Directory of Open Access Journals (Sweden)

    V. Vijaya Bhaskar

    2015-04-01

    Full Text Available A rapid, sensitive and selective pseudoMRM (pMRM-based method for the determination of solutol HS15 (SHS15 in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LC–MS/MS. The most abundant ions corresponding to SHS15 free polyethyleneglycol (PEG oligomers at m/z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for pMRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using evaporative light scattering detector (ELSD. Plasma concentrations of SHS15 were measured after oral administration at 2.50 g/kg dose and intravenous administration at 1.00 g/kg dose in male Sprague Dawley rats. SHS15 has poor oral bioavailability of 13.74% in rats. Differences in pharmacokinetics of oligomers were studied. A novel proposal was conveyed to the scientific community, where formulation excipient could be analyzed as a qualifier in the analysis of new chemical entities (NCEs to address the spiky plasma concentration profiles. Keywords: SHS15, LC–MS/MS, Spiky profiles, Validation

  11. Liquid chromatography/tandem mass spectrometry method for quantitative estimation of solutol HS15 and its applications.

    Science.gov (United States)

    Bhaskar, V Vijaya; Middha, Anil; Srivastava, Pratima; Rajagopal, Sriram

    2015-04-01

    A rapid, sensitive and selective pseudoMRM (pMRM)-based method for the determination of solutol HS15 (SHS15) in rat plasma was developed using liquid chromatography/tandem mass spectrometry (LC-MS/MS). The most abundant ions corresponding to SHS15 free polyethyleneglycol (PEG) oligomers at m / z 481, 525, 569, 613, 657, 701, 745, 789, 833, 877, 921 and 965 were selected for pMRM in electrospray mode of ionization. Purity of the lipophilic and hydrophilic components of SHS15 was estimated using evaporative light scattering detector (ELSD). Plasma concentrations of SHS15 were measured after oral administration at 2.50 g/kg dose and intravenous administration at 1.00 g/kg dose in male Sprague Dawley rats. SHS15 has poor oral bioavailability of 13.74% in rats. Differences in pharmacokinetics of oligomers were studied. A novel proposal was conveyed to the scientific community, where formulation excipient could be analyzed as a qualifier in the analysis of new chemical entities (NCEs) to address the spiky plasma concentration profiles.

  12. [Simultaneous determination of 16 flavonoids in the ginkgo dietary supplement tea by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Jiang, Yalan; Huang, Fang; Wu, Fuhai; Wu, Huiqin; Huang, Xiaolan; Deng, Xin

    2015-10-01

    A method for the determination of 16 functional components of ginkgo dietary supplement tea such as catechin, vitexin, puerarin, isoflavoues aglycone, silymarin, quercetin, luteolin, apigenin, naringenin, hesperitin dihydrochalcone, kaempferol, hesperitin, isorhamnetin, baicalein, nobiletin and tangeretin by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was proposed. The conditions of chromatography and mass spectrometry were optimized. The 16 flavonoids were separated on a C18 chromatographic column with acetonitrile and water (additional 0.1% formic acid) as mobile phases under gradient elution at a flow rate of 0.25 mL/min. The determination was conducted by tandem mass spectrometry in positive ESI mode under multiple reaction monitoring (MRM) mode. Good linearities for all the compounds, with correlation coefficients over 0.996, were acquired. The recoveries were in the range of 70.9% to 100.0% (n = 6), while the relative standard deviations (RSDs) were less than 10%. The results showed that the nine flavonoids, which were kaempferol, quercetin, hesperitin, vitexin, luteolin, catechin, apigenin, naringenin and isorhamnetin, were higher in contents among the 16 flavonoids in real samples, and they constituted up to 99.6% of the total flavonoids. The contents of these nine flavonoids can be considered as the quality control index of the ginkgo dietary supplement tea. The method proved to be rapid, selective, sensitive and stable, and it can be applied to control the quality of the ginkgo dietary supplement tea.

  13. Using a single tablet daily to treat latent tuberculosis infection in Brazil: bioequivalence of two different isoniazid formulations (300 mg and 100 mg) demonstrated by a sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry method in a randomised, crossover study.

    Science.gov (United States)

    Daher, André; Pitta, Luciana; Santos, Tereza; Barreira, Draurio; Pinto, Douglas

    2015-06-01

    The recommended treatment for latent tuberculosis (TB) infection in adults is a daily dose of isoniazid (INH) 300 mg for six months. In Brazil, INH was formulated as 100 mg tablets. The treatment duration and the high pill burden compromised patient adherence to the treatment. The Brazilian National Programme for Tuberculosis requested a new 300 mg INH formulation. The aim of our study was to compare the bioavailability of the new INH 300 mg formulation and three 100 mg tablets of the reference formulation. We conducted a randomised, single dose, open label, two-phase crossover bioequivalence study in 28 healthy human volunteers. The 90% confidence interval for the INH maximum concentration of drug observed in plasma and area under the plasma concentration vs. time curve from time zero to the last measurable concentration "time t" was 89.61-115.92 and 94.82-119.44, respectively. The main limitation of our study was that neither adherence nor the safety profile of multiple doses was evaluated. To determine the level of INH in human plasma, we developed and validated a sensitive, simple and rapid high-performance liquid chromatography-tandem mass spectrometry method. Our results showed that the new formulation was bioequivalent to the 100 mg reference product. This finding supports the use of a single 300 mg tablet daily strategy to treat latent TB. This new formulation may increase patients' adherence to the treatment and quality of life.

  14. Using a single tablet daily to treat latent tuberculosis infection in Brazil: bioequivalence of two different isoniazid formulations (300 mg and 100 mg demonstrated by a sensitive and rapid high-performance liquid chromatography-tandem mass spectrometry method in a randomised, crossover study

    Directory of Open Access Journals (Sweden)

    André Daher

    2015-06-01

    Full Text Available The recommended treatment for latent tuberculosis (TB infection in adults is a daily dose of isoniazid (INH 300 mg for six months. In Brazil, INH was formulated as 100 mg tablets. The treatment duration and the high pill burden compromised patient adherence to the treatment. The Brazilian National Programme for Tuberculosis requested a new 300 mg INH formulation. The aim of our study was to compare the bioavailability of the new INH 300 mg formulation and three 100 mg tablets of the reference formulation. We conducted a randomised, single dose, open label, two-phase crossover bioequivalence study in 28 healthy human volunteers. The 90% confidence interval for the INH maximum concentration of drug observed in plasma and area under the plasma concentration vs. time curve from time zero to the last measurable concentration “time t” was 89.61-115.92 and 94.82-119.44, respectively. The main limitation of our study was that neither adherence nor the safety profile of multiple doses was evaluated. To determine the level of INH in human plasma, we developed and validated a sensitive, simple and rapid high-performance liquid chromatography-tandem mass spectrometry method. Our results showed that the new formulation was bioequivalent to the 100 mg reference product. This finding supports the use of a single 300 mg tablet daily strategy to treat latent TB. This new formulation may increase patients’ adherence to the treatment and quality of life.

  15. Online liquid chromatography-tandem mass spectrometry cyanide determination in blood.

    Science.gov (United States)

    Lacroix, C; Saussereau, E; Boulanger, F; Goullé, J P

    2011-04-01

    An original liquid chromatography-tandem mass spectrometry (LC-MS-MS) method coupled to online extraction has been developed for cyanide determination in blood. A method involving fluorimetric detection after naphthalene-2,3-dicarboxyaldehyde (NDA) complexation by taurine in the presence of cyanide was previously described. Its performance was limited because of the absence of an internal standard (IS). Using cyanide isotope (13)C(15)N as IS allowed quantification in MS-MS. After the addition of (13)C(15)N, 25 μL of blood were diluted in water and deproteinized with methanol. Following derivatization with NDA and taurine for 10 min at 4°C, 100 μL was injected into the online LC-MS-MS system. An Oasis HLB was used as an extraction column, and a C18 Atlantis was the analytical column. The chromatographic cycle was performed with an ammonium formate (20 mM, pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 6 min. Detection was performed in negative electrospray ionization mode (ESI(-)) with a Quattro Micro. For quantification, transitions of derivatives formed with CN and (13)C(15)N were monitored, respectively, as follows: 299.3/191.3 and 301.3/193.3. The procedure was fully validated, linear from 26 to 2600 ng/mL with limit of detection of 10 ng/mL. This method, using a small blood sample, is not only simple, but also time saving. The specificity and sensitivity of LC-MS-MS coupled to online extraction and using (13)C(15)N as the IS make this method very suitable for cyanide determination in blood and could be useful in forensic toxicology.

  16. Profiling of kidney vascular endothelial cell plasma membrane proteins by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Liu, Zan; Xu, Bo; Nameta, Masaaki; Zhang, Ying; Magdeldin, Sameh; Yoshida, Yutaka; Yamamoto, Keiko; Fujinaka, Hidehiko; Yaoita, Eishin; Tasaki, Masayuki; Nakagawa, Yuki; Saito, Kazuhide; Takahashi, Kota; Yamamoto, Tadashi

    2013-06-01

    Vascular endothelial cells (VECs) play crucial roles in physiological and pathologic conditions in tissues and organs. Most of these roles are related to VEC plasma membrane proteins. In the kidney, VECs are closely associated with structures and functions; however, plasma membrane proteins in kidney VECs remain to be fully elucidated. Rat kidneys were perfused with cationic colloidal silica nanoparticles (CCSN) to label the VEC plasma membrane. The CCSN-labeled plasma membrane fraction was collected by gradient ultracentrifugation. The VEC plasma membrane or whole-kidney lysate proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and digested with trypsin in gels for liquid chromatography-tandem mass spectrometry. Enrichment analysis was then performed. The VEC plasma membrane proteins were purified by the CCSN method with high yield (approximately 20 μg from 1 g of rat kidney). By Mascot search, 582 proteins were identified in the VEC plasma membrane fraction, and 1,205 proteins were identified in the kidney lysate. In addition to 16 VEC marker proteins such as integrin beta-1 and intercellular adhesion molecule-2 (ICAM-2), 8 novel proteins such as Deltex 3-like protein and phosphatidylinositol binding clathrin assembly protein (PICALM) were identified. As expected, many key functions of plasma membranes in general and of endothelial cells in particular (i.e., leukocyte adhesion) were significantly overrepresented in the proteome of CCSN-labeled kidney VEC fraction. The CCSN method is a reliable technique for isolation of VEC plasma membrane from the kidney, and proteomic analysis followed by bioinformatics revealed the characteristics of in vivo VECs in the kidney.

  17. Determination of aflatoxins in medicinal plants by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Siddique, Nadeem A; Mujeeb, Mohd; Ahmad, Sayeed; Panda, Bibhu P; Makhmoor, Mohd

    2013-01-01

    The intention of the proposed work is to study the presence of the aflatoxins B1, B2, G1 and G2 in medicinal plants, namely Mucuna pruriens, Delphinium denudatum and Portulaca oleraceae. The aflatoxins were extracted, purified by immunoaffinity column chromatography and analysed by high-performance liquid chromatography-tandem quadrupole mass spectrometry with electrospray ionisation (HPLC-MS/MS). Fungal count was carried out in PDA media. A good linear relationship was found for AFB1, AFB2, AFG1 and AFG2 at 1-10 ppb (r>0.9995). The analyte accuracy under three different spiking levels was 86.7-108.1 %, with low per cent relative standard deviations in each case. The aflatoxins can be separated within 5 to7 min using an Agilent XDB C18-column. We found that AFB1 and AFB2 were in trace amounts below the detection limit in M. pruriens whilst they were not detected in D. denudatum. P. oleraceae was found to be contaminated with AFB1 and AFB2. AFG1 and AFG2 were not detected in M. pruriens, P. oleraceae and were below the detection limit in D. denudatum. This was consistent with very low numbers of fungal colonies observed after 6 hr of incubation. The analytical method developed is simple, precise, accurate, economical and can be effectively used to determine the aflatoxins in medicinal plants and therefore to control the quality of products. The aflatoxin levels in the plant extracts examined were related to the minimal fungal load in the medicinal plants examined.

  18. Simultaneous quantification of multiple urinary naphthalene metabolites by liquid chromatography tandem mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Daniel C Ayala

    Full Text Available Naphthalene is an environmental toxicant to which humans are exposed. Naphthalene causes dose-dependent cytotoxicity to murine airway epithelial cells but a link between exposure and human pulmonary disease has not been established. Naphthalene toxicity in rodents depends on P450 metabolism. Subsequent biotransformation results in urinary elimination of several conjugated metabolites. Glucuronide and sulfate conjugates of naphthols have been used as markers of naphthalene exposure but, as the current studies demonstrate, these assays provide a limited view of the range of metabolites generated from the parent hydrocarbon. Here, we present a liquid chromatography tandem mass spectrometry method for measurement of the glucuronide and sulfate conjugates of 1-naphthol as well as the mercapturic acids and N-acetyl glutathione conjugates from naphthalene epoxide. Standard curves were linear over 2 log orders. On column detection limits varied from 0.91 to 3.4 ng; limits of quantitation from 1.8 to 6.4 ng. The accuracy of measurement of spiked urine standards was -13.1 to + 5.2% of target and intra-day and inter-day variability averaged 7.2 (± 4.5 and 6.8 (± 5.0 %, respectively. Application of the method to urine collected from mice exposed to naphthalene at 15 ppm (4 hrs showed that glutathione-derived metabolites accounted for 60-70% of the total measured metabolites and sulfate and glucuronide conjugates were eliminated in equal amounts. The method is robust and directly measures several major naphthalene metabolites including those derived from glutathione conjugation of naphthalene epoxide. The assays do not require enzymatic deconjugation, extraction or derivatization thus simplifying sample work up.

  19. [Measurement of sialic acid from lipoproteins and human plasma by liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Guo, Shoudong; Sang, Hui; Yang, Nana; Kan, Yujie; Li, Fuyu; Li, Yu; Li, Fangyuan; Qin, Shucun

    2014-11-01

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established to quantify sialic acid (N-acetylneuraminic acid, NANA) from lipoproteins and human plasma. The method was used to investigate the different contents of NANA from lipoproteins between diabetic with an average age of 51.6 years and healthy participants with an average age of 50.7 years. The NANA from lipoprotein samples was hydrolyzed by acetic acid (pH = 2) at 80 °C for 2 h and analyzed by the optimized LC-MS/MS method after high speed centrifugation and filtration. The limits of detection and quantification of NANA were 7.4 and 24.5 pg, respectively. The linear range was 2.5-80 ng/mL for NANA and the correlation coefficient (R2) was more than 0.998. The levels of NANA in the plasma of type II diabetics and healthy participants were (548.3 ± 88.9) and (415.3 ± 55.5) mg/L, respectively; and the levels of NANA from very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL) of the type II diabetics and the healthy participants were (4.91 ± 0.19), (6.95 ± 0.28), (3.61 ± 0.22) μg/mg and (2.90 ± 0.27), (7.03 ± 0.04), (2.40 ± 0.09) μg/mg, respectively. The sialic acid levels of VLDL and HDL from the type II diabetics were markedly higher than those of the corresponding healthy participants with the similar ages (P lipoproteins, and is reproducible and time saving.

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

    Directory of Open Access Journals (Sweden)

    André Luiz da Costa MICHELOTTO

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Tanveer A. Wani

    2015-09-01

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

  2. 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...

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

    Science.gov (United States)

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

    2005-09-01

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

  4. 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.

  5. Confirmation of congenital adrenal hyperplasia by adrenal steroid profiling of filter paper dried blood samples using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rossi, Claudia; Calton, Lisa; Brown, Heather A; Gillingwater, Scott; Wallace, A Michael; Petrucci, Francesca; Ciavardelli, Domenico; Urbani, Andrea; Sacchetta, Paolo; Morris, Michael

    2011-04-01

    The specificity of screening for congenital adrenal hyperplasia by direct measurement of 17-hydroxyprogesterone in filter paper dried blood spot samples by immunoassay is low and has a high false-positive rate. In order to reduce the false-positive rate of this test, we developed a rapid, robust, specific confirmatory procedure in which cortisol, 4-androstene-3,17-dione and 17-hydroxyprogesterone were measured simultaneously by ultra-performance liquid chromatography-tandem mass spectrometry. After extraction, samples were analysed by ultra-performance liquid chromatography-tandem mass spectrometry and 17-hydroxyprogesterone was quantified accurately. Other steroids were determined using stable deuterated internal standards. In total, 25 patient blood spot samples and 92 control samples were analysed. The assay was linear for 17-hydroxyprogesterone, with a coefficient of determination >0.997 and imprecision ≤ 6.5%. An upper limit of normal for 17-hydroxyprogester-one of 4.45 nmol/L was established by analysing a cohort of samples from unaffected newborns. In addition, a cut-off of 3.5 for the peak areas ratio (17-hydroxyprogesterone+4-androstene-3,17-dione)/cortisol, allows confirmation of the affected steroidogenic enzyme. A high throughput method for the detection of steroids related to congenital adrenal hyperplasia has been developed, allowing the false-positive rate associated with screening for 17-hydroxyprogesterone by immunoassay to be determined.

  6. [Determination of 250 pesticide residues in vegetables using QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Aizhi; Wang, Quanlin; Cao, Lili; Li, Yu; Shen, Hao; Shen, Jian; Zhang, Shufen; Man, Zhengyin

    2016-02-01

    A multiresidue analytical method for the determination of 250 pesticide residues in vegetables was developed by using QuEChERS-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The target compounds were extracted with acetonitrile containing 1% (v/v) acetic acid, purified by a mixed sorbent of MgSO4, primary secondary amine (PSA), graphitized carbon black (GCB) and C18, separated on a Waters ACQUITY™ UPLC BEH C18 column (100 mm x 2. 1 mm, 1.7 µm) and detected by UPLC-MS/MS. Anhydrous magnesium sulfate was used as a dewatering agent. The effects of the amounts of MgSO4, PSA, GCB and C18 added on the recoveries of 250 pesticides were investigated. The results showed that the purification effect was best when 300 mg MgSO4, 200 mg PSA, 10 mg GCB and 100 mg C18 in 2 mL of the extract were added. For the 250 pesticide residues, the limits of detection (LODs) of the method were from 0. 01 to 50. 00 g/kg. The recoveries obtained ranged from 60. 1% to 120% at three spiked levels in Chinese chives with the relative standard deviations between 3. 5% and 19. 5% using matrix matched external standard method. The results showed that the method is able to meet requirements of the multiresidue detection of the 250 pesticides in vegetable. The method has the advantages of rapidity, simplicity, high sensitivity and better purification effect. It is suitable for the rapid determination of the common pesticides in vegetables, and it provides a strong guarantee for the risk assessments of the quality and safety of vegetables.

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

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2009-01-01

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

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

    DEFF Research Database (Denmark)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe

    2012-01-01

    An ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of 25 common pharmaceuticals in whole blood. The selected pharmaceuticals represent the most frequently detected drugs in our forensic laboratory with basic properties....../kg depending on the analyte. A good linear behavior was achieved for all analytes in the range from LOQ to 1.0 or 2.0 mg/kg blood. The absolute recoveries were between 55-87% for all compounds except norfluoxetine (44%). The method showed acceptable precision and accuracy for almost all analytes. Only unstable...

  9. Determination of the neuropharmacological drug nodakenin in rat plasma and brain tissues by liquid chromatography tandem mass spectrometry: Application to pharmacokinetic studies.

    Science.gov (United States)

    Song, Yingshi; Yan, Huiyu; Xu, Jingbo; Ma, Hongxi

    2017-09-01

    A rapid and sensitive liquid chromatography tandem mass spectrometry detection using selected reaction monitoring in positive ionization mode was developed and validated for the quantification of nodakenin in rat plasma and brain. Pareruptorin A was used as internal standard. A single step liquid-liquid extraction was used for plasma and brain sample preparation. The method was validated with respect to selectivity, precision, accuracy, linearity, limit of quantification, recovery, matrix effect and stability. Lower limit of quantification of nodakenin was 2.0 ng/mL in plasma and brain tissue homogenates. Linear calibration curves were obtained over concentration ranges of 2.0-1000 ng/mL in plasma and brain tissue homogenates for nodakenin. Intra-day and inter-day precisions (relative standard deviation, RSD) were <15% in both biological media. This assay was successfully applied to plasma and brain pharmacokinetic studies of nodakenin in rats after intravenous administration. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Ultra-performance liquid chromatography-tandem mass spectrometry method for the determination of febuxostat in dog plasma and its application to a pharmacokinetic study.

    Science.gov (United States)

    Zhang, Tianhong; Sun, Yuanpeng; Zhang, Peng; Gao, Jingmei; Wang, Shanshan; He, Zhonggui

    2013-02-01

    A rapid, sensitive and selective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the determination of febuxostat in dog plasma. Using paclitaxel as an internal standard (IS), a simple liquid-liquid extraction method with ethyl acetate was adopted for plasma sample pretreatment. Separation was carried out on an Acquity UPLC BEH C(18) column with a mobile phase consisting of acetonitrile and water (containing 0.2% formic acid). The assay was linear in the concentration ranged from 5 to 5000 ng/mL with a lower limit of quantification of 5 ng/mL for febuxostat. The single run analysis was as short as 2.0 min. Finally, the developed method was successfully applied to the pharmacokinetic study of febuxostat tablets following oral administration at a single dose of 40 mg in beagle dogs. Copyright © 2012 John Wiley & Sons, Ltd.

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

    Science.gov (United States)

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

    2015-10-01

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

  12. Quantitative determination of hederagenin in rat plasma and cerebrospinal fluid by ultra fast liquid chromatography-tandem mass spectrometry method.

    Science.gov (United States)

    Yang, Xuemei; Li, Guoliang; Chen, Lingyun; Zhang, Cong; Wan, Xinxiang; Xu, Jiangping

    2011-07-01

    A rapid, sensitive and selective method was developed for the quantitative determination of hederagenin in rat plasma and cerebrospinal fluid (CSF) by ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS). It has been successfully applied in a pharmacokinetic study of hederagenin in the central nervous system (CNS). Sample pretreatment involved a simple protein precipitation with methanol and a one-step extraction with ethyl acetate. Separation was carried out in a Shim-pack XR-ODS II (75 mm × 2.0 mm, i.d., 2.1 μm) column with gradient elution at a flow rate of 0.35 mL/min. The mobile phase was 5mM ammonium acetate and acetonitrile. Detection was performed in a triple-quadruple tandem mass spectrometer by multiple-reaction-monitoring mode via electrospray ionization. A linear calibration curve for hederagenin was obtained over a concentration range of 0.406 (lower limit of quantification, LLOQ) to 203 ng/mL (r² > 0.99) for both plasma and CSF. The intra-day and inter-day precision (relative standard deviation, RSD) values were less than 15%. At all quality control (QC) levels, the accuracy (relative error, RE) was within -9.0% and 11.1% for plasma and CSF, respectively. The pharmacokinetics results indicated that hederagenin could pass through the blood-brain barrier. This UFLC-MS/MS method demonstrates higher sensitivity and sample throughput than previous methods. It was also successfully applied to the pharmacokinetic study of hederagenin following oral administration of Fructus akebiae extract in rats. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Determination of genkwanin in rat plasma by liquid chromatography-tandem mass spectrometry: application to a bioavailability study.

    Science.gov (United States)

    Song, Yanqing; Zhang, Sixi; Liu, Hong; Jin, Xiangqun

    2013-10-01

    We developed and validated a sensitive, rapid, and specific liquid chromatography tandem mass spectrometry method to determine genkwanin in rat plasma. Genistein was used as the internal standard. After liquid-liquid extraction with ethyl acetate, the chromatographic separation of genkwanin was achieved by using a reversed-phase HPLC using Agela Venusil MP-C18 analytical column (2.1 mm × 50 mm, 5 μm particles) with a mobile phase of methanol (A)-water (B) (65:35, v/v) containing 5mM ammonium acetate and 0.1% formic acid. The detection was performed by negative ion electrospray ionization in multiple-reaction monitoring mode by using transitions of m/z 283.1→268.1 and m/z 269.1→133.0 for genkwanin and IS, respectively. Good linearity was observed in the concentration range of 3.84 ng/ml to 3,840 ng/ml (r(2)>0.99), and the lower limit of quantification was 3.84 ng/ml in 100 μl of rat plasma. The intra- and inter-day accuracy and precision of genkwanin were both within acceptable limits. This present method was successfully applied to a pharmacokinetic study of genkwanin in rats following oral (50mg/kg) and intravenous (5mg/kg) administration. For the oral administration group, the maximum mean concentration of genkwanin in plasma (Cmax, 36.9 ± 9.4 ng/ml) was achieved at 3.83 ± 1.33 h (Tmax), and the area under the plasma concentration versus time curve from 0 h to 12h (AUC0-12h) was 218 ± 40 ngh/ml. For the intravenous administration group, essential pharmacokinetic parameters such as Cmax (1,755 ± 197 ng/ml) and AUC0-12h (2,349 ± 573 ngh/ml) were shown. The result showed that the compound was poorly absorbed with an absolute bioavailability of approximately 1.1%. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2015-04-01

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

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

    Science.gov (United States)

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

    2009-04-01

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

  17. Quantitation of clevidipine in dog blood by liquid chromatography tandem mass spectrometry: application to a pharmacokinetic study.

    Science.gov (United States)

    Wei, Huihui; Gu, Yuan; Liu, Yanping; Chen, Yong; Liu, Changxiao; Si, Duanyun

    2014-11-15

    Clevidipine, a vascular selective calcium channel antagonist of the dihydropyridine class, is rapidly metabolized by ester hydrolysis because of incorporation of an ester linkage into the drug molecule. To characterize its pharmacokinetic profiles in dogs, a simple, rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for quantitation of clevidipine in dog blood. After one-step protein precipitation with methanol, the chromatographic separation was carried out on an Ecosil C18 column (150mm×4.6mm, 5μm) with a gradient mobile phase consisting of methanol and 5mM ammonium formate at a flow rate of 0.5mL/min. The quantitation analysis was performed using multiple reaction monitoring (MRM) at the specific ion transitions of m/z 454.1 [M-H](-)→m/z 234.1 for clevidipine and m/z 256.1 [M-H](-)→m/z 227.1 for elofesalamide (internal standard) in the negative ion mode with electrospray ionization (ESI) source. This validated LC-MS/MS method showed good linearity over the range 0.5-100ng/mL with the lower limit of quantitation (LLOQ) of 0.5ng/mL together with the satisfied intra- and inter-day precision, accuracy, extraction recovery and matrix effect. Stability testing indicated that clevidipine in dog blood with the addition of denaturant methanol was stable on workbench for 1h, at -80°C for up to 30 days, and after three freeze-thaw cycles. Extracted samples were also observed to be stable over 24h in an auto-sampler at 4°C. The validated method has been successfully applied to a pharmacokinetic study of clevidipine injection to 8 healthy Beagle dogs following intravenous infusion at a flow rate of 5mg/h for 0.5h. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. 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

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

    Science.gov (United States)

    van der Ham, M; Albersen, M; de Koning, T J; Visser, G; Middendorp, A; Bosma, M; Verhoeven-Duif, N M; de Sain-van der Velden, M G M

    2012-01-27

    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'-phosphate (PLP), pyridoxamine 5'-phosphate (PMP) and pyridoxine 5'-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(-1) trichloroacetic acid containing stable isotope labeled internal standards: PL-D(3) for PL and PM, PN-(13)C(4) for PN, PA-D(2) for PA and PLP-D(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→150.1 (PL), 169.1→134.1 (PM), 170.1→134.1 (PN), 184.1→148.1 (PA), 248.1→150.1 (PLP), 249.1→232.1 (PMP) and 250.1→134.1 (PNP). The method was validated at three concentration levels for each B6 vitamer in CSF. Recoveries of the internal standards were between 93% and 96%. Intra- and inter-assay variations were below 20%. Accuracy tests showed deviations from 3% (PN) to 39% (PMP). Limits of quantification were in the range of 0.03-5.37 nM. Poor results were obtained for quantification of PNP. The method was applied to CSF samples of 20 subjects and two patients on pyridoxine supplementation. Using minimal CSF volumes this method is suitable for implementation in a routine diagnostic setting. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. 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

  2. A validated liquid chromatography-tandem mass spectrometry method for the quantitative determination of 4 beta-hydroxycholesterol in human plasma

    NARCIS (Netherlands)

    van de Merbel, Nico C.; Bronsema, Kees J.; van Hout, Mischa W. J.; Nilsson, Ralf; Sillen, Henrik

    2011-01-01

    A novel liquid chromatography-tandem mass spectrometry method is described for the quantitative determination of the endogenous CYP 3A4/5 marker 4 beta-hydroxycholesterol in human K(2)-EDTA plasma. It is based on alkaline hydrolysis to convert esterified to free 4 beta-hydroxycholesterol, followed

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

    2016-01-01

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

  5. 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...

  6. [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.

  7. Liquid chromatography-tandem mass spectrometry detection of the quaternary ammonium compound mebezonium as an active ingredient in t61.

    Science.gov (United States)

    Kirschbaum, Katrin M; Grellner, Wolfgang; Rochholz, Gertrud; Musshoff, Frank; Madea, Burkhard

    2011-03-01

    Quaternary ammonium compounds pose an analytical challenge. Mebezonium, a muscle-relaxing agent contained in veterinary euthanasia solution T61, was analyzed in body fluids, organs, and injection sites of a veterinarian by liquid chromatography-tandem mass spectrometry (LC-MS-MS) method. Additionally, embutramide and tetracaine, which are two other active ingredients contained in T61, methadone, xylazine, and analgesics were detected by LC-MS-MS and high-performance liquid chromatography-ultraviolet detection methods. For detection of mebezonium a solid-phase extraction (SPE) combined with ionpairing reagent heptafluorobutyric acid was developed. Separation was achieved on Phenomenex Synergi Hydro RP C(18) column combined with ammonium formate buffer and acetonitrile (pH 3.5). To enrich other drugs, liquid-liquid extraction procedures were used. Most of these drugs were separated on a Restek Allure PFP Propyl column using the mentioned mobile phase. Mebezonium and embutramide were detected in femoral vein serum in concentrations of 10.9 and 2.0 mg/L, respectively. The concentration of xylazine and methadone in serum was 2.0 and 0.4 mg/L, respectively. The LC-MS-MS method with SPE combined with an ion-pairing reagent allowed the quantitation of mebezonium. Methadone was detected in toxic concentrations and was, in combination with xylazine and T61, considered to be the cause of death.

  8. 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.

  9. Validation of a chiral liquid chromatography-tandem mass spectrometry method for the determination of pantoprazole in dog plasma.

    Science.gov (United States)

    Chen, Meixia; Xia, Yu; Ma, Zhiyu; Li, Liang; Zhong, Dafang; Chen, Xiaoyan

    2012-10-01

    Pantoprazole (PAN), a selective proton pump inhibitor, is used clinically as a racemic mixture for the treatment of acid-related gastrointestinal disorders. To investigate its stereoselective pharmacokinetics, a chiral liquid chromatography-tandem mass spectrometry method was developed and validated to determine the pantoprazole enantiomers in dog plasma. After liquid-liquid extraction, a baseline resolution of enantiomers was achieved on an ovomucoid column using the mobile phase of methanol:acetonitrile:10mM ammonium formate (pH 7) (10.4:2.6:87, v/v/v) at 30°C within 10min. Stable isotopically labeled (+)-d(3)-pantoprazole and (-)-d(3)-pantoprazole were used as internal standards. Acquisition of mass spectrometric data was performed in multiple reaction monitoring mode via positive atmospheric pressure chemical ionization. The method was linear in the concentration range of 20.0-10,000ng/mL for each enantiomer using 25μL of dog plasma. The lower limit of quantification (LLOQ) for each enantiomer was 20.0ng/mL. Intra- and inter-day precision ranged from 3.2% to 10.3% for (+)-pantoprazole and 3.7-10.0% for (-)-pantoprazole. Accuracy varied from -1.4% to -0.2% for (+)-pantoprazole and -1.6% to 0.8% for (-)-pantoprazole. The validated method was applied successfully for stereoselective pharmacokinetic studies of racemic pantoprazole. Copyright © 2012 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Leigh, Jessica K; MacMahon, Shaun

    2016-12-14

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

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

    Directory of Open Access Journals (Sweden)

    Santosh Ghatol

    2013-04-01

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

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

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

    2018-01-01

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

  14. Liquid chromatography-tandem mass spectrometry analysis of perfluorooctane sulfonate and perfluorooctanoic Acid in fish fillet samples.

    Science.gov (United States)

    Paiano, Viviana; Fattore, Elena; Carrà, Andrea; Generoso, Caterina; Fanelli, Roberto; Bagnati, Renzo

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Viviana Paiano

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ji Sun Lee

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

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

    Directory of Open Access Journals (Sweden)

    Hei-Hwa Lee

    2016-03-01

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

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

    Science.gov (United States)

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

    2009-03-01

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

  19. Ultra-high-performance liquid chromatography tandem mass spectrometry method for the determination of gambogenic acid in dog plasma and its application to a pharmacokinetic study.

    Science.gov (United States)

    Chen, Jin Pei; Wang, Dian Lei; Yang, Li Li; Wang, Chen Yin; Wang, Shan Shan

    2014-12-01

    A highly sensitive and rapid ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of gambogenic acid in dog plasma. Gambogic acid was used as an internal standard (IS). After a simple liquid-liquid extraction by ethyl acetate, the analyte and internal standard were separated on an Acquity BEH C18 (100 × 2.1 mm, 1.7 µm; Waters ) column at a flow rate of 0.2 mL/min, using 0.1% formic acid-methanol (10:90, v/v) as mobile phase. Electrospray ionization source was applied and operated in the positive ion mode. Multiple reaction monitoring mode with the transitions m/z 631.3 → 507.3 and m/z 629.1 → 573.2 was used to quantify gambogenic acid and the internal standard, respectively. The calibration curves were linear in the range of 5-1000 ng/mL, with a coefficient of determination (r) of 0.999 and good calculated accuracy and precision. The low limit of quantification was 5 ng/mL. The intra-and inter-day precisions (relative standard deviations) were dogs at a dose of 1 mg/kg. Copyright © 2014 John Wiley & Sons, Ltd.

  20. Simultaneous Determination of 13 Anticoagulant Rodenticidesin Human Blood by Liquid Chromatography-Tandem Mass Spectrometry and its Application in Three Poisoning Cases.

    Science.gov (United States)

    Qiao, Zheng; Xiang, Ping; Shen, Baohua; Shen, Min; Yan, Hui

    2018-05-01

    Anticoagulant rodenticides are widely used for rodent control around the world. A rapid and sensitive method was developed and validated for the simultaneous determination of 13 anticoagulant rodenticides (coumafuryl, pindone, valone, warfarin, coumatetralyl, coumachlor, diphacinone, dicumarol, chlorophacinone, bromadiolone, difenacoum, flocoumafen, and brodifacoum) in human blood by liquid chromatography-tandem mass spectrometry. After liquid-liquid extraction, the anticoagulant rodenticides were separated on an Eclipse Plus C18 column. Linearities were observed for each analyte in blood ranging from 0.5 to 50 ng/mL, with correlation coefficients over 0.99. The limits of detection ranged from 0.01 to 0.2 ng/mL, and the limits of quantification were 0.5 ng/mL for all analytes. The intraday and interday precisions were <15%, and accuracies ranged from 80.3% to 111.0%. This validated method with high sensitivity has been applied in three anticoagulant rodenticide poisoning cases and has been used successfully in monitoring blood concentrations for months. © 2017 American Academy of Forensic Sciences.

  1. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2018-02-23

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

  3. Determination of Glyphosate, Maleic Hydrazide, Fosetyl Aluminum, and Ethephon in Grapes by Liquid Chromatography/Tandem Mass Spectrometry.

    Science.gov (United States)

    Chamkasem, Narong

    2017-08-30

    A simple high-throughput liquid chromatography/tandem mass spectrometry (LC-MS-MS) method was developed for the determination of maleic hydrazide, glyphosate, fosetyl aluminum, and ethephon in grapes using a reversed-phase column with weak anion-exchange and cation-exchange mixed mode. A 5 g test portion was shaken with 50 mM HOAc and 10 mM Na 2 EDTA in 1/3 (v/v) MeOH/H 2 O for 10 min. After centrifugation, the extract was passed through an Oasis HLB cartridge to retain suspended particulates and nonpolar interferences. The final solution was injected and directly analyzed in 17 min by LC-MS-MS. Two MS-MS transitions were monitored in the method for each target compound to achieve true positive identification. Four isotopically labeled internal standards corresponding to each analyte were used to correct for matrix suppression effects and/or instrument signal drift. The linearity of the detector response was demonstrated in the range from 10 to 1000 ng/mL for each analyte with a coefficient of determination (R 2 ) of ≥0.995. The average recovery for all analytes at 100, 500, and 2000 ng/g (n = 5) ranged from 87 to 111%, with a relative standard deviation of less than 17%. The estimated LOQs for maleic hydrazide, glyphosate, fosetyl-Al, and ethephon were 38, 19, 29, and 34 ng/g, respectively.

  4. Quantitative analysis of multiple fatty acid ethanolamides using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lin, Lin; Yang, Haifeng; Jones, Peter J H

    2012-12-01

    Fatty acid ethanolamides (FAE) represent a group of lipid signaling molecules associated with many physiological and pharmacological actions; however, low FAE tissue levels pose challenges in terms of analytical characterization. The objective was to develop a competent ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for analysis of multiple FAE in animal and human tissue samples. Analytes were extracted using lipid-phase and solid-phase extraction procedures. Chromatographic separation was achieved using a gradient elution in 8 min. FAE were quantified by MS/MS in positive electrospray ionization mode. Linearity was shown in lower and higher FAE concentration ranges, with a limit of quantification (LOQ) ≤0.2 ng/ml for FAE including alpha-linolenoylethanolamide (ALEA), arachidonoylethanolamide (AEA), docosahexaenoylethanolamide (DHEA), linoleoylethanolamide (LEA), oleoylethanolamide (OEA) and palmitoylethanolamide (PEA). Accuracy was shown to be between 92.4% and 108.8%, and precision was <10% for all FAE species. In sum, this sensitive and reproducible method can be used to simultaneously determine multiple FAE at low concentrations in order to facilitate further study of the role of FAE on physiological state. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. 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

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

    Directory of Open Access Journals (Sweden)

    Francesca Buiarelli

    2018-01-01

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

  7. 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.

  8. Serum markers in alkaptonuria: simultaneous analysis of homogentisic acid, tyrosine and nitisinone by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Hughes, Andrew T; Milan, Anna M; Davison, Andrew S; Christensen, Peter; Ross, Gordon; Gallagher, James A; Dutton, John J; Ranganath, Lakshminarayan R

    2015-09-01

    Alkaptonuria is a rare debilitating autosomal recessive disorder of tyrosine metabolism, where deficiency of homogentisate 1,2-dioxygenase results in increased homogentisic acid. Homogentisic acid is deposited as an ochronotic pigment in connective tissues, especially cartilage, leading to a severe early onset form of osteoarthritis, increased renal and prostatic stone formation and hardening of heart vessels. Treatment with the orphan drug, nitisinone, an inhibitor of 4-hydroxyphenylpyruvate dioxygenase has been shown to reduce urinary excretion of homogentisic acid. A reverse phase liquid chromatography tandem mass spectrometry method has been developed to simultaneously analyse serum homogentisic acid, tyrosine and nitisinone. Using matrix-matched calibration standards, two product ion transitions were identified for each compound (homogentisic acid, tyrosine, nitisinone) and their respective isotopically labelled internal standards ((13)C6-homogentisic acid, d2-tyrosine, (13)C6-nitisinone). Intrabatch accuracy was 94-108% for homogentisic acid, 95-109% for tyrosine and 89-106% for nitisinone; interbatch accuracy (n = 20) was 88-108% for homogentisic acid, 91-104% for tyrosine and 88-103% for nitisinone. Precision, both intra- and interbatch were alkaptonuria patients, pre- and post-nitisinone therapy. © The Author(s) 2015.

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

    Science.gov (United States)

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

    2018-04-04

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

  10. Principles and clinical applications of liquid chromatography - tandem mass spectrometry for the determination of adrenal and gonadal steroid hormones.

    Science.gov (United States)

    Kulle, A E; Welzel, M; Holterhus, P-M; Riepe, F G

    2011-10-01

    Liquid-chromatography - tandem mass spectrometry (LC-MS/MS) is becoming the method of choice for clinical steroid analysis. In most instances, it has the advantage of higher sensitivity, better reproducibility and greater specificity than commercial immunoassay techniques. The method requires only minimal sample preparation and a small sample volume. Furthermore, it has the potential to analyze multiple steroids simultaneously. Modern instruments guarantee high throughput, allowing an affordable price for the individual assay. All this makes LC-MS/MS an attractive method for use in a clinical setting. Reliable reference ranges for the detected analytes are the pre-requisite for their clinical use. If these are available, LC-MS/MS can find application in congenital disorders of steroid metabolism, such as congenital adrenal hyperplasia, disorders of sex development and disorders of salt homeostasis, as well as in acquired disorders of steroid metabolism, such as primary aldosteronism, Cushing's disease, Addison's disease, and hyperandrogenemia, as well as in psychiatric disease states such as depression or anxiety disorders. The principles of LC-MS/MS for steroid measurement, the pros and cons of LC-MS/MS compared with conventional immunoassays and the possible applications in clinical routine, with a special focus on pediatric endocrinology needs, are discussed here.

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

    Science.gov (United States)

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

    2017-07-01

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

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    Rayco Guedes-Alonso

    2013-01-01

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

  14. 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.

  15. [Determination of strobilurin fungicides in fruits and their mass fragmentation routes by ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhou, Yao; Yang, Huiqin; Shi, Yiyin; Chen, Jiaxian; Zhu, Jian; Deng, Xiaojun; Guo, Dehua

    2017-09-08

    A method was developed for the simultaneous determination of six strobilurin fungicide ( E -metominostrobin, azoxystrobin, kresoxim-methyl, picoxystrobin, pyraclostrobin and trifloxystrobin) residues in orange, banana, apple and pineapple samples by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The fragmentation routes of all the compounds were explained by the aid of a fragment predicting software ACD Lab/MS Fragmenter. The samples were extracted by acetonitrile, then cleaned up by amino solid phase extraction cartridges (SupelClean LC-NH 2 ). The extracts were separated on a ACQUITY UPLC BEH C 18 column (50 mm×2.1 mm, 1.7 μm) with gradient elution. Acetonitrile containing 0.1% (v/v) formic acid and 10 mmol/L ammonium acetate containing 0.1% (v/v) formic acid were used as mobile phases. The samples were detected by electrospray ionization (ESI)-MS/MS in positive ion and multiple reaction monitoring (MRM) mode, quantified by external standard method. Good linearities were obtained in the range of 5-100 μg/L (for pyraclostrobin, 1-20 μg/L) with correlation coefficients ( r 2 ) greater than 0.999. The recoveries ranged from 60.4% to 120% with the relative standard deviations between 2.15% and 15.1% ( n =6). The developed method can meet the inspection of the six strobilurin residues in the orange, banana, apple and pineapple samples.

  16. 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

    2015-06-03

    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.

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

    Science.gov (United States)

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

    2017-10-08

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

  18. Determination of fluoroquinolones in fish tissues, biological fluids, and environmental waters by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Ziarrusta, Haizea; Val, Nahia; Dominguez, Haizea; Mijangos, Leire; Prieto, Ailette; Usobiaga, Aresatz; Etxebarria, Nestor; Zuloaga, Olatz; Olivares, Maitane

    2017-11-01

    This work describes the optimization, validation, and application in real samples of accurate and precise analytical methods to determine ten fluoroquinolones (FQs) (norfloxacin, enoxacin, pefloxacin, ofloxacin, levofloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin, and sparfloxacin) in different environmental matrices, such as water (estuarine, seawater, and wastewater treatment plant effluent), fish tissues (muscle and liver), and fish biofluids (plasma and bile). The analysis step performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was fully optimized to improve the separation and detection steps. The extraction of analytes from fish tissues was accomplished using focused ultrasound solid-liquid extraction using methanol/acetic acid (95:5 v/v) as extractant. The preconcentration and clean-up steps were optimized in terms of extraction efficiency and cleanliness and the best strategy for each matrix was selected: (i) Oasis HLB for seawater and muscle, (ii) liquid-liquid extraction combined with Oasis HLB for the lipid-rich liver, (iii) the combination of Evolute-WAX and Oasis HLB for estuarine water and wastewater treatment plant effluent, and (iv) molecular imprinted polymers for biofluids. The methods afforded satisfactory apparent recoveries (80-126%) and repeatability (RSD < 15%), except for sparfloxacin, which showed a lack of correction with the available isotopically labeled surrogates ([ 2 H 8 ]-ciprofloxacin and [ 2 H 5 ]-enrofloxacin). Ciprofloxacin, norfloxacin, and ofloxacin were detected in both water and fish liver samples from the Biscay Coast at concentrations up to 278 ng/L and 4 ng/g, respectively. To the best of our knowledge, this work is one of the few analyzing up to ten FQs and in so many fish tissues and biofluids. Graphical abstract Determination of fluoroquinolones in different environmental matrices, such as water (estuarine, seawater, and wastewater treatment plant effluent), fish tissues (muscle

  19. Application of dispersive solid-phase extraction and ultra-fast liquid chromatography-tandem quadrupole mass spectrometry in food additive residue analysis of red wine.

    Science.gov (United States)

    Chen, Xiao-Hong; Zhao, Yong-Gang; Shen, Hao-Yu; Jin, Mi-Cong

    2012-11-09

    A novel and effective dispersive solid-phase extraction (dSPE) procedure with rapid magnetic separation using ethylenediamine-functionalized magnetic polymer as an adsorbent was developed. The new procedure had excellent clean-up ability for the selective removal of the matrix in red wine. An accurate, simple, and rapid analytical method using ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) for the simultaneous determination of nine food additives (i.e., acesulfame, saccharin, sodium cyclamate, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid, and neotame) in red wine was also used and validated. Recoveries ranging from 78.5% to 99.2% with relative standard deviations ranging from 0.46% to 6.3% were obtained using the new method. All target compounds showed good linearities in the tested range with correlation coefficients (r) higher than 0.9993. The limits of quantification for the nine food additives were between 0.10 μg/L and 50.0 μg/L. The proposed dSPE-UFLC-MS/MS method was successfully applied in the food-safety risk monitoring of real red wine in Zhejiang Province, China. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  20. Simultaneous determination of seven anticoagulant rodenticides in agricultural products by gel permeation chromatography and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Saito-Shida, Shizuka; Nemoto, Satoru; Matsuda, Rieko; Akiyama, Hiroshi

    2016-11-01

    A sensitive and reliable method for the simultaneous determination of hydroxycoumarin-type (brodifacoum, bromadiolone, coumatetralyl, and warfarin) and indandione-type (chlorophacinone, diphacinone, and pindone) rodenticides in agricultural products by gel permeation chromatography (GPC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The procedure involved extraction of the rodenticides from samples with acetone, followed by liquid-liquid partitioning with hexane/ethyl acetate (1:1, v/v) and 10% sodium chloride aqueous solution, then cleanup using GPC, and finally, analysis using LC-MS/MS. High recoveries from the GPC column were obtained for all rodenticides tested using a mobile phase of acetone/cyclohexane/triethylamine (400:1600:1, v/v/v). An ODS column, which contains low levels of metal impurities, gave satisfactory peak shapes for both hydroxycoumarin- and indandione-type rodenticides in the LC-MS/MS separation. The average recoveries of rodenticides from eight agricultural foods (apple, eggplant, cabbage, orange, potato, tomato, brown rice, and soybean) fortified at 0.0005-0.001 mg/kg ranged from 76 to 116%, except for bromadiolone in orange (53%) and diphacinone in soybean (54%), and the relative standard deviations ranged from 1 to 16%. The proposed method effectively removed interfering components, such as pigments and lipids, and showed high selectivity. In addition, the matrix effects were negligible for most of the rodenticide/food combinations. The results suggest that the proposed method is reliable and suitable for determining hydroxycoumarin- and indandione-type rodenticides in agricultural products.

  1. Simultaneous measurement of total Estradiol and Testosterone in human serum by isotope dilution liquid chromatography tandem mass spectrometry

    Science.gov (United States)

    Zhou, Hui; Wang, Yuesong; Gatcombe, Matthew; Farris, Jacob; Botelho, Julianne C.; Caudill, Samuel P.; Vesper, Hubert W.

    2017-01-01

    Reliable measurement of total testosterone and estradiol is critical for their use as biomarkers of hormone related disorders in patient care and translation research. We developed and validated a mass spectrometry method to simultaneously quantify these analytes in human serum without chemical derivatization. Serum is equilibrated with isotopic internal standards and treated with acidic buffer to release hormones from their binding proteins. Lipids are isolated and polar impurities are removed by two serial liquid-liquid extraction steps. Total testosterone and estradiol are measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) in combination of positive and negative electrospray ionization modes. The method shows broad analytical measurement range for both testosterone 0.03–48.5 nM (0.75–1400 ng/dL) and estradiol 11.0–5138 pM (2.99–1400 pg/mL) and excellent agreement with certified reference materials (mean bias less than 2.1% to SRM 971, BCR 576, 577, and 578) and a high order reference method (mean bias 1.25% for testosterone and −0.84% for estradiol). The high accuracy of the method was monitored and certified by CDC Hormone Standardization (HoSt) Program for two years with mean bias −0.7% (95%CI: −1.6% to 0.2%) for testosterone and 0.1% (95%CI: −2.2% to 2.3%) for estradiol. The method precision over a 2-year period for Quality Control pools at low, medium and high concentrations was 2.7–2.9% for testosterone and 3.3–5.3% for estradiol. With the consistently excellent accuracy and precision, this method is readily applicable for high-throughput clinical and epidemiological studies. PMID:28801832

  2. Simultaneous high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) analysis of cyanide and thiocyanate from swine plasma.

    Science.gov (United States)

    Bhandari, Raj K; Manandhar, Erica; Oda, Robert P; Rockwood, Gary A; Logue, Brian A

    2014-01-01

    An analytical procedure for the simultaneous determination of cyanide and thiocyanate in swine plasma was developed and validated. Cyanide and thiocyanate were simultaneously analyzed by high-performance liquid chromatography tandem mass spectrometry in negative ionization mode after rapid and simple sample preparation. Isotopically labeled internal standards, Na(13)C(15)N and NaS(13)C(15)N, were mixed with swine plasma (spiked and nonspiked), proteins were precipitated with acetone, the samples were centrifuged, and the supernatant was removed and dried. The dried samples were reconstituted in 10 mM ammonium formate. Cyanide was reacted with naphthalene-2,3-dicarboxaldehyde and taurine to form N-substituted 1-cyano[f]benzoisoindole, while thiocyanate was chemically modified with monobromobimane to form an SCN-bimane product. The method produced dynamic ranges of 0.1-50 and 0.2-50 μM for cyanide and thiocyanate, respectively, with limits of detection of 10 nM for cyanide and 50 nM for thiocyanate. For quality control standards, the precision, as measured by percent relative standard deviation, was below 8 %, and the accuracy was within ±10 % of the nominal concentration. Following validation, the analytical procedure successfully detected cyanide and thiocyanate simultaneously from the plasma of cyanide-exposed swine.

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

    Science.gov (United States)

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

    2017-10-27

    In recent years, new drugs, commonly known as new psychoactive substances (NPS), appeared on the market, which include, among others, synthetic cannabinoids, cathinones, and tryptamine analogs of psilocin. The aim of this work was to develop and validate a new method for simultaneous screening and quantification of 31 NPS in oral fluid by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The chosen target analytes represented different chemical and toxicological NPS classes, such as synthetic cathinones, piperazines, phenethylamines, synthetic cannabinoids, and their metabolites. The procedure involved a rapid sample preparation based on protein precipitation followed by clean-up utilizing microextraction by packed sorbent (MEPS); the quantitative analysis was performed by UHPLC-MS/MS. The MEPS clean-up, regardless of non-quantitative recoveries for some analytes, provided an effective removal of interfering compounds, as demonstrated by reduced matrix effects found at different concentrations for all the analytes. The validation protocol, based on SWGTOX guidelines, demonstrated the suitability of the proposed method for quantitative analysis: linearity range ranged over 3 or 4 orders of magnitude; precision and accuracy tests gave RSD% values below 25%, and accuracy ranged from 85.9% to 107%, accomplishing SWGTOX requirements. Limits of detection (LODs) ranged between 0.005 ng/mL and 0.850 ng/mL and limits of quantification (LOQs) from 0.015 to 2.600 ng/mL. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Determination of isoorientin levels in rat plasma after oral administration of Vaccinum bracteatum Thunb. methanol extract by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kim, Min-Ji; Kwon, Seung-Hwan; Jang, Choon-Gon; Maeng, Han-Joo

    2018-01-15

    A simple, sensitive and rapid liquid chromatography tandem mass spectrometry method (LC-MS/MS) was developed and validated for the determination of plasma isoorientin levels in rats. After simple protein precipitation using methanol, chromatographic analysis was performed using a Synergi 4μ polar-RP 80A column (150 × 2.0 mm, 4μm) under isocratic conditions and a mobile phase consisting of 0.1% formic acid in water and methanol (80:20, v/v) at a flow rate of 0.2 mL/min. In positive electrospray ionization mode, the protonated precursor and product ion transitions of isoorientin (m/z 449.0 → 299.1) and of puerarin (the internal standard; m/z 417.1 → 297.1) were acquired by multiple reaction monitoring. Calibration curves obtained for plasma showed good linearity over the concentration range 1-1000 ng/mL. The lower limit of quantification was 1 ng/mL. Intra- and inter-day precisions were within 8.8% relative standard deviation. Accuracies ranged from 92.1 and 109.7%. The isoorientin stability in rat plasma under typical handling/storage conditions also found to be acceptable. The developed method was applied successfully to a pharmacokinetic study of isoorientin orally administered as the methanol extract of Vaccinium bracteatum Thunb. or administered as pure isoorientin. Copyright © 2018 John Wiley & Sons, Ltd.

  5. Online turbulent flow extraction coupled with liquid chromatography-tandem mass spectrometry for high throughput screening of anabolic steroids in horse urine.

    Science.gov (United States)

    Shin, Hyun Du; Suh, Joon Hyuk; Kim, Junghyun; Cho, Hyun-Deok; Lee, Su Duk; Han, Kwan Seok; Wang, Yu; Han, Sang Beom

    2017-10-25

    A high throughput method for simultaneous screening of anabolic steroids and their metabolites (4-esterendione, trenbolone, boldenone, oxandrolone, nandrolone, methandrostenolone, testosterone, 1-androstendione, ethisterone, normethandrolone, methyltestosterone, 16β-Hydroxystanozolol, epitestosterone, bolasterone, norethandrolone, danazol, stanozolol and androstadienone) in equine urine by online turbulent flow extraction coupled with liquid chromatography-tandem mass spectrometry was developed. The use of turbulent flow chromatography could simplify pretreatment of horse urine, which has complex matrices as well as high viscosity. The urine was extracted by mixed-mode cation exchange solid phase extraction, and hydrolyzed using β-glucuronidase/arylsulfatase. Then, the sample was automatically loaded on the TurboFlow Cyclone extraction column for removal of further matrix, followed by separation on a fused core C18 column before MS/MS detection. Optimization and validation of the method were discussed in detail. All analytes were rapidly detected within 10min with high sensitivity (picogram to nanogram per milliliter level), and no interference was observed. The linearity range was from 0.1-10ng/mL for nine steroids and 1.0-50ng/mL for the others, with correlation of coefficient values over 0.995. Precision and accuracy ranged from 0.1 to 14.5% and 1.7 to 12.4%, respectively. The developed method was successfully applied to the analysis of anabolic steroids in horse urine after administration of a model drug. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. [Simultaneous determination of ethephon, thidiazuron, diuroN residues in cotton by using high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Xie, Wen; Shi, Yingzhu; Hou, Jianbo; Huang, Chaoqun; Zhao, Dong; Pan, Lulu; Dong, Suozhuai

    2014-02-01

    A method for the determination of ethephon, thidiazuron and diuron in cotton samples has been developed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with methanol-water. The separation was carried out on a C8 column (150 mm x 4.6 mm, 5 microm) with methanol-water (6:4, v/v) as mobile phase at a flow rate of 0.4 mL/min, and the injection volume was 20 microL. Then the sample solution was analyzed by HPLC-MS/MS in negative ion mode with multiple reaction monitoring (MRM). There were one precursor/two product ion transitions for each pesticide. The results showed that the working curves were linear in the range of 0-10 microg/L for ethephon and thidiazuron, and 0-1 microg/L for diuron. The correlation coefficients (r) were all over 0. 999. The limits of quantitation (LOQ) of ethephon, diuron were 40 microg/kg, that of thidiazuron was 4 microg/kg. The average recoveries varied from 89.4% to 100.2% with the relative standard deviations (RSDs) of 5.7%-11.5% at three spiked levels (LOQ, 2LOQ and 4LOQ). The method is simple, rapid and accurate, and can meet the requirements of the domestic and international legislation. The method adapts to confirm the residues of ethephon, thidiazuron and diuron pesticides in cotton samples.

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

    Science.gov (United States)

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

    2016-02-01

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

  8. A liquid chromatography/tandem mass spectrometry assay for the analysis of atomoxetine in human plasma and in vitro cellular samples

    Science.gov (United States)

    Appel, David I.; Brinda, Bryan; Markowitz, John S.; Newcorn, Jeffrey H.; Zhu, Hao-Jie

    2012-01-01

    A simple, rapid and sensitive method for quantification of atomoxetine by liquid chromatography- tandem mass spectrometry (LC-MS/MS) was developed. This assay represents the first LC-MS/MS quantification method for atomoxetine utilizing electrospray ionization. Deuterated atomoxetine (d3-atomoxetine) was adopted as the internal standard. Direct protein precipitation was utilized for sample preparation. This method was validated for both human plasma and in vitro cellular samples. The lower limit of quantification was 3 ng/ml and 10 nM for human plasma and cellular samples, respectively. The calibration curves were linear within the ranges of 3 ng/ml to 900 ng/ml and 10 nM to 10 μM for human plasma and cellular samples, respectively (r2 > 0.999). The intra- and inter-day assay accuracy and precision were evaluated using quality control samples at 3 different concentrations in both human plasma and cellular lysate. Sample run stability, assay selectivity, matrix effect, and recovery were also successfully demonstrated. The present assay is superior to previously published LC-MS and LC-MS/MS methods in terms of sensitivity or the simplicity of sample preparation. This assay is applicable to the analysis of atomoxetine in both human plasma and in vitro cellular samples. PMID:22275222

  9. 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.

  10. Determination of asperosaponin VI in dog plasma by high-performance liquid chromatography-tandem mass spectrometry and its application to a pilot pharmacokinetic study.

    Science.gov (United States)

    Shakya, Shailendra; Zhu, He; Ding, Li; Du, Xiao Lang; Qi, Xie Min; Yang, Xiao Lin; Yang, Zhong Lin

    2012-01-01

    A sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of asperosaponin VI in beagle dog plasma using glycyrrhizic acid as the internal standard (IS). Plasma samples were simply pretreated with methanol for deproteinization. Chromatographic separation was performed on a Hedera ODS-2 column using mobile phase of methanol-10 mm ammonium acetate buffer solution containing 0.05% acetic acid (71:29, v/v) at a flow rate of 0.38 mL/min. Asperosaponin VI and the IS were eluted at 2.8 and 1.9 min, respectively, ionized in negative ion mode, and then detected by multiple reaction monitoring. The detection used the transitions of the deprotonated molecules at m/z 927.5 → 603.4 for asperosaponin VI and m/z 821.4 → 645.4 for glycyrrhizic acid (IS). The assay was linear over the concentration range of 0.15-700 ng/mL and was successfully applied to a pilot pharmacokinetic study in beagle dogs. Copyright © 2011 John Wiley & Sons, Ltd.

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

    Directory of Open Access Journals (Sweden)

    Yunliang Zheng

    2014-01-01

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

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

    Science.gov (United States)

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

    2013-01-15

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

  13. QuEChERS Purification Combined with Ultrahigh-Performance Liquid Chromatography Tandem Mass Spectrometry for Simultaneous Quantification of 25 Mycotoxins in Cereals

    Science.gov (United States)

    Sun, Juan; Li, Weixi; Zhang, Yan; Hu, Xuexu; Wu, Li; Wang, Bujun

    2016-01-01

    A method based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) purification combined with ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC–MS/MS), was optimized for the simultaneous quantification of 25 mycotoxins in cereals. Samples were extracted with a solution containing 80% acetonitrile and 0.1% formic acid, and purified with QuEChERS before being separated by a C18 column. The mass spectrometry was conducted by using positive electrospray ionization (ESI+) and multiple reaction monitoring (MRM) models. The method gave good linear relations with regression coefficients ranging from 0.9950 to 0.9999. The detection limits ranged from 0.03 to 15.0 µg·kg−1, and the average recovery at three different concentrations ranged from 60.2% to 115.8%, with relative standard deviations (RSD%) varying from 0.7% to 19.6% for the 25 mycotoxins. The method is simple, rapid, accurate, and an improvement compared with the existing methods published so far. PMID:27983693

  14. Determination of ribavirin in human serum using liquid chromatography tandem mass spectrometry

    NARCIS (Netherlands)

    van der Lijke, H.; Alffenaar, J.-W. C.; Kok, W.Th.; Greijdanus, B.; Uges, D.R.A.

    2012-01-01

    A method has been developed for the determination of ribavirin in human serum for therapeutic drug monitoring purposes, using liquid chromatography electrospray ionization mass spectrometry. Separation was obtained with a mobile phase gradient starting and ending in 100% aqueous conditions using a

  15. 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.

  16. Analysis of 2-methylthio-derivatives of isoprenoid cytokinins by liquid chromatography-tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Tarkowski, Petr; Václavíková, Kateřina; Novák, Ondřej; Pertry, I.; Hanuš, Jan; Whenham, R.; Vereecke, D.; Šebela, M.; Strnad, Miroslav

    2010-01-01

    Roč. 680, 1-2 (2010), s. 86-91 ISSN 0003-2670 R&D Projects: GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cytokinins * Rhodococcus fascians * High-performance liquid chromatography Subject RIV: CE - Biochemistry Impact factor: 4.310, year: 2010

  17. Determination of oxycodone and its major metabolites noroxycodone and oxymorphone by ultra-high-performance liquid chromatography tandem mass spectrometry in plasma and urine: application to real cases.

    Science.gov (United States)

    Pantano, Flaminia; Brauneis, Stefano; Forneris, Alexandre; Pacifici, Roberta; Marinelli, Enrico; Kyriakou, Chrystalla; Pichini, Simona; Busardò, Francesco Paolo

    2017-08-28

    Oxycodone is a narcotic drug widely used to alleviate moderate and severe acute and chronic pain. Variability in analgesic efficacy could be explained by inter-subject variations in plasma concentrations of parent drug and its active metabolite, oxymorphone. To evaluate patient compliance and to set up therapeutic drug monitoring (TDM), an ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) assay was developed and validated for the parent drug and its major metabolites noroxycodone and oxymorphone. Extraction of analytes from plasma and urine samples was obtained by simple liquid-liquid extraction. The chromatographic separation was achieved with a reversed phase column using a linear gradient elution with two solvents: acetic acid 1% in water and methanol. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode via positive electrospray ionization (ESI). Separation of analytes was obtained in less than 5 min. Linear calibration curves for all the analytes under investigation in urine and plasma samples showed determination coefficients (r2) equal or higher than 0.990. Mean absolute analytical recoveries were always above 86%. Intra- and inter-assay precision (measured as coefficient of variation, CV%) and accuracy (measured as % error) values were always better than 13%. Limit of detection at 0.06 and 0.15 ng/mL and limit of quantification at 0.2 and 0.5 ng/mL for plasma and urine samples, respectively, were adequate for the purpose of the present study. Rapid extraction, identification and quantification of oxycodone and its metabolites both in urine and plasma by UHPLC-MS/MS assay was tested for its feasibility in clinical samples and provided excellent results for rapid and effective drug testing in patients under oxycodone treatment.

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

    Science.gov (United States)

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

    2018-03-27

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

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

    International Nuclear Information System (INIS)

    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

    2009-01-01

    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 μg kg -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 μg kg -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 μg kg -1 . Average recovery of CYA from shrimp was 85% (R.S.D. = 10%, n = 13) with an MDL of 3.5 μg kg -1

  20. Determination of six sulfonamide antibiotics, two metabolites and trimethoprim in wastewater by isotope dilution liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Le-Minh, Nhat; Stuetz, Richard M; Khan, Stuart J

    2012-01-30

    A highly sensitive method for the analysis of six sulfonamide antibiotics (sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethazine and sulfamethoxazole), two sulfonamide metabolites (N(4)-acetyl sulfamethazine and N(4)-acetyl sulfamethoxazole) and the commonly co-applied antibiotic trimethoprim was developed for the analysis of complex wastewater samples. The method involves solid phase extraction of filtered wastewater samples followed by liquid chromatography-tandem mass spectral detection. Method detection limits were shown to be matrix-dependent but ranged between 0.2 and 0.4 ng/mL for ultrapure water, 0.4 and 0.7 ng/mL for tap water, 1.4 and 5.9 ng/mL for a laboratory-scale membrane bioreactor (MBR) mixed liquor, 0.7 and 1.7 ng/mL for biologically treated effluent and 0.5 and 1.5 ng/g dry weight for MBR activated sludge. An investigation of analytical matrix effects was undertaken, demonstrating the significant and largely unpredictable nature of signal suppression observed for variably complex matrices compared to an ultrapure water matrix. The results demonstrate the importance of accounting for such matrix effects for accurate quantitation, as done in the presented method by isotope dilution. Comprehensive validation of calibration linearity, reproducibility, extraction recovery, limits of detection and quantification are also presented. Finally, wastewater samples from a variety of treatment stages in a full-scale wastewater treatment plant were analysed to illustrate the effectiveness of the method. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. 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

    2015-09-03

    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. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Automated processing of whole blood samples for the determination of immunosuppressants by liquid chromatography tandem-mass spectrometry.

    Science.gov (United States)

    Vogeser, Michael; Spöhrer, Ute

    2006-01-01

    Liquid chromatography tandem-mass spectrometry (LC-MS/MS) is an efficient technology for routine determination of immunosuppressants in whole blood; however, time-consuming manual sample preparation remains a significant limitation of this technique. Using a commercially available robotic pipetting system (Tecan Freedom EVO), we developed an automated sample-preparation protocol for quantification of tacrolimus in whole blood by LC-MS/MS. Barcode reading, sample resuspension, transfer of whole blood aliquots into a deep-well plate, addition of internal standard solution, mixing, and protein precipitation by addition of an organic solvent is performed by the robotic system. After centrifugation of the plate, the deproteinized supernatants are submitted to on-line solid phase extraction, using column switching prior to LC-MS/MS analysis. The only manual actions within the entire process are decapping of the tubes, and transfer of the deep-well plate from the robotic system to a centrifuge and finally to the HPLC autosampler. Whole blood pools were used to assess the reproducibility of the entire analytical system for measuring tacrolimus concentrations. A total coefficient of variation of 1.7% was found for the entire automated analytical process (n=40; mean tacrolimus concentration, 5.3 microg/L). Close agreement between tacrolimus results obtained after manual and automated sample preparation was observed. The analytical system described here, comprising automated protein precipitation, on-line solid phase extraction and LC-MS/MS analysis, is convenient and precise, and minimizes hands-on time and the risk of mistakes in the quantification of whole blood immunosuppressant concentrations compared to conventional methods.

  3. Kynurenine pathway metabolism following prenatal KMO inhibition and in Mecp2+/- mice, using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Forrest, Caroline M; Kennedy, Peter G E; Rodgers, Jean; Dalton, R Neil; Turner, Charles; Darlington, L Gail; Cobb, Stuart R; Stone, Trevor W

    2016-11-01

    To quantify the full range of tryptophan metabolites along the kynurenine pathway, a liquid chromatography - tandem mass spectrometry method was developed and used to analyse brain extracts of rodents treated with the kynurenine-3-mono-oxygenase (KMO) inhibitor Ro61-8048 during pregnancy. There were significant increases in the levels of kynurenine, kynurenic acid, anthranilic acid and 3-hydroxy-kynurenine (3-HK) in the maternal brain after 5 h but not 24 h, while the embryos exhibited high levels of kynurenine, kynurenic acid and anthranilic acid after 5 h which were maintained at 24 h post-treatment. At 24 h there was also a strong trend to an increase in quinolinic acid levels (P = 0.055). No significant changes were observed in any of the other kynurenine metabolites. The results confirm the marked increase in the accumulation of some neuroactive kynurenines when KMO is inhibited, and re-emphasise the potential importance of changes in anthranilic acid. The prolonged duration of metabolite accumulation in the embryo brains indicates a trapping of compounds within the embryonic CNS independently of maternal levels. When brains were examined from young mice heterozygous for the meCP2 gene - a potential model for Rett syndrome - no differences were noted from control mice, suggesting that the proposed roles for kynurenines in autism spectrum disorder are not relevant to Rett syndrome, supporting its recognition as a distinct, independent, condition. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. 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

    2016-03-05

    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. 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). 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). 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.

  5. Simultaneous determination of imperatorin and its 2 metabolites in dog plasma by using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Lu; Lu, Wen; Shen, Qi; Wang, Shengjia; Zhou, Hui; Yu, Lushan; Wang, Sicen; Jiang, Huidi; He, Langchong; Zeng, Su

    2012-11-01

    In this study, 2 metabolites of imperatorin, imperatorin hydroxylate (IMH) and imperatorin epoxide (IME), were identified for the first time in dog plasma. A sensitive, specific, and accurate high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was then developed for the simultaneous quantification of imperatorin and its 2 metabolites in dog plasma. Separation was achieved on an Agilent ZORBAX Extend-C(18) column (2.1 mm × 50 mm, 3.5 μm) at 30 °C. The mobile phase consisted of 0.02% ammonium acetate solution-methanol with a gradient program at a flow rate of 0.3 mL/min. Detection was performed using an electrospray ionization source operating in positive ion multiple reaction monitoring mode and by monitoring the ion transitions from 271 to 203 m/z for imperatorin, 309.4-224.1 m/z for IMH, 287-203 m/z for IME, and 441.3-325.2 m/z for simvastatin (the internal standard). Good linearity was shown over the concentration range of 1-500 ng/mL for imperatorin, and 0.2-500 ng/mL for IMH and IME. The validated method was successfully applied to a pharmacokinetic study of imperatorin in beagle dogs. The pharmacokinetic profiles of imperatorin and its 2 metabolites showed sex differences after the i.v. administration of imperatorin at a dose of 5 mg/kg. Copyright © 2012 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Pedro R. Costa

    2015-04-01

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

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

    Science.gov (United States)

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

    2015-04-13

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

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

    Science.gov (United States)

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

    2016-02-05

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

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

    Science.gov (United States)

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

    2012-01-13

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

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

    Science.gov (United States)

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

    2017-08-01

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

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

    Science.gov (United States)

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

    2017-01-01

    Objectives: N,N-Dimethylacetamide (DMAC) is widely used in industry as a solvent. It can be absorbed through human skin. Therefore, it is necessary to determine exposure to DMAC via biological monitoring. However, the precision of traditional gas chromatography (GC) is low due to the thermal decomposition of metabolites in the high-temperature GC injection port. To overcome this problem, we have developed a new method for the simultaneous separation and quantification of urinary DMAC metabolites using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods: Urine samples were diluted 10-fold in formic acid, and 1-μl aliquots were injected into the LC-MS/MS equipment. A C18 reverse-phase Octa Decyl Silyl (ODS) column was used as the analytical column, and the mobile phase consisted of a mixture of methanol and aqueous formic acid solution. Results: Urinary concentrations of DMAC and its known metabolites (N-hydroxymethyl-N-methylacetamide (DMAC-OH), N-methylacetamide (NMAC), and S- (acetamidomethyl) mercapturic acid (AMMA) ) were determined in a single run. The dynamic ranges of the calibration curves were 0.05-5 mg/l (r≥0.999) for all four compounds. The limits of detection for DMAC, DMAC-OH, NMAC, and AMMA in urine were 0.04, 0.02, 0.05, and 0.02 mg/l, respectively. Within-run accuracies were 96.5%-109.6% with relative standard deviations of precision being 3.43%-10.31%. Conclusions: The results demonstrated that the proposed method could successfully quantify low concentrations of DMAC and its metabolites with high precision. Hence, this method is useful for evaluating DMAC exposure. In addition, this method can be used to examine metabolite behaviors in human bodies after exposure and to select appropriate biomarkers. PMID:29213009

  12. [Determination of eight pesticide residues in tea by liquid chromatography-tandem mass spectrometry and its uncertainty evaluation].

    Science.gov (United States)

    Hu, Beizhen; Cai, Haijiang; Song, Weihua

    2012-09-01

    A method was developed for the determination of eight pesticide residues (fipronil, imidacloprid, acetamiprid, buprofezin, triadimefon, triadimenol, profenofos, pyridaben) in tea by liquid chromatography-tandem mass spectrometry. The sample was extracted by accelerated solvent extraction with acetone-dichloromethane (1:1, v/v) as solvent, and the extract was then cleaned-up with a Carb/NH2 solid phase extraction (SPE) column. The separation was performed on a Hypersil Gold C, column (150 mm x 2. 1 mm, 5 microm) and with the gradient elution of acetonitrile and 0. 1% formic acid. The eight pesticides were determined in the modes of electrospray ionization (ESI) and multiple reaction monitoring (MRM). The analytes were quantified by matrix-matched internal standard method for imidacloprid and acetamiprid, by matrix-matched external standard method for the other pesticides. The calibration curves showed good linearity in 1 - 100 microg/L for fipronil, and in 5 -200 microg/L for the other pesticides. The limits of quantification (LOQs, S/N> 10) were 2 p.g/kg for fipronil and 10 microg/kg for the other pesticides. The average recoveries ranged from 75. 5% to 115.0% with the relative standard deviations of 2.7% - 7.7% at the spiked levels of 2, 5, 50 microg/kg for fipronil and 10, 50, 100 microg/kg for the other pesticides. The uncertainty evaluation for the results was carried out according to JJF 1059-1999 "Evaluation and Expression of Uncertainty in Measurement". Items constituting measurement uncertainty involved standard solution, weighing of sample, sample pre-treatment, and the measurement repeatability of the equipment were evaluated. The results showed that the measurement uncertainty is mainly due to sample pre-treatment, standard curves and measurement repeatability of the equipment. The method developed is suitable for the conformation and quantification of the pesticides in tea.

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2017-11-15

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

  16. Determination of naphthalene-derived compounds in apples by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Esparza, X; Moyano, E; Cosialls, J R; Galceran, M T

    2013-06-11

    Naphthylacetic acid, naphthyloxy acetic acid and naphthylacetamide belong to a group of synthetic substances known as "auxin-like" compounds which are used as growth regulators in vegetables and fruits due to their structure similarities with the indoleacetic acid, the most important plant auxin. This paper reports a selective, sensitive and fast ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of naphthylacetamide (NAD) and the isomers (α and β) of naphthylacetic acid (NAA) and naphthyloxy acetic (NOA) acid in apple samples. A baseline separation between the respective isomers was achieved using an RP-Amide column with gradient elution. The UHPLC-MS/MS method developed, using electrospray and selected reaction monitoring (SRM) acquisition mode led to a reliable determination of these family of compounds in apple samples at low quantitation levels, down to 1.0 μg kg(-1) and 0.25 μg kg(-1) respectively. For confirmation of NAA accurate mass measurement is proposed giving at these conditions quantitation limits of 10 μg kg(-1) for this compound. The UHPLC-MS/MS method developed was used for the analysis of apple samples harvested in three different apple fields from Lleida (Spain) during the blooming period. NAD and NAA were found in samples collected during 4-5 weeks after application at concentrations between the quantification limits and 43 μg kg(-1) and 24 μg kg(-1), respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    van der Ham, Maria; de Koning, Tom J; Lefeber, Dirk; Fleer, André; Prinsen, Berthil H C M T; de Sain-van der Velden, Monique G M

    2010-05-01

    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 validated. The method utilized a simple sample-preparation procedure of protein precipitation for FSA and acid hydrolysis for TSA. Negative electrospray ionisation was used to monitor the transitions m/z 308.2-->87.0 (SA) and m/z 311.2--> 90.0 ((13)C(3)-SA). Conjugated sialic acid (CSA) was calculated by subtracting FSA from TSA. We established reference intervals for FSA, TSA and CSA in CSF in 217 control subjects. The method has been applied to patients' samples with known differences in SA metabolites like meningitis (n=6), brain tumour (n=2), leukaemia (n=5), and Salla disease (n=1). Limit of detection (LOD) was 0.54 microM for FSA and 0.45 mM for TSA. Intra- and inter-assay variation for FSA (21.8 microM) were 4.8% (n=10) and 10.4% (n=40) respectively. Intra- and inter-assay variation for TSA (35.6 microM) were 9.7% (n=10) and 12.8% (n=40) respectively. Tested patients showed values of TSA above established reference value. The validated method allows sensitive and specific measurement of SA metabolites in CSF and can be applied for clinical diagnoses. 2010 Elsevier B.V. All rights reserved.

  18. Determination of melatonin and its isomer in foods by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Kocadağlı, Tolgahan; Yılmaz, Cemile; Gökmen, Vural

    2014-06-15

    This study aimed to develop a reliable analytical method for the determination of melatonin and its isomers in various food products. The method entails ethanol extraction of solid samples (or dilution of liquid samples) prior to liquid chromatography coupled to triple quadruple mass spectrometry (LC-MS/MS) analysis of target analytes. The method was in-house validated and successfully applied to various food matrices. Recovery of melatonin from different matrices were found to be 86.0 ± 3.6%, 76.9 ± 5.4%, 98.6 ± 6.4%, and 67.0 ± 4.5% for beer, walnut, tomato and sour cherry samples, respectively. No melatonin could be detected in black and green tea, sour cherry, sour cherry concentrate, kefir (a fermented milk drink) and red wine while the highest amount of melatonin (341.7 ± 29.3 pg/g) was detected in crumb. The highest amounts of melatonin isomer were detected in yeast-fermented foods such as 170.7 ± 29.9 ng/ml in red wine, 14.3 ± 0.48 ng/ml in beer, and 15.7 ± 1.4 ng/g in bread crumb. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Peters, Frank T

    2011-01-01

    Liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) has become increasingly important in clinical and forensic toxicology as well as doping control and is now a robust and reliable technique for routine analysis in these fields. In recent years, methods for LC-MS(/MS)-based systematic toxicological analysis using triple quadrupole or ion trap instruments have been considerably improved and a new screening approach based on high-resolution MS analysis using benchtop time-of-flight MS instruments has been developed. Moreover, many applications for so-called multi-target screening and/or quantification of drugs, poisons, and or their metabolites in various biomatrices have been published. The present paper will provide an overview and discuss these recent developments focusing on the literature published after 2006. Copyright © 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  20. Liquid Chromatography-Tandem Mass Spectrometric Assay for Determination of Stavudine in Human Plasma

    Directory of Open Access Journals (Sweden)

    Fengdan Jin

    2014-01-01

    Full Text Available A LC-MS/MS method for determination of stavudine in human plasma was established and validated, and it was applied to the pharmaceutical formulations bioequivalence study. 0.5 mL plasma sample was extracted by liquid-liquid extraction. Stavudine was detected by a LC-MS/MS system. The pharmacokinetic parameters of stavudine in different formulations were calculated by noncompartment model statistics. The method was linear over the concentration ranges 5.00–1000 ng/mL in plasma. The intra- and interassay relative standard deviation (RSD was <10%. The average accuracies for the assay at three concentrations (5.00, 80.0, and 900 ng/mL were from 100.2% to 102.5%. Pharmacokinetic parameters of stavudine reference formulation were obtained as follows: Tmax was 0.6±0.2 h, Cmax was 480.7±150.9 g/L, t1/2 was 1.7±0.4 h, and AUC0-t was 872.8±227.8 g·h/L, and pharmacokinetic parameters of stavudine test formulation were obtained as follows: Tmax was 0.5±0.2 h, Cmax was 537.5±178.5 g/L, t1/2 was 1.7±0.3 h, and AUC0-t was (914.1±284.5 g·h/L. Calculated with AUC0-t, the bioavailability of two formulations was 105.0%.

  1. Proteomic profiling of human pleural effusion using two-dimensional nano liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Tyan, Yu-Chang; Wu, Hsin-Yi; Lai, Wu-Wei; Su, Wu-Chou; Liao, Pao-Chi

    2005-01-01

    Pleural effusion, an accumulation of pleural fluid, contains proteins originated from plasma filtrate and, especially when tissues are damaged, parenchyma interstitial spaces of lungs and/or other organs. This study details protein profiles in human pleural effusion from 43 lung adenocarcinoma patients by a two-dimensional nano-high performance liquid chromatography electrospray ionization tandem mass spectrometry (2D nano-HPLC-ESI-MS/MS) system. The experimental results revealed the identification of 1415 unique proteins from human pleural effusion. Among these 124 proteins identified with higher confidence levels, some proteins have not been reported in plasma and may represent proteins specifically present in pleural effusion. These proteins are valuable for mass identification of differentially expressed proteins involved in proteomics database and screening biomarker to further study in human lung adenocarcinoma. The significance of the use of proteomics analysis of human pleural fluid for the search of new lung cancer marker proteins, and for their simultaneous display and analysis in patients suffering from lung disorders has been examined.

  2. Determination of low-level acrylamide in drinking water by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Lucentini, Luca; Ferretti, Emanuele; Veschetti, Enrico; Achene, Laura; Turrio-Baldassarri, Luigi; Ottaviani, Massimo; Bogialli, Sara

    2009-01-01

    A simple and sensitive liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method has been developed and validated to confirm and quantify acrylamide monomer (AA) in drinking water using [13C3] acrylamide as internal standard (IS). After a preconcentration by solid-phase extraction with spherical activated carbon, analytes were chromatographed on IonPac ICE-AS1 column (9 x 250 mm) under isocratic conditions using acetonitrile-water-0.1 M formic acid (43 + 52 + 5, v/v/v) as the mobile phase. Analysis was achieved using a triple-quadrupole mass analyzer equipped with a turbo ion spray interface. For confirmation and quantification of the analytes, MS data acquisition was performed in the multireaction monitoring mode, selecting 2 precursor ion to product ion transitions for both AA and IS. The method was validated for linearity, sensitivity, accuracy, precision, extraction efficiency, and matrix effect. Linearity in tap water was observed over the concentration range 0.1-2.0 microg/L. Limits of detection and quantification were 0.02 and 0.1 microg/L, respectively. Interday and intraday assays were performed across 3 validation levels (0.1, 0.5, and 1.5 microg/L). Accuracy (as mean recovery) ranged from 89.3 to 96.2% with relative standard deviation water in compliance with European Union and U.S. Environmental Protection Agency standards.

  3. Multiclass analysis of antibiotic residues in honey by ultraperformance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Vidal, Jose Luis Martínez; Aguilera-Luiz, María Del Mar; Romero-González, Roberto; Frenich, Antonia Garrido

    2009-03-11

    A method has been developed and validated for the simultaneous analysis of different veterinary drug residues (macrolides, tetracyclines, quinolones, and sulfonamides) in honey. Honey samples were dissolved with Na(2)EDTA, and veterinary residues were extracted from the supernatant by solid-phase extraction (SPE), using OASIS HLB cartridges. The separation and determination was carried out by ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), using an electrospay ionization source (ESI) in positive mode. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring (MRM) of two ion transitions per compound to provide a high degree of sensitivity and specificity. The method was validated, and mean recoveries were evaluated at three concentration levels (10, 50, and 100 microg/kg), ranging from 70 to 120% except for doxycycline, erythromycin, and tylmicosin with recovery higher than 50% at the three levels assayed. Relative standard deviations (RSDs) of the recoveries were less than 20% within the intraday precision and less than 25% within the interday precision. The limits of quantification (LOQs) were always lower than 4 microg/kg. The developed procedure was applied to 16 honey samples, and erythromycin, sarafloxacin, and tylosin were found in a few samples.

  4. 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. Copyright © 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  5. Comparison of derivatization/ionization techniques for liquid chromatography tandem mass spectrometry analysis of oxylipins.

    Science.gov (United States)

    Meckelmann, Sven W; Hellhake, Stefan; Steuck, Maryvonne; Krohn, Michael; Schebb, Nils Helge

    2017-05-01

    The performance of two derivatization and ionization techniques for the quantitative reversed phase liquid chromatography (LC)- mass spectrometry (MS) analysis of hydroxy fatty acids (OH-PUFA) in plasma was evaluated: One used AMPP (N-(4-aminomethylphenyl)pyridinium chloride) leading to a positive charged amid-derivate which can be detected by electrospray ionization (ESI)-MS. Second yielded penta fluorobenzyl bromide (PFB) ester derivates allowing detection in electron capture atmospheric pressure chemical ionization (ecAPCI)-MS. The sensitivity of detection of a comprehensive set of hydroxy fatty acids of n6- and n3- poly unsaturated fatty acids was investigated. On the SCIEX3200 MS the applied PFB derivatization led to poor limits of detection (LOD) of 10-100nM (0.1-1pmol/0.03-0.3ng on column). By contrast, AMPP derivatization led to a similar sensitivity compared to the standard ESI(-) of non derivatized analytes (LOD about 1nM (10fmol/3pg on column)). For several analytes, including 9-HETE, 11-HETE and 17-HDHA the AMPP derivatization improved sensitivity enabling their detection in human plasma. However, precision was reduced by AMPP derivatization and variation in IS recovery indicated a strong matrix influence on the MS-signal. In sum, with the instrumentation used, neither of these derivatization methods improves in our hands the LC-MS based quantification of oxylipins. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Determination of fluspirilene in human plasma by liquid chromatography-tandem mass spectrometry with electrospray ionisation.

    Science.gov (United States)

    Swart, K J; Sutherland, F C; van Essen, G H; Hundt, H K; Hundt, A F

    1998-12-18

    An ultra-sensitive method for the determination of fluspirilene 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 mu 150 x 2.1 mm column with a mobile phase consisting of methanol-water-acetic acid (600:400:1) at a flow-rate of 0.3 ml/min. Detection was achieved by a Finnigan Matt mass spectrometer (LCQ) at unit resolution in full scan mode scanning the product ion spectrum from m/z 130-500 and monitoring the transition of the protonated molecular ion at m/z 476.2, to the sum of the largest product ions m/z 371, 342 and 274 (MS-MS). Electrospray ionisation was used for ion production. The mean recovery for fluspirilene was 90% with a lower limit of quantification of 21.50 pg/ml using 1 ml plasma for extraction. This is the first chromatographic method described for the determination of fluspirilene in plasma that is accurate and sensitive enough to be used in pharmacokinetic studies.

  7. Analysis of 2-methylthio-derivatives of isoprenoid cytokinins by liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tarkowski, Petr, E-mail: petr.tarkowski@upol.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Biochemistry, Faculty of Science, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Vaclavikova, Katerina, E-mail: katka.vaclavik@seznam.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Biochemistry, Faculty of Science, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Novak, Ondrej, E-mail: ondrej.novak@upol.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Pertry, Ine, E-mail: ine.pertry@ugent.BE [Department of Plant Biotechnology and Genetics, Ghent University, K.L.Ledeganckstraat 35, B-9000 Gent (Belgium); Hanus, Jan, E-mail: helehan@seznam.cz [Isotope Laboratory, Institute of Experimental Botany ASCR, Videnska 1083, 142 20 Prague (Czech Republic); Whenham, Robert [Apex Organics, Devon, England (United Kingdom); Vereecke, Danny, E-mail: danny.vereecke@hogent.BE [Department of Plant Production, University College Ghent, Ghent University, Schoonmeersstraat 52, B-9000 Gent (Belgium); Sebela, Marek, E-mail: marek.sebela@upol.cz [Department of Biochemistry, Faculty of Science, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Strnad, Miroslav, E-mail: miroslav.strnad@upol.cz [Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany ASCR, Slechtitelu 11, 783 71 Olomouc (Czech Republic)

    2010-11-08

    A sensitive and reliable high-performance liquid chromatographic method with tandem mass spectrometric detection has been developed and used for the determination of 2-methylthio-cytokinin derivatives produced by the phytopathogenic actinomycete Rhodococcus fascians. The cultivation medium containing secreted cytokinins was concentrated and subjected to a solid-phase extraction (C18 and ion-exchange). The purified samples were further separated and analyzed by HPLC-ESI-MS/MS. This allowed to achieve chromatographic resolution of six highly hydrophobic cytokinin species including 2-methylthio-isopentenyladenine, 2-methylthio-isopentenyladenosine, 2-methylthio-trans-zeatin and 2-methylthio-trans-zeatin riboside and their cis-isomers when a reversed-phase chromatographic column (C4) and a mobile phase consisting of acetonitrile and 20 mM ammonium formate, pH 5, were used. Quantification was performed by a standard isotope dilution method using a multiple-reaction monitoring (MRM) mode. In the MRM mode, limits of detection reached 20-30 fmol and linear ranges spanned four orders of magnitude. Recovery values were between 35% and 65% and the analytical accuracy between 95% and 149%. The proposed bioanalytical method, which takes advantage of effective chromatographic separation of six 2-methyltio-derivatives (including isomers of zeatin-type cytokinins) and sensitive mass spectrometric detection, may become useful for plant biologists studying the significance of these substances in plant-microbe interactions.

  8. Analysis of 2-methylthio-derivatives of isoprenoid cytokinins by liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Tarkowski, Petr; Vaclavikova, Katerina; Novak, Ondrej; Pertry, Ine; Hanus, Jan; Whenham, Robert; Vereecke, Danny; Sebela, Marek; Strnad, Miroslav

    2010-01-01

    A sensitive and reliable high-performance liquid chromatographic method with tandem mass spectrometric detection has been developed and used for the determination of 2-methylthio-cytokinin derivatives produced by the phytopathogenic actinomycete Rhodococcus fascians. The cultivation medium containing secreted cytokinins was concentrated and subjected to a solid-phase extraction (C18 and ion-exchange). The purified samples were further separated and analyzed by HPLC-ESI-MS/MS. This allowed to achieve chromatographic resolution of six highly hydrophobic cytokinin species including 2-methylthio-isopentenyladenine, 2-methylthio-isopentenyladenosine, 2-methylthio-trans-zeatin and 2-methylthio-trans-zeatin riboside and their cis-isomers when a reversed-phase chromatographic column (C4) and a mobile phase consisting of acetonitrile and 20 mM ammonium formate, pH 5, were used. Quantification was performed by a standard isotope dilution method using a multiple-reaction monitoring (MRM) mode. In the MRM mode, limits of detection reached 20-30 fmol and linear ranges spanned four orders of magnitude. Recovery values were between 35% and 65% and the analytical accuracy between 95% and 149%. The proposed bioanalytical method, which takes advantage of effective chromatographic separation of six 2-methyltio-derivatives (including isomers of zeatin-type cytokinins) and sensitive mass spectrometric detection, may become useful for plant biologists studying the significance of these substances in plant-microbe interactions.

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

    Science.gov (United States)

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

    2016-01-05

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

  10. Simultaneous determination of gallic acid and gentisic acid in organic anion transporter expressing cells by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wang, Li; Halquist, Matthew S; Sweet, Douglas H

    2013-10-15

    In order to elucidate the role of organic anion transporters (OATs) in the renal elimination of gallic acid and gentisic acid, a new, rapid, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous determination of gallic acid and gentisic acid in cell lysate, using Danshensu as the internal standard (IS). After a simple liquid-liquid extraction, the analytes were detected in negative ESI mode using selected reaction monitoring. The precursor-to-product ion transitions (m/z) were 169.0→125.0, 153.1→108.0, and 196.8→135.2 for gallic acid, gentisic acid, and the IS, respectively. Chromatographic separation was achieved on a C18 column using mobile phases consisting of water with 0.1% acetic acid (A) and acetonitrile with 0.05% formic acid. (B) The total run time was 3min and calibration curves were linear over the concentrations of 0.33-2400ng/mL for both compounds (r(2)>0.995). Good precision (between 3.11% and 14.1% RSD) and accuracy (between -12.7% and 11% bias) was observed for quality controls at concentrations of 0.33 (lower limit of quantification), 1, 50, and 2000ng/mL. The mean extraction recovery of gallic acid and gentisic acid was 80.7% and 83.5%, respectively. Results from post-column infusion and post-extraction methods indicated that the analytical method exhibited negligible matrix effects. Finally, this validated assay was successfully applied in a cellular uptake study to determine the intracellular concentrations of gallic acid and gentisic acid in OAT expressing cells. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Simultaneous detection of six urinary pteridines and creatinine by high-performance liquid chromatography-tandem mass spectrometry for clinical breast cancer detection.

    Science.gov (United States)

    Burton, Casey; Shi, Honglan; Ma, Yinfa

    2013-11-19

    Recent preliminary studies have implicated urinary pteridines as candidate biomarkers in a growing number of malignancies including breast cancer. While the developments of capillary electrophoresis-laser induced fluorescence (CE-LIF), high performance liquid chromatography (HPLC), and liquid chromatography-mass spectroscopy (LC-MS) pteridine urinalyses among others have helped to enable these findings, limitations including poor pteridine specificity, asynchronous or nonexistent renal dilution normalization, and a lack of information regarding adduct formation in mass spectrometry techniques utilizing electrospray ionization (ESI) have prevented application of these techniques to a larger clinical setting. In this study, a simple, rapid, specific, and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed and optimized for simultaneous detection of six pteridines previously implicated in breast cancer and creatinine as a renal dilution factor in urine. In addition, this study reports cationic adduct formation of urinary pteridines under ESI-positive ionization for the first time. This newly developed technique separates and detects the following six urinary pteridines: 6-biopterin, 6-hydroxymethylpterin, d-neopterin, pterin, isoxanthopterin, and xanthopterin, as well as creatinine. The method detection limit for the pteridines is between 0.025 and 0.5 μg/L, and for creatinine, it is 0.15 μg/L. The method was also validated by spiked recoveries (81-105%), reproducibility (RSD: 1-6%), and application to 25 real urine samples from breast cancer positive and negative samples through a double-blind study. The proposed technique was finally compared directly with a previously reported CE-LIF technique, concluding that additional or alternative renal dilution factors are needed for proper investigation of urinary pteridines as breast cancer biomarkers.

  12. Illicit Drug Analysis Using Two-Dimension Liquid Chromatography/Tandem Mass Spectrometry.

    Science.gov (United States)

    Mallet, Claude; Botch-Jones, Sabra

    2016-10-01

    For the identification of illicit drugs in forensic toxicological casework, analysis can be delayed and potentially compromised due to lengthy sample preparation techniques. For a complete forensic identification, a robust methodology is required and the current trend in forensic laboratories is the use of liquid chromatography coupled to mass spectrometry (LC/MS or LC/MS-MS). However, to achieve satisfactory results, extensive and time-consuming sample preparation protocols are required to reach sub-ng/mL levels. The concept of sequential 2D extraction was designed to capture the retention behavior of a target analyte in response to various extraction parameters. Therefore, optimized conditions can be selected to excise a region of interest during extraction. The utilization of multi-dimensional chromatography combined with a micro-extraction technique was evaluated to decrease sample preparation time while enhancing the separation integrity observed with current single-dimensional chromatography techniques. A wide range of illicit drugs were spiked in human urine and extracted using three extraction protocols for performance evaluation. The extraction process was performed using a reversed-phase solid phase extraction (SPE) in 1D, 2D-optimized, 2D-sequential and cumulative elution modes. The chosen 2D chromatography conditions that were used in this application were identified using a 6 × 6 automated methods development protocol (144 methods total). The extraction of urine samples containing target analytes was completed in less than 20 min. The analysis was performed using 200 µL of the final organic solvent (MeOH) extracts. The limit of detection for all drugs was measured at 100 pg/mL (ppt) from a 1 mL sample volume. Several analytes showed excellent signal at 10 pg/mL (ppt). © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Quantification of peramivir in dog plasma by liquid chromatography/tandem mass spectrometry employing precolumn derivatization.

    Science.gov (United States)

    Li, Xin; Li, Ying; Wang, Juan; Wang, Lili; Zhong, Wu; Ruan, Jinxiu; Zhang, Zhenqing

    2014-01-01

    Peramivir is a novel influenza neuraminidase inhibitor used for anti-influenza. In this article, a novel method was developed to determine peramivir in dog plasma using a derivatization treatment step to increase the retention time and enhance the signal intensity. The sample preparation consisted of a protein precipitation extraction followed by derivatization with 10M hydrochloric acid-methanol (10:90, v/v) and determined by liquid chromatography coupled with tandem mass spectrometry. The selected reaction monitoring mode of the positive ion was performed and the precursor to the product ion transitions of m/z 343→284 and m/z 299→152 were used to measure the derivative of peramivir and Ro 64-0802 (internal standard, an active metabolite of oseltamivir). The chromatographic separation was achieved using a ZORBAX RX-C8 (2.0mm×150mm×5μm) analytical column with an isocratic mobile phase composed of acetonitrile-water-formic acid (30:70:0.1, v/v/v, 0.2mL/min). The method was linear over a concentration range of 0.25-250ng/mL. The average intra-day/inter-day precision values were 4.04-8.17% and 3.02-7.08%, respectively, while the average accuracy value was 93.99-106.48%. This method has been successfully applied to the preclinical dog research of peramivir following intragastric administration. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Analysis of antithyroid drugs in surface water by using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Pérez-Fernández, Virginia; Marchese, Stefano; Gentili, Alessandra; García, María Ángeles; Curini, Roberta; Caretti, Fulvia; Perret, Daniela

    2014-11-07

    This paper describes development and validation of a new method for the simultaneous determination of six antithyroid drugs (ATDs) in surface waters by using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). Target compounds include two ATD classes: thiouracil derivatives (thiouracil (TU), methyl-thiouracil (MTU), propyl-thiouracil (PTU), phenyl-thiouracil (PhTU)) and imidazole derivatives (tapazole (TAP), and mercaptobenzimidazole (MBI)). Sensitivity and selectivity of the LC-multiple reaction monitoring (MRM) analysis allowed applying a simple pre-concentration procedure and "shooting" the concentrated sample into the LC-MS/MS system without any other treatment. Recoveries were higher than 75% for all analytes. Intra-day precision and inter-day precision, calculated as relative standard deviation (RSD), were below 19 and 22%, respectively. Limits of detection (LODs) ranged from 0.05 to 0.25 μg/L; limits of quantitation (LOQs) varied between 0.15 and 0.75 μg/L. The validated method was successfully applied to the analysis of ATD residues in surface water samples collected from the Tiber River basin and three lakes of Lazio (central Italy). The analytes were quantified based on matrix-matched calibration curves with mercaptobenzimidazole-d4 (MBI-d4) as the internal standard (IS). The most widespread compound was TAP, one of the most common ATDs used in human medicine, but also TU and MBI were often detected in the analysed samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Dispersive Liquid-Liquid Microextraction Combined with Ultrahigh Performance Liquid Chromatography/Tandem Mass Spectrometry for Determination of Organophosphate Esters in Aqueous Samples

    Directory of Open Access Journals (Sweden)

    Haiying Luo

    2014-01-01

    Full Text Available A new technique was established to identify eight organophosphate esters (OPEs in this work. It utilised dispersive liquid-liquid microextraction in combination with ultrahigh performance liquid chromatography/tandem mass spectrometry. The type and volume of extraction solvents, dispersion agent, and amount of NaCl were optimized. The target analytes were detected in the range of 1.0–200 µg/L with correlation coefficients ranging from 0.9982 to 0.9998, and the detection limits of the analytes were ranged from 0.02 to 0.07 µg/L (S/N=3. The feasibility of this method was demonstrated by identifying OPEs in aqueous samples that exhibited spiked recoveries, which ranged between 48.7% and 58.3% for triethyl phosphate (TEP as well as between 85.9% and 113% for the other OPEs. The precision was ranged from 3.2% to 9.3% (n=6, and the interprecision was ranged from 2.6% to 12.3% (n=5. Only 2 of the 12 selected samples were tested to be positive for OPEs, and the total concentrations of OPEs in them were 1.1 and 1.6 µg/L, respectively. This method was confirmed to be simple, fast, and accurate for identifying OPEs in aqueous samples.

  16. Determination of Fusarium toxins in functional vegetable milks applying salting-out-assisted liquid-liquid extraction combined with ultra-high-performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Hamed, Ahmed M; Arroyo-Manzanares, Natalia; García-Campaña, Ana M; Gámiz-Gracia, Laura

    2017-11-01

    Vegetable milks are considered as functional foods due to their physiological benefits. Although the consumption of these products has significantly increased, they have received little attention in legislation with regard to contaminants. However, they may contain mycotoxins resulting from the use of contaminated raw materials. In this work, ultra-high-performance liquid chromatography tandem mass spectrometry has been proposed for the determination of the most relevant Fusarium toxins (fumonisin B 1 and B 2 , HT-2 and T-2 toxins, zearalenone, deoxynivalenol and fusarenon-X) in different functional beverages based on cereals, legumes and seeds. Sample treatment consisted of a simple salting-out-assisted liquid-liquid extraction with no further clean-up. The method provided limits of quantification between 3.2 and 57.7 µg L -1 , recoveries above 80% and precision with RSD lower than 12%. The method was also applied for studying the occurrence of these mycotoxins in market samples of vegetable functional beverages and deoxynivalenol was found in three oat-based commercial drinks.

  17. A sensitive and selective liquid chromatography/tandem mass spectrometry method for quantitative analysis of efavirenz in human plasma.

    Directory of Open Access Journals (Sweden)

    Praveen Srivastava

    Full Text Available A selective and a highly sensitive method for the determination of the non-nucleoside reverse transcriptase inhibitor (NNRTI, efavirenz, in human plasma has been developed and fully validated based on high performance liquid chromatography tandem mass spectrometry (LC-MS/MS. Sample preparation involved protein precipitation followed by one to one dilution with water. The analyte, efavirenz was separated by high performance liquid chromatography and detected with tandem mass spectrometry in negative ionization mode with multiple reaction monitoring. Efavirenz and ¹³C₆-efavirenz (Internal Standard, respectively, were detected via the following MRM transitions: m/z 314.20243.90 and m/z 320.20249.90. A gradient program was used to elute the analytes using 0.1% formic acid in water and 0.1% formic acid in acetonitrile as mobile phase solvents, at a flow-rate of 0.3 mL/min. The total run time was 5 min and the retention times for the internal standard (¹³C₆-efavirenz and efavirenz was approximately 2.6 min. The calibration curves showed linearity (coefficient of regression, r>0.99 over the concentration range of 1.0-2,500 ng/mL. The intraday precision based on the standard deviation of replicates of lower limit of quantification (LLOQ was 9.24% and for quality control (QC samples ranged from 2.41% to 6.42% and with accuracy from 112% and 100-111% for LLOQ and QC samples. The inter day precision was 12.3% and 3.03-9.18% for LLOQ and quality controls samples, and the accuracy was 108% and 95.2-108% for LLOQ and QC samples. Stability studies showed that efavirenz was stable during the expected conditions for sample preparation and storage. The lower limit of quantification for efavirenz was 1 ng/mL. The analytical method showed excellent sensitivity, precision, and accuracy. This method is robust and is being successfully applied for therapeutic drug monitoring and pharmacokinetic studies in HIV-infected patients.

  18. Analysis of tacrolimus and creatinine from a single dried blood spot using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Koop, Dennis R; Bleyle, Lisa A; Munar, Myrna; Cherala, Ganesh; Al-Uzri, Amira

    2013-05-01

    Long term therapeutic drug monitoring and assessment of renal function are required in renal transplant recipients on immunosuppressant therapy such as tacrolimus. Dry blood spots (DBS) have been used successfully in the clinic for many years and offers a convenient, simple and non-invasive method for repeated blood tests. We developed and performed a preliminary validation of a method for the analysis of tacrolimus and creatinine from a single DBS using liquid chromatography-tandem mass spectrometric (LC-MS/MS). Tacrolimus and creatinine were extracted from a 6mm punch with a mixture of methanol/acetonitrile containing ascomycin and deuterated creatinine as internal standards. A 10 μl aliquot of the extract was analyzed directly after dilution for creatinine with normal phase high performance liquid chromatography and multiple reaction monitoring. The remainder of the extract was processed and analyzed for tacrolimus. The lower limit of quantification for tacrolimus was 1 ng/ml with accuracy of 0.34% bias and precision (CV) of 11.1%. The precision ranged from 1.33% to 7.68% and accuracy from -4.44% to 11.6% bias for the intra- and inter-day analysis. The lower limit of quantification of creatinine was 0.01 mg/dL with precision of 7.94%. Accuracy was based on recovery of additional creatinine spiked into whole blood samples and ranged from -2.45% bias at 5 mg/dL to 3.75% bias at 0.5 mg/dL. Intra- and inter-day precision was from 3.48 to 4.11%. The assay was further validated with DBS prepared from pediatric renal transplant recipients. There was excellent correlation between the levels of tacrolimus and creatinine obtained from the clinical laboratory and the DBS method developed. After additional validation, this assay may have a significant impact on compliance with medication intake as well as potentially lowering the cost associated with intravenous blood draws in clinical laboratories. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Simultaneous determination of four aflatoxins and ochratoxin A in ginger after inoculation with fungi by ultra-fast liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yang, Ying; Wen, Jing; Kong, Weijun; Liu, Qiutao; Luo, Hongli; Wang, Jian; Yang, Meihua

    2016-09-01

    Aflatoxins (AFs) and ochratoxin A (OTA) have been detected frequently in food, agricultural products and traditional Chinese medicines, and their presence poses serious health and economic problems worldwide. Ginger can easily be polluted with mycotoxins. In this study, ginger samples were cultivated for 15 days after inoculation with fungi and were prepared based on ultrasound-assisted solid-liquid extraction using methanol/water followed by immunoaffinity column clean-up and analysed by ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) for AFs and OTA. The limits of detection and quantification of AFs and OTA were 0.04-0.30 µg mL(-1) and 0.125-1.0 µg mL(-1) , respectively. The recoveries were 82.0-100.2%. After 15 days' cultivation, no macroscopic mildew was found in ginger. But, the content of AFB1 expressed an increasing trend in ginger, peel [less than the limit of quantification (LOQ)] to the innermost layer (51.86 µ mL(-1) ), AFB2 was only detected in the innermost layer at the level of 0.87 µ mL(-1) . A small amount (rapid determination and high sensitivity. Meanwhile, in practice, more attention should be paid to the safety and quality of ginger. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  20. Histamine and tele-methylhistamine quantification in cerebrospinal fluid from narcoleptic subjects by liquid chromatography tandem mass spectrometry with precolumn derivatization.

    Science.gov (United States)

    Croyal, Mikaël; Dauvilliers, Yves; Labeeuw, Olivier; Capet, Marc; Schwartz, Jean-Charles; Robert, Philippe

    2011-02-01

    An ultra-performance liquid chromatography tandem mass spectrometry (UPLC™-MS/MS) assay was developed for the simultaneous analysis of histamine, its major metabolite tele-methylhistamine, and an internal standard (N-tele-(R)-α-dimethylhistamine) from human cerebrospinal fluid (CSF) samples. The method involves derivatization of primary amines with 4-bromobenzenesulfonyl chloride and subsequent analysis by reversed phase liquid chromatography with mass spectrometry detection and positive electrospray ionization. The separation of derivatized biogenic amines was achieved within 3.5 min on an Acquity® BEH C(18) column by elution with a linear gradient of acetonitrile/water/formic acid (0.1%). The assay was linear in the concentration range of 50-5000 pM for each amine (5.5-555 pg/ml for histamine and 6.25-625 pg/ml for tele-methylhistamine). For repeatability and precision determination, coefficients of variation (CVs) were less than 11.0% over the tested concentration ranges, within acceptance criteria. Thus, the developed method provides the rapid, easy, highly sensitive, and selective requirement to quantify these amines in human CSF. No significant difference was found in the mean ± standard error levels of these amines between a group of narcoleptic patients (histamine=392 ± 64 pM, tele-methylhistamine=2431 ± 461 pM, n=7) and of neurological control subjects (histamine=402 ± 72 pM, tele-methylhistamine=2209 ± 463 pM, n=32). Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Determination of type A trichothecenes in coix seed by magnetic solid-phase extraction based on magnetic multi-walled carbon nanotubes coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Dong, Maofeng; Si, Wenshuai; Wang, Weimin; Bai, Bing; Nie, Dongxia; Song, Weiguo; Zhao, Zhihui; Guo, Yirong; Han, Zheng

    2016-09-01

    Magnetic solid-phase extraction (m-SPE) is a promising sample preparation approach due to its convenience, speed, and simplicity. For the first time, a rapid and reliable m-SPE approach using magnetic multi-walled carbon nanotubes (m-MWCNTs) as the adsorbent was proposed for purification of type A trichothecenes including T-2 toxins (T2), HT-2 toxins (HT-2), diacetoxyscirpenol (DAS), and neosolaniol (NEO) in coix seed. The m-MWCNTs were synthesized by assembling the magnetic nanoparticles (Fe3O4) with MWCNTs by sonication through an aggregation wrap mechanism, and characterized by transmission electron microscope. Several key parameters affecting the performance of the procedure were extensively investigated including extraction solutions, desorption solvents, and m-MWCNT amounts. Under the optimal sample preparation conditions followed by analysis with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), high sensitivity (limit of quantification in the range of 0.3-1.5 μg kg(-1)), good linearity (R (2) > 0.99), satisfactory recovery (73.6-90.6 %), and acceptable precision (≤2.5 %) were obtained. The analytical performance of the developed method has also been successfully evaluated in real coix seed samples. Graphical Abstract Flow chart of determination of type A trichothecenes in coix seed by magnetic solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

  2. Ultra high performance liquid chromatography-tandem mass spectrometry vs. commercial immunoassay for determination of vancomycin plasma concentration in children. Possible implications for everyday clinical practice.

    Science.gov (United States)

    Barco, Sebastiano; Castagnola, Elio; Gennai, Iulian; Barbagallo, Laura; Loy, Anna; Tripodi, Gino; Cangemi, Giuliana

    2016-10-01

    Vancomycin therapeutic drug monitoring (TDM) is necessary for effective and safetherapy. The aim of the this paper was to develop a specific and robust ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for vancomycin quantification starting from low plasma volumes to be applied for the routine TDM in children. Samples from children receiving intravenous vancomycin were analysed using a TSQ Quantum Access MAX Triple Quadrupole system coupled with an Accela 1250 UHPLC system after a rapid protein precipitation. Gradient separation chromatography was carried out using a Hypersil GOLD aQ C18 column (50 × 2.1 mm, particle size 1.9 μm). Method performance was validated following international guidelines. UHPLC-MS/MS allowed a rapid and specific quantification of vancomycin over the range 0.1-128 μg/mL from 50 μL of plasma with high reproducibility and accuracy in the absence of matrix effect. The comparison with the commercial immunoassay performed on 138 samples demonstrated the presence of a proportional bias. The concentrations of vancomycin measured with immunoassay were found to be 4.5% (95% CI: 1.3-7.7) higher than those determined with UHPLC-MS/MS. Importantly, a clinical discordance was found in about 10% of samples analysed. This new UHPLC-MS/MS method is accurate and specific for the measurement of vancomycin starting from small (50 μL) plasma volumes. The use of UHPLC-MS/MS is recommended to prevent a misclassification of therapeutic or toxic vancomycin levels in paediatrics.

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

    Science.gov (United States)

    Nguyen, Van Long

    2018-02-25

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-04-01

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

  5. 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...

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

    OpenAIRE

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

    2014-01-01

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

  7. [Simultaneous determination of glyphosate and glufosinate-ammonium residues in tea by ultra performance liquid chromatography-tandem mass spectrometry coupled with pre-column derivatization].

    Science.gov (United States)

    Wu, Xiaogang; Chen, Xiaoquan; Xiao, Haijun; Liu, Binqiu

    2015-10-01

    A method was developed for the determination of glyphosate (GLY) and glufosinate-ammonium (GLUF) in tea using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample was extracted with ultrapure water and dichloromethane for 30 min under ultrasonication, followed by a simple cleanup with a C18 solid phase extraction (SPE) cartridge, and then GLY and GLUF were derivatized using 9-fluorenylmethoxycarbonyl (FMOC-Cl) in borate buffer for 2 h. The derivatives of GLY and GLUF were separated on a Waters C18 column (50 mm x 2.1 mm, 1.7 μm) in a gradient elution mode, and finally detected with positive electrospray ionization-mass spectrometry (ESI-MS/MS ) in multiple reaction monitoring (MRM) mode. The quantification analysis was performed by external standard method. The method showed a good linearity (r > 0. 990) in the range of 0.003 125-0.1 mg/L. The limits of detection (LODs) of GLY and GLUF were 0.03 mg/kg. At the spiked levels of 0.375, 1.5 and 4.5 mg/kg, the recoveries of GLY and GLUF were 87.37%-99.11% and 81.44% -86.17% respectively, and the relative standard deviations (RSDs) (n = 6) of GLY and GLUF were 0.68%-1.35% and 1.01%-2.33%, respectively. This method is simple, rapid and characterized with acceptable sensitivity and accuracy to meet the requirements for the analysis of GLY and GLUF simultaneously in tea.

  8. Simultaneous Determination of Black Tea-Derived Catechins and Theaflavins in Tissues of Tea Consuming Animals Using Ultra-Performance Liquid-Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Ganguly, Souradipta; G., Taposh Kumar; Mantha, Sudarshan

    2016-01-01

    The bioavailability, tissue distribution and metabolic fate of the major tea polyphenols, catechins and theaflavins as well as their gallated derivatives are yet to be precisely elucidated on a single identification platform for assessment of their relative bioefficacy in vivo. This is primarily due to the lack of suitable analytical tools for their simultaneous determination especially in an in vivo setting, which continues to constrain the evaluation of their relative health beneficiary potential and therefore prospective therapeutic application. Herein, we report a rapid and sensitive Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) based method for the simultaneous determination of the major catechins and theaflavins in black tea infusions as well as in different vital tissues and body fluids of tea-consuming guinea pigs. This method allowed efficient separation of all polyphenols within seven minutes of chromatographic run and had a lower limit of quantification (LLOQ) of ~5 ng/ml. Using this method, almost all bioactive catechins and theaflavins could be simultaneously detected in the plasma of guinea pigs orally administered 5% black tea for 14 days. Our method could further detect the majority of these polyphenols in the lung and kidney as well as identify the major catechin metabolites in the urine of the tea-consuming animals. Overall, our study presents a novel tool for simultaneous detection and quantitation of both catechins and theaflavins in a single detection platform that could potentially enable precise elucidation of their relative bioavailability and bioefficacy as well as true health beneficiary potential in vivo. Such information would ultimately facilitate the accurate designing of therapeutic strategies utilizing high efficacy formulations of tea polyphenols for effective mitigation of oxidative damage and inflammation in humans as well as prevention of associated diseases. PMID:27695123

  9. Liquid chromatography-tandem mass spectrometry method for the measurement of serum mevalonic acid: a novel marker of hydroxymethylglutaryl coenzyme A reductase inhibition by statins.

    Science.gov (United States)

    Waldron, Jenna; Webster, Craig

    2011-05-01

    Mevalonic acid (MVA) is synthesized at an early and rate-limiting step in the biosynthesis of cholesterol by the enzyme hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase, and is a useful measure of statin efficacy or treatment. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the measurement of serum MVA has been developed. Following the in vitro conversion of MVA to mevalonic acid lactone (MVAL) in the serum, MVAL and a deuterated internal standard were extracted using an online solid-phase extraction procedure. Chromatographic separation was achieved using a Luna PFP column (Phenomenex), with enhanced selectivity and improved resolution for polar compounds. A gradient system was used, with mobile phase comprising methanol and water (5 mmol/L ammonium formate buffer, pH 2.5). Analysis was performed using an API 5000 tandem mass spectrometer (Applied Biosystems) in positive electrospray ionization mode. The method showed excellent recoveries (98 ± 8%) and imprecision (intra-assay coefficient of variation of 2.2% [6.5 ng/mL] and 2.6% [10.5 ng/mL], and inter-assay coefficient of variation of 9% [10.5 ng/mL]). The assay provides a calibration range up to 50 ng/mL with a limit of detection at 0.1 ng/mL. A simple, rapid and analytically specific method has been developed for the measurement of serum MVA, in the form of MVAL. The high analytical sensitivity of the method allows for accurate quantitation of MVAL in serum samples, both at the endogenous levels found in healthy individuals and in statin-treated patients where normal levels are expected to be greatly reduced through the inhibition of HMG-CoA reductase.

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

    Science.gov (United States)

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

    2017-01-01

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

  11. [Enantioselective determinination of R-warfarin/S-warfarin in human plasma using liquid chromatography-tandem mass spectrometry and its application in a drug-drug interaction study].

    Science.gov (United States)

    Jin, Shu; Zhang, Yi-Fan; Chen, Xiao-Yan; Liu, Ke; Zhong, Da-Fang

    2012-01-01

    To study the drug-drug interaction of morinidazole and warfarin and its application, a sensitive and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of R-warfarin/S-warfarin in human plasma. In a random, two-period crossover study, 12 healthy volunteers received a single oral dose of 5 mg racemic warfarin in the absence and presence of morinidazole. Blood samples were collected according to a pre-designed time schedule. R-warfarin, S-warfarin and methyclothiazide were extracted with ethylether : methylenechloride (3 : 2), then separated on a Astec Chirobiotic V (150 mm x 4.6 mm ID, 5 microm) column using 5 mmol x L(-1) ammonium acetate (pH 4.0) - acetonitrile as mobile phase at a flow-rate of 1.5 mL x min(-1). The mobile phase was splitted and 0.5 mL x min(-1) was introduced into MS. A tandem mass spectrometer equipped with electrospray ionization source was used as detector and operated in the negative ion mode. Quantification was performed using multiple reaction monitoring (MRM). The resolution of warfarin enantiomers is 1.56. The linear calibration curves for R-warfarin and S-warfarin both were obtained in the concentration range of 5 - 1 000 ng x mL(-1). Intra- and inter-day relative standard deviation (RSD) for R-warfarin and S-warfarin over the entire concentration range across three validation runs was both less than 10%, and relative error (RE) ranged from -4.9% to 0.7%, separately. The method herein described is effective and convenient, and suitable for the study of metabolic interaction between morinidazole and warfarin. The results showed that coadministration of warfarin with morinidazole did not affect the pharmacokinetics of either R-warfarin or S-warfarin.

  12. Quantification of piroxicam and 5'-hydroxypiroxicam in human plasma and saliva using liquid chromatography-tandem mass spectrometry following oral administration.

    Science.gov (United States)

    Calvo, Adriana Maria; Santos, Gabriel Mulinari; Dionísio, Thiago José; Marques, Maria Paula; Brozoski, Daniel Thomas; Lanchote, Vera Lúcia; Fernandes, Maria Helena Raposo; Faria, Flávio Augusto Cardoso; Santos, Carlos Ferreira

    2016-02-20

    Saliva sampling used to quantify piroxicam and 5'-hydroxypiroxicam is a noninvasive and painless method when compared to sequential blood sampling. For that, a rapid, selective and sensitive liquid chromatography-tandem mass spectrometric method for simultaneous determination of piroxicam and 5'-hydroxypiroxicam in saliva and human plasma was developed and validated. Piroxicam and its major metabolite were separated using a LiChroCART 125-4 RP Select-B Sorbent C18 column using a mixture of methanol and 2% phosphoric acid (pH 2.7) (70:30, v/v) for the mobile phase with a flow injection of 1mL/min. The run time was 4min. Volunteers had saliva and blood sampled before, 1, 2, 3, 4, 5, 6, 8, 11, 24, 48 and 72h after taking a 20mg oral dose of piroxicam. The pharmacokinetic parameters of piroxicam in plasma samples were as follows: AUC0-72 (64819hng/mL), predicted clearance (0.2L/h), distribution volume (14.8L), elimination half-life (50.7h) and saliva/plasma concentration ratio (0.003). The estimation of all pharmacokinetic parameters for 5'-hydroxypiroxicam would require collections beyond 72h; however, it was possible to quantify the mean maximum concentration (133ng/mL), time to peak concentration (53.6h), mean AUC0-72 (6213hng/mL), predicted clearance (110.3L/h) and saliva/plasma concentration ratio (0.04). The developed methods proved effective and sensitive for determining the lower quantification limit of piroxicam in plasma (6.1ng/mL) and saliva (0.15ng/mL) and of 5'-hydroxypiroxicam in plasma (1.2ng/mL) and saliva (0.15ng/mL). Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Pharmacokinetic determination of ephedrine in Herba Ephedrae and Wu Tou Tang decoctions in rats using ultra performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zheng, Zhijie; Yan, Tongmeng; Chen, Weiying; Ye, Ling; Tang, Lan; Liu, Zhongqiu

    2012-08-01

    A rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry method was developed and validated for the determination and quantification of ephedrine in rat plasma samples. An Acquity UPLC BEH C18 column (1.7 μm, 2.1 mm × 50 mm) was used for chromatographic separation. Electrospray ionization in the positive mode was used, and the precursor-fragment ion pairs of m/z 166/148 and m/z 289/97 were adopted to characterize ephedrine and testosterone (internal standard), respectively. The method was validated using 10, 100 and 500 ng/mL of ephedrine. It demonstrated adequate levels of precision and accuracy, matrix effect, extraction recovery and stability. Linearity over the concentration range of 0.5-2000 ng/mL was acceptable with a correlation coefficient (r²) better than 0.990. To determine the pharmacokinetic behaviour of this sympathomimetic compound in the Sprague-Dawley rats, ephedrine hydrochloride, Herba Ephedrae single-herb and Wu Tou Tang decoctions were administered orally, and ephedrine hydrochloride was also administered by intravenous injection, and blood samples were collected over 24 h. Ephedrine was measured in plasma and pharmacokinetic parameters were determined by using the standard non-compartmental method and calculated by using Practical Pharmacokinetic Program-Version 87/97. The AUC(0-t) and T(max) values were significantly different (p Tang decoction compared to the other oral treatments, suggesting that some components in the decoction may reduce the bioavailability of ephedrine.

  14. Validation of an accelerated solvent extraction liquid chromatography-tandem mass spectrometry method for Pacific ciguatoxin-1 in fish flesh and comparison with the mouse neuroblastoma assay.

    Science.gov (United States)

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

    2011-07-01

    Ciguatera fish poisoning (CFP) is a global foodborne illness caused by consumption of seafood containing ciguatoxins (CTXs) originating from dinoflagellates such as Gambierdiscus toxicus. P-CTX-1 has been suggested to be the most toxic CTX, causing ciguatera at 0.1 μg/kg in the flesh of carnivorous fish. CTXs are structurally complex and difficult to quantify, but there is a need for analytical methods for CFP toxins in coral reef fishes to protect human health. In this paper, we describe a sensitive and rapid extraction method using accelerated solvent extraction combined with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the detection and quantification of P-CTX-1 in fish flesh. By the use of a more sensitive MS system (5500 QTRAP), the validated method has a limit of quantification (LOQ) of 0.01 μg/kg, linearity correlation coefficients above 0.99 for both solvent- and matrix-based standard solutions as well as matrix spike recoveries ranging from 49% to 85% in 17 coral reef fish species. Compared with previous methods, this method has better overall recovery, extraction efficiency and LOQ. Fish flesh from 12 blue-spotted groupers (Cephalopholis argus) was assessed for the presence of CTXs using HPLC-MS/MS analysis and the commonly used mouse neuroblastoma assay, and the results of the two methods were strongly correlated. This method is capable of detecting low concentrations of P-CTX-1 in fish at levels that are relevant to human health, making it suitable for monitoring of suspected ciguateric fish both in the environment and in the marketplace.

  15. Investigation of absolute and relative response for three different liquid chromatography/tandem mass spectrometry systems; the impact of ionization and detection saturation.

    Science.gov (United States)

    Nilsson, Lars B; Skansen, Patrik

    2012-06-30

    The investigations in this article were triggered by two observations in the laboratory; for some liquid chromatography/tandem mass spectrometry (LC/MS/MS) systems it was possible to obtain linear calibration curves for extreme concentration ranges and for some systems seemingly linear calibration curves gave good accuracy at low concentrations only when using a quadratic regression function. The absolute and relative responses were tested for three different LC/MS/MS systems by injecting solutions of a model compound and a stable isotope labeled internal standard. The analyte concentration range for the solutions was 0.00391 to 500 μM (128,000×), giving overload of the chromatographic column at the highest concentrations. The stable isotope labeled internal standard concentration was 0.667 μM in all samples. The absolute response per concentration unit decreased rapidly as higher concentrations were injected. The relative response, the ratio for the analyte peak area to the internal standard peak area, per concentration unit was calculated. For system 1, the ionization process was found to limit the response and the relative response per concentration unit was constant. For systems 2 and 3, the ion detection process was the limiting factor resulting in decreasing relative response at increasing concentrations. For systems behaving like system 1, simple linear regression can be used for any concentration range while, for systems behaving like systems 2 and 3, non-linear regression is recommended for all concentration ranges. Another consequence is that the ionization capacity limited systems will be insensitive to matrix ion suppression when an ideal internal standard is used while the detection capacity limited systems are at risk of giving erroneous results at high concentrations if the matrix ion suppression varies for different samples in a run. Copyright © 2012 John Wiley & Sons, Ltd.

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

    Directory of Open Access Journals (Sweden)

    Vujović Maja M.

    2016-01-01

    Full Text Available Ambroxol hydrochloride is an expectorant agent, successfully applied in mucolytic therapy for acute and chronic bronchopulmonary diseases. The drug regulates not only mucus secretion but also showed antioxidant, anti-inflammatory and local anesthetic properties. To supplement the pharmacokinetic and toxicological studies of ambroxol, a rapid ultra-high performance liquid chromatography-tandem mass spectrometry method for the quantitation of ambroxol in rabbit serum was developed. A validation of the method was performed as per the ICH guidelines for the validation of bioanalytical methods. The chromatographic separation was achieved in a submicron Kinetex RP - C18 - column (2.1 mm x 50 mm, 1.3μm using the no buffer mobile phase. The ESI mass spectrometry in the MRM mode was used with a typical transitions m/z 378.9→263.8 for ambroxol and m/z 455.2→165.0 for IS. Linearity was determined with an average coefficient of determination >0.999 over the dynamic range from 0.5 - 200 ng/mL with LOD and LOQ of 0.25 ng/mL and 0.5 ng/mL, respectively. The results of the intra- and inter-day precision and accuracy determined in different days were all found to be within the acceptable limits ±15%. The present method was successfully applied to pharmacokinetic study in the rabbits after a single oral dose administration. [Projekat Ministarstva nauke Republike Srbije, br. 175045

  17. Simultaneous determination of clevidipine and its primary metabolite in dog plasma by liquid chromatography-tandem mass spectrometry: Application to pharmacokinetic study.

    Science.gov (United States)

    Zhou, Ying; Li, Huqun; He, Xiaomeng; Jia, Mengmeng; Ni, Yang; Xu, Mingzhen; Chen, Hui; Li, Weiyong

    2014-11-01

    A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of clevidipine and its primary metabolite H152/81 in dog plasma after protein precipitation with acetonitrile using felodipine as the internal standard (IS). Chromatographic separation was performed on a XB C18 column (2.1mm×50mm, 3.5μm) under isocratic conditions with the mobile phase consisting of acetonitrile and 20mM ammonium acetate buffer (pH 7.0) (40:60, v/v) at the flow rate of 0.3ml/min. The run time was 5.5min. Mass spectrometric analysis was performed on a triple quadrupole mass spectrometer operated in the multiple reaction monitoring (MRM) mode with the transitions of m/z 473.0→338.2 for clevidipine, m/z 356.1→324.0 for H152/81 and m/z 383.9→338.2 for the IS. The method was fully validated in terms of selectivity, linearity, lower limit of quantification (LLOQ), accuracy, precision, stability, matrix effect and recovery over a concentration range of 0.15-200ng/ml for clevidipine and 10-2000ng/ml for H152/81, respectively. The analytical method was applied to support a pharmacokinetic study of simultaneous determination of clevidipine and H152/81 in ten healthy beagle dogs. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Simultaneous detection of diagnostic biomarkers of alkaptonuria, ornithine carbamoyltransferase deficiency, and neuroblastoma disease by high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Hsu, Wei-Yi; Chen, Ching-Ming; Tsai, Fuu-Jen; Lai, Chien-Chen

    2013-05-01

    Urinary homovanillic acid (HVA)/vanillylmandelic acid (VMA), orotic acid (OA), and homogentisic acid (HGA) are diagnostic biomarkers of neuroblastoma, ornithine carbamoyl transferase deficiency (OCTD), and alkaptonuria (AKU), respectively. In this study, a high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous quantification of HVA, VMA, OA, and HGA in urine. After sample preparation, which involved only the dilution procedure, samples were quantified by LC-MS/MS. Full-scan MS/MS mode enabled the urinary markers to be quantified with a high degree of specificity and sensitivity. Rather than using a separate enzymatic method to normalize the concentration of creatinine in urine, we quantified the level of creatinine in urine in one LC-MS run. The limits of detection were 10 μg/l for HGA, 25 μg/l for HVA/VMA, and 50 μg/l for OA with a single-to-noise ratio of 3; the limits of quantification were 50 μg/l for HVA and HGA, 100 μg/l for VMA, and 250 μg/l for OA. The linear dynamic range for quantification of the analytes covered 2 to 3 orders of magnitude, depending on the analyte. The relative standard deviation of the developed LC-MS/MS method was less than 4% for the intra-day validation and 10% for the inter-day validation. The results show that our LC-MS/MS technique is a highly sensitive and rapid method for screening for biomarkers that are diagnostic of three metabolic diseases. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. [Determination of aflatoxin B1, B2, G1, G2 in armeniacae semen amarum by high-performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zheng, Run-Sheng; Xu, Hui; Wang, Wen-Li; Zhan, Ruo-Ting; Chen, Wei-Wen

    2013-10-01

    A simple, rapid and cost-effective high-performance liquid chromatography-tandem mass spectrometry (LC-MS/ MS) method was established for simultaneous determination of aflatoxins (AFB1, AFB2, AFG1, AFG2) in Armeniacae Semen Amarum and the application was performance in 11 samples collected from different markets, medical stores and hospitals. The sample was extracted with 84% acetonitrile/water and 250 microL extraction was directly injected into a LC-MS/MS system without further purification procedure after being redissolved with methanol. The LC separation was performed on a C18 column with a linear gradient elution program of 4 mmol x L(-1) NH4 Ac-0.1% formic acid solution and menthol as the mobile phase. Selected reaction monitoring (SRM) was used for selective determination of the four aflatoxins on a triple quadruple mass spectrometer, which was operated in positive ionization modes. All the four aflatoxins showed a good linear relationship with r > 0.999 0, the average recoveries were between 87.88% and 102.9% and the matrix effect was ranged from 90.71% to 99.30% in low, intermediate and high levels. Furthermore, the higher recovery was obtained by the method reported in this study, comparing to the cleanup procedure with the Mycosep 226 purification column. Eleven samples collected were detected and the contamination levels of the AFB1 were between 1.590-2.340 microg x kg(-1) and the AF (B1 + B2 + G1 + G2) was ranged from 2.340 to 3.340 microg x kg(-1). In summary, the developed method was suitable to detect and screen AFB1, AFB2, AFG1, AFG2 in Armeniacae Semen Amarum.

  20. Multi-residue method for determination of 58 pesticides, pharmaceuticals and personal care products in water using solvent demulsification dispersive liquid-liquid microextraction combined with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Caldas, Sergiane Souza; Rombaldi, Caroline; Arias, Jean Lucas de Oliveira; Marube, Liziane Cardoso; Primel, Ednei Gilberto

    2016-01-01

    A rapid and efficient sample pretreatment using solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was studied for the extraction of 58 pharmaceuticals and personal care products (PPCPs) and pesticides from water samples. Type and volume of extraction and disperser solvents, pH, salt addition, amount of salt and type of demulsification solvent were evaluated. Limits of quantification (LOQ) in the range from 0.0125 to 1.25 µg L(-1) were reached, and linearity was in the range from the LOQ of each compound to 25 μg L(-1). Recoveries ranged from 60% to 120% for 84% of the compounds, with relative standard deviations lower than 29%. The proposed method demonstrated, for the first time, that sample preparation by SD-DLLME with determination by LC-MS/MS can be successfully used for the simultaneous extraction of 32 pesticides and 26 PPCPs from water samples. The entire procedure, including the extraction of 58 organic compounds from the aqueous sample solution and the breaking up of the emulsion after extraction with water, rather than with an organic solvent, was environmentally friendly. In addition, this technique was less expensive and faster than traditional techniques. Finally, the analytical method under study was successfully applied to the analysis of all 58 pesticides and PPCPs in surface water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Simultaneous Determination of Food-Related Biogenic Amines and Precursor Amino Acids Using in Situ Derivatization Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction by Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry.

    Science.gov (United States)

    He, Yongrui; Zhao, Xian-En; Wang, Renjun; Wei, Na; Sun, Jing; Dang, Jun; Chen, Guang; Liu, Zhiqiang; Zhu, Shuyun; You, Jinmao

    2016-11-02

    A simple, rapid, sensitive, selective, and environmentally friendly method, based on in situ derivatization ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) using multiple reaction monitoring (MRM) mode has been developed for the simultaneous determination of food-related biogenic amines and amino acids. A new mass-spectrometry-sensitive derivatization reagent 4'-carbonyl chloride rosamine (CCR) was designed, synthesized, and first reported. Parameters and conditions of in situ DUADLLME and UHPLC-MS/MS were optimized in detail. Under the optimized conditions, the in situ DUADLLME was completed speedily (within 1 min) with high derivatization efficiencies (≥98.5%). With the cleanup and concentration of microextraction step, good analytical performance was obtained for the analytes. The results showed that this method was accurate and practical for quantification of biogenic amines and amino acids in common food samples (red wine, beer, wine, cheese, sausage, and fish).

  2. Salting-out assisted liquid-liquid extraction coupled to ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of tetracycline residues in infant foods.

    Science.gov (United States)

    Moreno-González, David; García-Campaña, Ana M

    2017-04-15

    The use of salting-out assisted liquid-liquid extraction (SALLE) combined with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) has been evaluated for the determination of tetracyclines in infant foods based on meat and vegetables or in milk. To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized. Analytical performances of the method were satisfactory, obtaining limits of quantification lower than 0.48μgkg -1 in all cases. The precision, expressed as relative standard deviation (%, RSD) was below 11.3%. The extraction efficiency for fortified samples ranged from 89.2 to 96.8%, with RSDs lower than 7.3%. Matrix effect was evaluated for all samples studied, being lower than |21|% in all cases. In relation to the low solvent consumption, the proposed methodology could be considered rapid, cheap and environmentally friendly. Its applicability has been successfully tested in a wide range of infant foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Air-assisted liquid-liquid microextraction integrated with QuEChERS for determining endocrine-disrupting compounds in fish by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Luo, Zhoufei; Lu, Jing; Li, Haipu; Tu, Yi; Wan, Yuehao; Yang, Zhaoguang

    2018-09-15

    A new, sensitive, and rapid method based on the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) approach and air-assisted liquid-liquid microextraction (AALLME) technology was developed for the determination of 20 endocrine-disrupting compounds (EDCs) in fish by high-performance liquid chromatography-tandem mass spectrometry. The method first integrates AALLME into QuEChERS to achieve clean-up and enrichment of the EDCs in one step. A self-made glass tube was enfolded with plasticine to withstand the high centrifugal force. The established method was developed by optimization of the parameters. High linearities (R 2  > 0.9924) and recoveries (78.2-118.6%) at three spiked levels (5, 10, and 20 ng g -1 ), and low relative standard deviation values (1.1-14.5%) and limits of detection (0.03-0.80 ng g -1 ) were obtained. The method comparison shows that the proposed method is superior as it involves less organic solvent usage, simple operation and high efficiency. This method was successfully applied to different fishes for analyzing EDCs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Dual ultrasonic-assisted dispersive liquid-liquid microextraction coupled with microwave-assisted derivatization for simultaneous determination of 20(S)-protopanaxadiol and 20(S)-protopanaxatriol by ultra high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhao, Xian-En; Lv, Tao; Zhu, Shuyun; Qu, Fei; Chen, Guang; He, Yongrui; Wei, Na; Li, Guoliang; Xia, Lian; Sun, Zhiwei; Zhang, Shijuan; You, Jinmao; Liu, Shu; Liu, Zhiqiang; Sun, Jing; Liu, Shuying

    2016-03-11

    This paper, for the first time, reported a speedy hyphenated technique of low toxic dual ultrasonic-assisted dispersive liquid-liquid microextraction (dual-UADLLME) coupled with microwave-assisted derivatization (MAD) for the simultaneous determination of 20(S)-protopanaxadiol (PPD) and 20(S)-protopanaxatriol (PPT). The developed method was based on ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detection using multiple-reaction monitoring (MRM) mode. A mass spectrometry sensitizing reagent, 4'-carboxy-substituted rosamine (CSR) with high reaction activity and ionization efficiency was synthesized and firstly used as derivatization reagent. Parameters of dual-UADLLME, MAD and UHPLC-MS/MS conditions were all optimized in detail. Low toxic brominated solvents were used as extractant instead of traditional chlorinated solvents. Satisfactory linearity, recovery, repeatability, accuracy and precision, absence of matrix effect and extremely low limits of detection (LODs, 0.010 and 0.015ng/mL for PPD and PPT, respectively) were achieved. The main advantages were rapid, sensitive and environmentally friendly, and exhibited high selectivity, accuracy and good matrix effect results. The proposed method was successfully applied to pharmacokinetics of PPD and PPT in rat plasma. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2016-09-05

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

  6. 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.

  7. High-performance Liquid Chromatographic Ultraviolet Detection of Nilotinib in Human Plasma from Patients with Chronic Myelogenous Leukemia, and Comparison with Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Nakahara, Ryosuke; Satho, Yuhki; Itoh, Hiroki

    2016-11-01

    A method for determining nilotinib concentration in human plasma is proposed using high-performance liquid chromatography and ultraviolet detection. Nilotinib and the internal standard dasatinib were separated using a mobile phase of 0.5% Na 2 PO 4 H 2 O (pH 2.5)-acetonitrile-methanol (55:25:20, v/v/v) on a Capcell Pak C18 MG II column (250 × 4.6 mm) at a flow rate of 1.0 ml/min, and ultraviolet measurement at 250 nm. The calibration curve exhibited linearity over the nilotinib concentration range of 50-2,500 ng/ml at 250 nm, with relative standard deviations (n = 5) of 7.1%, 2.5%, and 2.9% for 250, 1,500, and 2,500 ng/ml, respectively. The detection limit for nilotinib was 5 ng/ml due to three blank determinations (ρ = 3). This method was successfully applied to assaying nilotinib in human plasma samples from patients with chronic myelogenous leukemia. In addition, we compared the results with those measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at BML, Inc. (a commercial laboratory). A strong correlation was observed between the nilotinib concentrations measured by our high-performance liquid chromatographic method and those obtained by LC/MS-MS (r 2 = 0.988, P < 0.01). © 2016 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    2006-11-10

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-12-15

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

  10. Multiple analyte adduct formation in liquid chromatography-tandem mass spectrometry - Advantages and limitations in the analysis of biologically-related samples.

    Science.gov (United States)

    Dziadosz, Marek

    2018-05-01

    Multiple analyte adduct formation was examined and discussed in the context of reproducible signal detection in liquid chromatography-tandem mass spectrometry applied in the analysis of biologically-related samples. Appropriate infusion solutions were prepared in H 2 O/methanol (3/97, v/v) with 1 mM sodium acetate and 10 mM acetic acid. An API 4000 QTrap tandem mass spectrometer was used for experiments performed in the negative scan mode (-Q1 MS) and the negative enhanced product ion mode (-EPI). γ‑Hydroxybutyrate and its deuterated form were used as model compounds to highlight both the complexity of adduct formation in popular mobile phases used and the effective signal compensation by the application of isotope-labelled analytes as internal standards. Copyright © 2018 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

    Sun Xiaotao; Qiao Jinping; Zhu Lin; Qiao Hongwen; Zhong Jianguo

    2010-01-01

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

  12. Fluconazole Pharmacokinetics in Galleria mellonella Larvae and Performance Evaluation of a Bioassay Compared to Liquid Chromatography-Tandem Mass Spectrometry for Hemolymph Specimens

    DEFF Research Database (Denmark)

    Astvad, Karen Marie Thyssen; Meletiadis, Joseph; Whalley, Sarah

    2017-01-01

    The invertebrate model organism Galleria mellonella can be used to assess the efficacy of treatment of fungal infection. The fluconazole dose best mimicking human exposure during licensed dosing is unknown. We validated a bioassay for fluconazole detection in hemolymph and determined...... the fluconazole pharmacokinetics and pharmacodynamics in larval hemolymph in order to estimate a humanized dose for future experiments. A bioassay using 4-mm agar wells, 20 μl hemolymph, and the hypersusceptible Candida albicans DSY2621 was established and compared to a validated liquid chromatography-tandem mass...... spectrometry (LC-MS-MS) method. G. mellonella larvae were injected with fluconazole (5, 10, and 20 mg/kg of larval weight), and hemolymph was harvested for 24 h for pharmacokinetics calculations. The exposure was compared to the human exposure during standard licensed dosing. The bioassay had a linear standard...

  13. 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

  14. Age trends in estradiol and estrone levels measured using liquid chromatography tandem mass spectrometry in community-dwelling men of the Framingham Heart Study.

    Science.gov (United States)

    Jasuja, Guneet Kaur; Travison, Thomas G; Davda, Maithili; Murabito, Joanne M; Basaria, Shehzad; Zhang, Anqi; Kushnir, Mark M; Rockwood, Alan L; Meikle, Wayne; Pencina, Michael J; Coviello, Andrea; Rose, Adam J; D'Agostino, Ralph; Vasan, Ramachandran S; Bhasin, Shalender

    2013-06-01

    Age trends in estradiol and estrone levels in men and how lifestyle factors, comorbid conditions, testosterone, and sex hormone-binding globulin affect these age trends remain poorly understood, and were examined in men of the Framingham Heart Study. Estrone and estradiol concentrations were measured in morning fasting samples using liquid chromatography tandem mass spectrometry in men of Framingham Offspring Generation. Free estradiol was calculated using a law of mass action equation. There were 1,461 eligible men (mean age [±SD] 61.1±9.5 years and body mass index [BMI] 28.8±4.5kg/m(2)). Total estradiol and estrone were positively associated with age, but free estradiol was negatively associated with age. Age-related increase in total estrone was greater than that in total estradiol. Estrone was positively associated with smoking, BMI, and testosterone, and total and free estradiol with diabetes, BMI, testosterone, and comorbid conditions; additionally, free estradiol was associated negatively with smoking. Collectively, age, BMI, testosterone, and other health and behavioral factors explained only 18% of variance in estradiol, and 9% of variance in estrone levels. Men in the highest quintile of estrone levels had significantly higher age and BMI, and a higher prevalence of smoking, diabetes, and cardiovascular disease than others, whereas those in the highest quintile of estradiol had higher BMI than others. Total estrone and estradiol levels in men, measured using liquid chromatography tandem mass spectrometry, revealed significant age-related increases that were only partially accounted for by cross-sectional differences in BMI, diabetes status, and other comorbidities and health behaviors. Longitudinal studies are needed to confirm these findings.

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

    Science.gov (United States)

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

    2017-05-01

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

  16. 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.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  18. Food safety evaluation: Detection and confirmation of chloramphenicol in milk by high performance liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Nicolich, Rebecca S.; Werneck-Barroso, Eduardo; Marques, Marlice A. Sipoli

    2006-01-01

    A simple and rapid procedure for extraction of chloramphenicol (CAP) in milk and analysis by high-performance liquid chromatography coupled with quadrupole mass spectrometry in tandem was developed. The method consisted of one step of liquid-liquid extraction using ethyl acetate and acidified water (10 mmol L -1 formic acid) and HPLC-MS/MS detection. CAP-D5 was used as internal standard. The method was validated according to Commission Decision 2002/657/EC. The calibration curves were linear, with typical r 2 values higher than 0.98. Absolute recovery of CAP from milk proved to be more than 95%, however CAP-D5 absolute recovery was 75%. The method was accurate and reproducible, being successfully applied to the monitoring of CAP in milk samples obtained from the Brazilian market. Decision limit (CCα) was 0.05 ng mL -1 and detection capability (CCβ) was 0.09 ng mL -1

  19. Quantitative determination of sirolimus in dog blood using liquid chromatography-tandem mass spectrometry, and its applications to pharmacokinetic studies.

    Science.gov (United States)

    Lee, Jong-Hwa; Cha, Kwang-Ho; Cho, Wonkyung; Park, Junsung; Park, Hee Jun; Cho, Youngseok; Hwang, Sung-Joo

    2010-12-01

    A rapid, sensitive method of detecting sirolimus in blood was developed and applied in pharmacokinetic studies employing deionized water for hemolysis and a weakly basic mobile phase to enhance chromatographic peak intensity. Dog blood samples were processed via liquid-liquid extraction and the amounts of sirolimus and tacrolimus, an internal standard, were quantified by LC-MS/MS. Specificity, the lower limit of quantification, linearity, accuracy, precision, dilution, recovery, matrix effects, robustness and stability were within the acceptable range for assay validation. The concentration of sirolimus was quantifiable in blood samples for up to 36 h after the dog had received a 3 mg/kg dose of sirolimus. These observations suggest that sirolimus can be detected at low levels in dog blood using a basic mobile phase and metal-free hemolysis. This method is therefore applicable to pharmacokinetic studies in dogs. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  20. Quantification of Oxidized and Unsaturated Bile Alcohols in Sea Lamprey Tissues by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Ke Li

    2016-08-01

    Full Text Available A sensitive and reliable method was developed and validated for the determination of unsaturated bile alcohols in sea lamprey tissues using liquid-liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS. The liver, kidney, and intestine samples were extracted with acetonitrile and defatted by n-hexane. Gradient UHPLC separation was performed using an Acquity BEH C18 column with a mobile phase of water and methanol containing 20 mM triethylamine. Multiple reaction monitoring modes of precursor-product ion transitions for each analyte was used. This method displayed good linearity, with correlation coefficients greater than 0.99, and was validated. Precision and accuracy (RSD % were in the range of 0.31%–5.28%, while mean recoveries were between 84.3%–96.3%. With this technique, sea lamprey tissue samples were analyzed for unsaturated bile alcohol analytes. This method is practical and particularly suitable for widespread putative pheromone residue analysis.

  1. Ultra-high performance liquid chromatography-tandem mass spectrometry in high-throughput confirmation and quantification of 34 anabolic steroids in bovine muscle.

    Science.gov (United States)

    Vanhaecke, Lynn; Vanden Bussche, Julie; Wille, Klaas; Bekaert, Karen; De Brabander, Hubert F

    2011-08-26

    An ultra-high performance liquid chromatography tandem mass spectrometry multi-residue method for the determination of 34 anabolic steroids (10 estrogens including stilbenes, 14 androgens and 10 gestagens) in meat of bovine origin is reported. The extraction and clean-up procedure involved homogenization with methanol, defatting with hexane, liquid/liquid extraction with diethylether and finally SPE clean-up with coupled Si and NH(2) cartridges. The analytes were separated on a 1.9 μm Hypersil Gold column (100×2.1 mm) and quantified on a triple quadrupole mass spectrometer (TSQ Vantage) operating simultaneously in both positive and negative atmospheric pressure chemical ionisation (APCI) modes. This analytical procedure was subsequently validated according to EU criteria (CD 2002/657/EC), resulting in decision limits and detection capabilities ranging between 0.04 and 0.88 μg kg(-1) and 0.12 and 1.9 μg kg(-1), respectively. The method obtained for all, natural and synthetic steroids, adequate precisions and intra-laboratory reproducibilities (relative standard deviation below 20%), and the linearity ranged between 0.991 and 0.999. The performance characteristics fulfill the recommended concentrations fixed by the Community Reference Laboratories. The developed analysis is sensitive, and robust and therefore useful for confirmation and quantification of anabolic steroids for research purposes and residue control programs. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. 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.

  3. Comprehensive determination of flavouring additives and nicotine in e-cigarette refill solutions. Part I: Liquid chromatography-tandem mass spectrometry analysis.

    Science.gov (United States)

    Aszyk, Justyna; Kubica, Paweł; Kot-Wasik, Agata; Namieśnik, Jacek; Wasik, Andrzej

    2017-10-13

    Liquid chromatography-tandem mass spectrometry with electrospray ionization (HPLC-ESI-MS/MS) methods were developed for the simultaneous determination of 42 flavouring compounds and nicotine in liquids for e-cigarettes. The chromatographic separation was performed using an Ace ® Ultracore™ SuperC18™ (100×2.1mm, 2.5μm) column in both acidic and alkaline pH conditions to separate all the compounds. A simple "dilute & shoot" approach was used for the sample preparation. The method validation was performed by evaluating key analytical parameters such as linearity, accuracy, selectivity, precision, limit of detection (LOD) and limit of quantification (LOQ). The calibration curves showed good linearity within the specific ranges for the investigated compounds with correlation coefficients greater than 0.990 in each case. The recovery for all the investigated compounds varied from 89% to 110%. The intra- and inter-day precision were within the acceptable limits (±15%) at all tested concentrations. The applicability of the methods was examined by analysing 25 liquid samples from e-cigarettes commercially available on the Polish market. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Simultaneous analysis of fourteen tertiary amine stimulants in human urine for doping control purposes by liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    Lu Jianghai; Wang San; Dong Ying; Wang Xiaobing; Yang Shuming; Zhang Jianli; Deng Jing; Qin Yang; Xu Youxuan; Wu Moutian; Ouyang Gangfeng

    2010-01-01

    A method for the simultaneous screening and confirmation of the presence of fourteen tertiary amine stimulants in human urine by gas chromatography-mass spectrometry (GC-MS) in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated. Solid phase extraction (SPE) and liquid-liquid extraction (LLE) approaches were utilized for the pre-treatment of the urine samples. The study indicated that the capillary temperature played a significant role in the signal abundances of the protonated molecules of cropropamide and crotethamide under positive ion electrospray ionization (ESI) conditions. In addition, comparison studies of two different pre-treatment approaches as well as the two ionization modes were conducted. The LODs of the developed method for all the analytes were lower than the minimum required performance limit (MRPL) as set forth in the World Anti-Doping Agency (WADA) technical document for laboratories. The human urine sample obtained after oral administration of prolintane.HCl was successfully analyzed by the developed method, which demonstrated the applicability and reliability of the method for routine doping control analysis.

  5. Simultaneous determination of three pesticide adjuvant residues in plant-derived agro-products using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Li, Hui; Jiang, Zejun; Cao, Xiaolin; Su, Hang; Shao, Hua; Jin, Fen; Abd El-Aty, A M; Wang, Jing

    2017-12-15

    Herein, an accurate and reliable isotope-labelled internal standard method was developed and validated for simultaneous determination of three polar pesticide adjuvants, namely 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone in plant-derived agro-products. Matrices, including apple, cabbage, tomato, cucumber, rice, and wheat were extracted with a modified quick, easy, cheap, effective, rugged, and safe "QuEChERS" method and purified with a new clean-up sorbent (Z-Sep). A hydrophilic interaction liquid chromatography column (HILIC), exhibiting a lipophilic-hydrophilic character, was used to separate the three analytes over 10min using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Matrix effects in various matrices were evaluated and an isotope-labelled internal standard method was employed to compensate for ion enhancement/suppression effects. At three fortification levels (2.0, 5.0, and 20.0μg/kg), the mean recoveries ranged from 78.5 to 112.1% with relative standard deviations (RSDs)determination of the three tested pesticide adjuvant residues in agro-products of plant origin. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Simultaneous determination of kasugamycin and validamycin-A residues in cereals by consecutive solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Hong; Wang, Chenchen; Li, Huidong; Nie, Yan; Fang, Liping; Chen, Zilei

    2018-03-01

    Two polar aminoglycosides, kasugamycin and validamycin-A, were determined in cereals (brown rice, wheat and corn) by high-performance liquid chromatography-tandem mass spectrometry. The analytes were extracted from samples using methanol and water (70:30, v/v) at pH 5.5, purified using both a hydrophilic-hydrophobic-balanced cartridge and a strong cation-exchange cartridge, and then analysed using multiple reaction monitoring in positive electrospray ionisation mode with a special ReproSil 100 C 18 high-performance liquid chromatography column. This newly proposed method yielded good sensitivity and excellent chromatographic performance. The limits of quantification for kasugamycin and validamycin-A were 4.1 µg/kg and 1.0 µg/kg, respectively. The recoveries for both compounds at three fortification levels (4, 100 and 500 µg/kg for kasugamycin; 1, 10 and 100 µg/kg for validamycin-A) ranged from 75% to 110%, and the relative standard deviations were below 15%.

  7. Optimization of Sample Preparation for the Identification and Quantification of Saxitoxin in Proficiency Test Mussel Sample using Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kirsi Harju

    2015-11-01

    Full Text Available Saxitoxin (STX and some selected paralytic shellfish poisoning (PSP analogues in mussel samples were identified and quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS. Sample extraction and purification methods of mussel sample were optimized for LC-MS/MS analysis. The developed method was applied to the analysis of the homogenized mussel samples in the proficiency test (PT within the EQuATox project (Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk. Ten laboratories from eight countries participated in the STX PT. Identification of PSP toxins in naturally contaminated mussel samples was performed by comparison of product ion spectra and retention times with those of reference standards. The quantitative results were obtained with LC-MS/MS by spiking reference standards in toxic mussel extracts. The results were within the z-score of ±1 when compared to the results measured with the official AOAC (Association of Official Analytical Chemists method 2005.06, pre-column oxidation high-performance liquid chromatography with fluorescence detection (HPLC-FLD.

  8. Investigation of the effect of plasma albumin levels on regorafenib-induced hepatotoxicity using a validated liquid chromatography-tandem mass spectrometry method.

    Science.gov (United States)

    Pang, Yi Yun; Tan, Yeong Lan; Ho, Han Kiat

    2017-09-01

    Regorafenib is an oral multikinase inhibitor indicated for metastatic colorectal cancer and gastrointestinal stromal tumour. Due to its extensive plasma protein binding and low calculated hepatic extraction ratio, the hepatotoxicity observed with usage of the drug may be related to its plasma exposure. To investigate the highly dynamic free:bound drug concentration for regorafenib in the plasma, a bioanalytical liquid chromatography-tandem mass spectrometric assay was developed and validated in human plasma. The concentration range of the assay was 2-1000ng/mL. Sample preparation was via protein precipitation using acetonitrile with sorafenib as the internal standard. The supernatant was injected into an ultra-performance liquid chromatographic system coupled to a triple quadrupole mass spectrometer. The analytes were separated on an AQUITY UPLC BEH C 18 column (120Å, 1.7μm, 2.1mm×50mm) and eluted with a gradient elution system. The ions were detected in multiple reaction monitoring mode. The linearity, lower limit of quantification, intra-day and inter-day precision and accuracy conformed to FDA guidelines. The validated method was successfully applied to determine the effect of albumin levels in plasma on the extent of protein binding of regorafenib. The results indicated that physiologically-relevant levels of albumin were found to have no significant effect on the extent of protein binding of regorafenib, hence imposing minimal effect on drug disposition. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Identification of marker proteins for the adulteration of meat products with soybean proteins by multidimensional liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Leitner, Alexander; Castro-Rubio, Florentina; Marina, Maria Luisa; Lindner, Wolfgang

    2006-09-01

    Soybean proteins are frequently added to processed meat products for economic reasons and to improve their functional properties. Monitoring of the addition of soybean protein to meat products is of high interest due to the existence of regulations forbidding or limiting the amount of soybean proteins that can be added during the processing of meat products. We have used chromatographic prefractionation on the protein level by perfusion liquid chromatography to isolate peaks of interest from extracts of soybean protein isolate (SPI) and of meat products containing SPI. After enzymatic digestion using trypsin, the collected fractions were analyzed by nanoflow liquid chromatography-tandem mass spectrometry. Several variants and subunits of the major seed proteins, glycinin and beta-conglycinin, were identified in SPI, along with two other proteins. In soybean-protein-containing meat samples, different glycinin A subunits could be identified from the peak discriminating between samples with and without soybean proteins added. Among those, glycinin G4 subunit A4 was consistently found in all samples. Consequently, this protein (subunit) can be used as a target for new analytical techniques in the course of identifying the addition of soybean protein to meat products.

  10. Sensitive determination of D-lactic acid and L-lactic acid in urine by high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Henry, H; Marmy Conus, N; Steenhout, P; Béguin, A; Boulat, O

    2012-04-01

    D-lactic acid in urine originates mainly from bacterial production in the intestinal tract. Increased D-lactate excretion as observed in patients affected by short bowel syndrome or necrotizing enterocolitis reflects D-lactic overproduction. Therefore, there is a need for a reliable and sensitive method able to detect D-lactic acid even at subclinical elevation levels. A new and highly sensitive method for the simultaneous determination of L- and D-lactic acid by a two-step procedure has been developed. This method is based on the concentration of lactic acid enantiomers from urine by supported liquid extraction followed by high-performance liquid chromatography-tandem mass spectrometry. The separation was achieved by the use of an Astec Chirobiotic™ R chiral column under isocratic conditions. The calibration curves were linear over the ranges of 2-400 and 0.5-100 µmol/L respectively for L- and D-lactic acid. The limit of detection of D-lactic acid was 0.125 µmol/L and its limit of quantification was 0.5 µmol/L. The overall accuracy and precision were well within 10% of the nominal values. The developed method is suitable for production of reference values in children and could be applied for accurate routine analysis. Copyright © 2011 John Wiley & Sons, Ltd.

  11. 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

    International Nuclear Information System (INIS)

    Xia Xi; Ding Shuangyang; Li Xiaowei; Gong Xiao; Zhang Suxia; Jiang Haiyang; Li Jiancheng; Shen Jianzhong

    2009-01-01

    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 μg kg -1 , respectively. This validated method was successfully applied to the determination of melamine in real samples from market.

  12. Liquid chromatography-tandem mass spectrometry method for determination of panel of neurotransmitters in cerebrospinal fluid from the rat model for tauopathy.

    Science.gov (United States)

    Kovac, Andrej; Somikova, Zuzana; Zilka, Norbert; Novak, Michal

    2014-02-01

    Alzheimer's disease (AD) is still being recognized today as an unmet medical need. Currently, there is no cure and early preclinical diagnostic assay available for AD. Therefore much attention is now being directed at the development of novel methods for quantitative determination of AD biomarkers in the cerebrospinal fluid (CSF). Here, we describe the liquid chromatography-tandem mass spectrometry method for determination of 5-hydroxytryptamine (SER), 5-hydroxyindoleacetic acid (5-HIAA), homovanilic acid (HVA), noradrenaline (NADR), adrenaline (ADR), dopamine (DA), glutamic acid (Glu), γ-aminobutyric acid (GABA), 3,4-dihydroxyphenylacetic acid (DOPAC) and histamine (HIS) in cerebrospinal fluid (CSF) from the rat model for human tauopathy. The benzoyl chloride was used as pre-column derivatization reagents. Neurotransmitters and metabolites were analysed on ultra performance liquid chromatography (UPLC) on C18 column in combination with tandem mass spectrometry. The method is simple, highly sensitive and showed excellent linearity with regression coefficients higher than 0.99. The accuracy was in a range of 93-113% for all analytes. The inter-day precision (n=5 days), expressed as %RSD, was in a range 2-10% for all analytes. Using this method we detected significant changes of CSF levels of two important neurotransmitters/metabolites, ADR and 5-HIAA, which correlates with progression of neurodegeneration in our animal model. © 2013 Published by Elsevier B.V.

  13. Determining estrogenic steroids in Taipei waters and removal in drinking water treatment using high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Chen, C.-Y. [Institute of Environmental Health, College of Public Health, National Taiwan University, 17 Hsu-Chou Road, Taipei (10055), Taiwan (China)]. E-mail: dbms@ntu.edu.tw; Wen, T.-Y. [Institute of Environmental Health, College of Public Health, National Taiwan University, 17 Hsu-Chou Road, Taipei (10055), Taiwan (China); Wang, G.-S. [Institute of Environmental Health, College of Public Health, National Taiwan University, 17 Hsu-Chou Road, Taipei (10055), Taiwan (China); Department of Public Health, College of Public Health, National Taiwan University, 17 Hsu-Chou Road, Taipei (10055), Taiwan (China); Cheng, H.-W. [Institute of Environmental Health, College of Public Health, National Taiwan University, 17 Hsu-Chou Road, Taipei (10055), Taiwan (China); Lin, Y.-H. [Institute of Environmental Health, College of Public Health, National Taiwan University, 17 Hsu-Chou Road, Taipei (10055), Taiwan (China); Lien, G.-W. [Institute of Environmental Health, College of Public Health, National Taiwan University, 17 Hsu-Chou Road, Taipei (10055), Taiwan (China)

    2007-06-01

    River water and wastewater treatment plant (WWTP) effluents from metropolitan Taipei, Taiwan were tested for the presence of the pollutants estrone (E{sub 1}), estriol (E{sub 3}), 17{beta}-estradiol (E{sub 2}), and 17{alpha}-ethinylestradiol (EE{sub 2}) using a new methodology that involves high-flow solid-phase extraction and liquid chromatography/tandem mass spectrometry. The method was also used to investigate the removal of the analytes by conventional drinking water treatment processes. Without adjusting the pH, we extracted 1-L samples with PolarPlus C{sub 18} Speedisks under a flow rate exceeding 100 mL/min, in which six samples could be done simultaneously using an extraction station. The adsorbent was washed with 40% methanol/60% water and then eluted by 50% methanol/50% dichloromethane. The eluate was concentrated until almost dry and was reconstituted by 20 {mu}L of methanol. Quantitation was done by LC-MS/MS-negative electrospray ionization in the selected reaction monitoring mode with isotope-dilution techniques. The mobile phase was 10 mM N-methylmorpholine aqueous solution/acetonitrile with gradient elution. Mean recoveries of spiked Milli-Q water were 65-79% and precisions were within 2-20% of the tested concentrations (5.0-200 ng/L). The method was validated with spiked upstream river water; precisions were most within 10% of the tested concentrations (10-100 ng/L) with most RSDs < 10%. LODs of the environmental matrixes were 0.78-7.65 ng/L. A pre-filtration step before solid-phase extraction may significantly influence the measurement of E{sub 1} and EE{sub 2} concentrations; disk overloading by water matrix may also impact analyte recoveries along with ion suppression. In the Taipei water study, the four steroid estrogens were detected in river samples (ca. 15 ng/L for E{sub 2} and EE{sub 2} and 35-45 ng/L for E{sub 1} and E{sub 3}). Average levels of 19-26 ng/L for E{sub 1}, E{sub 2}, and EE{sub 2} were detected in most wastewater effluents

  14. Survey of Deoxynivalenol and Aflatoxin B1 in Instant Noodles and Bread Consumed in Thailand by Using Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Pralatnet, Sasithorn; Poapolathep, Saranya; Giorgi, Mario; Imsilp, Kanjana; Kumagai, Susumu; Poapolathep, Amnart

    2016-07-01

    One hundred wheat product samples (50 instant noodle samples and 50 bread samples) were collected from supermarkets in Bangkok, Thailand. Deoxynivalenol (DON) and aflatoxin B1 (AFB1) contamination in these products was analyzed using a validated liquid chromatography-tandem mass spectrometry method. The limit of quantification values of DON and AFB1 in the instant noodles and bread were 2 and 1 ng g(-1), respectively. The survey found that DON was quantifiable in 40% of collected samples, in 2% of noodles (0.089 μg g(-1)), and in 78% of breads (0.004 to 0.331 μg g(-1)). AFB1 was below the limit of quantification of the method in all of the tested samples. The results suggest that the risk of DON exposure via noodles and breads is very low in urban areas of Thailand. No risk can be attributable to AFB1 exposure in the same food matrices, but further studies with a larger sample size are needed to confirm these data.

  15. Determination of rivaroxaban in patient's plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS).

    Science.gov (United States)

    Derogis, Priscilla Bento Matos; Sanches, Livia Rentas; de Aranda, Valdir Fernandes; Colombini, Marjorie Paris; Mangueira, Cristóvão Luis Pitangueira; Katz, Marcelo; Faulhaber, Adriana Caschera Leme; Mendes, Claudio Ernesto Albers; Ferreira, Carlos Eduardo Dos Santos; França, Carolina Nunes; Guerra, João Carlos de Campos

    2017-01-01

    Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p plasma samples for rivaroxaban measurement by HPLC-MS/MS without interferences. The chromogenic and HPLC-MS/MS methods were highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels.

  16. Simultaneous Quantitation of Advanced Glycation End Products in Soy Sauce and Beer by Liquid Chromatography-Tandem Mass Spectrometry without Ion-Pair Reagents and Derivatization.

    Science.gov (United States)

    Nomi, Yuri; Annaka, Hironori; Sato, Shinji; Ueta, Etsuko; Ohkura, Tsuyoshi; Yamamoto, Kazuhiro; Homma, Seiichi; Suzuki, Emiko; Otsuka, Yuzuru

    2016-11-09

    The aim of this study was to develop a simple and sensitive method to analyze several advanced glycation end products (AGEs) simultaneously using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and to apply this method to the quantitation of AGEs in brown-colored foods. The developed method enabled to separate and quantitate simultaneously seven AGEs, and was applied to the determination of free AGEs contained in various kinds of soy sauce and beer. The major AGEs in soy sauce and beer were N ε -carboxymethyllysine (CML), N ε -carboxyethyllysine (CEL), and N δ -(5-hydro-5-methyl-4-imidazolon-2-yl)ornithine (MG-H1). Using the developed LC-MS/MS method, recovery test on soy sauce and beer samples showed the recovery values of 85.3-103.9% for CML, 95.9-107.4% for CEL, and 69.5-123.2% for MG-H1. In particular, it is the first report that free CML, CEL, and MG-H1 were present in beer. Furthermore, long-term storage and heating process of soy sauce increased CML and MG-H1.

  17. A high-throughput screening method of bisphenols, bisphenols digycidyl ethers and their derivatives in dairy products by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cheng, Yan; Nie, Xue-Mei; Wu, Han-Qiu; Hong, Yun-He; Yang, Bing-Cheng; Liu, Tong; Zhao, Dan; Wang, Jian-Feng; Yao, Gui-Hong; Zhang, Feng

    2017-01-15

    A simple and universal analytical method based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for high throughput screening of 21 bisphenols, bisphenols digycidyl ethers and their derivatives in dairy products was developed. Response Surface Methodology (RSM) was used to optimize sample preparation conditions based on a quick, easy, cheap, effective, rugged and safe (QuEChERS) method. The analytes were extracted by using 15 mL acetonitrile with 1% acetic acid, and the extracts were further purified by using 190 mg of C18 and 390 mg of PSA. The extracts were analyzed by UHPLC-MS/MS with electrospray ionization (ESI) source. Linearity was assessed by using matrix-matched standard calibration and good correlation coefficients (r 2  > 0.99) were obtained. The limits of quantitation (LOQs) for the analytes ranged from 0.02 to 5 μg kg -1 . The extraction recoveries were in a range of 88.2%-108.2%. Good method reproducibility in terms of intra- and inter-day precision was observed, yielding relative standard deviations (RSDs) less than 8.9% and 9.9%, respectively. The validation method results revealed that the proposed method was sensitive and reliable. Finally, this method was successfully applied to dairy product analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. A serum and platelet-rich plasma serotonin assay using liquid chromatography tandem mass spectrometry for monitoring of neuroendocrine tumor patients.

    Science.gov (United States)

    Korse, Catharina M; Buning-Kager, Johanna C G M; Linders, Theodora C; Heijboer, Annemieke C; van den Broek, Daan; Tesselaar, Margot E T; van Tellingen, Olaf; van Rossum, Huub H

    2017-06-01

    Serotonin is used for the diagnosis and follow-up of neuroendocrine tumors (NET). We describe the analytical and clinical validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) based serotonin assay for serum and platelet-rich plasma (PRP). An LC-MS/MS based method for serum and PRP serotonin was validated by determination of assay imprecision, carry-over, linearity, interference, recovery, sample stability and a matrix/method comparison of serum and PRP serotonin was made with whole blood serotonin. Furthermore, upper limits of normal were determined and serotonin concentrations of healthy individuals, 14 NET patients without evidence of disease and 51 NET patients with evidence of disease were compared. For serum and PRP fractions, total assay imprecision was serotonin upper limit of normal were 5.5nmol/10 9 platelet and 5.1nmol/10 9 platelet, respectively. NET patients with confirmed evidence of disease had significantly higher serum and PRP serotonin levels when compared to NET patients without evidence of disease and healthy volunteers. LC-MS/MS based serum and PRP serotonin assays were developed with suitable analytical characteristics. Furthermore, serum and PRP serotonin was found to be useful for monitoring NET patients. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Pang, Nannan; Wang, Tielong; Hu, Jiye

    2016-01-01

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

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

    Science.gov (United States)

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

    2013-11-21

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

  1. Determination of bisphenol A, triclosan and their metabolites in human urine using isotope-dilution liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Provencher, Gilles; Bérubé, René; Dumas, Pierre; Bienvenu, Jean-François; Gaudreau, Eric; Bélanger, Patrick; Ayotte, Pierre

    2014-06-27

    Bisphenol A (BPA) and triclosan (TCS) are ubiquitous environmental phenols exhibiting endocrine disrupting activities that may be involved in various health disorders in humans. There is a need to measure separately free forms and conjugated metabolites because only the former are biologically active. We have developed sensitive methods using isotope-dilution liquid chromatography-tandem mass spectrometry for individual measurements of free BPA and TCS as well as their metabolites, BPA glucuronide (BPAG), BPA monosulfate (BPAS), BPA disulfate (BPADS), TCS glucuronide (TCSG) and TCS sulfate (TCSS) in urine. Comparative analyses of urine samples from 46 volunteers living in the Quebec City area using the new methods and a GC-MS/MS method previously used in our laboratory revealed very strong correlations for total BPA (Spearman's rs=0.862, purine samples (>94% of total urinary concentrations). Unconjugated TCS concentrations represented a small proportion of total TCS species (median=1.6%) but its concentration was likely underestimated due to losses by adsorption to the surface of polypropylene tubes used for sample storage. To our knowledge, we are the first to report levels of free, sulfated and glucuronidated TCS levels in human urine. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Liquid chromatography-tandem mass spectrometry method for the analysis of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine, a biocidal disinfectant, in dairy products.

    Science.gov (United States)

    Slimani, Kahina; Pirotais, Yvette; Maris, Pierre; Abjean, Jean-Pierre; Hurtaud-Pessel, Dominique

    2018-10-01

    A novel and reliable method to quantify residual levels of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in dairy products using ion-pairing reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and fully validated. Sample extraction was done with salting-out technique using acetonitrile and sodium chloride. For LC-MS/MS, the analyte was detected using positive electrospray ionization (ESI+) and two multiple reaction monitoring (MRM) transitions were monitored. The method was validated in the 5-150 µg kg -1 range using total error approach. Thus, performance criteria of the method were evaluated. Relative standard deviations for trueness and precision were lower than 10%; with the exception of hard pressed cheese at 5 µg kg -1 for precision. The limit of quantification (LOQ) was around 5-7 µg kg -1 depending on the matrix of interest. The method was successfully applied to accurately quantify N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in 146 various dairy products with a maximum contamination level of 225 µg kg -1 in cheese. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Determination of acetamiprid, imidacloprid, and spirotetramat and their relevant metabolites in pistachio using modified QuEChERS combined with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Faraji, Mohammad; Noorbakhsh, Roya; Shafieyan, Hooshang; Ramezani, Mohammadkazem

    2018-02-01

    A QuEChERS based methodology was developed for the simultaneous identification and quantification of acetamiprid, imidacloprid, and spirotetramat and their relevant metabolites in pistachio by liquid chromatography-tandem mass spectrometry for the first time. First, sample extraction was done with MeCN:citrate buffer:NaHCO 3 followed by phase separation with the addition of MgSO 4 :NaCl. The supernatant was then cleaned by a primary-secondary amine (PSA), GCB, and MgSO 4 . The proposed method provides a linearity in the range of 5-200µgL -1 , and the linear regression coefficients were higher than 0.99. LOD and LOQ were obtained to be 2 and 5µgkg -1 for the studied insecticides, respectively, with the exception of imidacloprid-olefin (5 and 10µgkg -1 ). Acceptable recoveries (91-110%) were obtained for all the analytes with good intra- and inter-precisions (0.4≥RSD ≤11.0). The method was then used for the pistachio samples collected from a field trial to estimate the maximum residue limits (MRLs) in next step. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2018-01-19

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

  5. Evaluation of different hydrophilic stationary phases for the simultaneous determination of iminosugars and other low molecular weight carbohydrates in vegetable extracts by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Rodríguez-Sánchez, S; Quintanilla-López, J E; Soria, A C; Sanz, M L

    2014-11-01

    Iminosugars are considered potential drug candidates for the treatment of several diseases, mainly as a result of their α-glycosidase inhibition properties. A method by hydrophilic interaction liquid chromatography tandem mass spectrometry has been optimized for the first time for the simultaneous determination of complex mixtures of bioactive iminosugars and other low molecular weight carbohydrates (LMWC) in vegetable extracts. Three hydrophilic stationary phases (sulfoalkylbetaine zwitterionic, polyhydroxyethyl aspartamide and ethylene bridge hybrid (BEH) with trifunctionally bonded amide) were compared under both basic and acidic conditions. The best sensitivity (limits of detection between 0.025 and 0.28ngmL -1 ) and overall chromatographic performance in terms of resolution, peak width and analysis time were obtained with the BEH amide column using 0.1% ammonium hydroxide as a mobile phase additive. The optimized method was applied to the analysis of extracts of hyacinth bulbs, buckwheat seeds and mulberry leaves. Iminosugar and other LMWC structures were tentatively assigned by their high resolution daughter ions mass spectra. Several iminosugars such as glycosyl-fagomine in mulberry extract were also described for the first time. Among the extracts analysed, mulberry showed the widest diversity of iminosugars, whereas the highest content of them was found in hyacinth bulb (2.5mgg -1 ) followed by mulberry (1.95 mgg -1 ). Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Determination of endogenous inflammation-related lipid mediators in ischemic stroke rats using background subtracting calibration curves by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yang, Yang; Zhong, Qisheng; Mo, Canlong; Zhang, Hao; Zhou, Ting; Tan, Wen

    2017-11-01

    Accurate and reliable quantification of endogenous lipid mediators in complex biological samples is a daunting challenge. In this study, a robust and direct endogenous quantitative method using background subtracting calibration curves by liquid chromatography-tandem mass spectrometry was first developed for the determination of endogenous lipid mediators in ischemic stroke rats. Absolute quantification without surrogate matrix could be achieved by using background subtracting calibration curves, which were corrected and verified from standard curves constructed on original matrix. The recoveries of this method were in the range of 50.3-98.3%, the precision with the relative standard deviation was less than 13.8%, and the accuracy with the relative error was within ± 15.0%. In addition, background subtracting calibration curves were further verified by validation factors ranging from 90.3 to 110.9%. This validated method has been successfully applied to the analysis of seven endogenous inflammation-related lipid mediators in the brain tissues of ischemic stroke rats. The results indicated that prostaglandins as inflammatory factors and some lipid mediators with neuroprotective effects increased apparently (p endogenous compounds in the complex biological samples. Graphical abstract The analysis procedure of determining endogenous inflammation-related lipid mediators using BSCC by LC-MS/MS.

  7. A novel liquid chromatography-tandem mass spectrometry method for determination of menadione in human plasma after derivatization with 3-mercaptopropionic acid.

    Science.gov (United States)

    Liu, Ruijuan; Wang, Mengmeng; Ding, Li

    2014-10-01

    Menadione (VK3), an essential fat-soluble naphthoquinone, takes very important physiological and pathological roles, but its detection and quantification is challenging. Herein, a new method was developed for quantification of VK3 in human plasma by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after derivatization with 3-mercaptopropionic acid via Michael addition reaction. The derivative had been identified by the mass spectra and the derivatization conditions were optimized by considering different parameters. The method was demonstrated with high sensitivity and a low limit of quantification of 0.03 ng mL(-1) for VK3, which is about 33-fold better than that for the direct analysis of the underivatized compound. The method also had good precision and reproducibility. It was applied in the determination of basal VK3 in human plasma and a clinical pharmacokinetic study of menadiol sodium diphosphate. Furthermore, the method for the quantification of VK3 using LC-MS/MS was reported in this paper for the first time, and it will provide an important strategy for the further research on VK3 and menadione analogs. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Ultra-performance liquid chromatography-tandem mass spectrometry-based multiplex enzyme assay for six enzymes associated with hereditary hemolytic anemia.

    Science.gov (United States)

    Park, Chul Min; Lee, Kyunghoon; Jun, Sun-Hee; Song, Sang Hoon; Song, Junghan

    2017-08-15

    Deficiencies in erythrocyte metabolic enzymes are associated with hereditary hemolytic anemia. Here, we report the development of a novel multiplex enzyme assay for six major enzymes, namely glucose-6-phosphate dehydrogenase, pyruvate kinase, pyrimidine 5'-nucleotidase, hexokinase, triosephosphate isomerase, and adenosine deaminase, deficiencies in which are implicated in erythrocyte enzymopathies. To overcome the drawbacks of traditional spectrophotometric enzyme assays, the present assay was based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The products of the six enzymes were directly measured by using ion pairing UPLC-MS/MS, and the precision, linearity, ion suppression, optimal sample amounts, and incubation times were evaluated. Eighty-three normal individuals and 13 patients with suspected enzymopathy were analyzed. The UPLC running time was within 5min. No ion suppression was observed at the retention time for the products or internal standards. We selected an optimal dilution factor and incubation time for each enzyme system. The intra- and inter-assay imprecision values (CVs) were 2.5-12.1% and 2.9-14.3%, respectively. The linearity of each system was good, with R 2 values >0.97. Patient samples showed consistently lower enzyme activities than those from normal individuals. The present ion paring UPLC-MS/MS assay enables facile and reproducible multiplex evaluation of the activity of enzymes implicated in enzymopathy-associated hemolytic anemia. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Use of Imipenem To Detect KPC, NDM, OXA, IMP, and VIM Carbapenemase Activity from Gram-Negative Rods in 75 Minutes Using Liquid Chromatography-Tandem Mass Spectrometry

    Science.gov (United States)

    Kulkarni, M. V.; Zurita, A. N.; Pyka, J. S.; Murray, T. S.; Hodsdon, M. E.

    2014-01-01

    Resistance to extended-spectrum β-lactam antibiotics has led to a greater reliance upon carbapenems, but the expression of carbapenemases threatens to limit the utility of these drugs. Current methods to detect carbapenemase activity are suboptimal, requiring prolonged incubations during which ineffective therapy may be prescribed. We previously described a sensitive and specific assay for the detection of carbapenemase activity using ertapenem and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, we assessed 402 Gram-negative rods, including both Enterobacteriaceae and non-Enterobacteriaceae expressing IMP, VIM, KPC, NDM, and/or OXA carbapenemases, by using imipenem, meropenem, and ertapenem with LC-MS/MS assays. LC-MS/MS methods for the detection of intact and hydrolyzed carbapenems from an enrichment broth were developed. No ion suppression was observed, and the limits of detection for all three drugs were below 0.04 μg/ml. The sensitivity and specificity of meropenem and ertapenem for carbapenemase activity among non-Enterobacteriaceae were low, but imipenem demonstrated a sensitivity and specificity of 96% and 95%, respectively, among all Gram-negative rods (GNR) tested, including both Enterobacteriaceae and non-Enterobacteriaceae. LC-MS/MS allows for the analysis of more complex matrices, and this LC-MS/MS assay could easily be adapted for use with primary specimens requiring growth enrichment. PMID:24789180

  10. [Determination of deoxynivalenol in grain and its products by solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Huang, Juan; Chen, Guosong; Zhang, Xiaoyan; Shen, Chongyu; Lü, Chen; Wu, Bin; Liu, Yan; Chen, Huilan; Ding, Tao

    2012-11-01

    A method was established for the determination of deoxynivalenol (vomitoxin) in grain and its products based on solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was firstly extracted by acetonitrile-water (84:16, v/v). The extract was then cleaned-up by an HLB solid phase extraction cartridge. The separation was carried out on a Phenomenex Kinetex C18 column (100 mm x4. 6 mm, 2.6 microm) with a gradient elution using 0.3% per hundred ammonia solution-acetonitrile as mobile phases. The analysis of deoxynivalenol was performed under electrospray negative ionization mode. The limit of detection (LOD, S/N= 3) and the limit of quantification (LOQ, S/N = 10) were 20 microg/kg and 50 microg/kg, respectively. A good linearity (r > 0.99) was achieved for the target compound over the range of 20-1000 pg/L. The recoveries at the three spiked levels (50, 100, 500 microg/kg) in the blank matrices such as flour, barley, soybean, rice, cornmeal, cassava and wheat, were varied from 75.6% to 111.0% with the relative standard deviations no more than 13. 0%. The method is accurate, efficient, sensitive and practical. The cost of pretreatment is obviously reduced by replacing immunoaffinity columns and Mycosep columns with HLB columns which have the same purification effect.

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

    Directory of Open Access Journals (Sweden)

    Tun-Pin Hsueh

    2016-12-01

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

  12. [An ultrafast liquid chromatography-tandem mass spectrometric method for simultaneous determination of common artificial synthetic pigments in cooked meat products].

    Science.gov (United States)

    Chen, Xiaohong; Li, Xiaoping; Zhao, Yonggang; Pan, Shengdong; Jin, Micong

    2015-07-01

    A method based on ultrafast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) has been developed for the simultaneous determination of seven synthetic pigments in cooked meat product. After the cooked meat products were extracted by mixed extraction agent, purified by WAX column, the UFLC separation was performed on a Shim-pack XR-ODS II column (75 mm x 2.0 mm, 2.2 µm) with a linear gradient elution program of acetonitrile and ammonium acetate (AmAc, 5 mmol/L) as the mobile phase. Electrospray ionization was applied and operated in the negative ion mode. The limits of quantitation (LOQs) for the seven synthetic pigments were in the range of 0.7-5.0 µg/kg. The calibration curves showed good linearities for the seven analytes in their detection ranges, and the correlative coefficients (r) were more than 0.999. The recoveries were between 88.2%-106.5% with the RSDs in the range of 1.2%-5.0%. The method is sensitive, reproducible, quick and adapts to the simultaneous determination of the seven synthetic pigments in cooked meat product.

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

    Science.gov (United States)

    Chen, Guoqiang; Hoptroff, Michael; Fei, Xiaoqing; Su, Ya; Janssen, Hans-Gerd

    2013-11-22

    A sensitive and specific ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the measurement of climbazole deposition from hair care products onto artificial skin and human scalp. Deuterated climbazole was used as the internal standard. Atmospheric pressure chemical ionization (APCI) in positive mode was applied for the detection of climbazole. For quantification, multiple reaction monitoring (MRM) transition 293.0>69.0 was monitored for climbazole, and MRM transition 296.0>225.1 for the deuterated climbazole. The linear range ran from 4 to 2000 ng mL(-1). The limit of detection (LOD) and the limit of quantification (LOQ) were 1 ng mL(-1) and 4 ng mL(-1), respectively, which enabled quantification of climbazole on artificial skin and human scalp at ppb level (corresponding to 16 ng cm(-2)). For the sampling of climbazole from human scalp the buffer scrub method using a surfactant-modified phosphate buffered saline (PBS) solution was selected based on a performance comparison of tape stripping, the buffer scrub method and solvent extraction in in vitro studies. Using this method, climbazole deposition in in vitro and in vivo studies was successfully quantified. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Determination of rivaroxaban in patient’s plasma samples by anti-Xa chromogenic test associated to High Performance Liquid Chromatography tandem Mass Spectrometry (HPLC-MS/MS)

    Science.gov (United States)

    Derogis, Priscilla Bento Matos; Sanches, Livia Rentas; de Aranda, Valdir Fernandes; Colombini, Marjorie Paris; Mangueira, Cristóvão Luis Pitangueira; Katz, Marcelo; Faulhaber, Adriana Caschera Leme; Mendes, Claudio Ernesto Albers; Ferreira, Carlos Eduardo dos Santos; França, Carolina Nunes; Guerra, João Carlos de Campos

    2017-01-01

    Rivaroxaban is an oral direct factor Xa inhibitor, therapeutically indicated in the treatment of thromboembolic diseases. As other new oral anticoagulants, routine monitoring of rivaroxaban is not necessary, but important in some clinical circumstances. In our study a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was validated to measure rivaroxaban plasmatic concentration. Our method used a simple sample preparation, protein precipitation, and a fast chromatographic run. It was developed a precise and accurate method, with a linear range from 2 to 500 ng/mL, and a lower limit of quantification of 4 pg on column. The new method was compared to a reference method (anti-factor Xa activity) and both presented a good correlation (r = 0.98, p highly correlated and should be used as clinical tools for drug monitoring. The method was applied successfully in a group of 49 real-life patients, which allowed an accurate determination of rivaroxaban in peak and trough levels. PMID:28170419

  15. Determination of steroid hormones in fish tissues by microwave-assisted extraction coupled to ultra-high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Guedes-Alonso, Rayco; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan

    2017-12-15

    Steroid hormones produce adverse effects on biota as well as bioaccumulation in fish and seafood, making it necessary to develop methodologies to evaluate these compounds in samples related to the food chain. This work presents an analytical method for evaluating 15 steroid hormones in fish tissue. It is based on microwave-assisted extraction and solid-phase extraction coupled to ultra-high-performance liquid chromatography tandem mass spectrometry (MAE-SPE-UHPLC-MS/MS). The proposed method shows appropriate detection limits (0.14-49.0ngg -1 ), recoveries in the range of 50% and good repeatability. After optimization, the method was applied to different tissues from two small fishes of the Canary Islands that constitute an important level of the food web (Boops boops and Sphoeroides marmoratus) and were exposed to the outfall of the Las Palmas de Gran Canaria wastewater treatment plant. The concentrations of eight detected compounds ranged from below the quantification limits to 3.95μgg -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Ultra-high performance liquid chromatography tandem mass spectrometry for the determination of five glycopeptide antibiotics in food and biological samples using solid-phase extraction.

    Science.gov (United States)

    Deng, Fenfang; Yu, Hong; Pan, Xinhong; Hu, Guoyuan; Wang, Qiqin; Peng, Rongfei; Tan, Lei; Yang, Zhicong

    2018-02-23

    This paper demonstrated the development and validation of an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous determination of five glycopeptide antibiotics in food and biological samples. The target glycopeptide antibiotics were isolated from the samples by solvent extraction, and the extracts were cleaned with a tandem solid-phase extraction step using mixed strong cation exchange and hydrophilic/lipophilic balance cartridges. Subsequently, the analytes were eluted with different solvents, and then quantified by UHPLC-MS/MS in the positive ionization mode with multiple reaction monitoring. Under optimal conditions, good linear correlations were obtained for the five glycopeptide antibiotics in the concentration range of 1.0 μg/L to 20.0 μg/L, and with linear correlation coefficients >0.998. Employing this method, the target glycopeptide antibiotics in food and biological samples were identified with a recovery of 83.0-102%, and a low quantitation limit of 1.0 μg/kg in food and 2.0 μg/L in biological samples with low matrix effects. Copyright © 2018 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Zhang, Xinyu; Zheng, Feng; Lin, Zebin; Johansen, Sys Stybe; Yu, Tianfang; Liu, Yuming; Huang, Zhibin; Li, Jiaolun; Yan, Jie; Rao, Yulan

    2017-04-22

    The importance of ethanol non-oxidative metabolites as the specific biomarkers of alcohol consumption in clinical and forensic settings is increasingly acknowledged. Simultaneous determination of these metabolites can provide a wealth of information like drinking habit and history, but it was difficult to achieve because of their wide range of polarity. This work describes development and validation of a simple liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for 4 types of ethanol non-oxidative metabolites (ethyl glucuronide, ethyl sulfate, fatty acid ethyl esters and phosphatidylethanols) in 50 μL of human whole blood. Pretreatment method, column and MS conditions were optimized. For the first time, the four types of ethanol non-oxidative metabolites with enormous discrepancies of property were simultaneously extracted and analyzed in one run within 40 min. The limits of detections (LODs) were among 0.1-10 ng/mL, and good linearity was obtained. Deviations in precision and accuracy were all lower than 15% at three QC levels. This method was then applied to two forensic samples, resulting in information on drinking habits and drinking time which were very useful for the interpretation of the blood alcohol results. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Ultrasensitive liquid chromatography-tandem mass spectrometric methodologies for quantification of five HIV-1 integrase inhibitors in plasma for a microdose clinical trial.

    Science.gov (United States)

    Sun, Li; Li, Hankun; Willson, Kenneth; Breidinger, Sheila; Rizk, Matthew L; Wenning, Larissa; Woolf, Eric J

    2012-10-16

    HIV-1 integrase strand transfer inhibitors are an important class of compounds targeted for the treatment of HIV-1 infection. Microdosing has emerged as an attractive tool to assist in drug candidate screening for clinical development, but necessitates extremely sensitive bioanalytical assays, typically in the pg/mL concentration range. Currently, accelerator mass spectrometry is the predominant tool for microdosing support, which requires a specialized facility and synthesis of radiolabeled compounds. There have been few studies attempted to comprehensively assess a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach in the context of microdosing applications. Herein, we describe the development of automated LC-MS/MS methods to quantify five integrase inhibitors in plasma with the limits of quantification at 1 pg/mL for raltegravir and 2 pg/mL for four proprietary compounds. The assays involved double extractions followed by UPLC coupled with negative ion electrospray MS/MS analysis. All methods were fully validated to the rigor of regulated bioanalysis requirements, with intraday precision between 1.20 and 14.1% and accuracy between 93.8 and 107% at the standard curve concentration range. These methods were successfully applied to a human microdose study and demonstrated to be accurate, reproducible, and cost-effective. Results of the study indicate that raltegravir displayed linear pharmacokinetics between a microdose and a pharmacologically active dose.

  19. Determination of six polyether antibiotic residues in foods of animal origin by solid phase extraction combined with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Ha, Jing; Song, Ge; Ai, Lian-Feng; Li, Jian-Chen

    2016-04-01

    A new method using solid phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the determination of six polyether antibiotics, including lasalocid, salinomycin, monensin, narasin, madubamycin and nigericin residues, in foods of animal origin. The samples were extracted with acetonitrile and purified by ENVI-Carb SPE columns after comparing the impurity effect and maneuverability of several SPE cartridges. Subsequently, the analytes were separated on a Hypersil Gold column (2.1×150mm, 5μm) and analyzed by MS/MS detection. The limit of quantization (LOQ) for milk and chicken was 0.4μg/kg, and for chicken livers and eggs, it was 1μg/kg. The linearity was satisfactory with a correlation coefficient of >0.9995 at concentrations ranging from 2 to 100μg/L. The average recoveries of the analytes fortified at three levels ranged from 68.2 to 114.3%, and the relative standard deviations ranged from 4.5 to 12.1%. The method was suitable for quantitative analysis and confirmation of polyether antibiotic residues in foods of animal origin. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Trace analysis of icariin in human serum with dansyl chloride derivatization after oral administration of Epimedium decoction by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Gong, Yinhan; Yip, See Chung; Thamarai, Sennappan Kanagamani; Zhang, Jie; Lee, Hian Kee; Yong, E L

    2007-12-15

    Epimedium herbs are a type of complex traditional Chinese medicine (TCM) with high estrogenic bioactivity. The Epimedium herbal decoction mixture contains many compounds including icariin that can exert potent effects on numerous physiological processes related to human health. An ultrasensitive liquid chromatography tandem mass spectrometric (LC-MS/MS) method has been developed to determine trace levels of icariin in human serum with dansyl chloride derivatization after oral administration of the Epimedium herbal decoctions. The dansyl-icariin showed an intense protonated molecular ion at m/z 910. The collision-induced dissociation of this ion formed a distinctive product at m/z 764, corresponding to a characteristic removal of a rhamnose sugar moiety of icariin. The selected reaction monitoring, based on the m/z 910-->764 transition, was highly specific and ultrasenstive for icariin in human serum samples. The lower limit of quantitation was 10 pg/mL icariin spiked into blank serum. The ranges of coefficients of variation for interday assays and intraday assays were 0-15.0% and 1.1-17.5%, respectively, for a wide linear range from 10 pg/mL to 4 ng/mL. This method was successfully applied to measure trace levels of icariin in a human serum after oral administration of Epimedium decoction within 48 h for the first time.

  1. Development of a Multi-class Steroid Hormone Screening Method using Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS)

    Science.gov (United States)

    Boggs, Ashley S. P.; Bowden, John A.; Galligan, Thomas M.; Guillette, Louis J.; Kucklick, John R.

    2016-01-01

    Monitoring complex endocrine pathways is often limited by indirect measurement or measurement of a single hormone class per analysis. There is a burgeoning need to develop specific direct-detection methods capable of providing simultaneous measurement of biologically relevant concentrations of multiple classes of hormones (estrogens, androgens, progestogens, and corticosteroids). The objectives of this study were to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for multi-class steroid hormone detection using biologically relevant concentrations, then test limits of detection (LOD) in a high-background matrix by spiking charcoal-stripped fetal bovine serum (FBS) extract. Accuracy was tested with National Institute of Standards and Technology Standard Reference Materials (SRMs) with certified concentrations of cortisol, testosterone, and progesterone. 11-Deoxycorticosterone, 11-deoxycortisol, 17-hydroxypregnenolone, 17-hydroxyprogesterone, adrenosterone, androstenedione, cortisol, corticosterone, dehydroepiandrosterone, dihydrotestosterone, estradiol, estriol, estrone, equilin, pregnenolone, progesterone, and testosterone were also measured using isotopic dilution. Dansyl chloride (DC) derivatization was investigated maintaining the same method to improve and expedite estrogen analysis. Biologically relevant LODs were determined for 15 hormones. DC derivatization improved estrogen response two- to eight-fold, and improved chromatographic separation. All measurements had an accuracy ≤ 14 % difference from certified values (not accounting for uncertainty) and relative standard deviation ≤ 14 %. This method chromatographically separated and quantified biologically relevant concentrations of four hormone classes using highly specific fragmentation patterns and measured certified values of hormones that were previously split into three separate chromatographic methods. PMID:27039201

  2. Stir bar sorptive extraction and liquid chromatography-tandem mass spectrometry determination of polar and non-polar emerging and priority pollutants in environmental waters.

    Science.gov (United States)

    Aparicio, Irene; Martín, Julia; Santos, Juan Luis; Malvar, José Luis; Alonso, Esteban

    2017-06-02

    An analytical method based on stir bar sorptive extraction (SBSE) was developed and validated for the determination of environmental concern pollutants in environmental waters by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Target compounds include six water and oil repellents (perfluorinated compounds), four preservatives (butylated hydroxytoluene and three parabens), two plasticizers (bisphenol A and di(2-ethylhexyl)phthalate), seven surfactants (four linear alkylbenzene sulfonates, nonylphenol and two nonylphenol ethoxylates), a flame retardant (hexabromocyclododecane), four hormones, fourteen pharmaceutical compounds, an UV-filter (2-ethylhexyl 4-methoxycinnamate) and nine pesticides. To achieve the simultaneous extraction of polar and non-polar pollutants two stir bar coatings were tested, the classic polydimethylsiloxane (PDMS) coating and the novel ethylene glycol modified silicone (EG-silicone). The best extraction recoveries were obtained using EG-silicone coating. The effects of sample pH, volume and ionic strength and extraction time on extraction recoveries were evaluated. The analytical method was validated for surface water and tap water samples. The method quantification limits ranged from 7.0ngL -1 to 177ngL -1 . The inter-day precision, expressed as relative standard deviation, was lower than 20%. Accuracy, expressed as relative recovery values, was in the range from 61 to 130%. The method was applied for the determination of the 48 target compounds in surface and tap water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Multi-target determination of organic ultraviolet absorbents in organism tissues by ultrasonic assisted extraction and ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Peng, Xianzhi; Jin, Jiabin; Wang, Chunwei; Ou, Weihui; Tang, Caiming

    2015-03-06

    A sensitive and reliable method was developed for multi-target determination of 13 most widely used organic ultraviolet (UV) absorbents (including UV filters and UV stabilizers) in aquatic organism tissues. The organic UV absorbents were extracted using ultrasonic-assisted extraction, purified via gel permeation chromatography coupled with silica gel column chromatography, and determined by ultra-high performance liquid chromatography-tandem mass spectrometry. Recoveries of the UV absorbents from organism tissues mostly ranged from 70% to 120% from fish filet with satisfactory reproducibility. Method quantification limits were 0.003-1.0ngg(-1) dry weight (dw) except for 2-ethylhexyl 4-methoxycinnamate. This method has been applied to analysis of the UV absorbents in wild and farmed aquatic organisms collected from the Pearl River Estuary, South China. 2-Hydroxy-4-methoxybenzophenone and UV-P were frequently detected in both wild and farmed marine organisms at low ngg(-1)dw. 3-(4-Methylbenzylidene)camphor and most of the benzotriazole UV stabilizers were also frequently detected in maricultured fish. Octocrylene and 2-ethylhexyl 4-methoxycinnamate were not detected in any sample. This work lays basis for in-depth study about bioaccumulation and biomagnification of the UV absorbents in marine environment. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. An improved high-performance liquid chromatography-tandem mass spectrometric method to measure atrazine and its metabolites in human urine.

    Science.gov (United States)

    Panuwet, Parinya; Restrepo, Paula A; Magsumbol, Melina; Jung, Kyung Y; Montesano, M Angela; Needham, Larry L; Barr, Dana Boyd

    2010-04-15

    We report an improved solid-phase extraction-high-performance liquid chromatography-tandem mass spectrometry method with isotope dilution quantification to measure seven atrazine metabolites in urine. The metabolites measured were hydroxyatrazine (HA), diaminochloroatrazine (DACT), desisopropylatrazine (DIA), desethylatrazine (DEA), desethylatrazine mercapturate (DEAM), atrazine mercapturate (ATZM), and atrazine (ATZ). Using offline mixed-mode reversed-phase/cation-exchange solid-phase extraction dramatically increased recovery and sensitivity by reducing the influence of matrix components during separation and analysis. DACT extraction recovery improved to greater than 80% while the other analytes had similar extraction efficiencies as previously observed. Limits of detection were lower than our previous method (0.05-0.19 ng/mL) with relative standard deviations less than 10%. The total runtime was shorter (18 min) than the previous on-line method, thus it is suitable for large-scale sample analyses. We increased the throughput of our method twofold by using the newer extraction technique. Published by Elsevier B.V.

  5. [Simultaneous determination of delta-9-tetrahydrocannabinol cannabidiol and cannabinol in edible oil using ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhang, Aizhi; Wang, Quanlin; Mo, Shijie

    2010-11-01

    A method for the simultaneous determination of delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in edible oil was developed using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The target compounds were extracted with methanol, purified by an LC-Alumina-N solid phase extraction cartridge, separated and detected by the UPLC-MS/MS. Quantitative analysis was corrected by an isotope internal standard method using delta-9-THC-D3 as internal standard. Average recoveries for the target compounds varied from 68.0% to 101.6% with the relative standard deviations ranging from 7.0% to 20.1% at three spiked levels. The limits of detection (LOD) of the method were from 0.06-0.17 microg/kg and the limits of quantification (LOQ) were in the range of 0.20-0.52 microg/kg. The results showed that the method is able to meet the requirements for the simultaneous determination of THC, CBD and CBN in edible oil.

  6. Derivatization method of free cyanide including cyanogen chloride for the sensitive analysis of cyanide in chlorinated drinking water by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Kang, Hye-In; Shin, Ho-Sang

    2015-01-20

    A novel derivatization method of free cyanide (HCN + CN(-)) including cyanogen chloride in chlorinated drinking water was developed with d-cysteine and hypochlorite. The optimum conditions (0.5 mM D-cysteine, 0.5 mM hypochlorite, pH 4.5, and a reaction time of 10 min at room temperature) were established by the variation of parameters. Cyanide (C(13)N(15)) was chosen as an internal standard. The formed β-thiocyanoalanine was directly injected into a liquid chromatography-tandem mass spectrometer without any additional extraction or purification procedures. Under the established conditions, the limits of detection and the limits of quantification were 0.07 and 0.2 μg/L, respectively, and the interday relative standard deviation was less than 4% at concentrations of 4.0, 20.0, and 100.0 μg/L. The method was successfully applied to determine CN(-) in chlorinated water samples. The detected concentration range and detection frequency of CN(-) were 0.20-8.42 μg/L (14/24) in source drinking water and 0.21-1.03 μg/L (18/24) in chlorinated drinking water.

  7. [Determination of di (hydrogenated tallow alkyl) dimethyl ammonium compounds in textile auxiliaries by ultra-high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zhu, Feng

    2015-01-01

    A method has been developed for the determination of di (hydrogenated tallow alkyl) dimethyl ammonium compounds (DHTDMAC) in textile auxiliaries by ultra-high performance liquid chromatography-tandem mass spectrometry. (UPLC-MS/MS). The samples were extracted and diluted with acidified methanol by 5% (v/v) formic acid under ultrasonic assistance. The separation was performed on an Eclipse Plus C18 column (50 mm x 2.1 mm, 1.8 microm) using 0.1% (v/v) formic acid solution and methanol as the mobile phases. Identification and quantification were achieved by UPLC-MS/MS with electrospray ionization (ESI) source in positive ion mode and multiple reaction monitoring (MRM) mode. The results indicated that the calibration curve of DHTDMAC showed good linear relationship between peak area and mass concentration in the range of 10-280 microg/L with the correlation coefficient (r2) of 0.9991. The limit of detection (LOD, S/N=3) and the limit of quantification (LOQ, S/N= 10) of this method were 3 mg/kg and 10 mg/kg, respectively. The average recoveries from three typical textile auxiliary matrices including dispersant, antistatic agent and fabric softener, at three spiked levels were in the range of 97.2%-108.3% with the relative standard deviations (RSDs) of 1.5%-4.6%. The method is sensitive, accurate, simple and effective for the analysis of DHTDMAC in textile auxiliaries.

  8. The measurement of urinary 8-hidroxy-2'deoxyguanosine level with liquid chromatography-tandem mass spectrometry method in patients with polycystic ovary syndrome

    Directory of Open Access Journals (Sweden)

    Şeyda Özdemir

    2014-03-01

    Full Text Available Objective: The measurement of urinary 8-hidroxy- 2’deoxyguanosine (8-OHdG level by liquid chromatography-tandem mass (LC-MS/MS method in order to determine whether there is an obvious oxidative deoxyribonucleic acid (DNA damage in patients with Polycystic Ovary Syndrome (PCOS and its relationship with long term risks. Material Methods: Twenty-eight patients with PCOS diagnosis according to the criteria of 2003 Rotterdam Concensus Conference on PCOS were included in this study and twenty-seven healthy women were included as control group. After collecting first morning urine samples of patients and women in control group, the urinary 8-OHdG level were measured by LC-MS/MS method and the results were expressed as nmol/L. 8-OHdG/creatinine ratio (nmol/mol was used to compensate the variation of all nucleoside concentration in urine. The patients with PCOS and the control group were compared in terms of the 8-OHdG/creatinine ratio. Results: Statistically, there was not a significant difference between the patients with PCOS and the control group in terms of the 8-OHdG/creatinine ratio (p= 0.533. Conclusion: According to our research, due to an increase of antioxidant and DNA repair capacity, the urinary 8-OHdG/creatinine ratio as a determinant of oxidative stress in patients with PCOS was not different from the level analyzed in healthy women.

  9. Quantification of methionine and selenomethionine in biological samples using multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS).

    Science.gov (United States)

    Vu, Dai Long; Ranglová, Karolína; Hájek, Jan; Hrouzek, Pavel

    2018-05-01

    Quantification of selenated amino-acids currently relies on methods employing inductively coupled plasma mass spectrometry (ICP-MS). Although very accurate, these methods do not allow the simultaneous determination of standard amino-acids, hampering the comparison of the content of selenated versus non-selenated species such as methionine (Met) and selenomethionine (SeMet). This paper reports two approaches for the simultaneous quantification of Met and SeMet. In the first approach, standard enzymatic hydrolysis employing Protease XIV was applied for the preparation of samples. The second approach utilized methanesulfonic acid (MA) for the hydrolysis of samples, either in a reflux system or in a microwave oven, followed by derivatization with diethyl ethoxymethylenemalonate. The prepared samples were then analyzed by multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS). Both approaches provided platforms for the accurate determination of selenium/sulfur substitution rate in Met. Moreover the second approach also provided accurate simultaneous quantification of Met and SeMet with a low limit of detection, low limit of quantification and wide linearity range, comparable to the commonly used gas chromatography mass spectrometry (GC-MS) method or ICP-MS. The novel method was validated using certified reference material in conjunction with the GC-MS reference method. Copyright © 2018. Published by Elsevier B.V.

  10. Analysis of processing contaminants in edible oils. Part 1. Liquid chromatography-tandem mass spectrometry method for the direct detection of 3-monochloropropanediol monoesters and glycidyl esters.

    Science.gov (United States)

    MacMahon, Shaun; Mazzola, Eugene; Begley, Timothy H; Diachenko, Gregory W

    2013-05-22

    A new analytical method has been developed and validated for the detection of glycidyl esters (GEs) and 3-monochloropropanediol (3-MCPD) monoesters in edible oils. The target compounds represent two classes of potentially carcinogenic chemical contaminants formed during the processing of edible oils. Target analytes are separated from edible oil matrices using a two-step solid-phase extraction (SPE) procedure. The extracts are then analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). Chromatographic conditions that separate sn-1 and sn-2 monoesters of 3-MCPD have been developed for the first time. The method has been validated for GEs, sn-1 3-MCPD monoesters of lauric, myristic, linolenic, linoleic, oleic, and stearic acids, and sn-2 3-MCPD monoesters of oleic and palmitic acids in coconut, olive, and palm oils using an external calibration curve. The range of average recoveries and relative standard deviations (RSDs) across the three oil matrices at three spiking concentrations are 84-115% (3-16% RSD) for the GEs, 95-113% (1-10% RSD) for the sn-1 3-MCPD monoesters, and 76.8-103% (5.1-11.2% RSD) for the sn-2 3-MCPD monoesters, with limits of quantitation at or below 30 ng/g for the GEs, 60 ng/g for sn-1 3-MCPD monoesters, and 180 ng/g for sn-2 3-MCPD monoesters.

  11. Analysis of processing contaminants in edible oils. Part 2. Liquid chromatography-tandem mass spectrometry method for the direct detection of 3-monochloropropanediol and 2-monochloropropanediol diesters.

    Science.gov (United States)

    MacMahon, Shaun; Begley, Timothy H; Diachenko, Gregory W

    2013-05-22

    A method was developed and validated for the detection of fatty acid diesters of 2-monochloropropanediol (2-MCPD) and 3-monochloropropanediol (3-MCPD) in edible oils. These analytes are potentially carcinogenic chemical contaminants formed during edible oil processing. After separation from oil matrices using a two-step solid-phase extraction (SPE) procedure, the target compounds are quantitated using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI). The first chromatographic conditions have been developed that separate intact diesters of 2-MCPD and 3-MCPD, allowing for their individual quantitation. The method has been validated for 28 3-MCPD diesters of lauric, myristic, palmitic, linolenic, linoleic, oleic, and stearic acids in coconut, olive, and palm oils, as well as 3 2-MCPD diesters, using an external calibration curve. The range of average recoveries and relative standard deviations (RSDs) across the three oil matrices at three spiking concentrations are 88-118% (2-16% RSD) with maximum limits of quantitation of 30 ng/g (ppb).

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

    Science.gov (United States)

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

    2013-04-03

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

  13. Comparison of Electrospray Ionization and Atmospheric Chemical Ionization Coupled with the Liquid Chromatography-Tandem Mass Spectrometry for the Analysis of Cholesteryl Esters

    Directory of Open Access Journals (Sweden)

    Hae-Rim Lee

    2015-01-01

    Full Text Available The approach of two different ionization techniques including electrospray ionization (ESI and atmospheric pressure chemical ionization (APCI coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS was tested for the analysis of cholesteryl esters (CEs. The retention time (RT, signal intensity, protonated ion, and product ion of CEs were compared between ESI and APCI. RT of CEs from both ionizations decreased with increasing double bonds, while it increased with longer carbon chain length. The ESI process generated strong signal intensity of precursor ions corresponding to [M+Na]+ and [M+NH4]+ regardless of the number of carbon chains and double bonds in CEs. On the other hand, the APCI process produced a protonated ion of CEs [M+H]+ with a weak signal intensity, and it is selectively sensitive to detect precursor ions of CEs with unsaturated fatty acids. The ESI technique proved to be effective in ionizing more kinds of CEs than the APCI technique.

  14. Fluconazole Pharmacokinetics in Galleria mellonella Larvae and Performance Evaluation of a Bioassay Compared to Liquid Chromatography-Tandem Mass Spectrometry for Hemolymph Specimens

    Science.gov (United States)

    Astvad, Karen Marie Thyssen; Meletiadis, Joseph; Whalley, Sarah

    2017-01-01

    ABSTRACT The invertebrate model organism Galleria mellonella can be used to assess the efficacy of treatment of fungal infection. The fluconazole dose best mimicking human exposure during licensed dosing is unknown. We validated a bioassay for fluconazole detection in hemolymph and determined the fluconazole pharmacokinetics and pharmacodynamics in larval hemolymph in order to estimate a humanized dose for future experiments. A bioassay using 4-mm agar wells, 20 μl hemolymph, and the hypersusceptible Candida albicans DSY2621 was established and compared to a validated liquid chromatography-tandem mass spectrometry (LC–MS-MS) method. G. mellonella larvae were injected with fluconazole (5, 10, and 20 mg/kg of larval weight), and hemolymph was harvested for 24 h for pharmacokinetics calculations. The exposure was compared to the human exposure during standard licensed dosing. The bioassay had a linear standard curve between 1 and 20 mg/liter. Accuracy and coefficients of variation (percent) values were below 10%. The Spearman coefficient between assays was 0.94. Fluconazole larval pharmacokinetics followed one-compartment linear kinetics, with the 24-h area under the hemolymph concentration-time curve (AUC24 h) being 93, 173, and 406 mg · h/liter for the three doses compared to 400 mg · h/liter in humans under licensed treatment. In conclusion, a bioassay was validated for fluconazole determination in hemolymph. The pharmacokinetics was linear. An exposure comparable to the human exposure during standard licensed dosing was obtained with 20 mg/kg. PMID:28760893

  15. [Simultaneous determination of pyraclostrobin and thiophanate-methyl and its metabolite carbendazim residues in soil and citrus by QuEChERS-liquid chromatography- tandem mass spectrometry].

    Science.gov (United States)

    Li, Fuqin; Shi, Lihong; Wang, Fei; Sun, Caiyuan; Kang, Di; Zhang, Yuping; Chen, Lingzhu; Hu, Deyu

    2017-06-08

    A QuEChERS-liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of pyraclostrobin, thiophanate-methyl and its metabolite carbendazim in soil and citrus. The samples were extracted with methanol or acetonitrile, purified by primary secondary amine (PSA), then separated by LC, detected in multiple reaction monitoring (MRM) mass spectrometry mode via positive electrospray ionization. The analytes were quantified by matrix-matched standard solutions with external standard method. The limits of quantification (LOQs) of pyraclostrobin, thiophanate-methyl and carbendazim in different matrices were 5.8-7.0 μg/kg, 9.3-14.1 μg/kg and 2.1-2.6 μg/kg, respectively. For all the samples, the spiked recoveries ranged from 75.48% to 109.18%, and the relative standard deviations (RSDs) were 0.60%-5.11% ( n =5). The method is quick, easy, effective, sensitive and accurate. The matrix-matched calibration solutions can efficiently compensate matrix effects of the pyraclostrobin, thiophanate-methyl and carbendazim in LC-MS/MS analysis. The established method can be applied to the residue analysis of the real samples of soil, citrus peel, citrus pulp and citrus fruits.

  16. Identification of a novel low-level impurity in fungicide pyraclostrobin by high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Xia, Kaimin; Shen, ShanShan; Gao, Qun; Shang, Wei; Pan, Yuanjiang; Wu, Jun

    2017-05-10

    Pyraclostrobin is one kind of new type methoxy acrylate fungicides that has been widely used in agriculture at present, with a lot of advantages including broad spectrum, high efficiency and high selectivity. In this work, a novel low-level impurity in the pyraclostrobin at about 0.2% was separated and characterized by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS). Firstly, the impurity was speculated to possess the same skeleton structure as the main product pyraclostrobin while the methyl group on the methyl ester was substituted to be CH 2 CH 2 Cl on the basis of the on-line multi-stage mass spectrometric behaviors compared with that of pyraclostrobin. Then the accurate molecular weight and element composition of target impurity was verified to be C 20 H 19 Cl 2 N 3 O 4 by high resolution mass spectrometry. Finally, the proposed structure was further confirmed by the 1 H NMR data. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Distribution Assessments of Coumarins from Angelicae Pubescentis Radix in Rat Cerebrospinal Fluid and Brain by Liquid Chromatography Tandem Mass Spectrometry Analysis

    Directory of Open Access Journals (Sweden)

    Yan-Fang Yang

    2018-01-01

    Full Text Available Angelicae Pubescentis Radix (APR is a widely-used traditional Chinese medicine. Pharmacological studies have begun to probe its biological activities on neurological disorders recently. To assess the brain penetration and distribution of APR, a validated ultra-performance liquid chromatography tandem mass spectrometry method was applied to the simultaneous determinations of the main coumarins from APR in the rat cerebrospinal fluid (CSF and brain after oral administration of APR extract, including psoralen, xanthotoxin, bergapten, isoimperatorin, columbianetin, columbianetin acetate, columbianadin, oxypeucedanin hydrate, angelol B, osthole, meranzin hydrate and nodakenetin. Most of the tested coumarins entered the rat CSF and brain quickly, and double-peak phenomena in concentration-time curves were similar to those of their plasma pharmacokinetics. Columbianetin had the highest concentration in the CSF and brain, while psoralen and columbianetin acetate had the largest percent of CSF/plasma and brain/plasma, indicating that these three coumarins may be worthy of further research on the possible nervous effects. Correlations between the in vivo brain distributions and plasma pharmacokinetics of these coumarins were well verified. These results provided valuable information for the overall in vivo brain distribution characteristics of APR and also for its further studies on the active substances for the central nervous system.

  18. Distribution Assessments of Coumarins from Angelicae Pubescentis Radix in Rat Cerebrospinal Fluid and Brain by Liquid Chromatography Tandem Mass Spectrometry Analysis.

    Science.gov (United States)

    Yang, Yan-Fang; Zhang, Lei; Yang, Xiu-Wei

    2018-01-20

    Angelicae Pubescentis Radix (APR) is a widely-used traditional Chinese medicine. Pharmacological studies have begun to probe its biological activities on neurological disorders recently. To assess the brain penetration and distribution of APR, a validated ultra-performance liquid chromatography tandem mass spectrometry method was applied to the simultaneous determinations of the main coumarins from APR in the rat cerebrospinal fluid (CSF) and brain after oral administration of APR extract, including psoralen, xanthotoxin, bergapten, isoimperatorin, columbianetin, columbianetin acetate, columbianadin, oxypeucedanin hydrate, angelol B, osthole, meranzin hydrate and nodakenetin. Most of the tested coumarins entered the rat CSF and brain quickly, and double-peak phenomena in concentration-time curves were similar to those of their plasma pharmacokinetics. Columbianetin had the highest concentration in the CSF and brain, while psoralen and columbianetin acetate had the largest percent of CSF/plasma and brain/plasma, indicating that these three coumarins may be worthy of further research on the possible nervous effects. Correlations between the in vivo brain distributions and plasma pharmacokinetics of these coumarins were well verified. These results provided valuable information for the overall in vivo brain distribution characteristics of APR and also for its further studies on the active substances for the central nervous system.

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

    Science.gov (United States)

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

    2013-01-01

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

  20. Evaluation of treadmill exercise effect on muscular lipid profiles of diabetic fatty rats by nanoflow liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    Lee, Jong Cheol; Kim, Il Yong; Son, Yeri; Byeon, Seul Kee; Yoon, Dong Hyun; Son, Jun Seok; Song, Han Sol; Song, Wook; Seong, Je Kyung; Moon, Myeong Hee

    2016-07-01

    We compare comprehensive quantitative profiling of lipids at the molecular level from skeletal muscle tissues (gastrocnemius and soleus) of Zucker diabetic fatty rats and Zucker lean control rats during treadmill exercise by nanoflow liquid chromatography-tandem mass spectrometry. Because type II diabetes is caused by decreased insulin sensitivity due to excess lipids accumulated in skeletal muscle tissue, lipidomic analysis of muscle tissues under treadmill exercise can help unveil the mechanism of lipid-associated insulin resistance. In total, 314 lipid species, including phospholipids, sphingolipids, ceramides, diacylglycerols (DAGs), and triacylglycerols (TAGs), were analyzed to examine diabetes-related lipid species and responses to treadmill exercise. Most lysophospholipid levels increased with diabetes. While DAG levels (10 from the gastrocnemius and 13 from the soleus) were >3-fold higher in diabetic rats, levels of most of these decreased after exercise in soleus but not in gastrocnemius. Levels of 5 highly abundant TAGs (52:1 and 54:3 in the gastrocnemius and 48:2, 50:2, and 52:4 in the soleus) displaying 2-fold increases in diabetic rats decreased after exercise in the soleus but not in the gastrocnemius in most cases. Thus, aerobic exercise has a stronger influence on lipid levels in the soleus than in the gastrocnemius in type 2 diabetic rats.

  1. Multianalyte, high-throughput liquid chromatography tandem mass spectrometry method for the sensitive determination of fungicides and insecticides in wine.

    Science.gov (United States)

    Castro, Gabriela; Pérez-Mayán, Leticia; Rodríguez-Cabo, Tamara; Rodríguez, Isaac; Ramil, Maria; Cela, Rafael

    2018-01-01

    Evidence of pesticide transfer from grapes to wine, added to differences in the national regulations regarding the number and the maximum concentration of these species in wine, demands analytical procedures suitable for their routine control in this foodstuff. In this research, solid-phase extraction (SPE) and ultra-performance liquid chromatography (UPLC), with tandem mass spectrometry (MS/MS) detection, are combined to obtain a sensitive and rapid procedure to determine 50 pesticides in red and white wines. Efficiency and selectivity of sample preparation are correlated with the type of sorbent, the elution solvent, and the physicochemical properties of pesticides. SPE of 2-mL wine samples followed by direct injection of the extract in the UPLC-MS/MS system provides quantification limits (LOQs) below 1 ng mL -1 for 48 out of 50 compounds, linear responses up to 200 ng mL -1 , and acceptable accuracy, employing quantification against solvent-based standards, for 45 species. A total analysis time of 10 min, including compounds separation and re-equilibration of the UPLC column, was achieved. The developed methodology was applied to 25 wines (20 conventional and 5 ecological), produced in 7 different countries. Out of 27 pesticides quantified in these wines, 12 displayed occurrence frequencies above 24%; moreover, all wines, except one of the ecological ones, contained residues from at least one pesticide.

  2. Quantification of Hydroxychloroquine in Blood Using Turbulent Flow Liquid Chromatography-Tandem Mass Spectrometry (TFLC-MS/MS).

    Science.gov (United States)

    Chambliss, Allison B; Füzéry, Anna K; Clarke, William A

    2016-01-01

    Hydroxychloroquine (HQ) is used routinely in the treatment of autoimmune disorders such as rheumatoid arthritis and lupus erythematosus. Issues such as marked pharmacokinetic variability and patient non-compliance make therapeutic drug monitoring of HQ a useful tool for management of patients taking this drug. Quantitative measurements of HQ may aid in identifying poor efficacy as well as provide reliable information to distinguish patient non-compliance from refractory disease. We describe a rapid 7-min assay for the accurate and precise measurement of HQ concentrations in 100 μL samples of human blood using turbulent flow liquid chromatography coupled to tandem mass spectrometry. HQ is isolated from EDTA whole blood after a simple extraction with its deuterated analog, hydroxychloroquine-d4, in 0.33 M perchloric acid. Samples are then centrifuged and injected onto the TFLC-MS/MS system. Quantification is performed using a nine-point calibration curve that is linear over a wide range (15.7-4000 ng/mL) with precisions of <5 %.

  3. Multi-residue determination of 210 drugs in pork by ultra-high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Yin, Zhiqiang; Chai, Tingting; Mu, Pengqian; Xu, Nana; Song, Yue; Wang, Xinlu; Jia, Qi; Qiu, Jing

    2016-09-09

    This paper presents a multi-residue analytical method for 210 drugs in pork using ultra-high-performance liquid chromatography-Q-Trap tandem mass spectrometry (UPLC-MS/MS) within 20min via positive ESI in scheduled multi-reaction monitoring (MRM) mode. The 210 drugs, belonging to 21 different chemical classes, included macrolides, sulfonamides, tetracyclines, β-lactams, β-agonists, aminoglycosides, antiviral drugs, glycosides, phenothiazine, protein anabolic hormones, non-steroidal anti-inflammatory drugs (NSAIDs), quinolones, antifungal drugs, corticosteroids, imidazoles, piperidines, piperazidines, insecticides, amides, alkaloids and others. A rapid and simple preparation method was applied to process the animal tissues, including solvent extraction with an acetonitrile/water mixture (80/20, v/v), defatting and clean-up processes. The recoveries ranged from 52% to 130% with relative standard deviations (RSDs)<20% for spiked concentrations of 10, 50 and 250μg/kg. More than 90% of the analytes achieved low limits of quantification (LOQs)<10μg/kg. The decision limit (CCα), detection capability (CCβ) values were in the range of 2-502μg/kg and 4-505μg/kg, respectively. This method is significant for food safety monitoring and controlling veterinary drug use. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Simultaneous determination of β-agonists and monitoring in bovine tissues by liquid chromatography-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Kyunghun Jeong

    2018-01-01

    Full Text Available The misuse of β-agonists leads to a potential risk to public health and is forbidden in many countries. We developed a rapid, sensitive and reliable multi-residue detection method for zilpaterol, ractopamine, and clenbuterol in bovine tissues by liquid chromatography–tandem mass spectrometry. Residues were extracted in ethyl acetate after protein precipitation, and then analyzed by the developed method. Good linearities (R2 > 0.99 were observed, and the recoveries of zilpaterol, ractopamine, and clenbuterol were 99%, 74%, and 102%, respectively. The limits of quantitation for zilpaterol, ractopamine, and clenbuterol were 1.3, 5.0, and 1.7 ng/g, respectively. The method is also applied successfully to bovine tissues within the Korean National Residue Programme. None of the 3 β-agonists were detected from 50 domestic samples. However, zilpaterol (6.3 ng/g was quantified in one out of the 50 imported samples. The application of this method will be helpful in quality control analysis of β-agonists residues in bovine tissues.

  5. Determination of pharmaceutical and illicit drugs in oral fluid by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Di Corcia, D; Lisi, S; Pirro, V; Gerace, E; Salomone, A; Vincenti, M

    2013-05-15

    A simple and extremely fast procedure for the quantitative determination in oral fluid samples of 44 substances, including the most common drugs of abuse and several pharmaceutical drugs, was developed and fully validated. Preliminary sample treatment was limited to protein precipitation. The resulting acetonitrile solution was directly injected into an ultra-high performance liquid chromatograph (UHPLC) equipped with a C18 column (100mm×2.1mm, 1.7μm). The mobile phase eluted with linear gradient (water/formic acid 5mM: acetonitrile/formic acid 5mM; v:v) from 98:2 to 0:100 in 5.0min, followed by isocratic elution at 100% B for 1.0min. The flow rate was 0.6mL/min and the total run time was 9.0min including re-equilibration at the initial conditions. The analytes were revealed by a triple quadrupole mass spectrometer operating in the selected reaction monitoring mode. The method proved to be simple, accurate, rapid and highly sensitive, allowing the simultaneous detection of all compounds. The ease of sample treatment, together with the wide range of detectable substances, all with remarkable analytical sensitivity, make this procedure ideal for the screening of large populations in several forensic and clinical contexts, whenever oral fluid sampling has to be preferred to blood sampling, as for example in short retrospective investigations. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Simultaneous determination of three pesticides and their metabolites in unprocessed foods using ultraperformance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Rong, Lili; Wu, Xiaohu; Xu, Jun; Dong, Fengshou; Liu, Xingang; Pan, Xinglu; Du, Pengqiang; Wei, Dongmei; Zheng, Yongquan

    2018-02-01

    We have developed a rapid, multi-compound analytical method for measuring residues of the pesticides thiamethoxam and its metabolite, clothianidin; fipronil and its three metabolites, fipronil sulfone, fipronil sulfide, and fipronil desulfinyl; and pyraclostrobin in unprocessed foods (rice, corn, cucumbers, tomatoes, apples, and bananas) by ultra-performance liquid chromatography coupled to tandem mass spectrometry. Acetonitrile was used as the extraction solvent, and an octadecylsilane-dispersive SPE was used to clean up the analytes, which were then separated through a UPLC HSS T3 column connected to a tandem mass spectrometer via an electrospray ionisation source. The linearity of this method for the target analytes was excellent (R 2  ≥0.990) in the concentration range of 5-1000 μg kg -1 . The average recoveries of the seven compounds at concentrations of 10, 100, and 1000 μg kg -1 from six spiked matrix samples ranged from 73.6 to 110.6%, all with RSD values of ≤19.7%. The limit of quantification was 10 μg kg -1 . The method validated the effectiveness of the method for routine monitoring the residue of these pesticides and their metabolites in foods.

  7. Development and evaluation of a liquid chromatography tandem mass spectrometry method for simultaneous determination of salivary melatonin, cortisol and testosterone

    DEFF Research Database (Denmark)

    Jensen, Marie Aarrebo; Hansen, Åse Marie; Abrahamsson, Peter

    2011-01-01

    saliva. We used liquid-liquid extraction (LLE) followed by liquid chromatography coupled to electrospray tandem mass spectrometry (LC-ESI-MS/MS) recorded in positive ion mode. Saliva samples were collected by spitting directly into tubes and 250 µL were used for analysis. The limits of detection were 4...

  8. In situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction for the determination of neurotransmitters in Parkinson's rat brain microdialysates by ultra high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    He, Yongrui; Zhao, Xian-En; Zhu, Shuyun; Wei, Na; Sun, Jing; Zhou, Yubi; Liu, Shu; Liu, Zhiqiang; Chen, Guang; Suo, Yourui; You, Jinmao

    2016-08-05

    Simultaneous monitoring of several neurotransmitters (NTs) linked to Parkinson's disease (PD) has important scientific significance for PD related pathology, pharmacology and drug screening. A new simple, fast and sensitive analytical method, based on in situ derivatization-ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) in a single step, has been proposed for the quantitative determination of catecholamines and their biosynthesis precursors and metabolites in rat brain microdialysates. The method involved the rapid injection of the mixture of low toxic bromobenzene (extractant) and acetonitrile (dispersant), which containing commercial Lissamine rhodamine B sulfonyl chloride (LRSC) as derivatization reagent, into the aqueous phase of sample and buffer, and the following in situ DUADLLME procedure. After centrifugation, 50μL of the sedimented phase (bromobenzene) was directly injected for ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) detection in multiple reaction monitoring (MRM) mode. This interesting combination brought the advantages of speediness, simpleness, low matrix effects and high sensitivity in an effective way. Parameters of in situ DUADLLME and UHPLC-MS/MS conditions were all optimized in detail. The optimum conditions of in situ DUADLLME were found to be 30μL of microdialysates, 150μL of acetonitrile containing LRSC, 50μL of bromobenzene and 800μL of NaHCO3-Na2CO3 buffer (pH 10.5) for 3.0min at 37°C. Under the optimized conditions, good linearity was observed with LODs (S/N>3) and LOQs (S/N>10) of LRSC derivatized-NTs in the range of 0.002-0.004 and 0.007-0.015 nmol/L, respectively. It also brought good precision (3.2-12.8%, peak area CVs%), accuracy (94.2-108.6%), recovery (94.5-105.5%) and stability (3.8-8.1%, peak area CVs%) results. Moreover, LRSC derivatization significantly improved chromatographic resolution and MS detection sensitivity of NTs when compared with the

  9. 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. 2010 John Wiley & Sons, Ltd.

  10. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Method development and validation of liquid chromatography-tandem/mass spectrometry for aldosterone in human plasma: Application to drug interaction study of atorvastatin and olmesartan combination

    Directory of Open Access Journals (Sweden)

    Rakesh Das

    2014-01-01

    Full Text Available In the present investigation, a simple and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS method was developed for the quantification of aldosterone (ALD a hormone responsible for blood pressure in human plasma. The developed method was validated and extended for application on human subjects to study drug interaction of atorvastatin (ATSV and olmesartan (OLM on levels of ALD. The ALD in plasma was extracted by liquid-liquid extraction with 5 mL dichloromethane/ethyl ether (60/40% v/v. The chromatographic separation of ALD was carried on Xterra, RP-Column C18 (150 mm× 4.6 mm × 3.5 μm at 30°C followed by four-step gradient program composed of methanol and water. Step 1 started with 35% methanol for first 1 min and changed linearly to 90% in next 1.5 min in Step 2. Step 3 lasted for next 2 min with 90% methanol. The method finally concluded with Step 4 to achieve initial concentration of methanol that is, 35% thus contributing the total method run time of 17.5 min. The flow rate was 0.25 mL/min throughout the process. The developed method was validated for specificity, accuracy, precision, stability, linearity, sensitivity, and recovery. The method was linear and found to be acceptable over the range of 50-800 ng/mL. The method was successfully applied for the drug interaction study of ATSV + OLM in combination against OLM treatment on blood pressure by quantifying changes in levels of ALD in hypertensive patients. The study revealed levels of ALD were significantly higher in ATSV + OLM treatment condition when compared to OLM as single treated condition. This reflects the reason of low effectiveness of ATSV + OLM in combination instead of synergistic activity.

  12. Multi-class multi-residue analysis of veterinary drugs in meat using enhanced matrix removal lipid cleanup and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhao, Limian; Lucas, Derick; Long, David; Richter, Bruce; Stevens, Joan

    2018-05-11

    This study presents the development and validation of a quantitation method for the analysis of multi-class, multi-residue veterinary drugs using lipid removal cleanup cartridges, enhanced matrix removal lipid (EMR-Lipid), for different meat matrices by liquid chromatography tandem mass spectrometry detection. Meat samples were extracted using a two-step solid-liquid extraction followed by pass-through sample cleanup. The method was optimized based on the buffer and solvent composition, solvent additive additions, and EMR-Lipid cartridge cleanup. The developed method was then validated in five meat matrices, porcine muscle, bovine muscle, bovine liver, bovine kidney and chicken liver to evaluate the method performance characteristics, such as absolute recoveries and precision at three spiking levels, calibration curve linearity, limit of quantitation (LOQ) and matrix effect. The results showed that >90% of veterinary drug analytes achieved satisfactory recovery results of 60-120%. Over 97% analytes achieved excellent reproducibility results (relative standard deviation (RSD) meat matrices. The matrix co-extractive removal efficiency by weight provided by EMR-lipid cartridge cleanup was 42-58% in samples. The post column infusion study showed that the matrix ion suppression was reduced for samples with the EMR-Lipid cartridge cleanup. The reduced matrix ion suppression effect was also confirmed with 30%) for all tested veterinary drugs in all of meat matrices. The results showed that the two-step solid-liquid extraction provides efficient extraction for the entire spectrum of veterinary drugs, including the difficult classes such as tetracyclines, beta-lactams etc. EMR-Lipid cartridges after extraction provided efficient sample cleanup with easy streamlined protocol and minimal impacts on analytes recovery, improving method reliability and consistency. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. High-Resolution Liquid Chromatography Tandem Mass Spectrometry Enables Large Scale Molecular Characterization of Dissolved Organic Matter

    Directory of Open Access Journals (Sweden)

    Daniel Petras

    2017-12-01

    Full Text Available Dissolved organic matter (DOM is arguably one of the most complex exometabolomes on earth, and is comprised of thousands of compounds, that together contribute more than 600 × 1015 g carbon. This reservoir is primarily the product of interactions between the upper ocean's microbial food web, yet abiotic processes that occur over millennia have also modified many of its molecules. The compounds within this reservoir play important roles in determining the rate and extent of element exchange between inorganic reservoirs and the marine biosphere, while also mediating microbe-microbe interactions. As such, there has been a widespread effort to characterize DOM using high-resolution analytical methods including nuclear magnetic resonance spectroscopy (NMR and mass spectrometry (MS. To date, molecular information in DOM has been primarily obtained through calculated molecular formulas from exact mass. This approach has the advantage of being non-targeted, accessing the inherent complexity of DOM. Molecular structures are however still elusive and the most commonly used instruments are costly. More recently, tandem mass spectrometry has been employed to more precisely identify DOM components through comparison to library mass spectra. Here we describe a data acquisition and analysis workflow that expands the repertoire of high-resolution analytical approaches available to access the complexity of DOM molecules that are amenable to electrospray ionization (ESI MS. We couple liquid chromatographic separation with tandem MS (LC-MS/MS and a data analysis pipeline, that integrates peak extraction from extracted ion chromatograms (XIC, molecular formula calculation and molecular networking. This provides more precise structural characterization. Although only around 1% of detectable DOM compounds can be annotated through publicly available spectral libraries, community-wide participation in populating and annotating DOM datasets could rapidly increase the

  14. Novel capsule phase microextraction in combination with liquid chromatography-tandem mass spectrometry for determining personal care products in environmental water.

    Science.gov (United States)

    Lakade, Sameer S; Borrull, Francesc; Furton, Kenneth G; Kabir, Abuzar; Marcé, Rosa Maria; Fontanals, Núria

    2018-05-01

    A novel sample preparation technique named capsule phase microextraction (CPME) is presented here. The technique utilizes a miniaturized microextraction capsule (MEC) as the extraction medium. The MEC consists of two conjoined porous tubular polypropylene membranes, one of which encapsulates the sorbent through sol-gel technology, while the other encapsulates a magnetic metal rod. As such, MEC integrates both the extraction and stirring mechanisms into a single device. The aim of this article is to demonstrate the application potential of CPME as sample preparation technique for the extraction of a group of personal care products (PCPs) from water matrices. Among the different sol-gel sorbent materials (UCON ® , poly(caprolactone-dimethylsiloxane-caprolactone) (PCAP-DMS-CAP) and Carbowax 20M (CW-20M)) evaluated, CW-20M MEC demonstrated the best extraction performance for the selected PCPs. The extraction conditions for sol-gel CW-20M MEC were optimized, including sample pH, stirring speed, addition of salt, extraction time, sample volume, liquid desorption solvent, and time. Under the optimal conditions, sol-gel CW-20M MEC provided recoveries, ranging between 47 and 90% for all analytes, except for ethylparaben, which showed a recovery of 26%. The method based on CPME with sol-gel CW-20M followed by liquid chromatography-tandem mass spectrometry was developed and validated for the extraction of PCPs from river water and effluent wastewater samples. When analyzing different environmental samples, some analytes such as 2,4-dihydroxybenzophenone, 2,2-dihydroxy-4-4 methoxybenzophenone and 3-benzophenone were found at low ng L -1 .

  15. A new carbon-based magnetic material for the dispersive solid-phase extraction of UV filters from water samples before liquid chromatography-tandem mass spectrometry analysis.

    Science.gov (United States)

    Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

    2017-07-01

    Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4 -graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2  g -1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L -1 , with detection limits in the range of 1-5 ng L -1 . Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis. Graphical Abstract Workflow of the analytical method based on magnetic solid-phase extraction followed by LC-MS/MS determination.

  16. Ion-exchange solid-phase extraction combined with liquid chromatography-tandem mass spectrometry for the determination of veterinary drugs in organic fertilizers.

    Science.gov (United States)

    Zhao, Zhiyong; Zhang, Yanmei; Xuan, Yanfang; Song, Wei; Si, Wenshuai; Zhao, Zhihui; Rao, Qinxiong

    2016-06-01

    The analysis of veterinary drugs in organic fertilizers is crucial for an assessment of potential risks to soil microbial communities and human health. We develop a robust and sensitive method to quantitatively determine 19 veterinary drugs (amantadine, sulfonamides and fluoroquinolones) in organic fertilizers. The method involved a simple solid-liquid extraction step using the combination of acetonitrile and McIlvaine buffer as extraction solvent, followed by cleanup with a solid-phase extraction cartridge containing polymeric mixed-mode anion-exchange sorbents. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to separate and detect target analytes. We particularly focused on the optimization of sample clean-up step: different diluents and dilution factors were tested. The developed method was validated in terms of linearity, recovery, precision, sensitivity and specificity. The recoveries of all the drugs ranged from 70.9% to 112.7% at three concentration levels, with the intra-day and inter-day relative standard deviation lower than 15.7%. The limits of quantification were between 1.0 and 10.0μg/kg for all the drugs. Matrix effect was minimized by matrix-matched calibration curves. The analytical method was successfully applied for the survey of veterinary drugs contamination in 20 compost samples. The results indicated that fluoroquinolones had higher incidence rate and mean concentration levels ranging from 31.9 to 308.7μg/kg compared with other drugs. We expect the method will provide the basis for risk assessment of veterinary drugs in organic fertilizers. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Quantification of isoflavones in coffee by using solid phase extraction (SPE) and high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

    Science.gov (United States)

    Caprioli, Giovanni; Navarini, Luciano; Cortese, Manuela; Ricciutelli, Massimo; Torregiani, Elisabetta; Vittori, Sauro; Sagratini, Gianni

    2016-09-01

    A new method for extracting isoflavones from espresso coffee (EC) was coupled with high-performance liquid chromatography-tandem mass spectrometry (MS/MS) for the first time to analyse five isoflavones, which included both a glycosilated form, genistin and the aglycons daidzein, genistein, formononetin and biochanin A. Isoflavones were extracted from coffee samples using methanol, stored in a freezer overnight to precipitate proteic or lipidic residues and purified on SPE C18 cartridges before high-performance liquid chromatography-MS/MS analysis. The recovery percentages obtained by spiking the matrix at concentrations of 10 and 100 µg l(-1) with a standard mixture of isoflavones were in the range of 70 to 104%. The limits of detection and limits of quantification were in the range of 0.015-0.3 µg l(-1) and 0.05-1 µg l(-1) , respectively. Once validated, the method was used to analyze the concentrations of isoflavones in six ECs and ten ground coffee samples. Only formononetin and biochanin A were found, and their respective concentrations ranged from 0.36 to 0.41 µg l(-1) and from 0.58 to 3.26 µg l(-1) in ECs and from 0.36 to 4.27 µg kg(-1) and from 0.71 to 3.95 µg kg(-1) in ground coffees. This method confirms the high specificity and selectivity of MS/MS systems for detecting bioactives in complex matrices such as coffee.Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. A novel liquid chromatography/tandem mass spectrometry method for the quantification of glycine as biomarker in brain microdialysis and cerebrospinal fluid samples within 5min.

    Science.gov (United States)

    Voehringer, Patrizia; Fuertig, René; Ferger, Boris

    2013-11-15

    Glycine is an important amino acid neurotransmitter in the central nervous system (CNS) and a useful biomarker to indicate biological activity of drugs such as glycine reuptake inhibitors (GRI) in the brain. Here, we report how a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the fast and reliable analysis of glycine in brain microdialysates and cerebrospinal fluid (CSF) samples has been established. Additionally, we compare this method with the conventional approach of high performance liquid chromatography (HPLC) coupled to fluorescence detection (FD). The present LC-MS/MS method did not require any derivatisation step. Fifteen microliters of sample were injected for analysis. Glycine was detected by a triple quadrupole mass spectrometer in the positive electrospray ionisation (ESI) mode. The total running time was 5min. The limit of quantitation (LOQ) was determined as 100nM, while linearity was given in the range from 100nM to 100μM. In order to demonstrate the feasibility of the LC-MS/MS method, we measured glycine levels in striatal in vivo microdialysates and CSF of rats after administration of the commercially available glycine transporter 1 (GlyT1) inhibitor LY 2365109 (10mg/kg, p.o.). LY 2365109 produced 2-fold and 3-fold elevated glycine concentrations from 1.52μM to 3.6μM in striatal microdialysates and from 10.38μM to 36μM in CSF, respectively. In conclusion, we established a fast and reliable LC-MS/MS method, which can be used for the quantification of glycine in brain microdialysis and CSF samples in biomarker studies. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. 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

  20. Automated and sensitive determination of four anabolic androgenic steroids in urine by online turbulent flow solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry: a novel approach for clinical monitoring and doping control.

    Science.gov (United States)

    Guo, Feng; Shao, Jing; Liu, Qian; Shi, Jian-Bo; Jiang, Gui-Bin

    2014-07-01

    A novel method for automated and sensitive analysis of testosterone, androstenedione, methyltestosterone and methenolone in urine samples by online turbulent flow solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry was developed. The optimization and validation of the method were discussed in detail. The Turboflow C18-P SPE column showed the best extraction efficiency for all the analytes. Nanogram per liter (ng/L) level of AAS could be determined directly and the limits of quantification (LOQs) were 0.01 ng/mL, which were much lower than normally concerned concentrations for these typical anabolic androgenic steroids (AAS) (0.1 ng/mL). The linearity range was from the LOQ to 100 ng/mL for each compound, with the coefficients of determination (r(2)) ranging from 0.9990 to 0.9999. The intraday and interday relative standard deviations (RSDs) ranged from 1.1% to 14.5% (n=5). The proposed method was successfully applied to the analysis of urine samples collected from 24 male athletes and 15 patients of prostate cancer. The proposed method provides an alternative practical way to rapidly determine AAS in urine samples, especially for clinical monitoring and doping control. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Selective solid-phase extraction based on molecularly imprinted technology for the simultaneous determination of 20 triazole pesticides in cucumber samples using high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhao, Fengnian; She, Yongxin; Zhang, Chao; Cao, Xiaolin; Wang, Shanshan; Zheng, Lufei; Jin, Maojun; Shao, Hua; Jin, Fen; Wang, Jing

    2017-10-01

    A selective analytical method for the simultaneous determination of 20 triazole fungicides and plant growth regulators in cucumber samples was developed using solid-phase extraction with specific molecularly imprinted polymers (MIPs) as adsorbents. The MIPs were successfully prepared by precipitation polymerization using triadimefon as the template molecule, methacrylic acid as the functional monomer, trimethylolpropane trimethacrylate as the crosslinker, and acetonitrile as the porogen. The performance and recognition mechanism for both the MIPs and non-molecularly imprinted polymers were evaluated using adsorption isotherms and adsorption kinetics. Liquid chromatography-tandem quadrupole mass spectrometry was used to identify and quantify the target analytes. The solid-phase extraction using the MIPs was rapid, convenient, and efficient for extraction and enrichment of the 20 triazole pesticides from cucumber samples. The recoveries obtained at three concentration levels (1, 2, and 10μgL -1 ) ranged from 82.3% to 117.6% with relative standard deviations of less than 11.8% (n=5) for all analytes. The limits of detection for the 20 triazole pesticides were all less than 0.4μgL -1 , and were sufficient to meet international standards. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. A novel ultra high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of xanthones and steroidal saponins in crude and salt-processed Anemarrhenae Rhizoma aqueous extracts.

    Science.gov (United States)

    Ji, De; Su, Xiaonan; Huang, Ziyan; Wang, Qiaohan; Lu, Tulin

    2018-06-01

    We established a rapid and sensitive ultra high-performance liquid chromatography tandem mass spectrometry method for the simultaneous quantification of xanthones and steroidal saponins in rat plasma. Chromatographic separation was achieved on a C 18 column with a mobile phase comprising acetonitrile and 0.1% formic acid. The detection was performed by negative electrospray ionization in multiple reaction monitoring mode. The validated method showed good linearity within the tested range (r > 0.9945). The intra- and interday precision at high, medium, and low concentrations was less than 7.96%. The bias of accuracies ranged from -1.92 to 9.62%. The extraction recoveries of the compounds ranged from 84.78 to 88.69%, and the matrix effects ranged from 96.76 to 108.59%. This method was successfully applied to a pharmacokinetic comparison of crude and salt-processed Anemarrhenae Rhizoma aqueous extracts after oral administration in rats. The maximum plasma concentration and area under concentration-time curve of timosaponin BIII and timosaponin AIII increased significantly (P < 0.05 or 0.01) and those of timosaponin BII decreased significantly (P < 0.05) after processing. These results could contribute to the clinical application of crude and salt-processed Anemarrhenae Rhizoma and reveal the processing mechanism. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Science.gov (United States)

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

    2015-02-13

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

  4. Analysis of wax esters by silver-ion high-performance liquid chromatography-tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Vrkoslav, Vladimír; Urbanová, Klára; Háková, Martina; Cvačka, Josef

    2013-01-01

    Roč. 1302, Aug 9 (2013), s. 105-110 ISSN 0021-9673 R&D Projects: GA ČR GA203/09/0139 Institutional support: RVO:61388963 Keywords : jojoba * human hair * wax esters * mass spectrometry * silver-ion liquid chromatography * long-chain esters Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.258, year: 2013

  5. A validated method for simultaneous screening and quantification of twenty-three benzodiazepines and metabolites plus zopiclone and zaleplone in whole blood by liquid-liquid extraction and ultra-performance liquid chromatography- tandem mass spectrometry

    DEFF Research Database (Denmark)

    Simonsen, Kirsten Wiese; Hermansson, Sigurd; Steentoft, Anni

    2010-01-01

    , oxazepam, temazepam, triazolam, zaleplon, and zopiclone. Whole blood from drug-free volunteers was used for all experiments. Blood samples (0.200 g) were extracted with ethyl acetate at pH 9. Target drugs were quantified using a Waters ACQUITY UPLC system coupled to a Waters Quattro Premier XE triple......An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for detection of 23 benzodiazepines and related compounds in whole blood was developed and validated. The method is used for screening and quantitation of benzodiazepines in whole blood received from autopsy...... quadrupole in positive electrospray ionization, multiple reaction monitoring mode. The use of deuterated internal standards for most compounds verified that the accuracy of the method was not influenced by matrix effects. Extraction recoveries were 73-108% for all analytes. Lower limits of quantification...

  6. Simultaneous quantitation of hydrazine and acetylhydrazine in human plasma by high performance liquid chromatography-tandem mass spectrometry after derivatization with p-tolualdehyde.

    Science.gov (United States)

    Song, Lu; Gao, Dan; Li, Shangfu; Wang, Yanwei; Liu, Hongxia; Jiang, Yuyang

    2017-09-15

    A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for simultaneous quantitative analysis of hydrazine and acetylhydrazine in human plasma based on the strategy of p-tolualdehyde derivatization. The derivatization reactions were easily realized by ultrasonic manipulation for 40min. Good separation of the derivatization products was achieved using a C 18 column by gradient elution. The optimized mass transition ion-pairs (m/z) monitored for the two hydrazine derivatives were m/z 237.1≫>119.9 and m/z 176.9≫>117.8, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for hydrazine were 0.002 and 0.005ngmL -1 separately. And they were 0.03 and 0.05ngmL -1 for acetylhydrazine, respectively. The linear range was 0.005-50ngmL -1 for hydrazine and 0.05-500ngmL -1 for acetylhydrazine with R 2 greater than 0.999. The recovery range was determined to be 95.38-108.12% with the relative standard deviation (RSD) in the range of 1.24-14.89%. The method was successfully applied to detect 30 clinical plasma samples of pulmonary tuberculosis patients treated with isoniazid. The concentrations were from 0.04-1.99ngmL -1 for hydrazine and 0.06-142.43ngmL -1 for acetylhydrazine. The results indicated that our developed method had the potential for the detection of hydrazine toxicology in complex biological samples. Furthermore, the method has an important significance to clinical treatment with drugs. Copyright © 2017. Published by Elsevier B.V.

  7. Simultaneous determination of UV-filters and estrogens in aquatic invertebrates by modified quick, easy, cheap, effective, rugged, and safe extraction and liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    He, Ke; Timm, Anne; Blaney, Lee

    2017-08-04

    Ultraviolet-filters (UV-filters) and estrogens have attracted increased attention as contaminants of emerging concern (CECs) due to their widespread occurrence in the environment. Most of these CECs are hydrophobic and have the potential to accumulate in aquatic organisms. To date, co-analysis of UV-filters and estrogens has not been reported due, in part, to the complex environmental matrices. Here, a multi-residue method has been developed for simultaneous determination of five UV-filters and three estrogens in tissue from aquatic and marine organisms. The procedure involved a modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction with a novel reverse-solid-phase extraction (reverse-SPE) cleanup in place of dispersive-SPE, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. The tissue mass, acetonitrile content, and salt conditions for QuEChERS extraction, along with the reverse-SPE cartridge material and elution conditions, were thoroughly investigated and optimized. Five UV-filters (i.e., 3-(4-methylbenzylidene) camphor, benzophenone-3, ethylhexylmethoxycinnamate, homosalate, and octocrylene) and three estrogens (i.e., estrone, 17β-estradiol, and 17α-ethinylestradiol) were simultaneously analyzed by taking advantage of wrong-way-round ionization in LC-MS/MS. The optimized analytical protocol exhibited good recoveries (>80%) for target compounds and enabled their detection at concentrations as low as 0.2ng/g in 50mg tissue samples. The method was applied to determine concentrations of target analytes in four invertebrates (i.e., Orconectes virilis, Procambarus clarkii, Crassostrea virginica, and Ischadium recurvum). All eight target analytes were detected at least once in the tissue samples, with the highest concentration being 399ng/g of homosalate in O. virilis. These results highlight the ubiquitous bioaccumulation of CECs in aquatic and marine invertebrates. Copyright © 2017 Elsevier B.V. All rights

  8. Determination of fluoroquinolone antibiotics in environmental water samples based on magnetic molecularly imprinted polymer extraction followed by liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Chen Ligang; Zhang Xiaopan; Xu Yang; Du Xiaobo; Sun Xin; Sun Lei; Wang Hui; Zhao Qi; Yu Aimin; Zhang Hanqi; Ding Lan

    2010-01-01

    A simple method based on magnetic separation for selective extraction of fluoroquinolones (FQs) from environmental water samples has been developed using magnetic molecularly imprinted polymer (MMIP) as sorbent. The MMIP has been prepared using ciprofloxacin as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent and Fe 3 O 4 magnetite as magnetic component. The polymer has been characterized by scanning electron microscopy, Fourier-transform infrared spectrometry and vibrating sample magnetometry. Various parameters affecting the extraction efficiency were evaluated in order to achieve optimal concentration and reduce non-specific interactions. The analytes desorbed from the polymers were determined by liquid chromatography-tandem mass spectrometry. The matrix effect was evaluated by using different washing solvents for removing interfering compounds from the MMIPs after sample loading. Under the optimal conditions, the linearity of the method obtained is in the range of 20-2000 ng L -1 . The detection limits of FQs are in the range of 3.2-6.2 ng L -1 . The relative standard deviations of intra- and inter-day tests ranging from 2.5 to 7.2% and from 3.6 to 9.1% are obtained. In all three spiked levels (20, 100 and 200 ng L -1 ), the recoveries of FQs are in the range of 76.3-94.2%. The proposed method was successfully applied to determine FQs including ciprofloxacin, enrofloxacin, lomefloxacin, levofloxacin, fleroxacin and sparfloxacin in different water samples, such as lake water, river water, primary and final sewage effluent. Ciprofloxacin and fleroxacin were found in primary and final sewage effluent samples with the contents in the range of 26-87 ng L -1 .

  9. Determination of fluoroquinolone antibiotics in environmental water samples based on magnetic molecularly imprinted polymer extraction followed by liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Chen Ligang; Zhang Xiaopan; Xu Yang [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China); Du Xiaobo; Sun Xin [College of Physics, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Sun Lei; Wang Hui; Zhao Qi; Yu Aimin; Zhang Hanqi [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China); Ding Lan, E-mail: dinglan@jlu.edu.cn [College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, Jilin (China)

    2010-03-03

    A simple method based on magnetic separation for selective extraction of fluoroquinolones (FQs) from environmental water samples has been developed using magnetic molecularly imprinted polymer (MMIP) as sorbent. The MMIP has been prepared using ciprofloxacin as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linking agent and Fe{sub 3}O{sub 4} magnetite as magnetic component. The polymer has been characterized by scanning electron microscopy, Fourier-transform infrared spectrometry and vibrating sample magnetometry. Various parameters affecting the extraction efficiency were evaluated in order to achieve optimal concentration and reduce non-specific interactions. The analytes desorbed from the polymers were determined by liquid chromatography-tandem mass spectrometry. The matrix effect was evaluated by using different washing solvents for removing interfering compounds from the MMIPs after sample loading. Under the optimal conditions, the linearity of the method obtained is in the range of 20-2000 ng L{sup -1}. The detection limits of FQs are in the range of 3.2-6.2 ng L{sup -1}. The relative standard deviations of intra- and inter-day tests ranging from 2.5 to 7.2% and from 3.6 to 9.1% are obtained. In all three spiked levels (20, 100 and 200 ng L{sup -1}), the recoveries of FQs are in the range of 76.3-94.2%. The proposed method was successfully applied to determine FQs including ciprofloxacin, enrofloxacin, lomefloxacin, levofloxacin, fleroxacin and sparfloxacin in different water samples, such as lake water, river water, primary and final sewage effluent. Ciprofloxacin and fleroxacin were found in primary and final sewage effluent samples with the contents in the range of 26-87 ng L{sup -1}.

  10. Pre-column dilution large volume injection ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis of multi-class pesticides in cabbages.

    Science.gov (United States)

    Zhong, Qisheng; Shen, Lingling; Liu, Jiaqi; Yu, Dianbao; Li, Siming; Yao, Jinting; Zhan, Song; Huang, Taohong; Hashi, Yuki; Kawano, Shin-ichi; Liu, Zhaofeng; Zhou, Ting

    2016-04-15

    Pre-column dilution large volume injection (PD-LVI), a novel sample injection technique for reverse phase ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), was developed in this study. The PD-LVI UHPLC-MS/MS system was designed by slightly modifying the commercial UHPLC-MS/MS equipment with a mixer chamber. During the procedure of PD-LVI, sample solution of 200μL was directly carried by the organic mobile phase to the mixer and diluted with the aqueous mobile phase. After the mixture was introduced to the UHPLC column in a mobile phase of acetonitrile-water (15/85, v/v), the target analytes were stacked on the head of the column until following separation. Using QuEChERS extraction, no additional steps such as solvent evaporation or residue redissolution were needed before injection. The features of PD-LVI UHPLC-MS/MS system were systematically investigated, including the injection volume, the mixer volume, the precondition time and the gradient elution. The efficiency of this approach was demonstrated by direct analysis of 24 pesticides in cabbages. Under the optimized conditions, low limits of detection (0.00074-0.8 ng/kg) were obtained. The recoveries were in the range of 63.3-109% with relative standard deviations less than 8.1%. Compared with common UHPLC-MS/MS technique, PD-LVI UHPLC-MS/MS showed significant advantages such as excellent sensitivity and reliability. The mechanism of PD-LVI was demonstrated to be based on the column-head stacking effect with pre-column dilution. Based on the results, PD-LVI as a simple and effective sample injection technique of reverse phase UHPLC-MS/MS for the analysis of trace analytes in complex samples showed a great promising prospect. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Analysis of 17 neurotransmitters, metabolites and precursors in zebrafish through the life cycle using ultrahigh performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Santos-Fandila, A; Vázquez, E; Barranco, A; Zafra-Gómez, A; Navalón, A; Rueda, R; Ramírez, M

    2015-09-15

    An ultrahigh performance liquid chromatography-tandem mass spectrometry method for the identification and quantification of neurotransmitters, metabolites and precursors at different stages in zebrafish life was developed. Betaine, glutamine, glutamic acid, γ-aminobutyric acid, phosphocholine, glycerophosphocholine, cytidine 5'-diphosphocholine, choline, acetylcholine, dopamine, norepinephrine, serotonin, tyrosine, epinephrine, tryptophan, 5-hydroxyindolacetic acid and agmatine were selected as analytes. The method consisted of a simple deproteinization of samples using methanol and formic acid, subsequent injection onto the chromatographic equipment and quantification with a triple quadrupole mass spectrometer detector using an electrospray ionization interface in positive mode. Limits of detection ranged from 0.02 to 11ngmL(-1) and limits of quantification from 0.1 to 38ngmL(-1), depending on the analyte. The method was validated according to US Food and Drugs Administration (FDA) guideline for bioanalytical assays. Precision, expressed as relative standard deviation (%RSD), was lower than 15% in all cases, and the determination coefficient (R(2)) was equal or higher than 99.0% with a residual deviation for each calibration point lower than ±25%. Mean recoveries were between 85% and 115%. The method was applied to determine of these compounds in zebrafish from early stages of development to adulthood and showed the time-course of neurotransmitters and others neurocompounds through the life cycle. The possibility of measuring up to 17 compounds related with the main neurotransmitter systems in a simple analytical method will complement and reinforce the use of zebrafish in multiple applications in the field of neurosciences. The proposed method will facilitate future studies related with brain development. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Simultaneous determination of metolazone and valsartan in plasma by on-line SPE coupled with liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Jiezhao; Chen, Meiling; Li, Ying; Yu, Fanglin; Cheng, Xiaohui; Yang, Yang; Liu, Yan; Xie, Xiangyang; Li, Zhiping; Zhang, Hui; Mei, Xingguo

    2017-10-01

    Combination of metolazone (0.5 mg) and valsartan (80 mg) has been verified as a promising therapy treatment for hypertension. In order to facilitate to pharmacokinetic research, it needs a method for the simultaneously determination of metolazone and valsartan in biological samples. However, there are no relative reports so far. In order to facilitate to pharmacokinetic research, an on-line solid phase extraction coupled with liquid chromatography-tandem mass spectrometry method for the simultaneous determination of metolazone and valsartan in beagle dog plasma was developed and validated in this study. An on-line solid phase extraction column Retain PEP Javelin (10 mm × 2.1 mm) was used to remove impurities in plasma samples. The metolazone, valsartan and internal standard (losartan) were separated on a Poroshell 120 SB-C18 column (4.6 mm × 50 mm × 2.7 µm) with a gradient elution procedure. Acidified acetonitrile/water mixture was used as a mobile phase. The selected multiple-reaction monitoring mode in positive ion was performed and the parent to the product transitions m/z 366/259, m/z 436.2/291 and m/z 423.4/207 were used to measure the metolazone, valsartan and losartan. The method was linear over the range of 0.1-100 ng/mL and 1-1000 ng/mL for metolazone and valsartan, respectively. This method was validated in terms of specificity, linearity, sensitivity, precision, accuracy, matrix effect, and stability and then successfully applied to pharmacokinetic studies of the metolazone and valsartan combination tablets in beagle dogs.

  13. A simple automated solid-phase extraction procedure for measurement of 25-hydroxyvitamin D3 and D2 by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Knox, Susan; Harris, John; Calton, Lisa; Wallace, A Michael

    2009-05-01

    Measurement of 25-hydroxyvitamin D(3) (25OHD(3)) and D(2) (25OHD(2)) is challenging. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods have been described but they are often complex and difficult to automate. We have developed a simplified procedure involving an automated solid-phase extraction (SPE). Internal standard (hexadeuterated 25-hydroxyvitamin D(3)) was added to serum or plasma followed by protein precipitation with methanol. Following centrifugation, a robotic instrument (CTC PAL [Presearch] for ITSP SPE [MicroLiter Analytical Supplies, Inc]) performed a six-step SPE procedure and the purified samples were injected into the LC-MS/MS. Quantification of 25OHD(3) and 25OHD(2) was by electrospray ionization MS/MS in the multiple-reaction monitoring mode. The lower limit of quantitation was 4.0 nmol/L for 25OHD(3) and 7.5 nmol/L for 25OHD(2). Within- and between-assay precision was below 10% over the concentration range of 22.5-120 nmol/L for D(3) and 17.5-70 nmol/L for D(2) (n = 10). The calibration was linear up to 2500 nmol/L (r = 0.99). Recoveries ranged between 89% and 104% for both metabolites and no ion suppression was observed. The results obtained compared well (r = 0.96) with the IDS-OCTEIA 25-hydroxyvitamin D enzyme immunoassay for samples containing less than 125 nmol/L, at higher concentrations the immunodiagnostic system (IDS) method showed positive bias. Our simplified sample preparation and automated SPE method is suitable for the measurement of 25OHD(3) and D(2) in a routine laboratory environment. The system can process up to 300 samples per day with no cumbersome solvent evaporation step and minimal operator intervention.

  14. Two complementary liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods to study the excretion and metabolic interaction of edaravone and taurine in rats.

    Science.gov (United States)

    Tang, Dao-quan; Zheng, Xiao-xiao; Li, Yin-jie; Bian, Ting-ting; Yu, Yan-yan; Du, Qian; Yang, Dong-zhi; Jiang, Shui-shi

    2014-11-01

    In this study, two independent and complementary liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods were respectively developed and validated for the determination of edaravone or taurine in rat urine, feces and bile after intravenous administration, using 3-methyl-l-p-tolyl-5-pyrazolone and sulfanilic acid as the internal standards (IS). Edaravone was separated on an Agilent Eclipse Plus C18 column (100×2.1 mm, 3.5 μm) using methanol and water (containing 5 mM ammonium formate and 0.02% formic acid) as mobile phase, while taurine was performed on a Waters Atlantis HILIC Silica column (150×2.1 mm, 3 μm) using acetonitrile and water (containing 5mM ammonium formate and 0.2% formic acid) as mobile phase. The mass analysis was performed in a Triple Quadrupole mass spectrometer via multiple reaction monitoring (MRM) with negative ionization mode. The optimized mass transition ion pairs (m/z) for quantification were 173.1→92.2 and 187.2→106.0 for edaravone and its IS, 124.1→80.0 and 172.0→80.0 for taurine and its IS, respectively. The validated methods have been successfully applied to the excretion and metabolism interaction study of edaravone and taurine in rats after independent intravenous administration and co-administration with a single dose. The results demonstrated that there were no significant alternations on the metabolism and cumulative excretion rate of edaravone and taurine, implying that the proposed combination therapy was pharmacologically viable. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Pre-analytical and analytical variation of drug determination in segmented hair using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe; Linnet, Kristian

    2014-01-01

    Assessment of total uncertainty of analytical methods for the measurements of drugs in human hair has mainly been derived from the analytical variation. However, in hair analysis several other sources of uncertainty will contribute to the total uncertainty. Particularly, in segmental hair analysis pre-analytical variations associated with the sampling and segmentation may be significant factors in the assessment of the total uncertainty budget. The aim of this study was to develop and validate a method for the analysis of 31 common drugs in hair using ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) with focus on the assessment of both the analytical and pre-analytical sampling variations. The validated method was specific, accurate (80-120%), and precise (CV≤20%) across a wide linear concentration range from 0.025-25 ng/mg for most compounds. The analytical variation was estimated to be less than 15% for almost all compounds. The method was successfully applied to 25 segmented hair specimens from deceased drug addicts showing a broad pattern of poly-drug use. The pre-analytical sampling variation was estimated from the genuine duplicate measurements of two bundles of hair collected from each subject after subtraction of the analytical component. For the most frequently detected analytes, the pre-analytical variation was estimated to be 26-69%. Thus, the pre-analytical variation was 3-7 folds larger than the analytical variation (7-13%) and hence the dominant component in the total variation (29-70%). The present study demonstrated the importance of including the pre-analytical variation in the assessment of the total uncertainty budget and in the setting of the 95%-uncertainty interval (±2CVT). Excluding the pre-analytical sampling variation could significantly affect the interpretation of results from segmental hair analysis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Determination of natamycin in rabbit cornea by high-performance liquid chromatography-tandem mass spectrometry with protective soaking extraction technology.

    Science.gov (United States)

    Tianyang, Zhou; Ling, Zhu; Huiyun, Xia; Jijun, He; Junjie, Zhang

    2014-10-15

    A new selective and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the quantification of natamycin (NAT) in rabbit corneas with amphotericin B as the internal standard (IS). The cornea samples were processed by a simple and protective methanol soaking extraction technology. The NAT could be extracted completely from rabbit cornea after 24h of soaking with methanol under a mild condition. Chromatographic separation was performed on a C18 column (2.1mm×50mm, 3.5μm) using mobile phase with ammonium acetate buffer (pH 4.5; 4.0mM):acetonitrile (40:60, v/v) at a flow rate of 0.25ml/min. Quantification was performed using the transitions 666.2→503.2 m/z for NAT and 924.5→906.6 m/z for IS by positive ion electrospray ionization in multiple reaction monitoring mode. The assay was validated over a concentration range of 8.64ng/ml to 843ng/ml with lower limit of detection of 4.32ng/ml. The method was validated with respect to linearity, accuracy, precision, recovery, stability and extracting efficiency. The extraction recovery of NAT from cornea samples was approximately 100% with the new methanol soaking extraction procedure. The method has been successfully applied to the ocular pharmacokinetic studies of NAT eye drops in the cornea of Japanese white rabbit. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Study on the determination and chiral inversion of R-salbutamol in human plasma and urine by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhou, Ting; Zeng, Jing; Liu, Shan; Zhao, Ting; Wu, Jie; Lai, Wenshi; He, Mingzhi; Xu, Beining; Qu, Shanshan; Xu, Ling; Tan, Wen

    2015-10-01

    The chiral inversion has been a concerned issue during the research and development of a chiral drug. In this study, a sensitive chiral liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for determination of salbutamol enantiomers in human plasma and urine. The chiral inversion mechanism of R-salbutamol was fully investigated for the first time by studying the effects of physicochemical factors, including pH, temperature and time. A fitted model to predict the chiral inversion ratio of R-salbutamol was proposed using a Box-Behnken design. All the samples were separated on an Astec Chirobiotic T column and detected by a tandem mass spectrometer in multiple reaction monitoring mode. Lower limit of quantification of 0.100ng/mL was achieved under the optimized conditions. The method was fully validated and successfully applied to the clinical pharmacokinetic study of R-salbutamol in healthy volunteers. Chiral inversion of R-salbutamol to S-salbutamol has been detected in urine samples. The results indicated that pH and temperature were two dominant factors that caused the chiral inversion of R-salbutamol, which should be taken into consideration during the analysis of chiral drugs. The chiral inversion of R-salbutamol determined in this study was confirmed resulted from the gastric acid in stomach rather than caused by the analysis conditions. Moreover, the calculated results of the fitted model matched very well with the enantioselective pharmacokinetic study of R-salbutamol, and the individual difference of the chiral inversion ratio of R-salbutamol was related to the individual gastric environment. On the basis of the results, this study provides important and concrete information not only for the chiral analysis but also for the metabolism research of chiral drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Chiral analysis of bambuterol, its intermediate and active drug in human plasma by liquid chromatography-tandem mass spectrometry: Application to a pharmacokinetic study.

    Science.gov (United States)

    Zhou, Ting; Liu, Shan; Zhao, Ting; Zeng, Jing; He, Mingzhi; Xu, Beining; Qu, Shanshan; Xu, Ling; Tan, Wen

    2015-08-01

    A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed for simultaneous chiral analysis of an antiasthma drug bambuterol, its key intermediate monocarbamate bambuterol and its active drug terbutaline in human plasma. All samples were extracted with ethyl acetate and separated on an Astec Chirobiotic T column under isocratic elution with a mobile phase consisting of methanol and water with the addition of 20mm ammonium acetate and 0.005% (v/v) formic acid at 0.6mL/min. The analytes were detected by a Xevo TQ-S tandem mass spectrometer with positive electrospray ionization in multiple reaction monitoring mode. The established method has high sensitivity with the lower limit of quantifications of 25.00pg/mL for bambuterol enantiomers, and 50.00pg/mL for monocarbamate bambuterol and terbutaline enantiomers, respectively. The calibration curves for bambuterol enantiomers were linear in the range of 25.00-2500pg/mL, and for monocarbamate bambuterol and terbutaline enantiomers were linear in the range of 50.00-5000pg/mL. The intra- and inter-day precisions were <12.4%. All the analytes were separated in 18.0min. For the first time, the validated method was successfully applied to an enantioselective pharmacokinetic study of rac-bambuterol in 8 healthy volunteers. According to the results, this chiral LC-MS/MS assay provides a suitable and robust method for the enantioselectivity and interaction study of the prodrug bambuterol, the key intermediate monocarbamate bambuterol and its active drug terbutaline in human. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Determination of neonicotinoid pesticides residues in agricultural samples by solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Xie, Wen; Han, Chao; Qian, Yan; Ding, Huiying; Chen, Xiaomei; Xi, Junyang

    2011-07-15

    This work reports a new sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, confirmation and quantification of six neonicotinoid pesticides (dinotefuran, thiamethoxam, clothiandin, imidacloprid, acetamiprid and thiacloprid) in agricultural samples (chestnut, shallot, ginger and tea). Activated carbon and HLB solid-phase extraction cartridges were used for cleaning up the extracts. Analysis is performed by LC-MS/MS operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Quantification was carried by the internal standard method with D(4)-labeled imidacloprid. The method showed excellent linearity (R(2)≥0.9991) and precision (relative standard deviation, RSD≤8.6%) for all compounds. Limits of quantification (LOQs) were 0.01 mg kg(-1) for chestnut, shallot, ginger sample and 0.02 mg kg(-1) for tea sample. The average recoveries, measured at three concentrations levels (0.01 mg kg(-1), 0.02 mg kg(-1) and 0.1 mg kg(-1) for chestnut, shallot, ginger sample, 0.02 mg kg(-1), 0.04 mg kg(-1) and 0.2 mg kg(-1) for tea sample), were in the range 82.1-108.5%. The method was satisfactorily validated for the analysis of 150 agricultural samples (chestnut, shallot, ginger and tea). Imidacloprid and acetamiprid were detected at concentration levels ranging from 0.05 to 3.6 mg kg(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Trace analysis of three fungicides in animal origin foods with a modified QuEChERS method and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Mu, Zhaobin; Feng, Xiaoxiao; Zhang, Yun; Zhang, Hongyan

    2016-02-01

    A multi-residue method based on modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS), was developed and validated for the determination of three selected fungicides (propiconazole, pyraclostrobin, and isopyrazam) in seven animal origin foods. The overall recoveries at the three spiking levels of 0.005, 0.05, and 0.5 mg kg(-1) spanned between 72.3 and 101.4% with relative standard deviation (RSD) values between 0.7 and 14.9%. The method shows good linearity in the concentrations between 0.001 and 1 mg L(-1) with the coefficient of determination (R (2)) value >0.99 for each target analyte. The limit of detections (LODs) for target analytes were between 0.04 and 1.26 μg kg(-1), and the limit of quantifications (LOQs) were between 0.13 and 4.20 μg kg(-1). The matrix effect for each individual compound was evaluated through the study of ratios of the areas obtained in solvent and matrix standards. The optimized method provided a negligible matrix effect for propiconazole within 20%, whereas for pyraclostrobin and isopyrazam, the matrix effect was relatively significant with a maximum value of 49.8%. The developed method has been successfully applied to the analysis of 210 animal origin samples obtained from 16 provinces of China. The results suggested that the developed method was satisfactory for trace analysis of three fungicides in animal origin foods.

  1. Validation of a liquid chromatography-tandem mass spectrometry method for the simultaneous determination of sulfonamides, trimethoprim and dapsone in muscle, egg, milk and honey.

    Science.gov (United States)

    Varenina, Ivana; Bilandžić, Nina; Kolanović, Božica Solomun; Božić, Đurđica; Sedak, Marija; Đokić, Maja; Varga, Ines

    2016-01-01

    A quantitative multi-residue method that includes 13 sulfonamides, trimethoprim and dapsone was developed and validated according to Commission Decision 2002/657/EC for muscle, milk egg and honey samples. For all matrices, the same extraction procedure was used. Samples were extracted with an acetone/dichloromethane mixture and cleaned up on aromatic sulfonic acid (SO3H) SPE cartridges. After elution and concentration steps, analytes were identified and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Data were acquired according to the multiple reaction-monitoring approach (MRM) and analytes were quantified both by the isotope dilution and the matrix-matched approaches calculating the response factors for the scanned product ions. The developed method shows good linearity, specificity, precision (repeatability and within-laboratory reproducibility), and trueness. Estimated CCβ for sulfonamides ranged between 5.6 and 8.2 µg kg(-1) for eggs, between 11.1 and 69.9 µg kg(-1) for milk, between 64.7 and 87.9 µg kg(-1) for muscle, and between 2.7 and 5.3 µg kg(-1) for honey. CCβ values for dapsone were 3.1, 0.6, 0.7 and 1.5 µg kg(-1) and for trimethoprim were 3.1, 6.7, 81.7 and 3.0 µg kg(-1) calculated for eggs, milk, muscle and honey, respectively. Recovery for all matrices was in the range from 89.1% and 109.7%. In matrix effect testing, no significant deviations were found between different samples of muscle and milk; however, a matrix effect was observed when testing different types of honey. The validation results demonstrate that the method is suitable for routine veterinary drug analysis and confirmation of suspect samples.

  2. Quantification of Cannabinoids and their Free and Glucuronide Metabolites in Whole Blood by Disposable Pipette Extraction and Liquid Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Scheidweiler, Karl B.; Newmeyer, Matthew N.; Barnes, Allan J.; Huestis, Marilyn A.

    2016-01-01

    Identifying recent cannabis intake is confounded by prolonged cannabinoid excretion in chronic frequent cannabis users. We previously observed detection times ≤2.1 h for cannabidiol (CBD) and cannabinol (CBN) and THC-glucuronide in whole blood after smoking, suggesting their applicability for identifying recent intake. However, whole blood collection may not occur for up to 4 h during driving under the influence of drugs investigations, making a recent-use marker with a 6-8 h detection window helpful for improving whole blood cannabinoid interpretation. Other minor cannabinoids cannabigerol (CBG), Δ9-tetrahydrocannabivarin (THCV), and its metabolite 11-nor-9-carboxy-THCV (THCVCOOH) might also be useful. We developed and validated a sensitive and specific liquid chromatography-tandem mass spectrometry method for quantification of THC, its phase I and glucuronide phase II metabolites, and 5 five minor cannabinoids. Cannabinoids were extracted from 200 μL whole blood via disposable pipette extraction, separated on a C18 column, and detected via electrospray ionization in negative mode with scheduled multiple reaction mass spectrometric monitoring. Linear ranges were 0.5-100 μg/L for THC and THCCOOH; 0.5-50 μg/L for 11-OH-THC, CBD, CBN, and THC-glucuronide; 1-50 μg/L for CBG, THCV, and THCVCOOH; and 5-500 μg/L for THCCOOH-glucuronide. Inter-day accuracy and precision at low, mid and high quality control (QC) concentrations were 95.1-113% and 2.4-8.5%, respectively (n=25). Extraction recoveries and matrix effects at low and high QC concentrations were 54.0-84.4% and −25.8-30.6%, respectively. By simultaneously monitoring multiple cannabinoids and metabolites, identification of recent cannabis administration or discrimination between licit medicinal and illicit recreational cannabis use can be improved. PMID:27236483

  3. Development of a new multi-analyte assay for the simultaneous detection of opioids in serum and other body fluids using liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Eckart, K; Röhrich, J; Breitmeier, D; Ferner, M; Laufenberg-Feldmann, R; Urban, R

    2015-09-15

    A liquid chromatography-tandem mass spectrometry method using electrospray ionization in positive ionization mode was developed for the simultaneous detection of multiple opioid-type drugs in plasma. The presented assay allows the quantitative determination of alfentanil, buprenorphine, codeine, desomorphine, dextromethorphan, dextrorphan, dihydrocodeine, dihydromorphine, ethylmorphine, fentanyl, hydrocodone, hydromorphone, methadone, morphine, naloxone, naltrexone, oxycodone, oxymorphone, pentazocine, pethidine, pholcodine, piritramide, remifentanil, sufentanil, and tramadol as well as the metabolites 6-monoacetylmorphine, bisnortilidine, morphine-3-glucuronide, morphine-6-glucuronide, naltrexol, norbuprenorphine, norfentanyl, norpethidine, nortilidine, and O-desmethyltramadol. Serum and blood samples were purified by solid-phase extraction. The analytes were separated on a phenyl-hexyl (100mm) column by formic acid/acetonitrile gradient elution using an UPLC 1290 Infinity coupled with a 6490 Triple Quadrupole mass spectrometer. The limits of detection ranged from 0.02 to 0.6ng/mL and the lower limits of quantification ranged from 0.1 to 2.0ng/mL. The calibration curves were linear between Calibration Levels 1-6 for all 35 substances. Recovery rates ranged between 51 and 88% for all compounds except alfentanil, bisnortilidine, pethidine, and morphine-3-glucuronide. The matrix effect ranged from 86% for ethylmorphine to 105% for desomorphine. Using the validation procedure proposed by the German Society of Toxicological and Forensic Chemistry, acceptable precision and accuracy data for almost all analytes were obtained. The method was successfully applied to 206 authentic serum samples provided by the palliative and intensive care units of the University Medical Center and the police authorities. Furthermore, a suspected fatal intoxication is demonstrated by an analysis of the sufentanil in post mortem body fluids and tissues. Copyright © 2015 Elsevier B.V. All

  4. Simultaneous determination of multi-mycotoxins in palm kernel cake (PKC) using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    Science.gov (United States)

    Yibadatihan, S; Jinap, S; Mahyudin, N A

    2014-01-01

    Palm kernel cake (PKC) is a useful source of protein and energy for livestock. Recently, it has been used as an ingredient in poultry feed. Mycotoxin contamination of PKC due to inappropriate handling during production and storage has increased public concern about economic losses and health risks for poultry and humans. This concern has accentuated the need for the evaluation of mycotoxins in PKC. Furthermore, a method for quantifying mycotoxins in PKC has so far not been established. The aims of this study were therefore (1) to develop a method for the simultaneous determination of mycotoxins in PKC and (2) to validate and verify the method. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method using an electrospray ionisation interface (ESI) in both positive- and negative-ion modes was developed for the simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁ and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁ and FB₂), T-2 and HT-2 toxin in PKC. An optimum method using a 0.2 ml min⁻¹ flow rate, 0.2% formic acid in aqueous phase, 10% organic phase at the beginning and 90% organic phase at the end of the gradient was achieved. The extraction of mycotoxins was performed using a solvent mixture of acetonitrile-water-formic acid (79:20:1, v/v) without further clean-up. The mean recoveries of mycotoxins in spiked PKC samples ranged from 81% to 112%. Limits of detection (LODs) and limits of quantification (LOQs) for mycotoxin standards and PKC samples ranged from 0.02 to 17.5 μg kg⁻¹ and from 0.06 to 58.0 μg kg⁻¹, respectively. Finally, the newly developed method was successfully applied to PKC samples. The results illustrated the fact that the method is efficient and accurate for the simultaneous multi-mycotoxin determination in PKC, which can be ideal for routine analysis.

  5. Development and validation of a liquid chromatography-tandem mass spectrometry method for topotecan determination in beagle dog plasma and its application in a bioequivalence study.

    Science.gov (United States)

    Ye, Ling; Shi, Jian; Wan, Shanhe; Yang, Xiaoshan; Wang, Ying; Zhang, Jiajie; Zheng, Dayong; Liu, Zhongqiu

    2013-11-01

    Topotecan (TPT) is an important anti-cancer drug that inhibits topoisomerase I. A sensitive and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method that potentially determines TPT in beagle dog plasma is needed for a bioequivalence study of TPT formulations. We developed and validated LC-MS/MS to evaluate TPT in beagle dog plasma in terms of specificity, linearity, precision, accuracy, stability, extraction recovery and matrix effect. Plasma samples were treated with an Ostro(TM) sorbent plate (a robust and effective tool) to eliminate phospholipids and proteins before analysis. TPT and camptothecin (internal standard) were separated on an Acquity UPLC BEH C18 column (1.7 µm, 2.1 × 50 mm) with 0.1% formic acid and methanol as the mobile phase at a flow rate of 0.25 mL/min. TPT was analyzed using positive ion electrospray ionization in multiple-reaction monitoring mode. The obtained lower limit of quantitation was 1 ng/mL (signal-to-noise ratio > 10). The standard calibration curve for TPT was linear (correlation coefficient > 0.99) at the concentration range of 1-400 ng/mL. The intra-day and inter-day precision, accuracy, stability, extraction recovery and matrix effect of TPT were within the acceptable limits. The validated method was successfully applied in a bioequivalence study of TPT in healthy beagle dogs. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Analysis of β-N-methylamino-L-alanine (BMAA) in spirulina-containing supplements by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    McCarron, Pearse; Logan, Alan C; Giddings, Sabrina D; Quilliam, Michael A

    2014-01-01

    Over the last decade the amino acid beta-N-methylamino-L-alanine (BMAA) has come under intense scrutiny. International laboratory and epidemiological research continues to support the hypothesis that environmental exposure to BMAA (e.g., through dietary practices, water supply) can promote the risk of various neurodegenerative diseases. A wide variety of cyanobacteria spp. have previously been reported to produce BMAA, with production levels dependent upon species, strain and environmental conditions. Since spirulina (Arthrospira spp.) is a member of the cyanobacteria phylum frequently consumed via dietary supplements, the presence of BMAA in such products may have public health implications. In the current work, we have analyzed ten spirulina-containing samples for the presence of BMAA; six pure spirulina samples from two separate raw materials suppliers, and four commercially-available multi-ingredient products containing 1.45 g of spirulina per 8.5 g serving. Because of controversy surrounding the measurement of BMAA, we have used two complementary liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods: one based on reversed phase LC (RPLC) with derivatization and the other based on hydrophilic interaction LC (HILIC). Potential matrix effects were corrected for by internal standardization using a stable isotope labeled BMAA standard. BMAA was not detected at low limits of detection (80 ng/g dry weight) in any of these product samples. Although these results are reassuring, BMAA analyses should be conducted on a wider sample selection and, perhaps, as part of ongoing spirulina production quality control testing and specifications.

  7. The use of dried blood spots for quantification of 15 antipsychotics and 7 metabolites with ultra-high performance liquid chromatography - tandem mass spectrometry.

    Science.gov (United States)

    Patteet, Lisbeth; Maudens, Kristof E; Stove, Christophe P; Lambert, Willy E; Morrens, Manuel; Sabbe, Bernard; Neels, Hugo

    2015-06-01

    Therapeutic drug monitoring of antipsychotics is important in optimizing individual therapy. In psychiatric populations, classical venous blood sampling is experienced as frightening. Interest in alternative techniques, like dried blood spots (DBS), has consequently increased. A fast and easy to perform DBS method for quantification of 16 antipsychotics (amisulpride, aripiprazole, asenapine, bromperidol, clozapine, haloperidol, iloperidone, levosulpiride, lurasidone, olanzapine, paliperidone, pipamperone, quetiapine, risperidone, sertindole and zuclopenthixol) and 8 metabolites was developed. DBS were prepared using 25 μL of whole blood and extraction of complete spots was performed using methanol: methyl-t-butyl-ether (4:1). After evaporation, the extract was reconstituted in the mobile phase and 10 μL were injected on an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Separation using a C18 column and gradient elution with a flow rate of 0.5 mL/min resulted in a 6-min run-time. Ionization was performed in positive mode and a dynamic MRM method was applied. Median recovery was 66.4 % (range 28.7-84.5%). Accuracy was within the acceptance criteria, except for pipamperone (LLOQ and low concentration) and lurasidone (low concentration). Imprecision was only aberrant for lurasidone at low and medium concentration. All compounds were stable during 1 month at room temperature, 4 °C and -18 °C. Lurasidone was unstable when the extract was stored for 12 h on the autosampler. Absolute matrix effects (ME) (median 66.1%) were compensated by the use of deuterated IS (median 98.8%). The DBS method was successfully applied on 25-μL capillary DBS from patients and proved to be a reliable alternative for quantification of all antipsychotics except for olanzapine and N-desmethylolanzapine. Copyright © 2014 John Wiley & Sons, Ltd.

  8. Quantitation of donepezil and its active metabolite 6-O-desmethyl donepezil in human plasma by a selective and sensitive liquid chromatography-tandem mass spectrometric method

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Bhavin N. [Chemistry Department, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380 009, Gujarat (India); Analytical Laboratory, BA Research India Ltd., Bodakdev, Ahmedabad 380 054, Gujarat (India); Sharma, Naveen [Analytical Laboratory, BA Research India Ltd., Bodakdev, Ahmedabad 380 054, Gujarat (India); Sanyal, Mallika [Chemistry Department, St. Xaviers' College, Navrangpura, Ahmedabad 380 009, Gujarat (India); Shrivastav, Pranav S. [Chemistry Department, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380 009, Gujarat (India)], E-mail: pranav_shrivastav@yahoo.com

    2008-11-23

    A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous determination of donepezil (D) and its pharmacologically active metabolite, 6-O-desmethyl donepezil (6-ODD) in human plasma is developed using galantamine as internal standard (IS). The analytes and IS were extracted from 500 {mu}L aliquots of human plasma via solid-phase extraction (SPE) on Waters Oasis HLB cartridges. Chromatographic separation was achieved in a run time of 6.0 min on a Waters Novapak C18 (150 mm x 3.9 mm, 4 {mu}m) column under isocratic conditions. Detection of analytes and IS was done by tandem mass spectrometry, operating in positive ion and multiple reaction monitoring (MRM) acquisition mode. The protonated precursor to product ion transitions monitored for D, 6-ODD and IS were at m/z 380.1 {yields} 91.2, 366.3 {yields} 91.3 and 288.2 {yields} 213.2, respectively. The method was fully validated for its selectivity, interference check, sensitivity, linearity, precision and accuracy, recovery, matrix effect, ion suppression/enhancement, cross-specificity, stability and dilution integrity. A linear dynamic range of 0.10-50.0 ng mL{sup -1} for D and 0.02-10.0 ng mL{sup -1} for 6-ODD was evaluated with mean correlation coefficient (r) of 0.9975 and 0.9985, respectively. The intra-batch and inter-batch precision (%CV, coefficient of variation) across five quality control levels was less than 7.5% for both the analytes. The method was successfully applied to a bioequivalence study of 10 mg donepezil tablet formulation in 24 healthy Indian male subjects under fasting condition.

  9. Simultaneous determination of 41 multiclass organic pollutants in environmental waters by means of polyethersulfone microextraction followed by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Mijangos, Leire; Ziarrusta, Haizea; Olivares, Maitane; Zuloaga, Olatz; Möder, Monika; Etxebarria, Nestor; Prieto, Ailette

    2018-01-01

    A new procedure using polyethersulfone (PES) microextraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was developed in this work for the simultaneous determination of 41 multiclass priority and emerging organic pollutants including herbicides, hormones, personal care products, and pharmaceuticals, among others, in seawater, wastewater treatment plant (WWTP) effluents, and estuary samples. The optimization of the analysis included two different chromatographic columns and different variables (polarity, fragmentor voltage, collision energy, and collision cell accelerator) of the mass spectrometer. In the case of PES extraction, ion strength of the water, pH, addition of EDTA, and the amount of the polymeric material were thoroughly investigated. The developed procedure was compared with a previously validated one based on a standard solid-phase extraction (SPE). In contrast to the SPE protocol, the PES method allowed a cost-efficient extraction of complex aqueous samples with lower matrix effect from 120 mL of water sample. Satisfactory and comparable apparent recovery values (80-119 and 70-131%) and method quantification limits (MQLs, 0.4-26 and 0.2-23 ng/L) were obtained for PES and SPE procedures, respectively, regardless of the matrix. Repeatability values lower than 27% were obtained. Finally, the developed methods were applied to the analysis of real samples from the Basque Country and irbesartan, valsartan, acesulfame, and sucralose were the analytes most often detected at the highest concentrations (51-1096 ng/L). Graphical abstract Forty-one multiclass pollutant determination in environmental waters by means of PES/SPE-LC-MS/MS.

  10. Analysis of fenretinide and its metabolites in human plasma by liquid chromatography-tandem mass spectrometry and its application to clinical pharmacokinetics.

    Science.gov (United States)

    Cho, Hwang Eui; Min, H Kang

    2017-01-05

    A simple and accurate high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of N-(4-hydroxyphenyl)retinamide (fenretinide, 4-HPR) and its metabolites, 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR) and N-(4-methoxyphenyl)retinamide (4-MPR), in human plasma. Plasma samples were prepared using protein precipitation with ethanol. Chromatographic separation of the three analytes and N-(4-ethoxyphenyl)retinamide (4-EPR), an internal standard, was achieved on a Zorbax SB-C18 column (3.5μm, 50×2.1mm) using gradient elution with the mobile phase of 0.1% formic acid in water and acetonitrile (pH* 2.4) at a flow rate of 0.5mL/min. Electrospray ionization (ESI) mass spectrometry was operated in the positive ion mode with multiple reaction monitoring (MRM). The calibration curves obtained were linear over the concentration range of 0.2-50ng/mL with a lower limit of quantification of 0.2ng/mL. The relative standard deviation of intra-day and inter-day precision was below 7.64%, and the accuracy ranged from 94.92 to 105.43%. The extraction recoveries were found to be higher than 90.39% and no matrix effect was observed. The analytes were stable for the durations of the stability studies. The validated method was successfully applied to the analyses of the pharmacokinetic study for patients treated with 4-HPR in a clinical trial. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Quantification of theobromine and caffeine in saliva, plasma and urine via liquid chromatography-tandem mass spectrometry: a single analytical protocol applicable to cocoa intervention studies.

    Science.gov (United States)

    Ptolemy, Adam S; Tzioumis, Emma; Thomke, Arjun; Rifai, Sami; Kellogg, Mark

    2010-02-01

    Targeted analyses of clinically relevant metabolites in human biofluids often require extensive sample preparation (e.g., desalting, protein removal and/or preconcentration) prior to quantitation. In this report, a single ultra-centrifugation based sample pretreatment combined with a designed liquid chromatography-tandem mass spectrometry (LC-MS/MS) protocol provides selective quantification of 3,7-dimethylxanthine (theobromine) and 1,3,7-trimethylxanthine (caffeine) in human saliva, plasma and urine samples. The optimized chromatography permitted elution of both analytes within 1.3 min of the applied gradient. Positive-mode electrospray ionization and a triple quadruple MS/MS instrument operated in multiple reaction mode were used for detection. (13)C(3) isotopically labeled caffeine was included as an internal standard to improve accuracy and precision. Implementing a 20-fold dilution of the isolated low MW biofluid fraction prior to injection effectively minimized the deleterious contributions of all three matrices to quantitation. The assay was linear over a 160-fold concentration range from 2.5 to 400 micromol L(-1) for both theobromine (average R(2) 0.9968) and caffeine (average R(2) 0.9997) respectively. Analyte peak area variations for 2.5 micromol L(-1) caffeine and theobromine in saliva, plasma and urine ranged from 5 and 10% (intra-day, N=10) to 9 and 13% (inter-day, N=25) respectively. The intra- and inter-day precision of theobromine and caffeine elution times were 3 and theobromine ranged from 114 to 118% and 99 to 105% at concentration levels of 10 and 300 micromol L(-1). This validated protocol also permitted the relative saliva, plasma and urine distribution of both theobromine and caffeine to be quantified following a cocoa intervention. 2009 Elsevier B.V. All rights reserved.

  12. Food Safety is an Important Public Health Issue: Chloramphenicol Residues Determination by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) in honey.

    Science.gov (United States)

    Krivohlavek, Adela; Žuntar, Irena; Ivešić, Martina; Andačić, Ivana Mandić; Šikić, Sandra

    2014-12-01

    Honey is used for nutritional, medicinal and industrial purposes and antibiotic residues may harm its quality and constitute a danger to human health. The broad spectrum antibiotic chloramphenicol (CAP) was used for curative purposes in veterinary medicine, but is now forbidden in European Union (EU) because of its many serious side effects (e.g. aplastic anaemia, grey syndrome, severe bone marrow depression and hypersensitivity). The aim of this study was to facilitate analyses of the quality and safety of Croatian honey distributed to whole European Union market; an assessment that has not previously been made. CAP in honey was qualifying and quantifying by validated liquid chromatography tandem mass spectrometry with negative electrospray ionisation method (LC-MS/MS). The target antibiotic was separated on chromatographic column Zorbax SB C18 (150 mm x 2.1 mm, 3.5 μm) with a gradient elution using acetonitrile - 0.1% formic acid mobile phase at a flow rate of 0.3 mL/min, with column temperature 35°C for CAP and 5D-CAP as internal standard. Homogenised honey samples were diluted with acetate buffer solution and extracted on Oasis Hydrophilic-Lipophilic-Balanced (HLB) sorbents. The method was used to analyse 280 domestic honey samples collected throughout Croatia between 2005.-2013. Recoveries of the method for real (acacia, chestnut, linden and flower) honey samples were 102% with RSD 8.4%. The value CCα and CCβ were 0.09 and 0.12 μg/kg, respectively. Results showed only three subsequent positive detections (1.1%) of CAP in honey. Analysed honey samples from Croatia showed good quality and safety what is the one of the main objective in consumer health policy in EU.

  13. Fast determination of seven synthetic pigments from wine and soft drinks using magnetic dispersive solid-phase extraction followed by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Chen, Xiao-Hong; Zhao, Yong-Gang; Shen, Hao-Yu; Zhou, Li-Xin; Pan, Sheng-Dong; Jin, Mi-Cong

    2014-06-13

    A novel, simple and sensitive method based on the use of magnetic dispersive solid-phase extraction (M-dSPE) procedure combined with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) was developed to determine seven synthetic pigments (tartrazine, amaranth, carmine, sunset yellow, allura red, brilliant blue and erythrosine) in wines and soft drinks. An amino-functionalized low degrees of cross-linking magnetic polymer (NH2-LDC-MP) was synthesized via suspension polymerization, and characterized by transmission electron microscopy (TEM). The NH2-LDC-MP was used as the M-dSPE sorbent to remove the matrix from the solution, and the main factors affecting the extraction were investigated in detail. The obtained results demonstrated the higher extraction capacity of NH2-LDC-MP with recoveries between 84.0 and 116.2%. The limits of quantification (LOQs) for the seven synthetic pigments were between 1.51 and 5.0μg/L in wines and soft drinks. The developed M-dSPE UFLC-MS/MS method had been successfully applied to the real wines and soft drinks for food-safety risk monitoring in Zhejiang Province, China. The results showed that sunset yellow was in three out of thirty soft drink samples (2.95-42.6μg/L), and erythrosine in one out of fifteen dry red wine samples (3.22μg/L), respectively. It was confirmed that the NH2-LDC-MP was a kind of highly effective M-dSPE materials for the pigments analyses. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Determination of Phenolic Acids and Flavonoids in Taraxacum formosanum Kitam by Liquid Chromatography-Tandem Mass Spectrometry Coupled with a Post-Column Derivatization Technique

    Directory of Open Access Journals (Sweden)

    Hung-Ju Chen

    2011-12-01

    Full Text Available A liquid chromatography-tandem mass spectrometry method (LC-MS/MS was developed for the determination of phenolic acids and flavonoids in a medicinal Chinese herb Taraxacum formosanum Kitam. Initially, both phenolic acids and flavonoids were extracted with 50% ethanol in a water-bath at 60 °C for 3 h and eventually separated into acidic fraction and neutral fraction by using a C18 cartridge. A total of 29 compounds were separated within 68 min by employing a Gemini C18 column and a gradient solvent system of 0.1% formic acid and acetonitrile at a flow rate of 1.0 mL/min. Based on the retention behavior as well as absorption and mass spectra, 19 phenolic acids and 10 flavonoids were identified and quantified in T. formosanum, with the former ranging from 14.1 μg/g to 10,870.4 μg/g, and the latter from 9.9 μg/g to 325.8 μg/g. For further identification of flavonoids, a post-column derivatization method involving shift reagents such as sodium acetate or aluminum chloride was used and the absorption spectral characteristics without or with shift reagents were compared. An internal standard syringic acid was used for quantitation of phenolic acids, whereas (± naringenin was found suitable for quantitation of flavonoids. The developed LC-MS/MS method showed high reproducibility, as evident from the relative standard deviation (RSD values for intra-day and inter-day variability being 1.0–6.8% and 2.0–7.7% for phenolic acids and 3.7–7.4% and 1.5–8.1% for flavonoids, respectively, and thus may be applied for simultaneous determination of phenolic acids and flavonoids in Chinese herb and nutraceuticals.

  15. High-performance liquid chromatography-tandem mass spectrometry for simultaneous determination of raltegravir, dolutegravir and elvitegravir concentrations in human plasma and cerebrospinal fluid samples.

    Science.gov (United States)

    Tsuchiya, Kiyoto; Ohuchi, Mayu; Yamane, Naoe; Aikawa, Hiroaki; Gatanaga, Hiroyuki; Oka, Shinichi; Hamada, Akinobu

    2018-02-01

    A simple sample treatment procedure and sensitive liquid chromatography-tandem mass spectrometry method were developed for the simultaneous quantification of the concentrations of human immunodeficiency virus-1 integrase strand transfer inhibitors - raltegravir, dolutegravir and elvitegravir - in human plasma and cerebrospinal fluid (CSF). Plasma and CSF samples (20 μL each) were deproteinized with acetonitrile. Raltegravir-d 3 was used as the internal standard. Chromatographic separation was achieved on an XBridge C 18 column (50 × 2.1 mm i.d., particle size 3.5 μm) using acetonitrile-water (7:3, v/v) containing 0.1% formic acid as the mobile phase at a flow rate of 0.2 mL/min. The run time was 5 min. Calibration curves for all three drugs were linear in the range 5-1500 ng/mL for plasma and 1-200 ng/mL for CSF. The intra- and inter-day precision and accuracy of all three drugs in plasma were coefficient of variation (CV) <12.9% and 100.0 ± 12.2%, respectively, while those in CSF were CV <12.3% and 100.0 ± 7.9%, respectively. Successful validation under the same LC-MS/MS conditions for both plasma and CSF indicates this analytical method is useful for monitoring the levels of these integrase strand transfer inhibitors in the management of treatment of HIV-1 carriers. Copyright © 2017 John Wiley & Sons, Ltd.

  16. Analysis of glycosaminoglycans in cerebrospinal fluid from patients with mucopolysaccharidoses by isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Haoyue; Young, Sarah P; Auray-Blais, Christiane; Orchard, Paul J; Tolar, Jakub; Millington, David S

    2011-07-01

    New therapies for the treatment of mucopolysaccharidoses that target the brain, including intrathecal enzyme replacement, are being explored. Quantitative analysis of the glycosaminoglycans (GAGs) that accumulate in these disorders is required to assess the disease burden and monitor the effect of therapy in affected patients. Because current methods lack the required limit of quantification and specificity to analyze GAGs in small volumes of cerebrospinal fluid (CSF), we developed a method based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Samples of CSF (25 μL) were evaporated to dryness and subjected to methanolysis. The GAGs were degraded to uronic acid-N-acetylhexosamine dimers and mixed with internal standards derived from deuteriomethanolysis of GAG standards. Specific dimers derived from heparan, dermatan and chondroitin sulfates (HS, DS and CS) were separated by UPLC and analyzed by electrospray ionization MS/MS using selected reaction monitoring for each targeted GAG product and its corresponding internal standard. CSF from control pediatric subjects (n = 22) contained <0.38 mg/L HS, 0.26 mg/L DS, and 2.8 mg/L CS, whereas CSF from patients with Hurler syndrome (n = 7) contained concentrations of DS and HS that were at least 6-fold greater than the upper control limits. These concentrations were reduced by 17.5% to 82.5% after allogeneic transplantation and treatment with intrathecal and intravenous enzyme replacement therapy. The method described here has potential value in monitoring patients with mucopolysaccharidoses receiving treatment targeted to the brain.

  17. Profiling of oxidized phospholipids in lipoproteins from patients with coronary artery disease by hollow fiber flow field-flow fractionation and nanoflow liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Lee, Ju Yong; Byeon, Seul Kee; Moon, Myeong Hee

    2015-01-20

    Oxidized phospholipids (Ox-PLs) are oxidatively modified PLs that are produced during the oxidation of lipoproteins; oxidation of low density lipoproteins especially is known to be associated with the development of coronary artery disease (CAD). In this study, different lipoprotein classes (high density, low density, and very low density lipoproteins) from pooled plasma of CAD patients and pooled plasma from healthy controls were size-sorted on a semipreparative scale by multiplexed hollow fiber flow field-flow fractionation (MxHF5), and Ox-PLs that were extracted from each lipoprotein fraction were quantified by nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS/MS). The present study showed that oxidation of lipoproteins occurred throughout all classes of lipoproteins with more Ox-PLs identified from CAD patient lipoproteins: molecular structures of 283 unique PL species (including 123 Ox-PLs) from controls and 315 (including 169 Ox-PLs) from patients were identified by data-dependent collision-induced dissociation experiments. It was shown that oxidation of PLs occurred primarily with hydroxylation of PL; in particular, a saturated acyl chain such as 16:0, 18:0, or even 18:1 at the sn-1 location of the glycerol backbone along with sn-2 acyl chains with at least two double bonds were identified. The acyl chain combinations commonly found for hydroxylated Ox-PLs in the lipoproteins of CAD patients were 16:0/18:2, 16:0/20:4, 18:0/18:2, and 18:0/20:4.

  18. Ultra-high-pressure liquid chromatography tandem mass spectrometry determination of antidepressant and anxiolytic drugs in neonatal meconium and maternal hair.

    Science.gov (United States)

    Pichini, Simona; Cortes, Laura; Marchei, Emilia; Solimini, Renata; Pacifici, Roberta; Gomez-Roig, Mª Dolores; García-Algar, Oscar

    2016-01-25

    A procedure based on ultra-high-pressure liquid chromatography tandem mass spectrometry has been developed for the determination of 22 antidepressant and anxiolytic drugs ad metabolites in the three consecutive maternal hair segments representing the pregnancy trimesters and paired neonatal meconium samples. After hair washing with methyl alcohol and diethyl ether and subsequent addition of internal standards, hair samples were treated with 500 μl VMA-T M3 reagent for 1h at 100 °C. After cooling, 100 μl M3 extract were diluted with 400 μl water and a volume of 10 μl was injected into chromatographic system. Meconium samples were firstly treated with 1 ml methyl alcohol and the organic layer back-extracted twice with 1.5 ml of a mixture of ethylacetate:hexane (80:20, v/v). Chromatographic separation was achieved at ambient temperature using a reverse-phase column and a linear gradient elution with two solvents: 0.3% formic acid in acetonitrile and 5mM ammonium formate pH 3. The mass spectrometer was operated in positive ion mode, using multiple reaction monitoring via positive electrospray ionization. The method was linear from the limit of quantification (0.05-1 ng/mg hair and 5-25 ng/g meconium depending on analyte under investigation;) to 10 ng/mg hair and 1000 ng/g meconium, with an intra- and inter-assay imprecision and inaccuracy always less than 20% and an analytical recovery between 66.6% and 95.3%, depending on the considered analyte and biological matrix. Using the validated method, 7 mothers were found positive to one or more hair segments and 5 meconium samples were found positive to one or more antidepressant and anxiolytic drugs, assessing prenatal exposure to these drugs following maternal consumption in one or more pregnancy trimesters. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Liquid chromatography-tandem mass spectrometry method for simultaneous quantification of bisoprolol, ramiprilat, propranolol and midazolam in rat dried blood spots.

    Science.gov (United States)

    Cvan Trobec, Katja; Trontelj, Jurij; Springer, Jochen; Lainscak, Mitja; Kerec Kos, Mojca

    2014-05-01

    Dried blood spot (DBS) sampling represents a suitable method for pharmacokinetic studies in rats, particularly if serial sampling is needed. To study the pharmacokinetics of drugs in a rat heart failure (HF) model, we developed and validated a method for the simultaneous determination of bisoprolol, ramiprilat, propranolol and midazolam in DBS samples. Bisoprolol and ramipril are widely used in the treatment of HF, and midazolam and propranolol are markers of hepatic metabolism, which can be altered in HF. A 20μL sample of rat blood was pipetted onto Whatman 903 Protein Saver Card and allowed to dry. The whole spot was excised and 300μL of solvent (methanol with 10% ultrapure water and 0.1% formic acid) was added. After mixing and incubating the sample in an ultrasonic bath, a mixture of isotopically labeled internal standards was added. After centrifugation, the extracts were cleaned on an Ostro™ plate and analyzed using liquid chromatography-tandem mass spectroscopy. The method was successfully validated. No significant interference was observed in the retention times of analytes or internal standards. The intraday and interday accuracy and precision were within a ±15% interval. The method was linear in the range 5-250μg/L and the lower limit of quantification was 5μg/L for all four analytes. The absolute matrix effect ranged from 98.7% for midazolam to 121% for ramiprilat. The recovery was lowest for ramiprilat and highest for propranolol. Samples were stable at all tested temperatures. The method has been used successfully in a real-time pharmacokinetic study in rats. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Quantitative Analysis of Ingenol in Euphorbia species via Validated Isotope Dilution Ultra-high Performance Liquid Chromatography Tandem Mass Spectrometry

    Czech Academy of Sciences Publication Activity Database

    Béres, T.; Dragull, K.; Pospíšil, Jiří; Tarkowská, Danuše; Dančák, M.; Bíba, Ondřej; Tarkowski, P.; Doležal, K.; Strnad, Miroslav

    2018-01-01

    Roč. 29, č. 1 (2018), s. 23-29 ISSN 0958-0344 R&D Projects: GA ČR GA17-14007S; GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Euphorbia genus * ingenol * isotope-dilution method * mass spectrometry * ultra-high performance liquid chromatography Subject RIV: FD - Oncology ; Hematology OBOR OECD: Analytical chemistry Impact factor: 2.292, year: 2016

  1. Multi-component analysis of tetracyclines, sulfonamides and tylosin in swine manure by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Jacobsen, Anne Marie; Halling-Sørensen, Bent

    2006-03-01

    A multi-component method focussing on thorough sample preparation has been developed for simultaneous analysis of swine manure for three classes of antibiotic-tetracyclines, sulfonamides, and tylosin. Liquid manure was initially freeze-dried and homogenised by pulverization before extraction by pressurised liquid extraction. The extraction was performed at 75 degrees C and 2,500 psig in three steps using two cycles with 0.2 mol L(-1) citric acid buffer (pH 4.7) and one cycle with a mixture of 80% methanol with 0.2 mol L(-1) citric acid (pH 3). After liquid-liquid extraction with heptane to remove lipids, the pH of the manure was adjusted to 3 with formic acid and the sample was vacuum-filtered through 0.6 mum glass-fibre filters. Finally the samples were pre-concentrated by tandem SPE (SAX-HLB). Recoveries were determined for manure samples spiked at three concentrations (50-5,000 microg kg(-1) dry matter); quantification was achieved by matrix-matched calibration. Recoveries were >70% except for oxytetracycline (42-54%), sulfadiazine (59-73%), and tylosin (9-35%) and did not vary with concentration or from day-to-day. Limits of quantification (LOQ) for all compounds, determined as a signal-to-noise ratio of 10, were in the range 10-100 microg kg(-1) dry matter. The suitability of the method was assessed by analysis of swine manure samples from six different pig-production sites, e.g. finishing pigs, sows, or mixed production. Residues of antibiotics were detected in all samples. The largest amounts were found for tetracyclines (up to 30 mg kg(-1) dry matter for the sum of CTC and ECTC). Sulfonamides were detected at concentrations up to 2 mg kg(-1) dry matter (SDZ); tylosin was not detected in any samples.

  2. Quantification of pramipexole in human plasma by liquid chromatography tandem mass spectrometry using tamsulosin as internal standard.

    Science.gov (United States)

    Nirogi, Ramakrishna V S; Kandikere, Vishwottam; Shrivastava, Wishu; Mudigonda, Koteshwara; Maurya, Santosh; Ajjala, Devender

    2007-11-01

    A high-performance liquid chromatography/electrospray ionization tandem mass spectrometry method was developed and validated for the quantification of pramipexole in human plasma. Following liquid-liquid extraction, the analytes were separated using an isocratic mobile phase on a reverse-phase column and analyzed by MS/MS in the multiple reaction monitoring mode using the respective [M + H](+) ions, m/z 212/152 for pramipexole and m/z 409/228 for the IS. The method exhibited a linear dynamic range of 200-8000 pg/mL for pramipexole in human plasma. The lower limit of quantification was 200 pg/mL with a relative standard deviation of less than 8%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 3.5 min for each sample made it possible to analyze more than 200 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic, bioavailability or bioequivalence studies. Copyright (c) 2007 John Wiley & Sons, Ltd.

  3. Quantification of Fatty Acid Oxidation Products Using On-line High Performance Liquid Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Levison, Bruce S.; Zhang, Renliang; Wang, Zeneng; Fu, Xiaoming; DiDonato, Joseph A.; Hazen, Stanley L.

    2013-01-01

    Oxidized fatty acids formed via lipid peroxidation are implicated in pathological processes such as inflammation and atherosclerosis. A number of methods may be used to detect specific oxidized fatty acids containing a single or multiple combinations of epoxide, hydroxyl, ketone and hydroperoxide moieties on varying carbon chain lengths from C8 up to C30. Some of these methods are nonspecific and their use in biological systems is fraught with difficulty. Measures of specific-oxidized fatty acid derivatives help in identifying oxidation pathways in pathological processes. We used liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-MS/MS) as efficient, selective and sensitive methods for identifying and analyzing multiple specific fatty acid peroxidation products in human plasma and other biological matrices. We then distilled the essential components of a number of these analyses to provide an efficient protocol by which fatty acid oxidation products and their parent compounds can be determined. In this protocol, addition of synthetic internal standard to the sample, followed by base hydrolysis at elevated temperature, and liquid-liquid phase sample extraction with lighter than water solvents facilitates isolation of the oxidized fatty acid species. These species can be identified and accurately quantified using stable isotope dilution and multiple reaction monitoring. Use of a coupled multiplexed gradient HPLC system on the front end enables high-throughput chromatography and more efficient use of mass spectrometer time. PMID:23499838

  4. Quantitative determination of the anti-tumor agent tasquinimod in human urine by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    van de Merbel, Nico C; Walland, Peter; Tiensuu, Mikael; Sennbro, Carl J

    2014-06-15

    Tasquinimod is an anti-tumor drug that is currently in clinical development for the treatment of solid cancers. After oral administration, tasquinimod and a number of its metabolites are excreted in the urine. The quantitative determination of tasquinimod in urine is challenging because of the required sensitivity (down to 0.1nM or 40pg/mL), the highly variable nature of this biological matrix and the presence of potentially unstable metabolites, which may convert back to the parent drug. In this article, an LC-MS/MS method is described for the determination of tasquinimod in human urine in the concentration range 0.1-200nM. Liquid-liquid extraction with n-chlorobutane was used to extract tasquinimod from 100μL human urine and to remove interfering endogenous urinary constituents. Reversed-phase liquid chromatography coupled to a triple quadrupole mass spectrometer equipped with an ESI source was used for quantification of tasquinimod in a 2.5-min run. A stable-isotope labeled internal standard was used for response normalization. The intra- and inter-day coefficients of variation (precision) as well as the bias (accuracy) of the method were below 7%. Although considerable conversion of conjugated tasquinimod metabolites back to parent drug was observed when incurred samples were stored at 37°C for a prolonged time, tasquinimod as well as its metabolites were sufficiently stable under all relevant sampling, storage and analysis conditions. The method was successfully applied to determine the urinary excretion of tasquinimod in healthy volunteers and patients with renal impairment after a 0.5-mg oral dose. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Quantitative determination of amitriptyline and its metabolite in rat plasma by liquid chromatography-tandem mass spectrometry

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    Chae, Jungwoo; Baek, Inhwan; An, Junghwa; Kim, Eun Jung; Kwon, Kwangil [Chungnam National Univ., Daejeon (Korea, Republic of)

    2012-07-15

    A rapid, specific, and reliable LC-MS/MS-based bioanalytical method was developed and validated in rat plasma for the simultaneous quantitation of amitriptyline and its metabolite nortriptyline. Chromatographic separation of these analytes was achieved on a Gemini C18 column (50 X 4.60 mm, 5 {mu}m) using reversed-phase chromatography. The mobile phase was an isocratic solvent system consisting of 1% formic acid in water and methanol (10:90, v/v), at a flow rate of 0.2 mL/min. The analytical range was set as 0.1-500 ng/mL for amitriptyline and 0.08-500 ng/mL for nortriptyline using a 200 {mu}L plasma sample. The accuracy and precision of the assay were in accordance with FDA regulations for the validation of bioanalytical methods. The validated method was successfully applied to a pharmacokinetic study in six rats after oral administration of amitriptyline (15 mg/kg). This method allows laboratory scientists to rapidly determine amitriptyline and nortriptyline concentrations in plasma.

  6. Simultaneous determination of ten illegal azo dyes in feed by ultra-high performance liquid chromatography tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Piątkowska Marta

    2017-09-01

    Full Text Available Introduction: The paper presents the method of simultaneous determination of 10 illegal azo dyes in feed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry technique. Material and Methods: The dyes were extracted with hexane, evaporated to dryness, and analysed. Separation was achieved in 7 min in a gradient elution using acetonitrile (A and 0.1% formic acid (B as a mobile phase. Results: The validation results showed the repeatability of the method, which was evaluated at three levels (50, 500, and 5,000 μg/kg. All the matrix calibration curves for the working ranges were linear (R2 0.9904 to 1.0, the repeatability was between 2.1% and 24%, and recoveries ranged from 77.9% to 120%. The LOD and LOQ were at 1-2 and 5-10 μg/kg for different dyes, respectively. Furthermore, the method was applied in the homogeneity tests of the in-house prepared feed containing Sudan I at the levels of 0.5, 5, and 50 mg/kg. Conclusions: A sensitive, selective, and fast multiresidue method was successfully developed and validated. Its robustness was confirmed by the analysis of an experimental feed containing Sudan I.

  7. Ultra-high performance liquid chromatography tandem high-resolution mass spectrometry study of tricyclazole photodegradation products in water.

    Science.gov (United States)

    Gosetti, Fabio; Chiuminatto, Ugo; Mazzucco, Eleonora; Mastroianni, Rita; Bolfi, Bianca; Marengo, Emilio

    2015-06-01

    This paper reports the study of the photodegradation reactions that tricyclazole can naturally undergo, under the action of sunlight, in aqueous solutions of standard tricyclazole and of the commercial BEAM(TM) formulation. The analyses are carried out by ultra-high performance liquid chromatography technique coupled with high-resolution tandem mass spectrometry. Analysis of both tricyclazole and BEAM(TM) water solutions undergone to hydrolysis does not evidence new chromatographic peaks with respect to the not treated solutions. On the contrary, analysis of the same samples subjected to sunlight irradiation shows a decreased intensity of tricyclazole signal and the presence of new chromatographic peaks. Two photodegradation products of tricyclazole have been identified, one of which has been also quantified, being the commercial standard available. The pattern is similar for the solutions of the standard fungicide and of the BEAM(TM) formulation. The results obtained from eco-toxicological tests show that toxicity of tricyclazole standard solutions is greater than that of the irradiated ones, whereas toxicity levels of all the BEAM(TM) solutions investigated (non-irradiated, irradiated, and hydrolyzed) are comparable and lower than those shown by tricyclazole standard solutions. Experiments performed in paddy water solution show that there is no difference in the degradation products formed.

  8. Simultaneous determination of tryptophan and 8 metabolites in human plasma by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Boulet, Lysiane; Faure, Patrice; Flore, Patrice; Montérémal, Julien; Ducros, Véronique

    2017-06-01

    Tryptophan (Trp) is an essential amino-acid and the precursor of many biologically active substances such as kynurenine (KYN) and serotonin (5HT). Its metabolism is involved in different physiopathological states, such as cardiovascular diseases, cancer, immunomodulation or depression. Hence, the quantification of Trp catabolites, from both KYN and 5HT pathways, might be usefulfor the discovery of novel diagnostic and follow-up biomarkers. We have developed a simple method for quantification of Trp and 8 of its metabolites,involved in both KYN and 5HT pathways, using liquid chromatography coupled to tandem mass spectrometry. We also validated the methodin human plasma samples, according to NF EN ISO 15189 criteria. Our method shows acceptable intra- and inter-day coefficients of variation (CV) (<12% and <16% respectively). The linearity entirelycovers the human plasma range. Stabilities of whole blood and of residues weredetermined, as well as the use of 2 different types of collectiontube, enabling us to adapt our process. Matrix effects and reference values showed good agreement compared to the literature. We propose here a method allowing the simultaneous quantification of a panel of Trp catabolites, never used before to our knowledge. This method, witha quickchromatographic runtime (15min) and simple sample preparation, has beenvalidated according to NF EN ISO 15189 criteria. The method enables the detailed analysis of these metabolic pathways, which are thought to be involved in a number of pathological conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Determination of mycotoxins in plant-based beverages using QuEChERS and liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Miró-Abella, Eugènia; Herrero, Pol; Canela, Núria; Arola, Lluís; Borrull, Francesc; Ras, Rosa; Fontanals, Núria

    2017-08-15

    A method was developed for the simultaneous determination of 11 mycotoxins in plant-based beverage matrices, using a QuEChERS extraction followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry detection (UHPLC-(ESI)MS/MS). This multi-mycotoxin method was applied to analyse plant-based beverages such as soy, oat and rice. QuEChERS extraction was applied obtaining suitable extraction recoveries between 80 and 91%, and good repeatability and reproducibility values. Method Quantification Limits were between 0.05μgL -1 (for aflatoxin G 1 and aflatoxin B 1 ) and 15μgL -1 (for deoxynivalenol and fumonisin B 2 ). This is the first time that plant-based beverages have been analysed, and certain mycotoxins, such as deoxynivalenol, aflatoxin B 1 , aflatoxin B 2 , aflatoxin G 1 , aflatoxin G 2 , ochratoxin A, T-2 toxin and zearalenone, were found in the analysed samples, and some of them quantified between 0.1μgL -1 and 19μgL -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Comparison of different amino acid derivatives and analysis of rat brain microdialysates by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Uutela, Päivi; Ketola, Raimo A; Piepponen, Petteri; Kostiainen, Risto

    2009-02-09

    The efficiencies of three derivatisation reagents that react with either the amine (9-fluorenylmethyl chloroformate (FMOC)) or the carboxylic acid group (butanol) of amino acid or with both types of functional groups (propyl chloroformate) were compared in the analysis of amino acids by liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). Separation of 20 amino acids derivatised with these three reagents was studied on reversed-phase chromatography. Linearity, repeatability and limits of detection of the LC-ESI-MS/MS method were determined by analysing FMOC-, butanol- and propyl chloroformate-derivatised lysine, beta-aminobutyric acid, threonine and glutamic acid. The limits of detection for the derivatised amino acids (7.5-75fmol) were as much as 2-60 times lower than those of the corresponding underivatised molecules. The best linearity was observed for amino acids derivatised with propyl chloroformate or butanol (r(2)=0.996-0.999, range=100-8500nmolL(-1)). Propyl chloroformate was the best suited of the reagents tested for the analysis of amino acids with LC-MS/MS and was used for the analysis of amino acids in rat brain microdialysis samples.

  11. Quantitation of anacetrapib, stable-isotope labeled-anacetrapib (microdose), and four metabolites in human plasma using liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Chavez-Eng, C M; Lutz, R W; Li, H; Goykhman, D; Bateman, K P; Woolf, E

    2016-02-01

    An ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous determination of (4S,5R)-5-[3,5-bis (trifluoromethyl)phenyl]-3-{[4'-fluoro-5'-isopropyl-2'-methoxy-4-(trifluoromethyl)biphenyl-2-yl] methyl}-4-methyl-1,3-oxazolidin-2-one (anacetrapib, I) and [(13)C5(15)N]-anacetrapib, II in human plasma has been developed to support a clinical study to determine the absolute bioavailability of I. The analytes and the stable-isotope labeled internal standard ([(13)C7(15)N(2)H7]-anacetrapib, III) were extracted from 100μL of human plasma by liquid-liquid extraction using 20/80 isopropyl alcohol/hexane (v/v). The chromatographic separation of the analytes was achieved using Waters BEH Shield RP 18 (50×2.1mm×1.7μm) column and mobile phase gradient of 0.1% formic acid in water (Solvent A) and 0.1% formic acid in acetonitrile (Solvent B) at 0.6mL/min flow rate. The MS/MS detection was performed on AB Sciex 5000 or AB 5500 in positive electrospray ionization mode, operated in selected reaction monitoring mode. The assay was validated in the concentration range 1-2000ng/mL for I; and a lower curve range, 0.025-50ng/mL for II. In addition to the absolute bioavailability determination, it was desired to better elucidate the pharmacokinetic behavior of several hydroxylated metabolites of I. Toward this end, two exploratory assays for the hydroxy metabolites of I were qualified in the concentration range 0.5-500ng/mL. All metabolites were separated on a Supelco Ascentis Express Phenyl-Hexyl (50×2.1mm, 2.7μm) column. Metabolite M4 was analyzed in the negative mode with a mobile phase consisting of a gradient mixture of water (A) and acetonitrile (B). The other three metabolites, M1-M3 were analyzed in the positive mode using a mobile phase gradient of water with 0.1% formic acid (A) and acetonitrile with 0.1% formic acid (B). The assays were utilized to support a clinical study in which a microdosing approach was used to

  12. Simultaneous Determination of Coumarin and Its Derivatives in Tobacco Products by Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Zhiqin Ren

    2016-11-01

    Full Text Available In this paper an analytical method based on high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS for the determination of coumarin and its derivatives in tobacco products was developed. The MS/MS fragmentation pathways of the eight coumarins were elucidated. The new analytical method was defined based on two main axes, an extraction procedure with acetonitrile and analyte detection performed by HPLC-MS/MS in electron impact mode. The excellent selectivity and sensitivity achieved in multiple reaction monitoring (MRM mode allowed satisfactory confirmation and quantitation for the coumarin flavor additives. Under the optimized gradient elution conditions, it took only 4.5 min to separate all eight coumarins. Good linearity for all the analytes were confirmed by the correlation coefficient r2, ranging from 0.9987 to 0.9996. The limits of detection (LODs and limits of quantitation (LOQs of these compounds were in the range of 0.5–1.7 μg/kg and 1.7–5.2 μg/kg, respectively. The average recoveries at three spiked levels (LOQ, 1.5LOQ, 2LOQ were all in the range of 69.6%–95.1% with RSDs (n = 6 lower than 5.3%. The method of HPLC-MS/MS developed in this study was initially applied to the research of coumarin flavor additives in tobacco products collected from the located market in Beijing from China and proved to be accurate, sensitive, convenient and practical.

  13. Analysis of Digoxin and Metildigoxin in Whole Blood Using Solid-Phase Extraction and Liquid Chromatography Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Paula Melo

    2012-01-01

    Full Text Available A simple and rapid UPLC/MS/MS method has been developed and validated for the analysis of digoxin and metildigoxin in whole blood. Samples were prepared by SPE extraction with Oasis HLB columns. Separation was achieved with an ACQUITY UPLC HSS T3 column (2.1×100; 1.8 μm, at 35°C. The mobile phase consisted of acetonitrile (70% and ammonium formate 5 mM (30%. Total run time was 1.5 min operating at isocratic mode with a flow rate of 0.3 mL/min. Mass spectrometry detection was performed by positive mode electrospray, on the ammonium adducts with two transitions for each analyte and one for the IS (d3-digoxin. The method proved to be specific and linear over the range (0.3–10 ng/mL. This technique also showed high sensitivity with a 0.09 ng/mL LOD and a 0.28 ng/mL LOQ, for both substances. Percentage recovery ranged from 83 to 100% for digoxin and from 62 to 94% for metildigoxin. The intra- and interday precision CV were ≤10%.

  14. Simultaneous quantification of caffeine and its three primary metabolites in rat plasma by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Choi, Eu Jin; Bae, Soo Hyeon; Park, Jung Bae; Kwon, Min Jo; Jang, Su Min; Zheng, Yu Fen; Lee, Young Sun; Lee, Su-Jun; Bae, Soo Kyung

    2013-12-01

    A rapid, sensitive, simple and accurate LC-MS/MS method for the simultaneous quantitation of caffeine, and its three primary metabolites, theobromine, paraxanthine, and theophylline, in rat plasma was developed and validated. Chromatographic separation was performed on an Agilent Poroshell 120 EC-C18 column using 1 μg/mL acetaminophen as an internal standard. Each sample was run at 0.5 mL/min for a total run time of 7 min/sample. Detection and quantification were performed using a mass spectrometer in selected reaction-monitoring mode with positive electrospray ionization. The lower limit of quantification was 5 ng/mL for all analytes with linear ranges up to 5000 ng/mL for caffeine and 1000 ng/mL for its metabolites. The coefficient of variation for assay precision was less than 12.6%, with an accuracy of 93.5-114%. The assay was successfully applied to determine plasma concentrations of caffeine, theobromine, paraxanthine, and theophylline in rat administered various energy drinks containing the same caffeine content. Various energy drinks exhibited considerable variability in the pharmacokinetic profiles of caffeine and its three primary metabolites, even containing the same caffeine. Different additives of energy drinks might contribute to these results. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Simultaneous determination of fluoxetine and norfluoxetine in dried blood spots using high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    da Silva, Anne Caroline Cezimbra; Raasch, Juliana Raquel; Vargas, Tainara Gomes; Peteffi, Giovana Piva; Hahn, Roberta Zilles; Antunes, Marina Venzon; Perassolo, Magda Susana; Linden, Rafael

    2018-02-01

    Therapeutic drug monitoring (TDM) of the widely prescribed antidepressant fluoxetine (FLU) is recommended in certain situations, such as occurrence of toxicity, inadequate response or suspect of poor adherence. Dried blood spot (DBS) sampling is an increasingly studied alternative for TDM, particularly for outpatients, due to its ease of collection and inherent stability. The aim of this study was to develop and validate an LC-MS/MS assay for the simultaneous quantification of FLU and norfluoxetine (NFLU) in DBS. The assay is based on a liquid extraction of single DBS with 8mm of diameter, using FLU-D6 as the internal standard, followed by reversed phase separation in an Accucore® C18 column (100×2.1mm, 2.6μm). Mobile phase was composed of water and acetonitrile (gradient from 80:20 to 50:50, v/v), both containing formic acid 0.1%. The assay was validated and applied to 30 patients under FLU pharmacotherapy. The assay was linear in the range 10-750ngmL -1 . Precision assays presented CV% of 3.13-9.61 and 3.54-7.99 for FLU and NFLU, respectively, and accuracy in the range of 97.98-110.44% and 100.25-105.8%. FLU and NFLU were stable at 25 and 45°C for 7days. The assay was evaluated in 30 patients under FLU treatment. Concentrations of both compounds were higher in DBS than in plasma, and the use of the multiplying factors 0.71 and 0.68 for FLU and NFLU, respectively, allowed acceptable estimation of plasma concentrations, with median prediction bias of -0.55 to 0.55% and mean differences of 0.4 to 2.2ngmL -1 . The presented data support the clinical use of DBS for therapeutic drug monitoring of FLU. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  16. Measurement of water-soluble B vitamins in infant formula by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Huang, Min; Winters, Doug; Crowley, Richard; Sullivan, Darryl

    2009-01-01

    A method has been developed for the simultaneous measurement of multiple B vitamins (i.e., B1, B2, B3, B5, and B6) in infant formulas by LC-MSIMS. The vitamins were extracted with acidic solvent, followed by protein precipitation at a pH range of 4.5 to 5.5, and filtered. This simplified procedure eliminates many of the potential sources of laboratory error and facilitates rapid and efficient analysis. As is common in most cases, isotope internal standards were added to account for variations in sample preparation, as well as changes in MS measurement. In this method, isotope-labeled internal standards of B1, B3, B5, and B6 were used. The factors affecting analytical performance were investigated and optimized. In addition, the stability of these vitamins in the extraction solution was investigated. An acidic condition (5 mM HCl) was applied to successfully stabilize B1, which had shown a decrease in signal when other solvents were used. The quantitative extraction and good stability allowed isotope standards to be added to the filtered sample solution, instead of to the extraction solvent. The addition of the isotope to the small portion of the filtered sample solution significantly reduces cost. A comprehensive evaluation of the analysis of the standard reference material and good spike recovery of the vitamins (100 +/- 6%) demonstrates the accuracy of the method. The results for commercially available infant formula samples were also compared with those obtained using the current microbiological method.

  17. Differential Mobility Spectrometry for Improved Selectivity in Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry Analysis of Paralytic Shellfish Toxins

    Science.gov (United States)

    Beach, Daniel G.

    2017-08-01

    Paralytic shellfish toxins (PSTs) are neurotoxins produced by dinoflagellates and cyanobacteria that cause paralytic shellfish poisoning in humans. PST quantitation by LC-MS is challenging because of their high polarity, lability as gas-phase ions, and large number of potentially interfering analogues. Differential mobility spectrometry (DMS) has the potential to improve the performance of LC-MS methods for PSTs in terms of selectivity and limits of detection. This work describes a comprehensive investigation of the separation of 16 regulated PSTs by DMS and the development of highly selective LC-DMS-MS methods for PST quantitation. The effects of all DMS parameters on the separation of PSTs from one another were first investigated in detail. The labile nature of 11α-gonyautoxin epimers gave unique insight into fragmentation of labile analytes before, during, and after the DMS analyzer. Two sets of DMS parameters were identified that either optimized the resolution of PSTs from one another or transmitted them at a limited number of compensation voltage (CV) values corresponding to structural subclasses. These were used to develop multidimensional LC-DMS-MS/MS methods using existing HILIC-MS/MS parameters. In both cases, improved selectivity was observed when using DMS, and the quantitative capabilities of a rapid UPLC-DMS-MS/MS method were evaluated. Limits of detection of the developed method were similar to those without DMS, and differences were highly analyte-dependant. Analysis of shellfish matrix reference materials showed good agreement with established methods. The developed methods will be useful in cases where specific matrix interferences are encountered in the LC-MS/MS analysis of PSTs in complex biological samples.

  18. Dried Blood Spot Methodology in Combination With Liquid Chromatography/Tandem Mass Spectrometry Facilitates the Monitoring of Teriflunomide

    Science.gov (United States)

    Lunven, Catherine; Turpault, Sandrine; Beyer, Yann-Joel; O'Brien, Amy; Delfolie, Astrid; Boyanova, Neli; Sanderink, Ger-Jan; Baldinetti, Francesca

    2016-01-01

    Background: Teriflunomide, a once-daily oral immunomodulator approved for treatment of relapsing-remitting multiple sclerosis, is eliminated slowly from plasma. If necessary to rapidly lower plasma concentrations of teriflunomide, an accelerated elimination procedure using cholestyramine or activated charcoal may be used. The current bioanalytical assay for determination of plasma teriflunomide concentration requires laboratory facilities for blood centrifugation and plasma storage. An alternative method, with potential for greater convenience, is dried blood spot (DBS) methodology. Analytical and clinical validations are required to switch from plasma to DBS (finger-prick sampling) methodology. Methods: Using blood samples from healthy subjects, an LC-MS/MS assay method for quantification of teriflunomide in DBS over a range of 0.01–10 mcg/mL was developed and validated for specificity, selectivity, accuracy, precision, reproducibility, and stability. Results were compared with those from the current plasma assay for determination of plasma teriflunomide concentration. Results: Method was specific and selective relative to endogenous compounds, with process efficiency ∼88%, and no matrix effect. Inaccuracy and imprecision for intraday and interday analyses were blood deposit volume and punch position within spot, and hematocrit level had a limited but acceptable effect on measurement accuracy. Teriflunomide was stable for at least 4 months at room temperature, and for at least 24 hours at 37°C with and without 95% relative humidity, to cover sampling, drying, and shipment conditions in the field. The correlation between DBS and plasma concentrations (R2 = 0.97), with an average blood to plasma ratio of 0.59, was concentration independent and constant over time. Conclusions: DBS sampling is a simple and practical method for monitoring teriflunomide concentrations. PMID:27015245

  19. Simultaneous Determination of Underivatized Vitamin B1 and B6 in Whole Blood by Reversed Phase Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry

    Science.gov (United States)

    Puts, Johan; de Groot, Monique; Haex, Martin; Jakobs, Bernadette

    2015-01-01

    Background Vitamin B1 (thiamine-diphosphate) and B6 (pyridoxal-5’phosphate) are micronutrients. Analysis of these micronutrients is important to diagnose potential deficiency which often occurs in elderly people due to malnutrition, in severe alcoholism and in gastrointestinal compromise due to bypass surgery or disease. Existing High Performance Liquid Chromatography (HPLC) based methods include the need for derivatization and long analysis time. We developed an Ultra High Performance Liquid Chromatography Tandem Mass spectrometry (UHPLC-MS/MS) assay with internal standards for simultaneous measurement of underivatized thiamine-diphosphate and pyridoxal-5’phosphate without use of ion pairing reagent. Methods Whole blood, deproteinized with perchloric acid, containing deuterium labelled internal standards thiamine-diphosphate(thiazole-methyl-D3) and pyridoxal-5’phosphate(methyl-D3), was analyzed by UHPLC-MS/MS. The method was validated for imprecision, linearity, recovery and limit of quantification. Alternate (quantitative) method comparisons of the new versus currently used routine HPLC methods were established with Deming regression. Results Thiamine-diphosphate and pyridoxal-5’phosphate were measured within 2.5 minutes instrumental run time. Limits of detection were 2.8 nmol/L and 7.8 nmol/L for thiamine-diphosphate and pyridoxal-5’phosphate respectively. Limit of quantification was 9.4 nmol/L for thiamine-diphosphate and 25.9 nmol/L for pyridoxal-5’phosphate. The total imprecision ranged from 3.5–7.7% for thiamine-diphosphate (44–157 nmol/L) and 6.0–10.4% for pyridoxal-5’phosphate (30–130 nmol/L). Extraction recoveries were 101–102% ± 2.5% (thiamine-diphosphate) and 98–100% ± 5% (pyridoxal-5’phosphate). Deming regression yielded slopes of 0.926 and 0.990 in patient samples (n = 282) and national proficiency testing samples (n = 12) respectively, intercepts of +3.5 and +3 for thiamine-diphosphate (n = 282 and n = 12) and slopes of

  20. Coenzyme Q10 quantification in muscle, fibroblasts and cerebrospinal fluid by liquid chromatography/tandem mass spectrometry using a novel deuterated internal standard.

    Science.gov (United States)

    Duberley, Kate E C; Hargreaves, Iain P; Chaiwatanasirikul, Korn-Anong; Heales, Simon J R; Land, John M; Rahman, Shamima; Mills, Kevin; Eaton, Simon

    2013-05-15

    Neurological dysfunction is common in primary coenzyme Q10 (2,3-dimethoxy, 5-methyl, 6-polyisoprene parabenzoquinone; CoQ10 ; ubiquinone) deficiencies, the most readily treatable subgroup of mitochondrial disorders. Therapeutic benefit from CoQ10 supplementation has also been noted in other neurodegenerative diseases. CoQ10 can be measured by high-performance liquid chromatography (HPLC) in plasma, muscle or leucocytes; however, there is no reliable method to quantify CoQ10 in cerebrospinal fluid (CSF). Additionally, many methods use CoQ9 , an endogenous ubiquinone in humans, as an internal standard. Deuterated CoQ10 (d6 -CoQ10 ) was synthesised by a novel, simple, method. Total CoQ10 was measured by liquid chromatography/tandem mass spectrometry (LC/MS/MS) using d6 -CoQ10 as internal standard and 5 mM methylamine as an ion-pairing reagent. Chromatography was performed using a Hypsersil GOLD C4 column (150 × 3 mm, 3 µm). CoQ10 levels were linear over a concentration range of 0-200 nM (R(2) = 0.9995). The lower limit of detection was 2 nM. The inter-assay coefficient of variation (CV) was 3.6% (10 nM) and 4.3% (20 nM), and intra-assay CV 3.4% (10 nM) and 3.6% (20 nM). Reference ranges were established for CoQ10 in CSF (5.7-8.7 nM; n = 17), fibroblasts (57.0-121.6 pmol/mg; n = 50) and muscle (187.3-430.1 pmol/mg; n = 15). Use of d6 -CoQ10 internal standard has enabled the development of a sensitive LC/MS/MS method to accurately determine total CoQ10 levels. Clinical applications of CSF CoQ10 determination include identification of patients with cerebral CoQ10 deficiency, and monitoring CSF CoQ10 levels following supplementation. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Simultaneous Determination of Underivatized Vitamin B1 and B6 in Whole Blood by Reversed Phase Ultra High Performance Liquid Chromatography Tandem Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Johan Puts

    Full Text Available Vitamin B1 (thiamine-diphosphate and B6 (pyridoxal-5'phosphate are micronutrients. Analysis of these micronutrients is important to diagnose potential deficiency which often occurs in elderly people due to malnutrition, in severe alcoholism and in gastrointestinal compromise due to bypass surgery or disease. Existing High Performance Liquid Chromatography (HPLC based methods include the need for derivatization and long analysis time. We developed an Ultra High Performance Liquid Chromatography Tandem Mass spectrometry (UHPLC-MS/MS assay with internal standards for simultaneous measurement of underivatized thiamine-diphosphate and pyridoxal-5'phosphate without use of ion pairing reagent.Whole blood, deproteinized with perchloric acid, containing deuterium labelled internal standards thiamine-diphosphate(thiazole-methyl-D3 and pyridoxal-5'phosphate(methyl-D3, was analyzed by UHPLC-MS/MS. The method was validated for imprecision, linearity, recovery and limit of quantification. Alternate (quantitative method comparisons of the new versus currently used routine HPLC methods were established with Deming regression.Thiamine-diphosphate and pyridoxal-5'phosphate were measured within 2.5 minutes instrumental run time. Limits of detection were 2.8 nmol/L and 7.8 nmol/L for thiamine-diphosphate and pyridoxal-5'phosphate respectively. Limit of quantification was 9.4 nmol/L for thiamine-diphosphate and 25.9 nmol/L for pyridoxal-5'phosphate. The total imprecision ranged from 3.5-7.7% for thiamine-diphosphate (44-157 nmol/L and 6.0-10.4% for pyridoxal-5'phosphate (30-130 nmol/L. Extraction recoveries were 101-102% ± 2.5% (thiamine-diphosphate and 98-100% ± 5% (pyridoxal-5'phosphate. Deming regression yielded slopes of 0.926 and 0.990 in patient samples (n = 282 and national proficiency testing samples (n = 12 respectively, intercepts of +3.5 and +3 for thiamine-diphosphate (n = 282 and n = 12 and slopes of 1.04 and 0.84, intercepts of -2.9 and +20 for

  2. Determination of urine caffeine and its metabolites by use of high-performance liquid chromatography-tandem mass spectrometry: estimating dietary caffeine exposure and metabolic phenotyping in population studies.

    Science.gov (United States)

    Rybak, Michael E; Pao, Ching-I; Pfeiffer, Christine M

    2014-01-01

    We have developed and validated a high-performance liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for determining urine caffeine and 14 caffeine metabolites suitable for estimating caffeine exposure and metabolic phenotyping in population studies. Sample preparation consisted solely of a series of simple reagent treatments at room temperature. Stable isotope-labeled analogs were used as internal standards for all analytes. We developed rapid LC-MS/MS separations for both positive and negative ion mode electrospray ionizations to maximize measurement sensitivity. Limits of detection were 0.05-0.1 μmol/L depending on the analytes. Method imprecision, based on total coefficients of variation, was generally 1 μmol/L. Analyte recoveries were typically within 10 % of being quantitative (100 %), and good agreement was observed among analytes measured across different MS/MS transitions. We applied this method to the analysis of a convenience set of human urine samples (n = 115) and were able to detect a majority of the analytes in ≥99 % of samples as well as calculate caffeine metabolite phenotyping ratios for cytochrome P450 1A2 and N-acetyltransferase 2. Whereas existing LC-MS/MS methods are limited in number of caffeine metabolites for which they are validated, or are designed for studies in which purposely elevated caffeine levels are expected, our method is the first of its kind designed specifically for the rapid, sensitive, accurate, and precise measurement of urine caffeine and caffeine metabolites at concentrations relevant to population studies.

  3. Cannabinoids assessment in plasma and urine by high performance liquid chromatography-tandem mass spectrometry after molecularly imprinted polymer microsolid-phase extraction.

    Science.gov (United States)

    Sánchez-González, Juan; Salgueiro-Fernández, Rocío; Cabarcos, Pamela; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

    2017-02-01

    A molecularly imprinted polymer (MIP) selective for cannabinoids [Δ 9 -tetrahydrocannabinol (Δ9-THC), 11-nor-9-carboxy-Δ 9 -tetrahydrocannabinol (Δ9-THC-COOH), and 11-hydroxy-Δ 9 -tetrahydrocannabinol (Δ9-THC-OH)] has been synthesized, fully characterized, and applied to the assessment of plasma and urine analysis of marijuana abuse by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Δ9-THC-COOH was used as a template molecule, whereas ethylene glycol dimethacrylate (EGDMA) was used as a functional monomer, divinylbenzene (DVB) as a cross-linker, and 2,2'-azobisisobutyronitrile (AIBN) as an initiator. The prepared MIP was found to be highly selective for cannabinoids typically found in blood and urine, and also for cannabinol (CBN) and cannabidiol (CBD). MIP beads (50 mg) were loaded inside a cone-shaped device made of a polypropylene (PP) membrane for microsolid-phase extraction (μ-SPE) in batch mode. Optimum retention of analytes (0.1 to 1.0 mL of plasma/urine) was achieved by fixing plasma/urine pH at 6.5 and assisting the procedure by mechanical shaking (150 rpm, 40 °C, 12 min). Optimum elution conditions implied 2 mL of a 90:10 methanol/acetic acid and ultrasound extraction (35 kHz, 325 W) for 6 min. Good precision was assessed by intra-day and inter-day assays. In addition, the method was found to be accurate after intra-day and inter-day analytical recovery assays and after analyzing control serum and urine control samples. The limits of quantification were in the range of 0.36-0.49 ng L -1 (plasma analysis) and 0.47-0.57 ng L -1 (urine analysis). These values are low enough for confirmative conclusions regarding marijuana abuse through blood and urine analysis. Graphical Abstract ᅟ.

  4. MCX based solid phase extraction combined with liquid chromatography tandem mass spectrometry for the simultaneous determination of 31 endocrine-disrupting compounds in surface water of Shanghai.

    Science.gov (United States)

    Zhang, Hong-Chang; Yu, Xue-jun; Yang, Wen-chao; Peng, Jin-feng; Xu, Ting; Yin, Da-Qiang; Hu, Xia-lin

    2011-10-15

    A novel analytical method employing MCX (mixed-mode cationic exchange) based solid phase extraction (SPE) coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed to detect 31 endocrine-disrupting compounds (EDCs) in surface water samples simultaneously. The target EDCs belong to five classes, including seven estrogens, eight androgens, six progesterones, five adrenocortical hormones and five industrial compounds. In order to simultaneously concentrate the target EDCs and eliminate matrix interferences in the water samples, MCX SPE cartridges were employed for SPE, and then followed by a simple and highly efficient three-step sequential elution procedure. Two electrospray ionization (ESI) detection modes, positive (ESI+) and (ESI-), were optimized for HPLC-MS/MS analysis to obtain the highest sensitivity for all the EDCs. The limits of detection (LODs) were 0.02-1.9 ng L(-1), which are lower than or comparable to these reported in references. Wide linear ranges (LOD-100 ng L(-1) for ESI+ mode, and LOD-200 ng L(-1) for ESI- mode) were obtained with determination coefficients (R(2)) higher than 0.99 for all the compounds. With five internal standards, good recoveries (84.4-103.0%) of all the target compounds were obtained in selected surface water samples. The developed method was successfully applied to investigate the EDCs occurrence in the surface water of Shanghai by analyzing surface water samples from 11 sites. The results showed that nearly all the target compounds (30 in 31) were present in the surface water samples of Shanghai, of which three industrial compounds (4-t-OP, BPA, and BPF) showed the highest concentrations (median concentrations were 11.88-23.50 ng L(-1)), suggesting that industrial compounds were the dominating EDCs in the surface water of Shanghai, and much more attention should be paid on these compounds. Our present research demonstrated that SPE with MCX cartridges combined with HPLC-MS/MS was convenient

  5. Analysis of intracellular and extracellular microcystin variants in sediments and pore waters by accelerated solvent extraction and high performance liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Zastepa, Arthur; Pick, Frances R.; Blais, Jules M.; Saleem, Ammar

    2015-01-01

    Highlights: • First analytical method for intracellular microcystins (MCs) in sediment. • Includes a suite of variants (LR, 7dm LR, RR, YR, WR, LA, LF, LY, LW) and nodularin. • Reports the first measurements of MCs in sediment pore waters. • MCs detected in >100 year old lake sediments suggesting long-term preservation. • Sediment-pore water distribution (K d ) differed between variants suggesting differences in environmental fate. - Abstract: The fate and persistence of microcystin cyanotoxins in aquatic ecosystems remains poorly understood in part due to the lack of analytical methods for microcystins in sediments. Existing methods have been limited to the extraction of a few extracellular microcystins of similar chemistry. We developed a single analytical method, consisting of accelerated solvent extraction, hydrophilic–lipophilic balance solid phase extraction, and reversed phase high performance liquid chromatography-tandem mass spectrometry, suitable for the extraction and quantitation of both intracellular and extracellular cyanotoxins in sediments as well as pore waters. Recoveries of nine microcystins, representing the chemical diversity of microcystins, and nodularin (a marine analogue) ranged between 75 and 98% with one, microcystin-RR (MC-RR), at 50%. Chromatographic separation of these analytes was achieved within 7.5 min and the method detection limits were between 1.1 and 2.5 ng g −1 dry weight (dw). The robustness of the method was demonstrated on sediment cores collected from seven Canadian lakes of diverse geography and trophic states. Individual microcystin variants reached a maximum concentration of 829 ng g −1 dw on sediment particles and 132 ng mL −1 in pore waters and could be detected in sediments as deep as 41 cm (>100 years in age). MC-LR, -RR, and -LA were more often detected while MC-YR, -LY, -LF, and -LW were less common. The analytical method enabled us to estimate sediment-pore water distribution coefficients (K d

  6. Analysis of intracellular and extracellular microcystin variants in sediments and pore waters by accelerated solvent extraction and high performance liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zastepa, Arthur, E-mail: arthur.zastepa@gmail.com; Pick, Frances R.; Blais, Jules M.; Saleem, Ammar

    2015-05-04

    Highlights: • First analytical method for intracellular microcystins (MCs) in sediment. • Includes a suite of variants (LR, {sup 7dm}LR, RR, YR, WR, LA, LF, LY, LW) and nodularin. • Reports the first measurements of MCs in sediment pore waters. • MCs detected in >100 year old lake sediments suggesting long-term preservation. • Sediment-pore water distribution (K{sub d}) differed between variants suggesting differences in environmental fate. - Abstract: The fate and persistence of microcystin cyanotoxins in aquatic ecosystems remains poorly understood in part due to the lack of analytical methods for microcystins in sediments. Existing methods have been limited to the extraction of a few extracellular microcystins of similar chemistry. We developed a single analytical method, consisting of accelerated solvent extraction, hydrophilic–lipophilic balance solid phase extraction, and reversed phase high performance liquid chromatography-tandem mass spectrometry, suitable for the extraction and quantitation of both intracellular and extracellular cyanotoxins in sediments as well as pore waters. Recoveries of nine microcystins, representing the chemical diversity of microcystins, and nodularin (a marine analogue) ranged between 75 and 98% with one, microcystin-RR (MC-RR), at 50%. Chromatographic separation of these analytes was achieved within 7.5 min and the method detection limits were between 1.1 and 2.5 ng g{sup −1} dry weight (dw). The robustness of the method was demonstrated on sediment cores collected from seven Canadian lakes of diverse geography and trophic states. Individual microcystin variants reached a maximum concentration of 829 ng g{sup −1} dw on sediment particles and 132 ng mL{sup −1} in pore waters and could be detected in sediments as deep as 41 cm (>100 years in age). MC-LR, -RR, and -LA were more often detected while MC-YR, -LY, -LF, and -LW were less common. The analytical method enabled us to estimate sediment-pore water

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

    Science.gov (United States)

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

    2018-04-06

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

  8. Simultaneous measurement of thirteen steroid hormones in women with polycystic ovary syndrome and control women using liquid chromatography-tandem mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Candace C Keefe

    Full Text Available BACKGROUND: The measurement of adrenal and ovarian androgens in women with PCOS has been difficult based on poor specificity and sensitivity of assays in the female range. METHODS: Women with PCOS (NIH criteria; n = 52 and control subjects with 25-35 day menstrual cycles, no evidence of hyperandrogenism and matched for BMI (n = 42 underwent morning blood sampling. Liquid chromatography-tandem mass spectrometry (LC-MS/MS was used to simultaneously measure 13 steroids from a single blood sample to measure adrenal and ovarian steroids. Androgen and progesterone results were compared in the same samples using RIA. RESULTS: Testosterone, androstenedione, progesterone and 17OH progesterone levels were higher when measured using RIA compared to LC-MS/MS, although the testosterone RIA demonstrated the best agreement with the LC-MS/MS using a Bland-Altman analysis. Results using LC-MS/MS demonstrated that the concentration of androgens and their precursors were higher in women with PCOS than controls [median (2.5, 97.5th %ile; 1607 (638, 3085 vs. 1143 (511, 4784 ng/dL; p = 0.03]. Women with PCOS had higher testosterone [49 (16, 125 vs. 24 (10, 59 ng/dL], androstenedione [203 (98, 476 vs. 106 (69, 223 ng/dL] and 17OH progesterone levels [80 (17, 176 vs. 44 (17, 142 ng/dL] compared to controls (all P<0.02, but no differences in serum concentrations of the adrenal steroids DHEAS, cortisol, corticosterone and their 11 deoxy precursors. Women with PCOS also had an increase in the product:precursor ratio for 3β-hydroxysteroid dehydrogenase [22% (6, 92 vs. 20% (4, 43; p = 0.009]. CONCLUSION: LC-MS/MS was superior to RIA in measuring androstenedione, progesterone and 17OH progesterone levels, while testosterone measurements were better matched in the two assays. Androgen levels were higher in women with PCOS in the absence of a difference in adrenal-predominant steroids. These data support previous findings that the ovary is an important source

  9. Development and validation of an ultra-high performance liquid chromatography-tandem mass spectrometry method to measure creatinine in human urine.

    Science.gov (United States)

    Fraselle, S; De Cremer, K; Coucke, W; Glorieux, G; Vanmassenhove, J; Schepers, E; Neirynck, N; Van Overmeire, I; Van Loco, J; Van Biesen, W; Vanholder, R

    2015-04-15

    Despite decades of creatinine measurement in biological fluids using a large variety of analytical methods, an accurate determination of this compound remains challenging. Especially with the novel trend to assess biomarkers on large sample sets preserved in biobanks, a simple and fast method that could cope with both a high sample throughput and a low volume of sample is still of interest. In answer to these challenges, a fast and accurate ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to measure creatinine in small volumes of human urine. In this method, urine samples are simply diluted with a basic mobile phase and injected directly under positive electrospray ionization (ESI) conditions, without further purification steps. The combination of an important diluting factor (10(4) times) due to the use of a very sensitive triple quadrupole mass spectrometer (XEVO TQ) and the addition of creatinine-d3 as internal standard completely eliminates matrix effects coming from the urine. The method was validated in-house in 2012 according to the EMA guideline on bioanalytical method validation using Certified Reference samples from the German External Quality Assessment Scheme (G-Equas) proficiency test. All obtained results for accuracy and recovery are within the authorized tolerance ranges defined by G-Equas. The method is linear between 0 and 5 g/L, with LOD and LOQ of 5 × 10(-3) g/L and 10(-2) g/L, respectively. The repeatability (CV(r) = 1.03-2.07%) and intra-laboratory reproducibility (CV(RW) = 1.97-2.40%) satisfy the EMA 2012 guideline. The validated method was firstly applied to perform the German G-Equas proficiency test rounds 51 and 53, in 2013 and 2014, respectively. The obtained results were again all within the accepted tolerance ranges and very close to the reference values defined by the organizers of the proficiency test scheme, demonstrating an excellent accuracy of the developed method. The

  10. Development and validation of a liquid chromatography tandem mass spectrometry method for the determination of cannabinoids and phase I and II metabolites in meconium.

    Science.gov (United States)

    Prego-Meleiro, Pablo; Lendoiro, Elena; Concheiro, Marta; Cruz, Angelines; López-Rivadulla, Manuel; de Castro, Ana

    2017-05-12

    A liquid chromatography-tandem mass spectrometry (LC-MSMS) method was developed and fully validated for the determination of Δ 9 -tetrahydrocannabinol (THC), 11-hydroxyTHC (OHTHC), 11-nor-9-carboxyTHC (THCCOOH), 8-β-11-dihydroxyTHC (diOHTHC), cannabinol, cannabidiol, and THC and THCCOOH glucuronides in 0.25±0.02g meconium. Samples were homogenized in methanol and subjected to cation exchange solid-phase extraction. Chromatographic separation was performed on a Kinetex C18 column (50 mm×2.1mm, 2.6μm) at 35°C, with a gradient of 0.1% formic acid in water and acetonitrile at a flow rate of 0.3 mL/min; total run time was 10min. Two transitions per analyte were monitored in MRM mode. The method was specific and sensitive; LOD was from 1 to 2ng/g, and LOQ from 4 to 10ng/g; linearity ranged from 4 to 400 ng/g for all the analytes, except for THC glucuronide (10-400ng/g); intra-assay, inter-assay and total imprecision were <11.2%, <13.45% and <15.6%, respectively; accuracy ranged from 93.9% to 109.0% of the target concentration; matrix effect, extraction and process efficiency ranged from -26.4% to -71.4%, 49.9% to 69.5% and 14.3% to 45.0%, respectively. The inclusion of THC and THCCOOH glucuronides avoided the need for the hydrolysis process, thus facilitating sample pretreatment. Application of the method to 19 authentic meconium specimens from uncontrolled pregnancies or women suspicious of drug consumption revealed fetal cannabis exposure in 4 newborns. THCCOOH (24.1-288.8ng/g), diOHTHC (53.2-332.4ng/g), THC (4.2-7.7ng/g), CBN (30.7-93.3ng/g) and CBD (7.1-251.5ng/g) were detected in all cases; THCCOOH glucuronide (190.2-306.8ng/g) in 3 cases; and OHTHC (11.9ng/g) in the remaining one; however, THC glucuronide was not identified in any specimen. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2017-04-01

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

  12. Evaluation of cannabinoids concentration and stability in standardized preparations of cannabis tea and cannabis oil by ultra-high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Pacifici, Roberta; Marchei, Emilia; Salvatore, Francesco; Guandalini, Luca; Busardò, Francesco Paolo; Pichini, Simona

    2017-08-28

    Cannabis has been used since ancient times to relieve neuropathic pain, to lower intraocular pressure, to increase appetite and finally to decrease nausea and vomiting. The combination of the psychoactive cannabis alkaloid Δ9-tetrahydrocannabinol (THC) with the non-psychotropic alkaloids cannabidiol (CBD) and cannabinol (CBN) demonstrated a higher activity than THC alone. The Italian National Institute of Health sought to establish conditions and indications on how to correctly use nationally produced cannabis to guarantee therapeutic continuity in individuals treated with medical cannabis. The evaluation of cannabinoids concentration and stability in standardized preparations of cannabis tea and cannabis oil was conducted using an easy and fast ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) assay. Extraction efficiency of oil was significantly higher than that of water with respect to the different cannabinoids. This was especially observed in the case of the pharmacologically active THC, CBD and their acidic precursors. Fifteen minutes boiling was sufficient to achieve the highest concentrations of cannabinoids in the cannabis tea solutions. At ambient temperature, a significant THC and CBD decrease to 50% or less of the initial concentration was observed over 3 and 7 days, respectively. When refrigerated at 4 °C, similar decreasing profiles were observed for the two compounds. The cannabinoids profile in cannabis oil obtained after pre-heating the flowering tops at 145 °C for 30 min in a static oven resulted in a complete decarboxylation of cannabinoid acids CBDA and THCA-A. Nevertheless, it was apparent that heat not only decarboxylated acidic compounds, but also significantly increased the final concentrations of cannabinoids in oil. The stability of cannabinoids in oil samples was higher than that in tea samples since the maximum decrease (72% of initial concentration) was observed in THC coming from unheated flowering

  13. Correlation between Serum Levels of 3,3',5'-Triiodothyronine and Thyroid Hormones Measured by Liquid Chromatography-Tandem Mass Spectrometry and Immunoassay.

    Science.gov (United States)

    Sakai, Hiroyuki; Nagao, Hidenori; Sakurai, Mamoru; Okumura, Takako; Nagai, Yoshiyuki; Shikuma, Junpei; Ito, Rokuro; Imazu, Tetsuya; Miwa, Takashi; Odawara, Masato

    2015-01-01

    For measuring serum 3,3',5'-triiodothyronine (rT3) levels, radioimmunoassay (RIA) has traditionally been used owing to the lack of other reliable methods; however, it has recently become difficult to perform. Meanwhile, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has recently been attracting attention as a novel alternative method in clinical chemistry. To the best of our knowledge, there are no studies to date comparing results of the quantification of human serum rT3 between LC-MS/MS and RIA. We therefore examined the feasibility of LC-MS/MS as a novel alternative method for measuring serum rT3, thyroxine (T4), and 3,5,3'-triiodothyronine (T3) levels. Assay validation was performed by LC-MS/MS using quality control samples of rT3, T4, and T3 at 4 various concentrations which were prepared from reference compounds. Serum samples of 50 outpatients in our department were quantified both by LC-MS/MS and conventional immunoassay for rT3, T4, and T3. Correlation coefficients between the 2 measurement methods were statistically analyzed respectively. Matrix effects were not observed with our method. Intra-day and inter-day precisions were less than 10.8% and 9.6% for each analyte at each quality control level, respectively. Intra-day and inter-day accuracies were between 96.2% and 110%, and between 98.3% and 108.6%, respectively. The lower limit of quantification was 0.05 ng/mL. Strong correlations were observed between the 2 measurement methods (correlation coefficient, T4: 0.976, p < 0.001; T3: 0.912, p < 0.001; rT3: 0.928, p < 0.001). Our LC-MS/MS system requires no manual cleanup operation, and the process after application of a sample is fully automated; furthermore, it was found to be highly sensitive, and superior in both precision and accuracy. The correlation between the 2 methods over a wide range of concentrations was strong. LC-MS/MS is therefore expected to become a useful tool for clinical diagnosis and research.

  14. Correlation between Serum Levels of 3,3',5'-Triiodothyronine and Thyroid Hormones Measured by Liquid Chromatography-Tandem Mass Spectrometry and Immunoassay.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Sakai

    Full Text Available For measuring serum 3,3',5'-triiodothyronine (rT3 levels, radioimmunoassay (RIA has traditionally been used owing to the lack of other reliable methods; however, it has recently become difficult to perform. Meanwhile, liquid chromatography-tandem mass spectrometry (LC-MS/MS has recently been attracting attention as a novel alternative method in clinical chemistry. To the best of our knowledge, there are no studies to date comparing results of the quantification of human serum rT3 between LC-MS/MS and RIA. We therefore examined the feasibility of LC-MS/MS as a novel alternative method for measuring serum rT3, thyroxine (T4, and 3,5,3'-triiodothyronine (T3 levels.Assay validation was performed by LC-MS/MS using quality control samples of rT3, T4, and T3 at 4 various concentrations which were prepared from reference compounds. Serum samples of 50 outpatients in our department were quantified both by LC-MS/MS and conventional immunoassay for rT3, T4, and T3. Correlation coefficients between the 2 measurement methods were statistically analyzed respectively.Matrix effects were not observed with our method. Intra-day and inter-day precisions were less than 10.8% and 9.6% for each analyte at each quality control level, respectively. Intra-day and inter-day accuracies were between 96.2% and 110%, and between 98.3% and 108.6%, respectively. The lower limit of quantification was 0.05 ng/mL. Strong correlations were observed between the 2 measurement methods (correlation coefficient, T4: 0.976, p < 0.001; T3: 0.912, p < 0.001; rT3: 0.928, p < 0.001.Our LC-MS/MS system requires no manual cleanup operation, and the process after application of a sample is fully automated; furthermore, it was found to be highly sensitive, and superior in both precision and accuracy. The correlation between the 2 methods over a wide range of concentrations was strong. LC-MS/MS is therefore expected to become a useful tool for clinical diagnosis and research.

  15. Isotope dilution liquid chromatography-tandem mass spectrometry for simultaneous identification and quantification of beta-casomorphin 5 and beta-casomorphin 7 in yoghurt.

    Science.gov (United States)

    Nguyen, D D; Solah, V A; Johnson, S K; Charrois, J W A; Busetti, F

    2014-03-01

    A highly selective and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous identification and quantification of beta-casomorphin 5 (BCM5) and beta-casomorphin 7 (BCM7) in yoghurt. The method used deuterium labelled BCM5-d10 and BCM7-d10 as surrogate standards for confident identification and accurate and quantification of these analytes in yoghurt. Linear responses for BCM5 and BCM7 (R(2)=0.9985 and 0.9986, respectively) was observed in the range 0.01-10ng/μL. The method limits of detection (MLDs) in yoghurt extracts were found to be 0.5 and 0.25ng/g for BCM5 and BCM7, respectively. Analyses of spiked samples were used to provide confirmation of accuracy and precision of the analytical method. Recoveries relative to the surrogate standards of these spikes were in the range of 95-106% for BCM5 and 103-109% for BCM7. Precision from analysis of spiked samples was expressed as relative standard deviation (%RSD) and values were in the range 1-16% for BCM5 and 1-6% for BCM7. Inter-day reproducibility was between 2.0-6.4% for BCM5 and between 3.2-6.1% for BCM7. The validated isotope dilution LC-MS/MS method was used to measure BCM5 and BCM7 in ten commercial and laboratory prepared samples of yoghurt and milk. Neither BCM5 nor BCM7 was detected in commercial yoghurts. However, they were observed in milk and laboratory prepared yoghurts and interestingly their levels decreased during processing. BCM5 decreased from 1.3ng/g in milk to 1.1ng/g in yoghurt made from that milk at 0day storage and

  16. Sensitive measurement of serum 1α,25-dihydroxyvitamin D by liquid chromatography/tandem mass spectrometry after removing interference with immunoaffinity extraction.

    Science.gov (United States)

    Yuan, Chao; Kosewick, Justin; He, Xiang; Kozak, Marta; Wang, Sihe

    2011-05-15

    Vitamin D plays important roles in bone health and a variety of other pathophysiological conditions. 1α,25-Dihydroxyvitamin D is the active form of vitamin D. Quantification of serum 1α,25-dihydroxyvitamin D is useful for evaluation of several diseases including chronic renal failure, hypoparathyroidism, sarcoidosis, and rickets. Measurement of 1α,25-dihydroxyvitamin D is very challenging due to its low circulating concentration and presence of interfering substances in serum. In this report, a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for quantifying serum 1α,25-dihydroxyvitamin D is described. Lithium adducts of 1α,25-dihydroxyvitamin D were formed prior to mass spectrometry analysis to improve ionization efficiency. We tested a number of different sample preparation procedures and found that immunoaffinity extraction was the method of choice because it completely removed isobaric interferences and matrix effects present in patient serum. Extraction efficiency, expressed as absolute recovery, was greater than 60% in both patient serum and charcoal-stripped serum. This method was linear from 3.4 to 206.2 pg/mL for 1α,25-dihydroxyvitamin D(3) and 3.9 to 212.6 pg/mL for 1α,25-dihydroxyvitamin D(2) with an accuracy of 89.8-98.4% and 97.5-115.7%, respectively. Inter-assay and intra-assay coefficients of variance (CVs) for both analytes at two different concentration levels ranged from 2.5-7.0%. Comparison with a radioimmunoassay for measuring total 1α,25-dihydroxyvitamin D concentration using 40 patient samples showed a Deming regression slope of 0.751, a y-intercept of 0.84 pg/mL, an r value of 0.7909, and a mean percentage difference of -27.1%. Comparison with a reference LC/MS/MS method (n = 20) showed a Deming regression slope of 1.020, a y-intercept of 1.32 pg/mL, an r value of 0.9797, and a mean percentage difference of -2.9%. In conclusion, usage of immunoaffinity extraction enabled a sensitive LC/MS/MS method for

  17. Analysis of intracellular and extracellular microcystin variants in sediments and pore waters by accelerated solvent extraction and high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Zastepa, Arthur; Pick, Frances R; Blais, Jules M; Saleem, Ammar

    2015-05-04

    The fate and persistence of microcystin cyanotoxins in aquatic ecosystems remains poorly understood in part due to the lack of analytical methods for microcystins in sediments. Existing methods have been limited to the extraction of a few extracellular microcystins of similar chemistry. We developed a single analytical method, consisting of accelerated solvent extraction, hydrophilic-lipophilic balance solid phase extraction, and reversed phase high performance liquid chromatography-tandem mass spectrometry, suitable for the extraction and quantitation of both intracellular and extracellular cyanotoxins in sediments as well as pore waters. Recoveries of nine microcystins, representing the chemical diversity of microcystins, and nodularin (a marine analogue) ranged between 75 and 98% with one, microcystin-RR (MC-RR), at 50%. Chromatographic separation of these analytes was achieved within 7.5 min and the method detection limits were between 1.1 and 2.5 ng g(-1) dry weight (dw). The robustness of the method was demonstrated on sediment cores collected from seven Canadian lakes of diverse geography and trophic states. Individual microcystin variants reached a maximum concentration of 829 ng g(-1) dw on sediment particles and 132 ng mL(-1) in pore waters and could be detected in sediments as deep as 41 cm (>100 years in age). MC-LR, -RR, and -LA were more often detected while MC-YR, -LY, -LF, and -LW were less common. The analytical method enabled us to estimate sediment-pore water distribution coefficients (K(d)), MC-RR had the highest affinity for sediment particles (log K(d)=1.3) while MC-LA had the lowest affinity (log K(d)=-0.4), partitioning mainly into pore waters. Our findings confirm that sediments serve as a reservoir for microcystins but suggest that some variants may diffuse into overlying water thereby constituting a new route of exposure following the dissipation of toxic blooms. The method is well suited to determine the fate and persistence of different

  18. Differential extraction of endogenous and exogenous 25-OH-vitamin D from serum makes the accurate quantification in liquid chromatography-tandem mass spectrometry assays challenging.

    Science.gov (United States)

    Lankes, Ulrich; Elder, Peter A; Lewis, John G; George, Peter

    2015-01-01

    Extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis is the method of choice when it comes to the accurate quantification of 25-OH-vitamin D in blood samples. It is generally assumed that the addition of exogenous internal standard allows for the determination of the endogenous analyte concentration. In this study we investigated the extraction properties of endogenous and exogenous 25-OH-vitamin D. Eight samples were used for the evaluation of the extraction procedure and 59 patients' samples for a method comparison. The methanol-to-sample ratio (v/v) and the sample-to-hexane ratio (v/v) were varied and the LC-MS/MS signals of endogenous 25-OH-vitamin D3, spiked 25-OH-vitamin D2 and internal standard of the extracts recorded. The optimized 'in-house' LC-MS/MS assay was compared to two automated chemiluminescence immunoassays from DiaSorin and Abbott. Mathematical analysis of the data revealed a differential extraction of endogenous 25-OH-vitamin D3, spiked 25-OH-vitamin D2 and non-equilibrated internal standard. Exogenous 25-OH-vitamin D can be measured accurately if a definite methanol-to-sample ratio is used. Endogenous 25-OH-vitamin D is affected by critical quantification issues due to a differential slope in the extraction profile. The actual 25-OH-vitamin D concentration can be one-third above the measured extractable concentration. Results confirm that the 'in-house' LC-MS/MS assay provides reproducible 25-OH-vitamin D results. Discordant concentrations of 25-OH-vitamin D from LC-MS/MS assays can be caused by selection of suboptimal extraction conditions. Furthermore, a different sample pretreatment or solvent extraction system may result in a different dissociation and extraction yield of endogenous 25-OH-vitamin D and therefore contribute to variations of LC-MS/MS results. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  19. Determination of fluorotelomer alcohols and their degradation products in biosolids-amended soils and plants using ultra-high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zhang, Hongna; Wen, Bei; Hu, Xiaoyu; Wu, Yali; Luo, Lei; Chen, Zien; Zhang, Shuzhen

    2015-07-24

    Degradation of fluorotelomer alcohols (FTOHs) was recognized as an additional source of perfluorocarboxylic acids (PFCAs). Quantification of FTOHs and their degradation products can help shed light on the sources and fates of PFCAs in the environment. In this study, an analytical method was developed for the determination of 6:2 and 8:2 FTOHs, and their degradation products of poly- and perfluorinated acids, including fluorotelomer saturated and unsaturated carboxylic acids (FTCAs and FTUCAs), secondary polyfluorinated alcohols and PFCAs in biosolids-amended soils and plants using ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The extract efficiencies of different methods including ethyl acetate and methanol (MeOH) for FTOHs and acetonitrile, MeOH, methyl tert-butyl ether (MTBE), NaOH-MeOH and NaOH-MTBE for poly- and perfluorinated acids were tested. The results showed that 6:2 and 8:2 FTOHs and their degradation products could be simultaneously and satisfactorily extracted by MeOH, cleaned up by Envi-Carb graphitized carbon and solid phase extraction, respectively, and determined by UPLC-MS/MS separately. NaOH in the extractant caused the conversion of 6:2 FTCA and 8:2 FTCA into the corresponding FTUCAs. The selected methods have matrix recoveries ranged from 52% to 102%, and detection limits of 0.01-0.46ng/g dry weight for FTOHs and their degradation products in soil and plant. The optimized method was applied successfully to quantify FTOHs and their degradation products in two biosolids-amended soils and plants. The total concentrations of FTOHs in the soils were 44.1±5.8 and 82.6±7.1ng/g, and in plants tissues 3.58±0.25 and 8.33±0.66ng/g. The total concentrations of poly- and perfluorinated acids in the soils were 168.0±13.2 and 349.6±11.2ng/g, and in plants tissues 78.0±6.4 and 75.5±5.3ng/g. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Quantification of the enzyme activities of iduronate-2-sulfatase, N-acetylgalactosamine-6-sulfatase and N-acetylgalactosamine-4-sulfatase using liquid chromatography-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Ryuichi Mashima

    2018-03-01

    Full Text Available Mucopolysaccharidosis (MPS is a genetic disorder characterized by the accumulation of glycosaminoglycans in the body. Of the multiple MPS disease subtypes, several are caused by defects in sulfatases. Specifically, a defect in iduronate-2-sulfatase (ID2S leads to MPS II, whereas N-acetylgalactosamine-6-sulfatase (GALN and N-acetylgalactosamine-4-sulfatase (ARSB defects relate to MPS IVA and MPS VI, respectively. A previous study reported a combined assay for these three disorders in a 96-well plate using a liquid chromatography-tandem mass spectrometry (LC-MS/MS-based technique (Kumar et al., Clin Chem 2015 61(11:1363-1371. In our study, we applied this methodology to a Japanese population to examine the assay precision and the separation of populations between disease-affected individuals and controls for these three disorders. Within our assay conditions, the coefficient of variation (CV, % values for an interday assay of ID2S, GALN, and ARSB were 9%, 18%, and 9%, respectively (n = 7. The average enzyme activities of ID2S, GALN, and ARSB in random neonates were 19.6 ± 5.8, 1.7 ± 0.7, and 13.4 ± 5.2 μmol/h/L (mean ± SD, n = 240, respectively. In contrast, the average enzyme activities of ID2S, GALN, and ARSB in disease-affected individuals were 0.5 ± 0.2 (n = 6, 0.3 ± 0.1 (n = 3, and 0.3 (n = 1 μmol/h/L, respectively. The representative analytical range values corresponding to ID2S, GALN, and ARSB were 39, 17, and 168, respectively. These results raise the possibility that the population of disease-affected individuals could be separated from that of healthy individuals using the LC-MS/MS-based technique.

  1. Ultra-high-performance liquid chromatography tandem mass spectrometry determination of GHB, GHB-glucuronide in plasma and cerebrospinal fluid of narcoleptic patients under sodium oxybate treatment.

    Science.gov (United States)

    Tittarelli, Roberta; Pichini, Simona; Pedersen, Daniel S; Pacifici, Roberta; Moresco, Monica; Pizza, Fabio; Busardò, Francesco Paolo; Plazzi, Giuseppe

    2017-05-01

    Sodium oxybate (Xyrem ® ), the sodium salt of γ- hydroxybutyric acid (GHB), is a first-line treatment of the symptoms induced by type 1 narcolepsy (NT1) and it is highly effective in improving sleep architecture, decreasing excessive daytime sleepiness and the frequency of cataplexy attacks. Using an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) validated method, GHB was determined together with its glucuronide (GHB-gluc), in plasma and cerebrospinal fluid (CSF) samples of NT1 patients under sodium oxybate treatment. To characterize the plasma pharmacokinetics of GHB, three subjects with NT1 were administered at time 0 and 4h with 1.25, 1.5 and 3.55g Xyrem ® , respectively and had their blood samples collected at 7 time points throughout an 8-h session. CSF specimens, collected for orexin A measurement from the same three subjects 6h after their second administration, were also tested. The results obtained suggested that GHB plasma values increased disproportionally with the rising doses, (C max0-4 : 12.53, 32.95 and 69.62μg/mL; C max4-8 : 44.93, 75.03 and 111.93μg/mL for total Xyrem ® dose of 2.5, 3 and 7g respectively) indicating non-linear dose-response. GHB-Gluc was present only in traces in all plasma samples from treated patients, not changing with increasing Xyrem ® doses. GHB values of 5.62, 6.10 and 17.74μg/mL for 2, 3 and 7g Xyrem ® were found in CSF with a significant difference from control values. GHB-Gluc was found in negligible concentrations with no differences to those of control individuals. In conclusion this simple and fast UHPLC-MS/MS method proved useful for pharmacokinetic studies and therapeutic drug monitoring of GHB in narcoleptic patients treated with sodium oxybate. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. High-performance liquid chromatography-tandem mass spectrometry as a reference for analysis of tacrolimus to assess two immunoassays in patients with liver and renal transplants.

    Science.gov (United States)

    Salm, P; Taylor, P J; Clark, A; Balderson, G A; Grygotis, A; Norris, R L; Lynch, S V; Shaw, L M; Pond, S M

    1997-12-01

    The accuracy and imprecision of three assays used for therapeutic monitoring of tacrolimus were tested using blood-containing weighed-in amounts of the drug, an enzyme-linked immunosorbent assay (ELISA), a microparticle enzyme immunoassay (MEIA I), and a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS2) assay. Accuracy was acceptable for the HPLC-MS2 assay at all concentrations tested (ELISA at 1.0 and 4.0 microg/l. Accuracy was not acceptable for the ELISA at 15.0 and 50.0 microg/l or for the MEIA I at all concentrations tested. Imprecision was acceptable for the HPLC-MS2 assay at all concentrations tested (coefficient of variation ELISA at 15.0 and 50.0 microg/l, and for the MEIA I at 15.0 and 50.0 microg/l. Imprecision was not acceptable for the ELISA at 1.0 and 4.0 microg/l or for the MEIA I at 1.0 and 4.0 microg/l. This assessment with weighed-in amounts of tacrolimus verified the HPLC-MS2 assay as a reference method. The performance of the two immunoassays with HPLC-MS2 was then compared in the clinical setting using blood from patients with liver (n = 30) and renal (n = 37) transplants. In the liver transplant group (127 samples), the range of tacrolimus concentrations measured by HPLC-MS2, ELISA, and MEIA I was 1.9 to 31.8, 2.1 to 35.0, and less than 0.1 to 36.5 mg/l, respectively. In the renal transplant group (129 samples), the ranges were 1.7 to 26.1, 1.9 to 24.4, and 0.9 to 28.5 microg/l, respectively. Compared with the HPLC-MS2, the ELISA had minimal bias (0.1 to 0.2 microg/l) but unacceptable variability in values (SD > 13%). The MEIA I had unacceptable bias (1.7-1.8 microg/l) and variability (SD > 23%). These data indicated that neither the ELISA nor MEIA I is interchangeable with HPLC-MS2. Moreover, in view of the current trend to reduce the therapeutic dose of tacrolimus, quantitative results using the MEIA I would not be obtainable during therapeutic drug monitoring in some patients in whom effective therapeutic

  3. Analytical and clinical performance of the new Fujirebio 25-OH vitamin D assay, a comparison with liquid chromatography-tandem mass spectrometry (LC-MS/MS) and three other automated assays

    OpenAIRE

    Saleh, Lanja; Mueller, Daniel; von Eckardstein, Arnold

    2015-01-01

    BACKGROUND: We evaluated the analytical and clinical performance of the new Lumipulse® G 25-OH vitamin D assay from Fujirebio, and compared it to a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and three other commercial automated assays. METHODS: Total 25 hydroxy vitamin D (25(OH)D) levels were measured in 100 selected serum samples from our routine analysis with Fujirebio 25(OH)D assay. The results were compared with those obtained with LC-MS/MS and three other automat...

  4. Method Optimization for Rapid Measurement of Carbohydrates in Plasma by Liquid Chromatography Tandem Mass Spectrometry

    International Nuclear Information System (INIS)

    Nguyen, Ductoan; Yu, Jondong; Mho, Sunil; Lee, Gwang; Lee, Haelee; Paik, Manjeong; Yee, Sungtae

    2013-01-01

    In conclusion, the developed HPLC coupled with ESI-MS was a powerful technique for the separation and characterization of carbohydrates by either SIM or MRM mode. The present method will be useful for the monitoring of carbohydrate profile in biological fluids from various diseases including diabetic ketoacidosis, hypoglycemia and hyperosmolar coma. Carbohydrates are one of the most abundant classes of organic compounds in nature, which not only constitute complex biomolecules in human and animals but are also distributed in plants and bacteria

  5. A new combined method of stable isotope-labeling derivatization-ultrasound-assisted dispersive liquid-liquid microextraction for the determination of neurotransmitters in rat brain microdialysates by ultra high performance liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Zheng, Longfang; Zhao, Xian-En; Zhu, Shuyun; Tao, Yanduo; Ji, Wenhua; Geng, Yanling; Wang, Xiao; Chen, Guang; You, Jinmao

    2017-06-01

    In this work, for the first time, a new hyphenated technique of stable isotope-labeling derivatization-ultrasound-assisted dispersive liquid-liquid microextraction has been developed for the simultaneous determination of monoamine neurotransmitters (MANTs) and their biosynthesis precursors and metabolites. The developed method was based on ultra high performance liquid chromatography tandem mass spectrometry detection using multiple-reaction monitoring mode. A pair of mass spectrometry sensitizing reagents, d 0 -10-methyl-acridone-2-sulfonyl chloride and d 3 -10-methyl-acridone-2-sulfonyl chloride, as stable isotope probes was utilized to facilely label neurotransmitters, respectively. The heavy labeled MANTs standards were prepared and used as internal standards for quantification to minimize the matrix effects in mass spectrometry analysis. Low toxic bromobenzene (extractant) and acetonitrile (dispersant) were utilized in microextraction procedure. Under the optimized conditions, good linearity was observed with the limits of detection (S/N>3) and limits of quantification (S/N>10) in the range of 0.002-0.010 and 0.015-0.040nmol/L, respectively. Meanwhile, it also brought acceptable precision (4.2-8.8%, peak area RSDs %) and accuracy (recovery, 96.9-104.1%) results. This method was successfully applied to the simultaneous determination of monoamine neurotransmitters and their biosynthesis precursors and metabolites in rat brain microdialysates of Parkinson's disease and normal rats. This provided a new method for the neurotransmitters related studies in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Development of a high performance liquid chromatography method and a liquid chromatography-tandem mass spectrometry method with pressurized liquid extraction for simultaneous quantification and confirmation of cyromazine, melamine and its metabolites in foods of animal origin

    International Nuclear Information System (INIS)

    Yu Huan; Tao Yanfei; Chen Dongmei; Wang Yulian; Liu Zhaoying; Pan Yuanhu; Huang Lingli; Peng Dapeng; Dai Menghong; Liu Zhenli; Yuan Zonghui

    2010-01-01

    Simple and sensitive methods have been developed for simultaneous detection of cyromazine, melamine and their metabolites (ammeline, ammelide and cyanuric acid) in samples of animal origins. These include a high performance liquid chromatography (HPLC) method and a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and are useful in regular monitoring and in toxicity studies of these molecules. Representative samples used in this study include muscles and livers of swine, bovine, sheep and chicken, kidneys of swine, bovine and sheep, and milk powder. A new sample preparation procedure with pressurized liquid extraction (PLE) at 1400 psi and 70 deg. C was investigated. Quantification of these five compounds by HPLC was achieved using an APS-2 column with UV detection at 230 nm. Limit of detection (LOD) was at 10 μg kg -1 , and limit of quantification (LOQ) was at 40 μg kg -1 . Recoveries of the five analytes in spiked samples ranged from 72.2% to 115.4% with RSD less than 12%. Confirmatory analysis of the analytes was performed using LC-MS/MS in selected reaction monitoring (SRM) mode. The LOD and LOQ were 5 μg kg -1 and 15 μg kg -1 , respectively. This is the first simultaneous analysis of cyromazine, melamine, ammeline, ammelide and cyanuric acid residues in complex tissue samples using PLE and HPLC. It is expected that these methods will find many practical applications in evaluating the safety of cyromazine, melamine and their metabolites.

  7. Trace determination of organophosphate esters in white wine, red wine, and beer samples using dispersive liquid-liquid microextraction combined with ultra-high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Pang, Long; Yang, Huiqiang; Yang, Peijie; Zhang, Hongzhong; Zhao, Jihong

    2017-08-15

    In this study, dispersive liquid-liquid microextraction coupled with ultra-high-performance liquid chromatography-tandem mass spectrometry was developed for the analysis of five representative organophosphate esters (OPEs) in wine samples. Under optimized conditions, the proposed method resulted in good linearity (R 2 >0.9933) over the range of 0.1-100μgL -1 , with limits of detection (LODs, S/N =3) and quantification (LOQs, S/N =10) in the ranges of 0.48-18.8ngL -1 and 1.58-62.5ngL -1 , respectively. Inter- and intra-assay precisions of RSD% ranged from 3.21% to 6.13% and from 1.69% to 7.63%, respectively. The spiked recoveries of target OPEs from white wine, red wine, and beer samples were in the ranges of 80-122%, 76-120%, and 76-110%, respectively, at two different concentration levels. The total concentrations of five OPEs found in white wine, red wine, and beer samples were in the ranges of 0.29-0.85μgL -1 , 1.00-3.05μgL -1 , and 0.86-1.47μgL -1 , respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. An evaporation-assisted dispersive liquid-liquid microextraction technique as a simple tool for high performance liquid chromatography tandem-mass spectrometry determination of insecticides in wine.

    Science.gov (United States)

    Timofeeva, Irina; Kanashina, Daria; Moskvin, Leonid; Bulatov, Andrey

    2017-08-25

    A sample pre-treatment technique based on evaporation-assisted dispersive liquid-liquid microextraction (EVA-DLLME), followed by HPLC-MS/MS has been developed for the determination of organophosphate insecticides (malathion, diazinon, phosalone) in wine samples. The procedure includes the addition of mixture of organic solvents (with density higher than water), consisting of the extraction (low density) and volatile (high density) solvents, to aqueous sample followed by heating of the mixture obtained, what promotes the volatile solvent evaporation and moving extraction solvent droplets from down to top of the aqueous sample and, as a consequence, microextraction of target analytes. To initiate the evaporation process an initiator is required. It was established that hexanol (extraction solvent) and dichloromethane (volatile solvent) mixture (1:1, v/v) provides effective microextraction of the insecticides from wine samples with recovery from 92 to 103%. The conditions of insecticides' microextraction such as selection of extraction solvent, ratio of hexanol/dichloromethane and hexanol/sample, type and concentration of initiator, and effect of ethanol as one of the main components of wine have been studied. Under optimal experimental conditions the linear detection ranges were found to be 10 -7 -10 -3 gL -1 for malathion, 10 -9 -10 -4 gL -1 for diazinon, and 10 -6 -10 -2 gL -1 for phosalone. The LODs, calculated from a blank test, based on 3σ, found to be 3×10 -8 gL -1 for malathion, 3×10 -10 gL -1 for diazinon and 3×10 -7 gL -1 for phosalone. The advantages of EVA-DLLME are the rapidity, simplicity, high sample throughput and low cost. As an outcome, the analytical results agreed fairly well with the results obtained by a reference GC-MS method. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Analysis of Sheng-Mai-San, a Ginseng-Containing Multiple Components Traditional Chinese Herbal Medicine Using Liquid Chromatography Tandem Mass Spectrometry and Physical Examination by Electron and Light Microscopies

    Directory of Open Access Journals (Sweden)

    Yung-Yi Cheng

    2016-09-01

    Full Text Available Sheng-Mai-San is a multi-component traditional Chinese herbal preparation. Due to the fact granulated additives, such as starch, carboxymethyl cellulose, lactose and raw herbal powder may alter the content of the bioactive markers in the herbal products, a developed ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS method was used to measure the herbal biomarkers of ginsenoside Rb1, Rb2, Rc, Rd, Re, Rg1, Rh1, compound K, ophiopogonin D and schizandrin from the Sheng-Mai-San herbal formulation. Besides, scanning electron microscopy (SEM was used to observe the morphology of the herbal granular powders. Light microscopy with Congo red and iodine-KI reagent staining was used to identify the cellulose fiber and cornstarch added to pharmaceutical herbal products. The swelling power (SP, water solubility index (WSI, and crude fiber analysis were used to determine the contents of cellulose fiber and cornstarch in pharmaceutical herbal products. In this study, we developed a novel skill to assess the quantification of appended cornstarch in pharmaceutical herbal products using Aperio ImageScope software. Compared with the traditional cornstarch analysis, our analysis method is a rapid, simple and conversion process which could be applied to detect the percentage of added cornstarch in unknown powder products. The various range of the herbal content for the five pharmaceutical manufacturers varied by up to several hundreds-fold. The physical examination reveals that the morphology of the herbal pharmaceutical products is rough and irregular with sharp layers. This study provides a reference standard operating procedure guide for the quality control of the Chinese herbal pharmaceutical products of Sheng-Mai-San.

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

    Science.gov (United States)

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

    2018-01-01

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

  11. Analysis of Sheng-Mai-San, a Ginseng-Containing Multiple Components Traditional Chinese Herbal Medicine Using Liquid Chromatography Tandem Mass Spectrometry and Physical Examination by Electron and Light Microscopies.

    Science.gov (United States)

    Cheng, Yung-Yi; Tsai, Tung-Hu

    2016-09-01

    Sheng-Mai-San is a multi-component traditional Chinese herbal preparation. Due to the fact granulated additives, such as starch, carboxymethyl cellulose, lactose and raw herbal powder may alter the content of the bioactive markers in the herbal products, a developed ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was used to measure the herbal biomarkers of ginsenoside Rb₁, Rb₂, Rc, Rd, Re, Rg₁, Rh₁, compound K, ophiopogonin D and schizandrin from the Sheng-Mai-San herbal formulation. Besides, scanning electron microscopy (SEM) was used to observe the morphology of the herbal granular powders. Light microscopy with Congo red and iodine-KI reagent staining was used to identify the cellulose fiber and cornstarch added to pharmaceutical herbal products. The swelling power (SP), water solubility index (WSI), and crude fiber analysis were used to determine the contents of cellulose fiber and cornstarch in pharmaceutical herbal products. In this study, we developed a novel skill to assess the quantification of appended cornstarch in pharmaceutical herbal products using Aperio ImageScope software. Compared with the traditional cornstarch analysis, our analysis method is a rapid, simple and conversion process which could be applied to detect the percentage of added cornstarch in unknown powder products. The various range of the herbal content for the five pharmaceutical manufacturers varied by up to several hundreds-fold. The physical examination reveals that the morphology of the herbal pharmaceutical products is rough and irregular with sharp layers. This study provides a reference standard operating procedure guide for the quality control of the Chinese herbal pharmaceutical products of Sheng-Mai-San.

  12. Use of on-line supercritical fluid extraction-supercritical fluid chromatography/tandem mass spectrometry to analyze disease biomarkers in dried serum spots compared with serum analysis using liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Suzuki, Makoto; Nishiumi, Shin; Kobayashi, Takashi; Sakai, Arata; Iwata, Yosuke; Uchikata, Takato; Izumi, Yoshihiro; Azuma, Takeshi; Bamba, Takeshi; Yoshida, Masaru

    2017-05-30

    The analytical stability and throughput of biomarker assays based on dried serum spots (DSS) are strongly dependent on the extraction process and determination method. In the present study, an on-line system based on supercritical fluid extraction-supercritical fluid chromatography coupled with tandem mass spectrometry (SFE-SFC/MS/MS) was established for analyzing the levels of disease biomarkers in DSS. The chromatographic conditions were investigated using the ODS-EP, diol, and SIL-100A columns. Then, we optimized the SFE-SFC/MS/MS method using the diol column, focusing on candidate biomarkers of oral, colorectal, and pancreatic cancer that were identified using liquid chromatography (LC)/MS/MS. By using this system, four hydrophilic metabolites and 17 hydrophobic metabolites were simultaneously detected within 15 min. In an experiment involving clinical samples, PC 16:0-18:2/16:1-18:1 exhibited 93.8% sensitivity and 64.3% specificity, whereas PC 17:1-18:1/17:0-18:2 showed 81.3% sensitivity and 92.9% specificity for detecting oral cancer. In addition, assessments of the creatine levels demonstrated 92.3% sensitivity and 78.6% specificity for detecting colorectal cancer. The results of this study indicate that our method has great potential for clinical diagnosis and would be suitable for large-scale screening. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Determination of Glyphosate, its Degradation Product Aminomethylphosphonic Acid, and Glufosinate, in Water by Isotope Dilution and Online Solid-Phase Extraction and Liquid Chromatography/Tandem Mass Spectrometry

    Science.gov (United States)

    Meyer, Michael T.; Loftin, Keith A.; Lee, Edward A.; Hinshaw, Gary H.; Dietze, Julie E.; Scribner, Elisabeth A.

    2009-01-01

    The U.S. Geological Survey method (0-2141-09) presented is approved for the determination of glyphosate, its degradation product aminomethylphosphonic acid (AMPA), and glufosinate in water. It was was validated to demonstrate the method detection levels (MDL), compare isotope dilution to standard addition, and evaluate method and compound stability. The original method USGS analytical method 0-2136-01 was developed using liquid chromatography/mass spectrometry and quantitation by standard addition. Lower method detection levels and increased specificity were achieved in the modified method, 0-2141-09, by using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The use of isotope dilution for glyphosate and AMPA and pseudo isotope dilution of glufosinate in place of standard addition was evaluated. Stable-isotope labeled AMPA and glyphosate were used as the isotope dilution standards. In addition, the stability of glyphosate and AMPA was studied in raw filtered and derivatized water samples. The stable-isotope labeled glyphosate and AMPA standards were added to each water sample and the samples then derivatized with 9-fluorenylmethylchloroformate. After derivatization, samples were concentrated using automated online solid-phase extraction (SPE) followed by elution in-line with the LC mobile phase; the compounds separated and then were analyzed by LC/MS/MS using electrospray ionization in negative-ion mode with multiple-reaction monitoring. The deprotonated derivatized parent molecule and two daughter-ion transition pairs were identified and optimized for glyphosate, AMPA, glufosinate, and the glyphosate and AMPA stable-isotope labeled internal standards. Quantitative comparison between standard addition and isotope dilution was conducted using 473 samples analyzed between April 2004 and June 2006. The mean percent difference and relative standard deviation between the two quantitation methods was 7.6 plus or minus 6.30 (n = 179), AMPA 9.6 plus or minus 8

  14. Liquid chromatography-tandem mass spectrometric assay for the quantitative determination of the tyrosine kinase inhibitor quizartinib in mouse plasma using salting-out liquid-liquid extraction

    NARCIS (Netherlands)

    Retmana, Irene A; Wang, Jing; Schinkel, Alfred H; Schellens, Jan H M; Beijnen, Jos H; Sparidans, Rolf W

    2017-01-01

    A bioanalytical assay for quizartinib -a potent, and selective FLT3 tyrosine kinase inhibitor- in mouse plasma was developed and validated. Salting-out assisted liquid-liquid extraction (SALLE), using acetonitrile and magnesium sulfate, was selected as sample pretreatment with deuterated quizartinib

  15. Solid-phase extraction in combination with dispersive liquid-liquid microextraction and ultra-high performance liquid chromatography-tandem mass spectrometry analysis: the ultra-trace determination of 10 antibiotics in water samples.

    Science.gov (United States)

    Liang, Ning; Huang, Peiting; Hou, Xiaohong; Li, Zhen; Tao, Lei; Zhao, Longshan

    2016-02-01

    A novel method, solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME), was developed for ultra-preconcentration of 10 antibiotics in different environmental water samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry detection. The optimized results were obtained as follows: after being adjusted to pH 4.0, the water sample was firstly passed through PEP-2 column at 10 mL min(-1), and then methanol was used to elute the target analytes for the following steps. Dichloromethane was selected as extraction solvent, and methanol/acetonitrile (1:1, v/v) as dispersive solvent. Under optimal conditions, the calibration curves were linear in the range of 1-1000 ng mL(-1) (sulfamethoxazole, cefuroxime axetil), 5-1000 ng mL(-1) (tinidazole), 10-1000 ng mL(-1) (chloramphenicol), 2-1000 ng mL(-1) (levofloxacin oxytetracycline, doxycycline, tetracycline, and ciprofloxacin) and 1-400 ng mL(-1) (sulfadiazine) with a good precision. The LOD and LOQ of the method were at very low levels, below 1.67 and 5.57 ng mL(-1), respectively. The relative recoveries of the target analytes were in the range from 64.16% to 99.80% with relative standard deviations between 0.7 and 8.4%. The matrix effect of this method showed a great decrease compared with solid-phase extraction and a significant value of enrichment factor (EF) compared with dispersive liquid-liquid microextraction. The developed method was successfully applied to the extraction and analysis of antibiotics in different water samples with satisfactory results.

  16. In situ derivatization-liquid liquid extraction as a sample preparation strategy for the determination of urinary biomarker prolyl-4-hydroxyproline by liquid chromatography-tandem mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Cimlová, Jana; Kružberská, Pavla; Švagera, Z.; Hušek, Petr; Šimek, Petr

    2012-01-01

    Roč. 47, č. 3 (2012), s. 294-302 ISSN 1076-5174 R&D Projects: GA ČR GA203/09/2014; GA MZd NS9755; GA MŠk 7F09028 Institutional research plan: CEZ:AV0Z50070508 Keywords : alkyl chloroformate derivatization * liquid liquid extraction * urine Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.214, year: 2012 http://onlinelibrary.wiley.com/doi/10.1002/jms.2952/full

  17. A highly selective dispersive liquid-liquid microextraction approach based on the unique fluorous affinity for the extraction and detection of per- and polyfluoroalkyl substances coupled with high performance liquid chromatography tandem-mass spectrometry.

    Science.gov (United States)

    Wang, Juan; Shi, Yali; Cai, Yaqi

    2018-04-06

    In the present study, a highly selective fluorous affinity-based dispersive liquid-liquid microextraction (DLLME) technique was developed for the extraction and analysis of per- and polyfluoroalkyl substances (PFASs) followed by high performance liquid chromatography tandem-mass spectrometry. Perfluoro-tert-butanol with multiple C-F bonds was chosen as the extraction solvent, which was injected into the aqueous samples with a dispersive solvent (acetonitrile) in a 120:800 (μL, v/v) mixture for PFASs enrichment. The fluorous affinity-based extraction mechanism was confirmed by the significantly higher extraction recoveries for PFASs containing multiple fluorine atoms than those for compounds with fewer or no fluorine atoms. The extraction recoveries of medium and long-chain PFASs (CF 2  > 5) exceeded 70%, except perfluoroheptanoic acid, while those of short-chain PFASs were lower than 50%, implying that the proposed DLLME may not be suitable for their extraction due to weak fluorous affinity. This highly fluoroselective DLLME technique can greatly decrease the matrix effect that occurs in mass spectrometry detection when applied to the analysis of urine samples. Under the optimum conditions, the relative recoveries of PFASs with CF 2  > 5 ranged from 80.6-121.4% for tap water, river water and urine samples spiked with concentrations of 10, 50 and 100 ng/L. The method limits of quantification for PFASs in water and urine samples were in the range of 0.6-8.7 ng/L. Furthermore, comparable concentrations of PFASs were obtained via DLLME and solid-phase extraction, confirming that the developed DLLME technique is a promising method for the extraction of PFASs in real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Fast quantification of short chain fatty acids and ketone bodies by liquid chromatography-tandem mass spectrometry after facile derivatization coupled with liquid-liquid extraction.

    Science.gov (United States)

    Zeng, Mingfei; Cao, Huachuan

    2018-04-15

    Short chain fatty acids (SCFA) and ketone bodies recently emerged as important physiological relevant metabolites because of their association with microbiota, immunology, obesity and other metabolic states. They were commonly analyzed by GC-MS with long run time and laborious sample preparation. In this study we developed a novel LC-MS/MS method using fast derivatization coupled with liquid-liquid extraction to detect SCFA and ketone bodies in plasma and feces. Several different derivatization reagents were evaluated to compare the efficiency, the sensitivity and chromatographic separation of structural isomers. O‑benzylhydroxylamine was selected for its superior overall performance in reaction time and isomeric separation that allowed the measurement of each SCFAs and ketone bodies free from interferences. The derivatization procedure is facile and reproducible in aqueous-organic medium, which abolished the evaporation procedure hampering the analysis of volatile short chain acids. Enhancement in sensitivity remarkably improved the detection limit of SCFA and ketone bodies to sub-fmol level. This novel method was applied to quantify these metabolites in fecal and plasma samples from lean and DIO mouse. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Novel amphiphilic polymeric ionic liquid-solid phase micro-extraction membrane for the preconcentration of aniline as degradation product of azo dye Orange G under sonication by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cai, Mei-Qiang; Wei, Xiao-Qing; Du, Chun-Hui; Ma, Xu-Ming; Jin, Mi-Cong

    2014-07-04

    A novel amphiphilic polymeric ionic liquid membrane containing a hydrophilic bromide anion and a hydrophobic carbonyl group was synthesized in dimethylformamide (DMF) systems using the ionic liquid 1-butyl-3-vinylimidazolium bromide (BVImBr) and the methylmethacrylate (MMA) as monomers. The prepared amphiphilic ploy-methylmethacrylate-1-butyl-3-vinylimidazolium bromide (MMA-BVImBr) was characterized by a scanning electron microscope and an infrared spectrum instrument. The results of solid-phase micro-extraction membrane (SPMM) experiments showed that the adsorption capacity of membrane was about 0.76μgμg(-1) for aniline. Based on this, a sensitive method for the determination of trace aniline, as a degradation product of azo dye Orange G under sonication, was developed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The calibration curve showed a good linearity ranging from 0.5 to 10.0μgL(-1) with a correlation coefficient value of 0.9998. The limit of quantification was 0.5μgL(-1). The recoveries ranged from 90.6% to 96.1%. The intra- and inter-day relative standard deviations were less than 8.3% and 10.9%. The developed SPMM-LC-MS/MS method was used successfully for preconcentration of trace aniline produced during the sonication of Orange G solution. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Liquid-liquid extraction of strongly protein bound BMS-299897 from human plasma and cerebrospinal fluid, followed by high-performance liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

    Xue, Y J; Pursley, Janice; Arnold, Mark

    2007-04-11

    BMS-299897 is a gamma-secretase inhibitor that is being developed for the treatment of Alzheimer's disease. Liquid-liquid extraction (LLE), chromatographic/tandem mass spectrometry (LC/MS/MS) methods have been developed and validated for the quantitation of BMS-299897 in human plasma and cerebrospinal fluid (CSF). Both methods utilized (13)C6-BMS-299897, the stable label isotope analog, as the internal standard. For the human plasma extraction method, two incubation steps were required after the addition of 5 mM ammonium acetate and the internal standard in acetonitrile to release the analyte bound to proteins prior to LLE with toluene. For the human CSF extraction method, after the addition of 0.5 N HCl and the internal standard, CSF samples were extracted with toluene and no incubation was required. The organic layers obtained from both extraction methods were removed and evaporated to dryness. The residues were reconstituted and injected into the LC/MS/MS system. Chromatographic separation was achieved isocratically on a MetaChem C18 Hypersil BDS column (2.0 mm x 50 mm, 3 microm). The mobile phase contained 10 mM ammonium acetate pH 5 and acetonitrile. Detection was by negative ion electrospray tandem mass spectrometry. The standard curves ranged from 1 to 1000 ng/ml for human plasma and 0.25-100 ng/ml for human CSF. Both standard curves were fitted to a 1/x weighted quadratic regression model. For both methods, the intra-assay precision was within 8.2% CV, the inter-assay precision was within 5.4% CV, and assay accuracy was within +/-7.4% of the nominal values. The validation and sample analysis results demonstrated that both methods had acceptable precision and accuracy across the calibration ranges.

  1. Measurement of serum 3-epi-25-hydroxyvitamin D3, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in infant, paediatric and adolescent populations of Korea using ultra-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Cho, Sung E; Kim, Sollip; Kim, Young D; Lee, Hyojung; Seo, Dong H; Song, Junghan; Um, Tae H; Cho, Chong R; Kim, Nam H; Hwang, Jong H

    2017-09-01

    Background We evaluated the performance of ultra-performance liquid chromatography-tandem mass spectrometry to measure serum 3-epi-25-hydroxyvitamin D 3 , 25-hydroxyvitamin D 3 and 25-hydroxyvitamin D 2 concentrations in 519 infant, paediatric and adolescent serum samples in Korea. Methods We used a Kinetex XB-C18 column and isocratic methanol/water (77.5/22.5, v/v) with 0.025% (v/v) high-performance liquid chromatography solvent additive flowing at 0.25 mL/min, yielding an 11 min/sample run time. A TQD triple quadrupole mass spectrometer in electrospray ionization positive ion mode with multiple reaction monitoring transition via an MSMS vitamin D kit was used to evaluate precision, carryover, ion suppression and linearity. Samples were prepared using the 4-phenyl-1,2,4-triazoline-3,5-dione derivatization method. Results Intra- and inter-run precisions were 1.23-13.28% and 1.02-10.08%, respectively. Group carryovers were -0.27% and 0.10%, respectively. There was no ion suppression. The calibration curve showed good linearity from calibrator Level 1 (11.75 nmol/L) to 6 (375 nmol/L) with R 2  > 0.9999. The 3-epi-25-hydroxyvitamin D 3 and 25-hydroxyvitamin D 3 peaks were clearly separated in the extracted ion chromatogram. Infant serum samples 3-epi-25-hydroxyvitamin D 3 concentrations were significantly higher than paediatric and adolescent concentrations. Conclusions The ultra-performance liquid chromatography-tandem mass spectrometry assay performed acceptably, clearly separating 3-epi-25-hydroxyvitamin D 3 from 25-hydroxyvitamin D 3 . High 3-epi-25-hydroxyvitamin D 3 concentrations were observed in infant but not in paediatric and adolescent serum samples.

  2. Determination of Grayanotoxins from Rhododendron brachycarpum in Dietary Supplements and Homemade Wine by Liquid Chromatography-Quadrupole Time-of-Flight-Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry.

    Science.gov (United States)

    Hwang, Taeik; Noh, Eunyoung; Jeong, Ji Hye; Park, Sung-Kwan; Shin, Dongwoo; Kang, Hoil

    2018-02-28

    A sensitive and specific high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) method combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of grayanotoxins I and III in dietary supplements and homemade wine. Grayanotoxins I and III were successfully extracted using solid-phase extraction cartridges, characterized by LC-QTOF-MS, and quantitated by LC-MS/MS. The LC-MS/MS calibration curves were linear over concentrations of 10-100 ng/mL (grayanotoxin I) and 20-400 ng/mL (grayanotoxin III). Grayanotoxins I and III were found in 51 foodstuffs, with quantitative determinations revealing total toxin concentrations of 18.4-101 000 ng/mL (grayanotoxin I) and 15.3-56 000 ng/mL (grayanotoxin III). The potential of the validated method was demonstrated by successful quantitative analysis of grayanotoxins I and III in dietary supplements and homemade wine; the method appears suitable for the routine detection of grayanotoxins I and III from Rhododendron brachycarpum.

  3. Ultrasound-assisted leaching-dispersive solid-phase extraction followed by liquid-liquid microextraction for the determination of polybrominated diphenyl ethers in sediment samples by gas chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Fontana, Ariel R; Lana, Nerina B; Martinez, Luis D; Altamirano, Jorgelina C

    2010-06-30

    Ultrasound-assisted leaching-dispersive solid-phase extraction followed by dispersive liquid-liquid microextraction (USAL-DSPE-DLLME) technique has been developed as a new analytical approach for extracting, cleaning up and preconcentrating polybrominated diphenyl ethers (PBDEs) from sediment samples prior gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. In the first place, PBDEs were leached from sediment samples by using acetone. This extract was cleaned-up by DSPE using activated silica gel as sorbent material. After clean-up, PBDEs were preconcentrated by using DLLME technique. Thus, 1 mL acetone extract (disperser solvent) and 60 microL carbon tetrachloride (extraction solvent) were added to 5 mL ultrapure water and a DLLME technique was applied. Several variables that govern the proposed technique were studied and optimized. Under optimum conditions, the method detection limits (MDLs) of PBDEs calculated as three times the signal-to-noise ratio (S/N) were within the range 0.02-0.06 ng g(-1). The relative standard deviations (RSDs) for five replicates were or =0.9991. Validation of the methodology was carried out by standard addition method at two concentration levels (0.25 and 1 ng g(-1)) and by comparing with a reference Soxhlet technique. Recovery values were > or =80%, which showed a satisfactory robustness of the analytical methodology for determination of low PBDEs concentration in sediment samples. Copyright 2010 Elsevier B.V. All rights reserved.

  4. 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.

  5. Comprehensive profiling of mercapturic acid metabolites from dietary acrylamide as short-term exposure biomarkers for evaluation of toxicokinetics in rats and daily internal exposure in humans using isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu [Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, Zhejiang (China); Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, Fuli Institute of Food Science, Zhejiang University, Hangzhou 310058, Zhejiang (China); Wang, Qiao; Cheng, Jun [Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, Zhejiang (China); Zhang, Jingshun; Xu, Jiaojiao [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang (China); Ren, Yiping, E-mail: renyiping@263.net [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang (China)

    2015-09-24

    Mercapturic acid metabolites from dietary acrylamide are important short-term exposure biomarkers for evaluating the in vivo toxicity of acrylamide. Most of studies have focused on the measurement of two metabolites, N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA). Thus, the comprehensive profile of acrylamide urinary metabolites cannot be fully understood. We developed an isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of all four mercapturic acid adducts of acrylamide and its primary metabolite glycidamide under the electroscopy ionization negative (ESI-) mode in the present study. The limit of detection (LOD) and limit of quantification (LOQ) of the analytes ranged 0.1–0.3 ng/mL and 0.4–1.0 ng/mL, respectively. The recovery rates with low, intermediate and high spiking levels were calculated as 95.5%–105.4%, 98.2%–114.0% and 92.2%–108.9%, respectively. Acceptable within-laboratory reproducibility (RSD < 7.0%) substantially supported the use of current method for robust analysis. Rapid pretreatment procedures and short run time (8 min per sample) ensured good efficiency of metabolism profiling, indicating a wide application for investigating short-term internal exposure of dietary acrylamide. Our proposed UHPLC-MS/MS method was successfully applied to the toxicokinetic study of acrylamide in rats. Meanwhile, results of human urine analysis indicated that the levels of N-acetyl-S-(2-carbamoylethyl)-L-cysteine-sulfoxide (AAMA-sul), which did not appear in the mercapturic acid metabolites in rodents, were more than the sum of GAMA and N-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-L-cysteine (iso-GAMA). Thus, AAMA-sul may alternatively become a specific biomarker for investigating the acrylamide exposure in humans. Current proposed method provides a substantial methodology support for comprehensive

  6. Comprehensive profiling of mercapturic acid metabolites from dietary acrylamide as short-term exposure biomarkers for evaluation of toxicokinetics in rats and daily internal exposure in humans using isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry

    International Nuclear Information System (INIS)

    Zhang, Yu; Wang, Qiao; Cheng, Jun; Zhang, Jingshun; Xu, Jiaojiao; Ren, Yiping

    2015-01-01

    Mercapturic acid metabolites from dietary acrylamide are important short-term exposure biomarkers for evaluating the in vivo toxicity of acrylamide. Most of studies have focused on the measurement of two metabolites, N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA). Thus, the comprehensive profile of acrylamide urinary metabolites cannot be fully understood. We developed an isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of all four mercapturic acid adducts of acrylamide and its primary metabolite glycidamide under the electroscopy ionization negative (ESI-) mode in the present study. The limit of detection (LOD) and limit of quantification (LOQ) of the analytes ranged 0.1–0.3 ng/mL and 0.4–1.0 ng/mL, respectively. The recovery rates with low, intermediate and high spiking levels were calculated as 95.5%–105.4%, 98.2%–114.0% and 92.2%–108.9%, respectively. Acceptable within-laboratory reproducibility (RSD < 7.0%) substantially supported the use of current method for robust analysis. Rapid pretreatment procedures and short run time (8 min per sample) ensured good efficiency of metabolism profiling, indicating a wide application for investigating short-term internal exposure of dietary acrylamide. Our proposed UHPLC-MS/MS method was successfully applied to the toxicokinetic study of acrylamide in rats. Meanwhile, results of human urine analysis indicated that the levels of N-acetyl-S-(2-carbamoylethyl)-L-cysteine-sulfoxide (AAMA-sul), which did not appear in the mercapturic acid metabolites in rodents, were more than the sum of GAMA and N-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-L-cysteine (iso-GAMA). Thus, AAMA-sul may alternatively become a specific biomarker for investigating the acrylamide exposure in humans. Current proposed method provides a substantial methodology support for comprehensive

  7. Identification and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide (THC-COOH-glu) in hair by ultra-performance liquid chromatography tandem mass spectrometry as a potential hair biomarker of cannabis use.

    Science.gov (United States)

    Pichini, Simona; Marchei, Emilia; Martello, Simona; Gottardi, Massimo; Pellegrini, Manuela; Svaizer, Fiorenza; Lotti, Andrea; Chiarotti, Marcello; Pacifici, Roberta

    2015-04-01

    We developed and validated an ultra-high-pressure liquid chromatography-tandem mass spectrometry method to identify and quantify 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in hair of cannabis consumers. After hair washing with methyl alcohol and diethyl ether and subsequent addition of amiodarone as internal standard hair samples were treated with 500 μl VMA-T M3 buffer reagent for 1 h at 100 °C. After cooling, 10 μl VMA-T M3 extract were injected into chromatographic system. Chromatographic separation was carried out on a reversed phase column using a linear gradient elution with two solvents: 5 mM ammonium formate pH 3.0 (solvent A) and 0.1% formic acid in acetonitrile (solvent B). The flow rate was kept constant at 0.4 ml/min during the analysis. The separated analytes were detected with a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode via positive electrospray ionization. Linear calibration curves were obtained for 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide with correlation coefficients (r(2)) of 0.99 and a limit of quantification of 0.25 pg/mg hair. Analytical recovery was between 79.6% and 100.7% and intra- and inter-assay imprecision and inaccuracy were always lower than 15%. Ultra-high-pressure liquid chromatography-tandem mass spectrometry analysis of 20 different hair samples of cannabis consumers disclosed the presence of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide in the range of 0.5-8.6 pg/mg hair. These data provided a good start to consider 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid glucuronide as alternative hair biomarker of cannabis consumption. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. High-throughput and simultaneous analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry in the positive and negative ionization modes.

    Science.gov (United States)

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

    2011-06-01

    In this report, a high-throughput and sensitive method for analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in the positive and negative ionization modes using tolbutamide as internal standard is presented. After pretreatment of a plasma sample by solid-phase extraction with an Oasis HLB cartridge, muscle relaxants were analyzed by UPLC with Acquity UPLC BEH C(18) column and Acquity TQD tandem quadrupole mass spectrometer equipped with an electrospray ionization interface. The calibration curves for muscle relaxants spiked into human plasma equally showed good linearities in the nanogram per milliliter order range. The detection limits (signal-to-noise ratio = 3) was as low as 0.1-2 ng/mL. The method gave satisfactory recovery rates, accuracy, and precision for quality control samples spiked with muscle relaxants. To further validate the present method, 250 mg of chlorphenesin carbamate was orally administered to a healthy male volunteer, and the concentrations of chlorphenesin carbamate in plasma were measured 0.5, 1, 2, 4, 6, and 8 h after dosing; their concentrations in human plasma were between 0.62 and 2.44 μg/mL. To our knowledge, this is the first report describing simultaneous analysis of over more than two central-acting muscle relaxants by liquid chromatography-tandem mass spectrometry. This has been realized by the capability of our instrument for simultaneous multiple reaction monitoring of the target compounds in both positive and negative ionization modes. Therefore, the present method seems very useful in forensic and clinical toxicology and pharmacokinetic studies.

  9. Residue analysis of sixty pesticides in red swamp crayfish using QuEChERS with high-performance liquid chromatography-tandem mass spectrometry

    Science.gov (United States)

    In this study, a multi-residue analytical method using QuEChERS extraction and dispersive solid-phase extraction (d-SPE) cleanup followed by high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) was developed for rapid determination of 60 pesticide residues in whole crayfish a...

  10. Solid-phase extraction combined with dispersive liquid-liquid microextraction and chiral liquid chromatography-tandem mass spectrometry for the simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

    Science.gov (United States)

    Zhao, Pengfei; Deng, Miaoduo; Huang, Peiting; Yu, Jia; Guo, Xingjie; Zhao, Longshan

    2016-09-01

    This report describes, for the first time, the simultaneous enantioselective determination of proton-pump inhibitors (PPIs-omeprazole, lansoprazole, pantoprazole, and rabeprazole) in environmental water matrices based on solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and chiral liquid chromatography-tandem mass spectrometry. The optimized results of SPE-DLLME were obtained with PEP-2 column using methanol-acetonitrile (1/1, v/v) as elution solvent, dichloroethane, and acetonitrile as extractant and disperser solvent, respectively. The separation and determination were performed using reversed-phase chromatography on a cellulose chiral stationary phase, a Chiralpak IC (250 mm × 4.6 mm, 5 μm) column, under isocratic conditions at 0.6 mL min(-1) flow rate. The analytes were detected in multiple reaction monitoring (MRM) mode by triple quadrupole mass spectrometry. Isotopically labeled internal standards were used to compensate matrix interferences. The method provided enrichment factors of around 500. Under optimal conditions, the mean recoveries for all eight enantiomers from the water samples were 89.3-107.3 % with 0.9-10.3 % intra-day RSD and 2.3-8.1 % inter-day RSD at 20 and 100 ng L(-1) levels. Correlation coefficients (r (2)) ≥ 0.999 were achieved for all enantiomers within the range of 2-500 μg L(-1). The method detection and quantification limits were at very low levels, within the range of 0.67-2.29 ng L(-1) and 2.54-8.68 ng L(-1), respectively. This method was successfully applied to the determination of the concentrations and enantiomeric fractions of the targeted analytes in wastewater and river water, making it applicable to the assessment of the enantiomeric fate of PPIs in the environment. Graphical Abstract Simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

  11. Optimisation of pressurized liquid extraction using a multivariate chemometric approach for the determination of anticancer drugs in sludge by ultra high performance liquid chromatography-tandem mass spectrometry

    OpenAIRE

    Seira , Jordan; Claparols , Catherine; Joannis-Cassan , Claire; Albasi , Claire; Montréjaud-Vignoles , Mireille; Sablayrolles , Caroline

    2013-01-01

    International audience; The present paper describes an analytical method for the determination of 2 widely administered anticancer drugs, ifosfamide and cyclophosphamide, contained in sewage sludge. The method relies on the extraction from the solid matrix by pressurized liquid extraction, sample purification by solid-phase extraction and analysis by ultra high performance liquid chromatography coupled with tandem mass spectrometry. The different parameters affecting the extraction efficiency...

  12. A dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by injector port silylation coupled with gas chromatography-tandem mass spectrometry for the determination of nine bisphenols in bottled carbonated beverages.

    Science.gov (United States)

    Mandrah, Kapil; Satyanarayana, G N V; Roy, Somendu Kumar

    2017-12-15

    In the present study, a method has been efficiently developed for the first time to determine nine bisphenol analogues [bisphenol A (BPA), bisphenol C (BPC), bisphenol AF (BPAF), bisphenol E (BPE), bisphenol F (BPF), bisphenol G (BPG), bisphenol M (BPM), bisphenol S (BPS), and bisphenol Z (BPZ)] together in bottled carbonated beverages (collected from the local market of Lucknow, India) using dispersive liquid-liquid microextraction process. This is based on solidification of floating organic droplet (DLLME-SFO) followed by injector port silylation coupled with gas chromatography-tandem mass spectrometry. The process investigated parameters of DLLME-SFO (including the type of extraction and disperser solvents with their volumes, effect of pH, ionic strength, and the sample volume), factors influencing to injection port derivatization like, collision energy, injector port temperature, derivatizing reagent with sample injection volume, and type of organic solvent. BPA, BPF, BPZ, and BPS were detected in each sample; whereas, other bisphenols were also detected in some carbonated beverage samples. After optimizing the required conditions, good linearity of analytes was achieved in the range of 0.097-100ngmL -1 with coefficients of determination (R 2 )≥0.995. Intra-day and inter day precision of the method was good, with relative standard deviation (% RSD)≤10.95%. The limits of detection (LOD) and limits of quantification (LOQ) values of all bisphenols were ranged from 0.021 to 0.104ngmL -1 and 0.070 to 0.343ngmL -1 , respectively. The recovery of extraction was good (73.15-95.08%) in carbonated beverage samples and good enrichment factors (96.36-117.33) were found. Thus, the developed method of microextraction was highly precise, fast, and reproducible to determine the level of contaminants in bottled carbonated beverages. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Analysis of endocrine disruptor compounds in marine sediments by in cell clean up-pressurized liquid extraction-liquid chromatography tandem mass spectrometry determination.

    Science.gov (United States)

    Salgueiro-González, N; Turnes-Carou, I; Muniategui-Lorenzo, S; López-Mahía, P; Prada-Rodríguez, D

    2014-12-10

    A less time-, solvent- and sorbent-consuming analytical methodology for the determination of bisphenol A and alkylphenols (4-tert-octylphenol, 4-octylphenol, 4-n-nonylphenol, nonylphenol) in marine sediment was developed and validated. The method was based on selective pressurized liquid extraction (SPLE) with a simultaneous in cell clean up combined with liquid chromatography-electrospray ionization tandem mass spectrometry in negative mode (LC-ESI-MS/MS). The SPLE extraction conditions were optimized by a Plackett-Burman design followed by a central composite design. Quantitation was performed by standard addition curves in order to correct matrix effects. The analytical features of the method were satisfactory: relative recoveries varied between 94 and 100% and repeatability and intermediate precision were <6% for all compounds. Uncertainty assessment of measurement was estimated on the basis of an in-house validation according to EURACHEM/CITAC guide. Quantitation limits of the method (MQL) ranged between 0.17 (4-n-nonylphenol) and 4.01 ng g(-1) dry weight (nonylphenol). Sensitivity, selectivity, automaticity and fastness are the main advantages of this green methodology. As an application, marine sediment samples from Galicia coast (NW of Spain) were analysed. Nonylphenol and 4-tert-octylphenol were measured in all samples at concentrations between 20.1 and 1409 ng g(-1) dry weight, respectively. Sediment toxicity was estimated and no risk to aquatic biota was found. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Study of the factors affecting the performance of microextraction by packed sorbent (MEPS) using liquid scintillation counter and liquid chromatography-tandem mass spectrometry

    International Nuclear Information System (INIS)

    Altun, Zeki; Abdel-Rehim, Mohamed

    2008-01-01

    Microextraction by packed sorbent (MEPS) is a new technique for sample preparation that can be connected on-line with LC or GC. In MEPS, approximately 1-2 mg of the solid packing material is inserted into a syringe (100-250 μL) as a plug. Sample preparation takes place on the packed bed. The bed can be packed or coated to provide selective and suitable sampling conditions. The new method is very promising for extraction of drugs and metabolites from biological samples. In this paper, some factors affecting the performance of MEPS such as recovery, carry-over, leakage, washing volume and elution volume were studied using C18 and hydroxylated polystyrene-divinylbenzene copolymer (ENV+) as sorbents. Radioactively labelled bupivacaine in plasma samples was used as test analyte. For the extraction of this drug, using methanol/water 95:5 (v/v) (0.25% ammonium hydroxide) was used as elution solvent. The analyte response increased with increasing the elution volume and it was linear upp up to 100 μL utilizing liquid scintillation counter. Further, for concentrating the sample, we found that MEPS may be used such that the sample can be drawn through the needle, up and down, several times. The analyte leakage increases as the volume washing increases, though higher washing volumes may also result in cleaner extracts. To eliminate analyte carry-over, the sorbents were washed first with 3 x 250 μL elution solution and then with 3 x 250 μL washing solution. In addition, the reproducibility measurements show relatively good relative standard deviation (RSD) % values concerning analyte recovery and analyte leakage. The present study provides an understanding of basic aspects when optimizing methods for MEPS. In this study, MEPS was used off-line with liquid scintillation counter and on-line with LC-MS/MS

  15. Study of the factors affecting the performance of microextraction by packed sorbent (MEPS) using liquid scintillation counter and liquid chromatography-tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Altun, Zeki [Karlstad University, Faculty of Technology and Science, SE-651 88 Karlstad (Sweden); Abdel-Rehim, Mohamed [Karlstad University, Faculty of Technology and Science, SE-651 88 Karlstad (Sweden); Clinical Pharmacology and DMPK, AstraZeneca R and D Soedertaelje, SE-151 85 Soedertaelje (Sweden)], E-mail: Mohamed.Abdel-Rehim@Astrazeneca.com

    2008-12-23

    Microextraction by packed sorbent (MEPS) is a new technique for sample preparation that can be connected on-line with LC or GC. In MEPS, approximately 1-2 mg of the solid packing material is inserted into a syringe (100-250 {mu}L) as a plug. Sample preparation takes place on the packed bed. The bed can be packed or coated to provide selective and suitable sampling conditions. The new method is very promising for extraction of drugs and metabolites from biological samples. In this paper, some factors affecting the performance of MEPS such as recovery, carry-over, leakage, washing volume and elution volume were studied using C18 and hydroxylated polystyrene-divinylbenzene copolymer (ENV+) as sorbents. Radioactively labelled bupivacaine in plasma samples was used as test analyte. For the extraction of this drug, using methanol/water 95:5 (v/v) (0.25% ammonium hydroxide) was used as elution solvent. The analyte response increased with increasing the elution volume and it was linear upp up to 100 {mu}L utilizing liquid scintillation counter. Further, for concentrating the sample, we found that MEPS may be used such that the sample can be drawn through the needle, up and down, several times. The analyte leakage increases as the volume washing increases, though higher washing volumes may also result in cleaner extracts. To eliminate analyte carry-over, the sorbents were washed first with 3 x 250 {mu}L elution solution and then with 3 x 250 {mu}L washing solution. In addition, the reproducibility measurements show relatively good relative standard deviation (RSD) % values concerning analyte recovery and analyte leakage. The present study provides an understanding of basic aspects when optimizing methods for MEPS. In this study, MEPS was used off-line with liquid scintillation counter and on-line with LC-MS/MS.

  16. Extraction protocol and liquid chromatography/tandem mass spectrometry method for determining micelle-entrapped paclitaxel at the cellular and subcellular levels: Application to a cellular uptake and distribution study.

    Science.gov (United States)

    Zheng, Nan; Lian, Bin; Du, Wenwen; Xu, Guobing; Ji, Jiafu

    2018-01-01

    Paclitaxel-loaded polymeric micelles (PTX-PM) are commonly used as tumor-targeted nanocarriers and display outstanding antitumor features in clinic, but its accumulation and distribution in vitro are lack of investigation. It is probably due to the complex micellar system and its low concentration at the cellular or subcellular levels. In this study, we developed an improved extraction method, which was a combination of mechanical disruption and liquid-liquid extraction (LLE), to extract the total PTX from micelles in the cell lysate and subcellular compartments. An ultra-performance liquid chromatography tandem mass spectroscopy (UPLC-MS/MS) method was optimized to detect the low concentration of PTX at cellular and subcellular levels simultaneously, using docetaxel as internal standard (IS). The method was proved to release PTX totally from micelles (≥95.93%) with a consistent and reproducible extraction recovery (≥75.04%). Good linearity was obtained at concentrations ranging from 0.2 to 20ng/mL. The relative error (RE%) for accuracy varied from 0.68 to 7.56%, and the intra- and inter-precision (relative standard deviation, RSD%) was less than 8.64% and 13.14%, respectively. This method was fully validated and successfully applied to the cellular uptake and distribution study of PTX-loaded PLGA-PEG micelles in human breast cancer cells (MCF-7). Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Hydrophilic interaction liquid chromatography-tandem mass spectrometry quantitative method for the cellular analysis of varying structures of gemini surfactants designed as nanomaterial drug carriers.

    Science.gov (United States)

    Donkuru, McDonald; Michel, Deborah; Awad, Hanan; Katselis, George; El-Aneed, Anas

    2016-05-13

    Diquaternary gemini surfactants have successfully been used to form lipid-based nanoparticles that are able to compact, protect, and deliver genetic materials into cells. However, what happens to the gemini surfactants after they have released their therapeutic cargo is unknown. Such knowledge is critical to assess the quality, safety, and efficacy of gemini surfactant nanoparticles. We have developed a simple and rapid liquid chromatography electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantitative determination of various structures of gemini surfactants in cells. Hydrophilic interaction liquid chromatography (HILIC) was employed allowing for a short simple isocratic run of only 4min. The lower limit of detection (LLOD) was 3ng/mL. The method was valid to 18 structures of gemini surfactants belonging to two different structural families. A full method validation was performed for two lead compounds according to USFDA guidelines. The HILIC-MS/MS method was compatible with the physicochemical properties of gemini surfactants that bear a permanent positive charge with both hydrophilic and hydrophobic elements within their molecular structure. In addition, an effective liquid-liquid extraction method (98% recovery) was employed surpassing previously used extraction methods. The analysis of nanoparticle-treated cells showed an initial rise in the analyte intracellular concentration followed by a maximum and a somewhat more gradual decrease of the intracellular concentration. The observed intracellular depletion of the gemini surfactants may be attributable to their bio-transformation into metabolites and exocytosis from the host cells. Obtained cellular data showed a pattern that grants additional investigations, evaluating metabolite formation and assessing the subcellular distribution of tested compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Determination of pharmaceuticals in sewage sludge by pressurized liquid extraction (PLE) coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS).

    Science.gov (United States)

    Radjenović, J; Jelić, A; Petrović, M; Barceló, D

    2009-03-01

    In this study, we aimed at optimizing a sensitive and reliable method for a simultaneous determination of 31 pharmaceuticals belonging to predominant therapeutic classes identified in different types of sewage sludge proceeding from conventional and advanced wastewater treatment. Freeze-dried sewage sludge was extracted by pressurized liquid extraction technique using accelerated solvent extractor Dionex 300. 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 linearity, precision, accuracy, and method detection limits (MDLs). The method turned out to be specific, sensitive, and reliable for the analysis of sludge of different composition, type, and retention time in the process. The developed sample preparation protocol and previously published method for LC-MS/MS analysis (Gros et al., Talanta 70:678-690, 2006) were successfully applied to monitor the target pharmaceuticals in different types of sewage sludge, i.e., primary sludge, secondary sludge, treated sludge, and sludge proceeding from pilot-scale membrane bioreactors (MBRs) operating in parallel to the conventional activated sludge treatment. Among the investigated pharmaceuticals, 20 were detected in the sludge proceeding from full-scale installations, whereas the MBR sludge concentrations were below MDLs for several compounds. The highest concentrations were recorded for treated and primary sludge. For example, the mean concentration of ibuprofen in the digested sludge was 299.3 +/- 70.9 ng g(-1) dw, whereas in the primary sludge, it was enriched up to 741.1 ng g(-1) dw. Other pharmaceuticals detected at relatively high concentrations were diclofenac, erythromycin, glibenclamide, ketoprofen, ofloxacin, azithromycin (up to 380.7, 164.2, 190.7, 336.3, 454.7, 299.6 ng g(-1) dw in the primary sludge, respectively), gemfibrozil, loratidine, and fluoxetine (up

  19. Comparison of two microextraction methods based on solidification of floating organic droplet for the determination of multiclass analytes in river water samples by liquid chromatography tandem mass spectrometry using Central Composite Design.

    Science.gov (United States)

    Asati, Ankita; Satyanarayana, G N V; Patel, Devendra K

    2017-09-01

    Two low density organic solvents based liquid-liquid microextraction methods, namely Vortex assisted liquid-liquid microextraction based on solidification of floating organic droplet (VALLME-SFO) and Dispersive liquid-liquid microextraction based on solidification of floating organic droplet(DLLME-SFO) have been compared for the determination of multiclass analytes (pesticides, plasticizers, pharmaceuticals and personal care products) in river water samples by using liquid chromatography tandem mass spectrometry (LC-MS/MS). The effect of various experimental parameters on the efficiency of the two methods and their optimum values were studied with the aid of Central Composite Design (CCD) and Response Surface Methodology(RSM). Under optimal conditions, VALLME-SFO was validated in terms of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery for which the respective values were (0.011-0.219ngmL -1 ), (0.035-0.723ngmL -1 ), (0.050-0.500ngmL -1 ), (R 2 =0.992-0.999), (40-56), (80-106%). However, when the DLLME-SFO method was validated under optimal conditions, the range of values of limit of detection, limit of quantification, dynamic linearity range, determination of coefficient, enrichment factor and extraction recovery were (0.025-0.377ngmL -1 ), (0.083-1.256ngmL -1 ), (0.100-1.000ngmL -1 ), (R 2 =0.990-0.999), (35-49), (69-98%) respectively. Interday and intraday precisions were calculated as percent relative standard deviation (%RSD) and the values were ≤15% for VALLME-SFO and DLLME-SFO methods. Both methods were successfully applied for determining multiclass analytes in river water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Validation of a method for simultaneous determination of nitroimidazoles, benzimidazoles and chloramphenicols in swine tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Xia, Xi; Wang, Yuanyuan; Wang, Xia; Li, Yun; Zhong, Feng; Li, Xiaowei; Huang, Yaoling; Ding, Shuangyang; Shen, Jianzhong

    2013-05-31

    This paper presents a sensitive and confirmatory multi-residue method for the analysis of 23 veterinary drugs and metabolites belonging to three classes (nitroimidazoles, benzimidazoles, and chloramphenicols) in porcine muscle, liver, and kidney. After extracted with ethyl acetate and basic ethyl acetate sequentially, the crude extracts were defatted with hexane and further purified using Oasis MCX solid-phase extraction cartridges. Rapid determination was carried out by ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Data acquisition was performed under positive and negative mode simultaneously. Recoveries based on matrix-matched calibrations for meat, liver, and kidney ranged from 50.6 to 108.1%. The method quantification limits were in the range of 3-100ng/kg. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Development of QuEChERS-based extraction and liquid chromatography-tandem mass spectrometry method for quantifying flumethasone residues in beef muscle.

    Science.gov (United States)

    Park, Ki Hun; Choi, Jeong-Heui; Abd El-Aty, A M; Cho, Soon-Kil; Park, Jong-Hyouk; Kwon, Ki Sung; Park, Hee Ra; Kim, Hyung Soo; Shin, Ho-Chul; Kim, Mi Ra; Shim, Jae-Han

    2012-12-01

    A rapid, specific, and sensitive method based on liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the positive ion mode using multiple reaction monitoring (MRM) was developed and validated to quantify flumethasone residues in beef muscle. Methods were compared between the original as well as the EN quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based extraction. Good linearity was achieved at concentration levels of 5-30 μg/kg. Estimated recovery rates at spiking levels of 5 and 10 μg/kg ranged from 72.1 to 84.6%, with relative standard deviations (RSDs)noise ratios (S/Ns) of 3 and 10, respectively. The method was successfully applied to analyze real samples obtained from large markets throughout the Korean Peninsula. The method proved to be sensitive and reliable and, thus, rendered an appropriate means for residue analysis studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. An on-spot internal standard addition approach for accurately determining colistin A and colistin B in dried blood spots using ultra high-performance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Tsai, I-Lin; Kuo, Ching-Hua; Sun, Hsin-Yun; Chuang, Yu-Chung; Chepyala, Divyabharathi; Lin, Shu-Wen; Tsai, Yun-Jung

    2017-10-25

    Outbreaks of multidrug-resistant Gram-negative bacterial infections have been reported worldwide. Colistin, an antibiotic with known nephrotoxicity and neurotoxicity, is now being used to treat multidrug-resistant Gram-negative strains. In this study, we applied an on-spot internal standard addition approach coupled with an ultra high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify colistin A and B from dried blood spots (DBSs). Only 15μL of whole blood was required for each sample. An internal standard with the same yield of extraction recoveries as colistin was added to the spot before sample extraction for accurate quantification. Formic acid in water (0.15%) with an equal volume of acetonitrile (50:50v/v) was used as the extraction solution. With the optimized extraction process and LC-MS/MS conditions, colistin A and B could be quantified from a DBS with respective limits of quantification of 0.13 and 0.27μgmL -1 , and the retention times were spot internal standard addition approach which benefited the precision and accuracy. Results showed that DBS sampling coupled with the sensitive LC-MS/MS method has the potential to be an alternative approach for colistin quantification, where the bias of prodrug hydrolysis in liquid samples is decreased. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Analysis of Veterinary Drug and Pesticide Residues Using the Ethyl Acetate Multiclass/Multiresidue Method in Milk by Liquid Chromatography-Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Husniye Imamoglu

    2016-01-01

    Full Text Available A rapid and simple multiclass, ethyl acetate (EtOAc multiresidue method based on liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS detection was developed for the determination and quantification of 26 veterinary drugs and 187 total pesticide residues in milk. Sample preparation was a simple procedure based on liquid–liquid extraction with ethyl acetate containing 0.1% acetic acid, followed by centrifugation and evaporation of the supernatant. The residue was dissolved in ethyl acetate with 0.1% acetic acid and centrifuged prior to LC-MS/MS analysis. Chromatographic separation of analytes was performed on an Inertsil X-Terra C18 column with acetic acid in methanol and water gradient. The repeatability and reproducibility were in the range of 2 to 13% and 6 to 16%, respectively. The average recoveries ranged from 75 to 120% with the RSD (n=18. The developed method was validated according to the criteria set in Commission Decision 2002/657/EC and SANTE/11945/2015. The validated methodology represents a fast and cheap alternative for the simultaneous analysis of veterinary drug and pesticide residues which can be easily extended to other compounds and matrices.

  4. Simultaneous determination of flurbiprofen and its hydroxy metabolite in human plasma by liquid chromatography-tandem mass spectrometry for clinical application.

    Science.gov (United States)

    Lee, Hye-In; Choi, Chang-Ik; Byeon, Ji-Yeong; Lee, Jung-Eun; Park, So-Young; Kim, Young-Hoon; Kim, Se-Hyung; Lee, Yun-Jeong; Jang, Choon-Gon; Lee, Seok-Yong

    2014-11-15

    Flurbiprofen (FLB) is one of the phenylalkanoic acid derivatives of non-steroidal anti-inflammatory drugs used for the management of pain and inflammation in patients with arthritis. We developed and validated a rapid and sensitive high-performance liquid chromatography analytical method utilizing tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of FLB and its major metabolite, 4'-hydroxyflurbiprofen (4'-OH-FLB), in human plasma. Probenecid was used as an internal stan