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Tandem Mass Spectrometry Method (tandem + mass_spectrometry_method)
Kinds of Tandem Mass Spectrometry Method Selected AbstractsApplication of liquid chromatography,Tandem mass spectrometry method for the analysis of new nonselective ,-adrenergic blocker 1-(1- H -indol-4-yloxy)-3-{[2-(2-methoxy phenoxy)ethylo]amino}propan-2-ol (2F109) in rat plasmaCHIRALITY, Issue 7 2007Maria Walczak Abstract A sensitive and specific liquid chromatography electrospray ionization,tandem mass spectrometry method for the enantioselective determination of the novel ,-adrenolytic compound, 1-(1- H -indol-4-yloxy)-3-{[2-(2-methoxyphenoxy)ethylo]amino} propan-2-ol, in rat plasma has been developed and validated. Chromatography was performed on a reversed-phase Chiralcel OD-RH analytical column (150 × 4.6 mm, 5 ,m, Daicel Chemical Industries, Tokyo, Japan) with isocratic elution using a mobile phase containing acetonitrile and water with 0.01% formic acid. Detection was achieved by an Applied Biosystems MDS Sciex (Concord, Ontario, Canada) API 2000 triple quadrupole mass spectrometer. Electrospray ionization (ESI) was used for ion production. The limit of detection in the MRM mode was found to be 1.25 ng/ml. The limit of quantification of both enantiomers was 2.5 ng/ml. The precision and accuracy for both intra- and inter-day determination of 2F109 enantiomers ranged from 2.6 to 12% and from 89.1 to 107.1%. This analytical method allowed us to carry out pharmacokinetic studies in rats. Our findings demonstrate that 2F109 shows stereoselective disposition in rat plasma after i.v. administration. The terminal half-lives of (+)-(R)-2F109 and (,)-(S)-2F109 were 33.5 and 42.6 min, respectively. The AUC0,inf of (+)-(R)-2F109 exceeded that of (,)-(S)-2F109. Chirality, 2007. © 2007 Wiley-Liss, Inc. [source] A semi-automated solid-phase extraction liquid chromatography/tandem mass spectrometry method for the analysis of tetrahydrocannabinol and metabolites in whole blood,RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2009Eshwar Jagerdeo Marijuana is one of the most commonly abused illicit substances in the USA, making cannabinoids important to detect in clinical and forensic toxicology laboratories. Historically, cannabinoids in biological fluids have been derivatized and analyzed by gas chromatography/mass spectrometry (GC/MS). There has been a gradual shift in many laboratories towards liquid chromatography/mass spectrometry (LC/MS) for this analysis due to its improved sensitivity and reduced sample preparation compared with GC/MS procedures. This paper reports a validated method for the analysis of ,9 -tetrahydrocannabinol (THC) and its two main metabolites, 11-nor-9-carboxy-,9 -tetrahydrocannabinol (THC-COOH) and 11-hydroxy-,9 -tetrahydrocannabinol (THC-OH), in whole blood samples. The method has also been validated for cannabinol (CBD) and cannabidiol (CDN), two cannabinoids that were shown not to interfere with the method. This method has been successfully applied to samples both from living people and from deceased individuals obtained during autopsy. This method utilizes online solid-phase extraction (SPE) with LC/MS. Pretreatment of samples involves protein precipitation, sample concentration, ultracentrifugation, and reconstitution. The online SPE procedure was developed using Hysphere C8-EC sorbent. A chromatographic gradient with an Xterra MS C18 column was used for the separation. Four multiple-reaction monitoring (MRM) transitions were monitored for each analyte and internal standard. Linearity generally fell between 2 and 200,ng/mL. The limits of detection (LODs) ranged from 0.5 to 3,ng/mL and the limits of quantitation (LOQs) ranged from 2 to 8,ng/mL. The bias and imprecision were determined using a simple analysis of variance (ANOVA: single factor). The results demonstrate bias as <7%, and imprecision as <9%, for all components at each quantity control level. Published in 2009 by John Wiley & Sons, Ltd. [source] A liquid chromatography/tandem mass spectrometry method for detecting UGT-mediated bioactivation of drugs as their N -acetylcysteine adducts in human liver microsomesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2009Hiroshi Harada The detection of the reactive metabolites of drugs has recently been gaining increasing importance. In vitro trapping studies using trapping agents such as glutathione are usually conducted for the detection of reactive metabolites, especially those of cytochrome P450-mediated metabolism. In order to detect the UDP-glucuronosyltransferase (UGT)-mediated bioactivation of drugs, an invitro trapping method using N -acetylcysteine (NAC) as a trapping agent followed by liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed in this study. After the test compounds (diclofenac and ketoprofen) had been incubated in human liver microsomes with uridine diphosphoglucuronic acid (UDPGA) and NAC, the NAC adducts formed through their acyl glucuronides were analyzed using LC/MS/MS with electrospray ionization (ESI). The NAC adduct showed a mass shift of 145 units as compared to its parent, and the characteristic ion fragmentations reflected the parent. This is a concise and high-throughput method for evaluating reactive metabolites by UGT-mediated bioactivation. Copyright © 2009 John Wiley & Sons, Ltd. [source] Development of a multi-mycotoxin liquid chromatography/tandem mass spectrometry method for sweet pepper analysisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 1 2009Sofie Monbaliu A multi-mycotoxin method was developed for the simultaneous determination of trichothecenes (nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, neosolaniol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin, T-2 toxin), aflatoxins (aflatoxin-B1, aflatoxin-B2, aflatoxin-G1 and aflatoxin-G2), Alternaria toxins (alternariol, alternariol methyl ether and altenuene), fumonisins (fumonisin-B1, fumonisin-B2 and fumonisin-B3), ochratoxin A, zearalenone, beauvericin and sterigmatocystin in sweet pepper. Sweet pepper was extracted with ethyl acetate/formic acid (99:1, v/v). After splitting up the extract, two-thirds of the extract was cleaned up using an aminopropyl column followed by an octadecyl column. The remaining part was cleaned up using a strong anion-exchange column. After recombination of both cleaned parts of the sample extract, the combined solvents were evaporated and the residue was dissolved in mobile phase; 20,µL was injected into the chromatographic system, so only one run was used to separate and detect the mycotoxins in positive electrospray ionization using selected reaction monitoring. The samples were analyzed with a Micromass Quattro Micro triple quadrupole mass spectrometer (Waters, Milford, MA, USA). The mobile phase consisted of variable mixtures of water and methanol, 1% acetic acid and 5,mM ammonium acetate. The limits of detection of the multi-mycotoxin method varied from 0.32,µg.kg,1 to 42.48,µg.kg,1. The multi-mycotoxin liquid chromatography/tandem mass spectrometry (LC/MS/MS) method fulfilled the method performance criteria required by the Commission Regulation (EC) No 401/2006. Sweet peppers inoculated by Fusarium species were analyzed using the developed method. Beauvericin (9,484,µg.kg,1) and fumonisins (fumonisin-B1 up to 4330,µg.kg,1, fumonisin-B2 up to 4900,µg.kg,1, and fumonisin-B3 up to 299,µg.kg,1) were detected. Copyright © 2008 John Wiley & Sons, Ltd. [source] Development of a validated liquid chromatography/tandem mass spectrometry method for the distinction of thyronine and thyronamine constitutional isomers and for the identification of new deiodinase substratesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2008Susanne Piehl Thyronines (THs) and thyronamines (TAMs) are two groups of endogenous iodine-containing signaling molecules whose representatives differ from each other only regarding the number and/or the position of the iodine atoms. Both groups of compounds are substrates of three deiodinase isozymes, which catalyze the sequential reductive removal of iodine from the respective precursor molecule. In this study, a novel analytical method applying liquid chromatography/tandem mass spectrometry (LC-MS/MS) was developed. This method permitted the unequivocal, simultaneous identification and quantification of all THs and TAMs in the same biological sample. Furthermore, a liquid-liquid extraction procedure permitting the concurrent isolation of all THs and TAMs from biological matrices, namely deiodinase (Dio) reaction mixtures, was established. Method validation experiments with extracted TH and TAM analytes demonstrated that the method was selective, devoid of matrix effects, sensitive, linear over a wide range of analyte concentrations and robust in terms of reproducible recoveries, process efficiencies as well as intra-assay and inter-assay stability parameters. The method was applied to study the deiodination reactions of iodinated THs catalyzed by the three deiodinase isozymes. With the HPLC protocol developed herein, sufficient chromatographic separation of all constitutional TH and TAM isomers was achieved. Accordingly, the position of each iodine atom removed from a TH substrate in a Dio-catalyzed reaction was backtracked unequivocally. While several established deiodination reactions were verified, two as yet unknown reactions, namely the phenolic ring deiodination of 3,,5,-diiodothyronine (3,,5,-T2) by Dio2 and the tyrosyl ring deiodination of 3-monoiodothyronine (3-T1) by Dio3, were newly identified. Copyright © 2008 John Wiley & Sons, Ltd. [source] Development of a liquid chromatography/tandem mass spectrometry assay for the quantification of rabeprazole in human plasmaRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2005Jinchang Huang A simple and sensitive liquid chromatography/tandem mass spectrometry method, employing electrospray ionization, has been developed and validated to quantify rabeprazole in human plasma using omeprazole as the internal standard. The method was validated to demonstrate the specificity, lower limit of quantification, accuracy, and precision of measurements. Selected reaction monitoring was specific for rabeprazole and omeprazole (the internal standard, IS); no endogenous materials interfered with the analysis of rabeprazole and IS from blank plasma. The assay was linear over the concentration range 0.2,200,ng/mL using a 2,µL aliquot of plasma. The correlation coefficients for the calibration curves ranged from 0.9988,0.9994. The intra- and inter-day precision, calculated from quality control samples, were less than 6.65%. A mixture of methanol and water (50:50) was used as the isocratic mobile phase, with 0.1% of formic acid in water, that did not affect the stability of rabeprazole or IS. A simple sample preparation method of protein precipitation with methanol was chosen. The method was employed in a pharmacokinetic study after oral administration of 20,mg rabeprazole to 24 healthy volunteers. Copyright © 2005 John Wiley & Sons, Ltd. [source] A highly automated 96-well solid phase extraction and liquid chromatography/tandem mass spectrometry method for the determination of fentanyl in human plasmaRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2001Wilson Z. Shou A high-throughput bioanalytical method based on automated sample transfer, automated solid phase extraction, and fast liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis, has been developed for the determination of the analgesic fentanyl in human plasma. Samples were transferred into 96-well plates using an automated sample handling system. Automated solid phase extraction (SPE) was carried out using a 96-channel programmable liquid-handling workstation using a mixed-mode sorbent. The extracted samples were then dried down, reconstituted and injected onto a silica column using an aqueous/organic mobile phase with tandem mass spectrometric detection. The method has been validated over the concentration range 0.05,100,ng/mL fentanyl in human plasma, based on a 0.25-mL sample size. The assay is sensitive, specific and robust. More than 2000 samples have been analyzed using this method. The automation of the sample preparation steps not only increased the analysis throughput, but also facilitated the transfer of the method between different bioanalytical laboratories of the same organization. Copyright© 2001 John Wiley & Sons, Ltd. [source] A liquid chromatography/tandem mass spectrometry method for determination of aristolochic acid-I in rat plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 2 2010Yiming Liu Abstract A sensitive, rapid and specific liquid chromatography,electrospray ionization,tandem mass spectrometry method was developed and validated for the determination of aristolochic acid-I (AA-I) in rat plasma. Finasteride was used as the internal standard (IS). The analyte was separated on a Zorbax Eclipse XDB-C18 column by isocratic elution with methanol-10,mM ammonium acetate (75:25, v/v, pH = 7.3) at a flow rate of 0.25,mL/min, and analyzed by mass spectrometry in positive multiple reaction monitoring mode. The precursor-to-product ion transitions of m/z 359.0 , 298.2 and m/z 373.1 , 305.2 were used to detect AA-I and IS, respectively. Good linearity was achieved over a range of 0.4,600,ng/mL. Intra- and inter-day precisions measured as relative standard deviation were less than 13.5%, and accuracy ranged from 94.2 to 97.5%. The developed method was successfully applied in the pharmacokinetic study of AA-I in rats. Copyright © 2009 John Wiley & Sons, Ltd. [source] A sensitive and specific liquid chromatography/tandem mass spectrometry method for determination of echinacoside and its pharmacokinetic application in ratsBIOMEDICAL CHROMATOGRAPHY, Issue 6 2009Hao Yang Abstract A rapid and sensitive method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the determination of echinacoside in rat plasma was established and fully validated. A single step of liquid,liquid extraction with n -butanol was utilized. Chromatographic separation of the analyte and the internal standard (IS), chlorogenic acid, from the sample matrix was performed using a Capcell-MG C18 analytical column (100 2.0 mm × 5 µm), with a gradient of acetonitrile and water containing 0.1% acetic acid as the mobile phase. Detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization source operated in negative ion selected reaction monitoring mode. The method was linear in the concentration range 10,2500 ng/mL. The deviations of both intra- and inter-day precisions (RSD) were 7.1% and the assay accuracies were within 99.2,106.5%. Echinacoside proved to be stable during sample storage, preparation and analysis when an antioxidant solution was used. The method was successfully applied to a pharmacokinetic study in rats after an intragastric administration of echinacoside (100 mg/kg). With the lower limit of quantification at 10 ng/mL, this method proved to have sufficient selectivity, sensitivity and reproducibility for the pharmacokinetic study of echinacoside. Copyright © 2009 John Wiley & Sons, Ltd. [source] Quantification of intracellular homocysteine by stable isotope dilution liquid chromatography/tandem mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 1 2007Yuehua Huang Abstract A precise and accurate stable isotope dilution liquid chromatography/tandem mass spectrometry method for the analysis of intracellular homocysteine has been developed. An internal standard, [2H8]-homocystine, was added to cell pellets from EA.hy 926 cells grown in culture under low and high folate concentrations. d,l -dithiothreitol was used to reduce cellular homocystine to homocysteine. Cellular proteins were precipitated by the addition of formic acid in acetonitrile. After centrifugation, a portion of the supernatant was analyzed by liquid chromatography/tandem mass spectrometry. Using a Supelcosil cyano column with an Applied Biosystems API 4000 triple quadrupole mass spectrometer, the SRM transitions for homocysteine (m/z 136 to m/z 90) and [2H4]-homocysteine (m/z 140 to m/z 94) were monitored. The method was validated by conducting five replicate analyses on three different days at four different concentrations (concentrations at the lower limit of quantitation and expected lower quartile, mid-range and upper quartile). The limit of detection was 2 ng/106 EA.hy 926 cells. Using this method, the intracellular homocysteine concentration in EA.hy 926 cells ranged from 10 to 36 ng/106 cells. Copyright © 2006 John Wiley & Sons, Ltd. [source] Influence of CYP2C9 and CYP2C19 genetic polymorphisms on pharmacokinetics and pharmacodynamics of gliclazide in healthy Chinese Han volunteersJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 3 2010H. Shao PhD Summary Background and objective:,CYP2C9 is the major contributor to gliclazide metabolic clearance in vitro, while the pharmacokinetics of gliclazide modified release are affected mainly by CYP2C19 genetic polymorphisms in vivo. This study aims to investigate the influence of CYP2C9 and CYP2C19 genetic polymorphisms on the pharmacokinetics and pharmacodynamics of gliclazide in healthy Chinese Han volunteers. Methods:, Eighteen healthy Han subjects with various combinations of CYP2C9 and CYP2C19 genotypes received 80 mg gliclazide. Plasma gliclazide concentrations were measured by a liquid chromatography,tandem mass spectrometry method for 84 h and plasma glucose and insulin levels were measured up to 15 h post-dose. Results and discussion:, There was no difference in either pharmacokinetic and or pharmacodynamic parameters of gliclazide when group A (CYP2C9*1/*1, CYP2C19 extensive metabolizers) was compared with group B (CYP2C9*1/*3, CYP2C19 *1/*1). When group C (CYP2C9*1/*1 and CYP2C19 poor metabolizers) was compared with group A, the AUC0,, and Cmax in group C were significantly higher [83·94 ± 40·41 vs. 16·39 ± 5·10 ,g·h/mL (P = 0·000) and 1·50 ± 0·85 vs. 0·45 ± 0·18 ,g/mL (P = 0·000)], and the oral clearance was significantly lower [1·17 ± 0·63 vs. 5·38 ± 1·86 L/h (P = 0·000)]. The half-life of gliclazide was also significantly prolonged in group C subjects when compared with that of group A (33·47 ± 12·39 vs. 19·34 ± 10·45 h), but the difference was not significant (P = 0·052). The increase in serum glucose level at 11 h after dosing (,Cglu11) in group C was significantly higher than that of group A (,1·08 ± 0·42 vs. 0·22 ± 1·01 mmol/L, P = 0·022). The corresponding insulin levels showed no difference between the two groups. Conclusion:,CYP2C9*3 was not associated with any change in the disposition of gliclazide. CYP2C19 polymorphisms appear to exert the dominant influence on the pharmacokinetics of gliclazide in healthy Chinese Han subjects, and may also affect the observed pharmacodynamics of the drug as a result. [source] A rapid and sensitive liquid chromatography/positive ion tandem mass spectrometry method for the determination of cimetropium in human plasma by liquid,liquid extractionJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2006Heon-Woo Lee Abstract We have developed and validated a simple detection system with high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometry (ESI-MS/MS) for determining cimetropium levels in human plasma using scopolamine butyl bromide as an internal standard (I.S.). The acquisition was performed in the multiple reaction monitoring (MRM) mode, by monitoring the transitions: m/z 357.9 > 103.1 for cimetropium and m/z 359.9 > 103.1 for butyl-scopolamine. The method involves a simple single-step liquid,liquid extraction with dichloromethane. The analyte was chromatographed on an YMC C18 reversed-phase chromatographic column by isocratic elution with 10 mM ammonium formate buffer,methanol (19 : 81, v/v; adjusted to pH 4.0 with formic acid). The results were linear over the studied range (0.2,100 ng ml,1), with r2 = 1.0000, and the total analysis time for each run was 2 min. Intra- and interassay precisions were 0.70,8.54% and 1.08,4.85%, respectively, and intra- and interassay accuracies were 97.56,108.23% and 97.48,103.91%, respectively. The lower limit of quantification (LLOQ) was 0.2 ng ml,1. At this concentration, mean intra- and interassay precisions were 8.54% and 4.85%, respectively, and mean intra- and interassay accuracies were 97.56% and 98.91%, respectively. The mean recovery ranged from 62.71 ± 4.06 to 64.23 ± 2.32%. Cimetropium was found to be stable in plasma samples under typical storage and processing conditions. The devised assay was successfully applied to a pharmacokinetic study of cimetropium bromide administered as a single oral dose (150 mg) to healthy volunteers. Copyright © 2006 John Wiley & Sons, Ltd. [source] Liquid chromatography,tandem mass spectrometry method for simultaneous determination of cyclosporine A and its three metabolites AM1, AM9 and AM4N in whole blood and isolated lymphocytes in renal transplant patientsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 15 2010Hana Brozmanová Abstract A LC-MS/MS method was developed and validated for the determination of cyclosporine A (CsA) and its three phase 1 metabolites AM1, AM9, and AM4N in whole blood and lymphocytes isolated on the Histopaque gradient. 200,,L of whole blood was precipitated with 10,mol/L zinc sulfate in acetonitrile/methanol (40:60, v/v) and lymphocytes isolated from 1.5,mL blood were extracted with acetonitrile/methanol (40:60, v/v). The analytes and internal standard cyclosporine D were separated on RP column BEH C18, 2.1×50,mm, 1.7,,m using gradient LC-MS/MS analysis in positive electrospray mode. Time of analysis was 5,min. Linearity in blood was 5,2000,,g/L for CsA, AM1, and AM9; 2,500,,g/L for AM4N; and 2,500,,g/L for all substances in lymphocytes. Coefficient of variations was 1.8,9.8% and recovery was 92.0,110.0%. The method was used in early and chronic renal transplant patients for therapeutic drug monitoring of CsA to compare either its share in lymphocytes as target organ or binding to one lymphocyte. The same parameters were calculated for all metabolites tested. [source] Rapid and sensitive on-line liquid chromatographic/tandem mass spectrometric determination of an ethylene oxide-DNA adduct, N7-(2-hydroxyethyl)guanine, in urine of nonsmokersRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2008Chih-Chun Jean Huang Ethylene oxide (EtO) is classified as a known human carcinogen. The formation of EtO-DNA adducts is considered as an important early event in the EtO carcinogenic process. An isotope-dilution on-line solid-phase extraction and liquid chromatography coupled with tandem mass spectrometry method was then developed to analyze one of the EtO-DNA adducts, N7-(2-hydroxyethyl)guanine (N7-HEG), in urine of 46 nonsmokers with excellent accuracy, sensitivity and specificity. The merits of this method include small sample volume (only 120,µL urine required), automated sample cleanup, and short total run time (12 minutes per sample). This method demonstrates its high-throughput capacity for future molecular epidemiology studies on the potential health effects resulting from the low-dose EtO exposure. Copyright © 2008 John Wiley & Sons, Ltd. [source] In-house validation of a liquid chromatography/electrospray tandem mass spectrometry method for confirmation of chloramphenicol residues in muscle according to Decision 2002/657/ECRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2005Floriana Vinci In this work we present an in-house validation study for the confirmatory analysis of chloramphenicol (CAP) in muscle according to the Commission Decision 2002/657/EC requirements. CAP is extracted in acetonitrile and after liquid-liquid partitioning with n -hexane is identified and quantitatively determined by ion trap liquid chromatography/electrospray ionisation tandem mass spectrometry (LC/ESI-MS/MS) analysis in the negative ion mode. CAP was identified using the precursor ion and at least two product ions, meeting the qualitative and quantitative criteria set by the European Commission in the Decision 2002/657/EC for confirmation of prohibited veterinary drug residues. We calculated mean drug recoveries, CC, and CC, of the method, and reported data on specificity, ruggedness and within-laboratory reproducibility. Finally, we point out and discuss some problems and questions arising from controversy about the application of Decision 2002/657/EC. Copyright © 2005 John Wiley & Sons, Ltd. [source] Simultaneous determination of t,t -muconic, S -phenylmercapturic and S -benzylmercapturic acids in urine by a rapid and sensitive liquid chromatography/electrospray tandem mass spectrometry methodRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2004Anna Barbieri We describe a rapid and sensitive high-performance liquid chromatography/electrospray tandem mass spectrometry (HPLC/ESI-MS/MS) method for simultaneous determination of the most relevant metabolites of benzene and toluene, t,t- muconic acid (t,t -MA), S -phenylmercapturic acid (S-PMA), and S -benzylmercapturic acid (S-BMA). Urine samples were purified before analysis by solid-phase microextraction (SPE) on SAX cartridges with 50,mg sorbent mass. The developed method fulfils all the standard requirements of precision and accuracy. Calibration curves were linear within the concentration range of the standards (0,80,,g/Lurine for t,t -MA, and 0,25,,g/Lurine for S-PMA and S-BMA), and had correlation coefficients ,0.997. Limits of detection were 6.0,,g/L for t,t -MA, 0.3,,g/L for S-PMA, and 0.4,,g/L for S-BMA. The method was used to determine t,t -MA, S-PMA and S-BMA levels in urine of 31 gasoline-station workers, with personal monitoring data obtained from radial symmetry passive diffusive samplers. In the context of mean work-shift exposures of 75.9,,g/m3 (range 9.4,220.2) for benzene and 331.9,,g/m3 (78.2,932.1) for toluene, metabolite concentrations in end-of-shift urine samples ranged from 23.5,275.3,,g/gcreatinine for t,t -MA, non-detectable to 0.9,,g/gcreatinine for S-PMA, and 3.8,74.8,,g/gcreatinine for S-BMA. No significant correlation was found between the environmental concentrations and urinary metabolites (p,>,0.05 for all cases); the ratios of benzene metabolites could be influenced by exposure levels and co-exposure to xylenes and toluene. The high throughput of this procedure should facilitate exploration of the metabolic effects of benzene-related co-exposure to toluene and alkylbenzenes in large populations of subjects exposed to gasoline. Copyright © 2004 John Wiley & Sons, Ltd. [source] A direct injection high-throughput liquid chromatography tandem mass spectrometry method for the determination of a new orally active ,v,3 antagonist in human urine and dialysateRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2003Wei Zeng A generic high-throughput liquid chromatography (HTLC) tandem mass spectrometry (MS/MS) assay for the determination of compound I in human urine and dialysate (hemodialysis) was developed and validated. By using the HTLC on-line extraction technique, sample pretreatment was not necessary. The sample was directly injected onto a narrow bore large particle size extraction column (50,×,1.0,mm, 60,,m) where the sample matrix was rapidly washed away using a high flow rate (5,mL/min) aqueous mobile phase while analytes were retained. The analytes were subsequently eluted from the extraction column onto an analytical column using an organic-enriched mobile phase prior to mass spectrometric detection. The analytes were then eluted from the analytical column to the mass spectrometer for the determination. The linear dynamic range was 2.0,6000,ng/mL for the urine assay and 0.1,300,ng/mL for the dialysate assay. Intraday accuracy and precision were evaluated by analyzing five replicates of calibration standards at all concentrations used to construct the standard curve. For the urine assay, the precision (RSD%, n,=,5) ranged from 1.9 to 8.0% and the accuracy ranged from 87.8 to 105.2% of nominal value. For the dialysate assay, the precision (RSD%, n,=,5) ranged from 1.1 to 10.0% and the accuracy from 94.5 to 105.2% of nominal value. In-source fragmentation of the acyl glucuronide metabolite (compound III) did not interfere with the determination of parent compound I. The developed HTLC/MS/MS methodology was specific for compound I in the presence of compound III. Column life-time is increased and sample analysis time is decreased over traditional reversed-phase methods when direct injection assays for urine and dialysate are coupled with the technology of HTLC. Copyright © 2003 John Wiley & Sons, Ltd. [source] Sensitive and selective liquid chromatography,tandem mass spectrometry method for the determination of metoclopramide in human plasma: application to a bioequivalence studyBIOMEDICAL CHROMATOGRAPHY, Issue 9 2010Jaswanth Kumar Inamadugu Abstract A simple, sensitive and rapid method has been developed and validated for determination of the metoclopramide (MCP) in 100,,L human plasma. The analytical procedure involves a liquid,liquid extraction method using tramadol as an internal standard (IS). Chromatographic separation was carried out on a HyPURITY ADVANCE column using a mobile phase consisting of acetonitrile and 10,mm ammonium acetate buffer in the ratio of 80:20 (v/v) at a flow rate of 0.3,mL/min. The total run time of analysis was 2.5,min and elution of MCP and IS occurred at 0.9 and 1.3,min, respectively. A linear response function was established for the range of concentrations 0.53,42.07,ng/mL (r > 0.99). The intra- and inter-day precision values for MCP met the acceptance as per FDA guidelines. MCP was stable in a battery of stability studies viz., bench-top, auto-sampler and freeze,thaw cycles. The developed assay method was successfully applied to an oral bioequivalence study in humans. Copyright © 2010 John Wiley & Sons, Ltd. [source] Liquid chromatography tandem mass spectrometry method for determination of bisoprolol in human plasma using d5-bisoprolol as the internal standardBIOMEDICAL CHROMATOGRAPHY, Issue 6 2010Gang-yi Liu Abstract A simple, reliable and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) protocol was developed and validated for quantification of bisoprolol in human plasma. The sample was pretreated with a simple procedure of protein precipitation and an isotope-labeled d5-bisoprolol was used as internal standard. The chromatographic separation was performed on a Capcell Pak C18 MG III column (100,mm × 2.0,mm, 5,µm). The protonated ion of the analyte was detected in positive ionization by multiple reaction monitoring mode. The mass transition pairs of m/z 326.3 , 116.3 and m/z 331.3 , 121.3 were used to detect bisoprolol and the internal standard, respectively. Linearity, accuracy, precision, recovery, matrix effect, dilution test and stability were evaluated during method validation over the range of 0.5,100,ng/mL. The validated method was successfully applied to analyze human plasma samples in a bisoprolol bioavailability study. Copyright © 2009 John Wiley & Sons, Ltd. [source] Liquid chromatography,mass spectrometry for analysis of a novel ,2 -adrenoceptor agonist trantinterol and its metabolites in beagle dog urineBIOMEDICAL CHROMATOGRAPHY, Issue 3 2010Yanjuan Wang Abstract A liquid chromatography,tandem mass spectrometry method was developed for the identification of metabolites of trantinterol, a novel ,2 -adrenoceptor agonist, in beagle dog urine. The separation of metabolites was performed on a reversed-phase C8 column using 0.1% formic acid in water and methanol (70 : 30, v/v) as the mobile phase. The structural information and elemental information of metabolites were acquired by an electrospray ionization tandem mass spectrometer and a quadrupole time-of-flight mass spectrometer, respectively. A total of 13 metabolites were detected and characterized on the basis of their tandem MS/MS fragmentation patterns. The accurate masses of nine metabolites were determined and two metabolites were further confirmed by comparing with reference standards. The metabolic pathways of trantinterol in beagle dog are proposed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Measurement of fexofenadine concentration in micro-sample human plasma by a rapid and sensitive LC-MS/MS employing protein precipitation: application to a clinical pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 3 2010Daqing Guo Abstract A simple, rapid and sensitive liquid chromatography/positive ion electro-spray tandem mass spectrometry method (LC-MS/MS) was developed and validated for the quantification of fexofenadine with 100,,L human plasma employing glipizide as internal standard (IS). Protein precipitation was used in the sample preparation procedure. Chromatographic separation was achieved on a reversed-phase C18 column (5,,m, 100 × 2.1,mm) with methanol,:,buffer (containing 10,mmol/L ammonium acetate and 0.1% formic acid; 70,:,30, v/v) as mobile phase. The total chromatographic runtime was approximately 3.0,min with retention time for fexofenadine and IS at approximately 1.9 and 2.1,min, respectively. Detection of fexofenadine and IS was achieved by LC-MS/MS in positive ion mode using 502.1 , 466.2 and 446.0 , 321.1 transitions, respectively. The method was proved to be accurate and precise at linearity range of 1,600,ng/mL with a correlation coefficient (r) of ,0.9976. The validated method was applied to a pharmacokinetic study in human volunteers following oral administration of 60 or 120,mg fexofenadine formulations, successfully. Copyright © 2009 John Wiley & Sons, Ltd. [source] A liquid chromatography/tandem mass spectrometry method for determination of aristolochic acid-I in rat plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 2 2010Yiming Liu Abstract A sensitive, rapid and specific liquid chromatography,electrospray ionization,tandem mass spectrometry method was developed and validated for the determination of aristolochic acid-I (AA-I) in rat plasma. Finasteride was used as the internal standard (IS). The analyte was separated on a Zorbax Eclipse XDB-C18 column by isocratic elution with methanol-10,mM ammonium acetate (75:25, v/v, pH = 7.3) at a flow rate of 0.25,mL/min, and analyzed by mass spectrometry in positive multiple reaction monitoring mode. The precursor-to-product ion transitions of m/z 359.0 , 298.2 and m/z 373.1 , 305.2 were used to detect AA-I and IS, respectively. Good linearity was achieved over a range of 0.4,600,ng/mL. Intra- and inter-day precisions measured as relative standard deviation were less than 13.5%, and accuracy ranged from 94.2 to 97.5%. The developed method was successfully applied in the pharmacokinetic study of AA-I in rats. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of fenofibric acid in human plasma by ultra performance liquid chromatography,electrospray ionization mass spectrometry: application to a bioequivalence studyBIOMEDICAL CHROMATOGRAPHY, Issue 9 2009Dasandi Bhavesh Abstract A rapid, specific and sensitive ultra-performance liquid chromatography tandem mass spectrometry method was developed for the determination of fenofibric acid in human plasma. The method involves simple, one-step liquid,liquid extraction procedure coupled with an Acquity UPLCTM BEH C18 column (50 × 2.1 mm, i.d., 1.7 µm) with isocratic elution at a flow-rate of 0.2 mL/min and mefenamic acid was used as the internal standard. The Quattro Premier XE mass spectrometry was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. Using 250 µL plasma, the methods were validated over the concentration rang 0.05,7.129 µg/mL, with a lower limit of quantification of 0.05 µg/mL. The intra- and inter-day precision and accuracy were within 9.3%. The recovery was 66.7% and 52.6% for fenofibric acid, and mefenamic acid, respectively. Total run time was 1.8 min only for each sample, which makes it possible to analyze more than 350 samples per day. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of teniposide in rat plasma by ultra performance liquid chromatography electrospray ionization tandem mass spectrometry after intravenous administrationBIOMEDICAL CHROMATOGRAPHY, Issue 9 2009Jing Wang Abstract A novel, specific and rapid ultra performance liquid chromatography electrospray ionization tandem mass spectrometry method has been developed and validated for determination of teniposide in rat plasma. A one-step liquid,liquid extraction method was used and the separation was carried out on an Acquity UPLCTM BEH C18 column with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.20 mL/min. A triple quadrupole tandem mass spectrometer in multiple-reaction monitoring mode via an electrospray ionization interface was used for the detection of teniposide. The detection was complete within 3.0 min. A linear calibration curve was obtained over the concentration range 10,10,000 ng/mL for teniposide, with a lower limit of quantification of 10 ng/mL. The intra-day precision and inter-day precision (relative standard deviation) were less than 10.23 and 13.09%, respectively. The developed method was applied for the first time to the pharmacokinetic study of teniposide in rats following a single intravenous administration of 4.5 mg/kg teniposide. Copyright © 2009 John Wiley & Sons, Ltd. [source] Limitation of immunoaffinity column for the removal of abundant proteins from plasma in quantitative plasma proteomicsBIOMEDICAL CHROMATOGRAPHY, Issue 5 2009Tomoko Ichibangase Abstract In plasma proteomics, before a proteome analysis, it is essential to prepare protein samples without high-abundance proteins, including albumin, via specific preparation techniques, such as immunoaffinity capture. However, our preliminary experiments suggested that functional changes with use alter the ability of the immunoaffinity column. Thus, in this study, to evaluate the changes of the removal ability of abundant proteins from plasma by the immunoaffinity column, plasma proteome analysis was performed for the long-term test for the reproducibility of the affinity column using the fluorogenic derivatization,liquid chromatography,tandem mass spectrometry method combined with an IgY column. The specific adsorption for albumin decreased with an increase in the number of the column usage before its expiration date. Moreover, it was demonstrated that hydrophobic high molecular weight compounds in plasma adsorbed onto the column materials surface contributed to the functional changes from specific immunoaffinity adsorption into hydrophobic interaction. These results suggested that, in quantitative plasma proteomics studies, it is important to keep in mind the risk of not only the nonselective loss but also the changes in the adsorption ability of the immunoafinity column. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simultaneous quantification of a non-nucleoside reverse transcriptase inhibitor efavirenz, a nucleoside reverse transcriptase inhibitor emtricitabine and a nucleotide reverse transcriptase inhibitor tenofovir in plasma by liquid chromatography positive ion electrospray tandem mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 4 2009Ramakrishna Nirogi Abstract A high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method for the simultaneous quantification of efavirenz, emtricitabine and tenofovir was developed and validated with 100 µL human plasma. Following solid-phase extraction, the analytes were separated using a gradient 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 316 to 168 for efavirenz, m/z 248,130 for emtricitabine and m/z 288,176 for tenofovir, m/z 482,258 for rosuvastatin (IS), m/z 260,116 for propranolol (IS). The method exhibited a 100-fold linear dynamic range for all the three analytes in human plasma (20,2000, 2,200 and 20,2000 ng/mL for efavirenz, emtricitabine and tenofovir respectively). The lower limit of quantification was 2 ng/mL for emtricitabine and 20 ng/mL for both efavirenz and tenofovir with a relative standard deviation of less than 11%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The total chromatographic run time of 4 min for each sample made it possible to analyze more than 250 human plasma samples per day. The method is precise and sensitive enough for its intended purpose. The method is also successfully applied to quantify efavirenz, emtricitabine and tenofovir concentrations in a rodent pharmacokinetic study. Copyright © 2008 John Wiley & Sons, Ltd. [source] Development and validation of an on-line two-dimensional reversed-phase liquid chromatography,tandem mass spectrometry method for the simultaneous determination of prostaglandins E2 and F2, and 13,14-dihydro-15-keto prostaglandin F2, levels in human plasmaBIOMEDICAL CHROMATOGRAPHY, Issue 3 2009Junji Komaba Abstract We developed and validated an on-line reverse-phase two-dimensional LC/MS/MS (2D-LC/MS/MS) system for simultaneous determination of the levels of prostaglandin (PG) E2 as well as PGF2, and its metabolite 13,14-dihydro-15-keto PGF2, (F2, -M) in human plasma. Analytes were extracted by a three-step solid-phase extraction. Samples were then analyzed by on-line 2D-LC/MS/MS with electrospray ionization in negative mode. The 2D-LC system is composed of two reverse-phase analytical columns with a trapping column linking the two analytical columns. While an acidic buffer was used for both separation dimensions, differing organic solvents were employed for each dimension: methanol for the first and acetonitrile for the second to increase resolving power. The 2D-LC/MS/MS method was highly selective and sensitive with a significantly lower limit of quantitation (0.5 pg/mL for PGE2 and 2.5 pg/mL for PGF2, and F2, -M, respectively). Linearity of the 2D-LC/MS/MS system was demonstrated for the calibration ranges of 0.5,50 pg/mL for PGE2 and 2.5,500 pg/mL for PGF2, and F2, -M, respectively. Acceptable precision and accuracy were obtained throughout the calibration curve ranges. This highly selective and sensitive method was successfully utilized to determine the endogenous levels of PGE2, PGF2,, and F2, -M in plasma samples from six (four male and two female) normal volunteers. The mean concentrations for each analyte were 0.755 pg/mL for PGE2, 5.70 pg/mL for PGF2, and 9.48 pg/mL for F2, -M. Copyright © 2008 John Wiley & Sons, Ltd. [source] Simultaneous determination of mifepristone and monodemethyl-mifepristone in human plasma by liquid chromatography,tandem mass spectrometry method using levonorgestrel as an internal standard: application to a pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 1 2009Cheng Tang Abstract A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine mifepristone and monodemethyl-mifepristone in human plasma using levonorgestrel as the internal standard (IS). After solid-phase extraction of the plasma samples, mifepristone, monodemethyl-mifepristone and the IS were subjected to LC-MS/MS analysis using electro-spray ionization (ESI) in the multiple reaction monitoring (MRM) mode. Chromatographic separation was performed on an XTERRA MS C18 column (150 × 2.1 mm i.d., 5 µm). The method had a chromatographic run time of 4.5 min and linear calibration curves over the concentration ranges of 5,2000 ng/mL for mifepristone and monodemethyl-mifepristone. The recoveries of the method were found to be 94.5,103.7% for mifepristone and 70.7,77.3% for monodemethyl-mifepristone. The method had a lower limit of quantification (LLOQ) of 5.0 ng/mL and a lower limit of detection (LOD) of 1.0 ng/mL for both mifepristone and monodemethyl-mifepristone. The intra- and inter-batch precision was less than 15% for all quality control samples at concentrations of 10, 100 and 1000 ng/mL. These results indicate that the method was efficient with a short run time (4.5 min) and acceptable accuracy, precision and sensitivity. The validated LC-MS/MS method was successfully used in a pharmacokinetic study in healthy female volunteers after oral administration of 25 mg mifepristone tablet. Copyright © 2008 John Wiley & Sons, Ltd. [source] Determination of caudatin-2,6-dideoxy-3 -O- methy- , - d -cymaropyranoside in rat plasma using liquid chromatography,tandem mass spectrometryBIOMEDICAL CHROMATOGRAPHY, Issue 6 2008Yunru Peng Abstract A selective, sensitive and rapid liquid chromatography,tandem mass spectrometry method has been developed for the determination of caudatin-2,6-dideoxy-3 -O- methy- , - d -cymaropyranoside (CDMC) in rat plasma. This method involves a plasma clean-up step using liquid,liquid extraction, followed by LC separation and positive electrospray ionization mass spectrometry detection (LC/ESI-MS/MS). Chromatographic separation of the analytes was achieved using a C18 column with a mobile phase of acetonitrile and water (70:30, v/v) at a flow rate of 1.0 mL/min. Low energy collision tandem mass spectrometric analysis (CID-MS/MS) using the multiple reaction monitoring (MRM) mode was used for analyte quantification. For the MRM analysis of CDMC, the following transition at m/z 658.4 , 529.6 derived from the protonated molecule [M + Na]+. A calibration curve was linear in the 5,500 ng/mL range for CDMC, and the limit of detection was 5 ng/mL. The inter- and intra-day precisions (RSD) were ,8.5 and ,9.1%, respectively. The accuracy (RE) was ± 10.9%. The novel developed LC/ESI-MS/MS method was successfully applied to pharmacokinetic studies of CDMC after oral administration to rats. The total chromatographic run time of this method was 5.0 min per sample, allowing for analysis of a large number of samples per batch. Copyright © 2008 John Wiley & Sons, Ltd. [source] Sensitive liquid chromatography tandem mass spectrometry method for the quantification of sitagliptin, a DPP-4 inhibitor, in human plasma using liquid,liquid extractionBIOMEDICAL CHROMATOGRAPHY, Issue 2 2008Ramakrishna Nirogi Abstract A sensitive high-performance liquid chromatography,positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of sitagliptin, a DPP-4 inhibitor, 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 408,235 for sitagliptin and m/z 310,148 for the internal standard. The assay exhibited a linear dynamic range of 0.1,250 ng/mL for sitagliptin in human plasma. The lower limit of quantification was 0.1 ng/mL with a relative standard deviation of less than 6%. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. A run time of 2.0 min for each sample made it possible to analyze more than 300 human plasma samples per day. The validated method has been successfully used to analyze human plasma samples for application in pharmacokinetic studies. Copyright © 2007 John Wiley & Sons, Ltd. [source] | |||||||||||||