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LC/MS/MS System (lc/ms/m + system)
Selected AbstractsSimultaneous determination of morphine, codeine, 6-acetylmorphine, cocaine and benzoylecgonine in hair by liquid chromatography/electrospray ionization tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2009Da-Kong Huang A fast and sensitive liquid chromatography/triple quadrupole tandem mass spectrometry (LC/MS/MS) method was developed for the simultaneous determination of morphine, codeine, 6-acetylmorphine (6-AM), cocaine and benzoylecgonine (BE) in hair. Pulverized hair samples were extracted with methanol, and a 50,µL supernatant aliquot was injected into the LC/MS/MS system. Chromatography was performed with an XBridgeÔ phenyl column (3.5,µm particle size, 4.6,×,150,mm), and the mobile phase was composed of methanol and 10,mM ammonium acetate adjusted to pH 4.00 with 99% formic acid (95:5, v/v). A separation run with isocratic elution was completed in 10,min at a flow rate of 500,µL/min. Positive electrospray ionization and multiple reaction monitoring (MRM) with one precursor ion/product ion transition were used for the identification of each analyte. Deuterated analogues as internal standards were used for quantification and qualification. Linearity was established in the concentration range of 100,3000,pg/mg. The limits of detection were 10,pg/mg for morphine, codeine and 6-AM; and 1,pg/mg for cocaine and BE. The precision and accuracy were determined by spiking hair samples at six concentration levels. For all analytes, the relative standard deviations of intra- and inter-day precision were 0.1,6.3% and 1.5,10.6%, respectively. The accuracy ranged from 92.7 to 109.7%. The validated LC/MS/MS method was successfully applied to the analysis of 79 authentic hair samples. Copyright © 2009 John Wiley & Sons, Ltd. [source] Determination of iodoacetic acid using liquid chromatography/electrospray tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2008Benjamin P.-Y. A rapid analytical method based on liquid chromatography/tandem mass spectrometry (LC/MS/MS) using electrospray ionization in negative ion detection mode was developed for the analysis of underivatized iodoacetic acid in water. The method was applied to model reaction mixtures in the study of the formation of iodoacetic acid after chlorinated tap water was boiled in the presence of potassium iodide or iodized table salt. Samples can be directly analyzed by the LC/MS/MS system without extraction or chemical derivatization. Limit of detection was determined to be 0.3,µg/L (or 0.3,ng/mL) and limit of quantitation was about 1,µg/L (1,ng/mL). Copyright © 2008 John Wiley & Sons, Ltd. [source] Separation of a BMS drug candidate and acyl glucuronide from seven glucuronide positional isomers in rat plasma via high-performance liquid chromatography with tandem mass spectrometric detectionRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 11 2006Y.-J. Xue A high-performance liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for the determination of a BMS drug candidate and its acyl glucuronide (1- O - , glucuronide) in rat plasma. A 50-µL aliquot of each plasma sample was fortified with acetonitrile containing the internal standard to precipitate proteins and extract the analytes of interest. After mixing and centrifugation, the supernatant from each sample was transferred to a 96-well plate and injected into an LC/MS/MS system. Chromatographic separation was achieved isocratically on a Phenomenex Luna C18, 3,mm,×,150,mm, 3,µm column. The mobile phase contained 0.075% formic acid in 70:30 (v/v) acetonitrile/water. Under the optimized chromatographic conditions, the BMS drug candidate and its acyl glucuronide were separated from its seven glucuronide positional isomers within 10,min. Resolution of the parent from all glucuronides and acyl glucuronide from its positional isomers was critical to avoid their interference with quantitation of parent or acyl glucuronide. Detection was by positive ion electrospray MS/MS on a Sciex API 4000. The standard curve, which ranged from 5 to 5000,ng/mL, was fitted to a 1/x2 weighted quadratic regression model for both the BMS drug candidate and its acyl glucuronide. Whole blood and plasma stability experiments were conducted to establish the sample collection, storage, and processing conditions. The validation results demonstrated that this method was rugged and repeatable. The same methodology has also been used in mouse and human plasma for the determination of the BMS drug candidate and its acyl glucuronide. Copyright © 2006 John Wiley & Sons, Ltd. [source] Development of a low volume plasma sample precipitation procedure for liquid chromatography/tandem mass spectrometry assays used for drug discovery applicationsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2005Xiaoying Xu The demand for high sensitivity bioanalytical methods has dramatically increased in the drug discovery stage; in addition, there has been a growing trend of reducing the sample volume that is required for these assays. A sensitive high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) procedure has been developed and tested to meet these needs. The assay requires only a low plasma sample volume (10,µL) and employs a protein precipitation procedure using a 1:6 plasma/acetonitrile ratio. The supernatant is injected directly into the LC/MS/MS system using the selected reaction monitoring (SRM) procedure for detection. A generic HPLC gradient based on a methanol/water mobile phase with a flow rate set to 0.8,mL/min was used. The test method showed very good linearity between 0.1,1000,ng/mL (R2,=,0.9737), precision (%RSD,=,6,9), accuracy (%RE,=,,2) and reproducibility (%RSD,=,11). A drug discovery IV/PO study was assayed using both the new low volume method and our standard volume (50,µL) method. The correlation of the two sets of data from the two methods was excellent (R2,=,0.9287). This new assay procedure has been successfully used in our laboratory for over 100 different rat or mouse discovery PK studies. Copyright © 2005 John Wiley & Sons, Ltd. [source] Determination of the ionophoric coccidiostats narasin, monensin, lasalocid and salinomycin in eggs by liquid chromatography/tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2005Leen Mortier A sensitive and selective liquid chromatographic tandem mass spectrometric method (LC/MS/MS) for the simultaneous detection of the ionophoric coccidiostats narasin, monensin, lasalocid and salinomycin in whole eggs has been developed. A very simple sample preparation consisting of an extraction with an organic solvent was carried out. Sample extracts were injected into the LC/MS/MS system on a C18 column and an isocratic elution was performed. Nigericin was used as internal standard. The precursor ions produced by electrospray positive ionisation were selected for collisional dissociation with argon into product ions. Validation of the methods was performed based on Commission Decision 2002/657/EC.1 CC, was found to be 1,,g/kg for all four compounds. Monitoring of Belgian egg samples in 2004 revealed that residues of salinomycin, lasalocid and monensin could be found. Copyright © 2005 John Wiley & Sons, Ltd. [source] Direct-injection high performance liquid chromatography ion trap mass spectrometry for the quantitative determination of olanzapine, clozapine and N -desmethylclozapine in human plasmaRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 13 2002Manfred Kollroser A specific and sensitive direct-injection high performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC/ESI-MS/MS) method has been developed for the rapid identification and quantitative determination of olanzapine, clozapine, and N -desmethylclozapine in human plasma. After the addition of the internal standard dibenzepin and dilution with 0.1% formic acid, plasma samples were injected into the LC/MS/MS system. Proteins and other large biomolecules were removed during an online sample cleanup using an extraction column (1,×,50,mm i.d., 30,µm) with a 100% aqueous mobile phase at a flow rate of 4,mL/min. The extraction column was subsequently brought inline with the analytical column by automatic valve switching. Analytes were separated on a 5,µm Symmetry C18 (Waters) analytical column (3.0,×,150,mm) with a mobile phase of acetonitrile/0.1% formic acid (20:80, v/v) at a flow rate of 0.5,mL/min. The total analysis time was 6,min per sample. The inter- and intra-assay coefficients of variation for all compounds were <11%. By eliminating the need for extensive sample preparation, the proposed method offers very large savings in total analysis time. Copyright © 2002 John Wiley & Sons, Ltd. [source] Direct determination of phosphorylated intracellular anabolites of stavudine (d4T) by liquid chromatography/tandem mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2001Alain Pruvost The objective was to develop and validate a routine assay for active intracellular anabolites of stavudine (d4T), a nucleoside reverse transcriptase inhibitor in human PBMC, applicable to pharmacokinetic studies and treatment monitoring. This was achieved using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS), which theoretically allies optimum sensitivity, specificity and high sample throughput. After cellular lysis in a Tris/methanol buffer, the extract spiked with 2[H8]-ATP (internal standard) is directly injected into the LC/MS/MS system. Phosphorylated metabolites of d4T as well as deoxythymidine-triphosphate, the competitor on the reverse transcriptase, are separated from d4T on a reverse-phase microbore column with ion pairing. The detection is performed in the multiple reaction monitoring (MRM) mode after drug ionisation in negative mode electrospray. The limit of quantitation for d4T-TP was 138 fmol per 7,mL blood (9.8 fmol per 106 cells) and CV% for repeatability and intermediate precision were lower than 15%. Stability of compounds was checked before and during the process of isolation of PBMC. Cellular samples from several d4T-treated patients were successfully analysed using this method and d4T-triphosphate and deoxythymidine triphosphate were recovered. In conclusion, we have developed and validated a routine LC/MS/MS method that allows the simultaneous determination of mono-, di- and triphosphorylated anabolites of d4T in PBMC as well as the natural corresponding triphosphate in one analysis. For the first time, the chain terminator ratio (d4T-TP/dT-TP) could be directly measured. This method can be used simply and routinely on more than 35 samples per day. Extension to other nucleoside analogues is under development. Copyright © 2001 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] Development and validation of a high-sensitivity liquid chromatography/tandem mass spectrometry (LC/MS/MS) method with chemical derivatization for the determination of ethinyl estradiol in human plasma,BIOMEDICAL CHROMATOGRAPHY, Issue 7 2004Wilson Z. Shou Abstract An ultra-sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the analysis of oral contraceptive ethinyl estradiol (EE) was developed and validated over the curve range of 2.5,500 pg/mL using 1 mL of human plasma sample. Ethinyl estradiol and the internal standard, ethinyl estradiol tetra-deuterated (EE-d4), were extracted from the plasma matrix with methyl t -butyl ether, derivatized with dansyl chloride and then back-extracted into hexane. The hexane phase was evaporated to dryness, reconstituted and injected onto the LC/MS/MS system. The chromatographic separation was achieved on a Luna C18 column (50 × 2 mm, 5 µm) with an isocratic mobile phase of 20:80 (v/v) water:acetonitrile with 1% formic acid. The of,ine derivatization procedure introduced the easily ionizable tertiary amine function group to EE. This greatly improved analyte sensitivity in electrospray ionization and enabled us to achieve the desired lower limit of quantitation at 2.5 pg/mL. This high sensitivity method can be used for therapeutic drug monitoring or supporting bio-equivalence and drug,drug interaction studies in human subjects. Copyright © 2004 John Wiley & Sons, Ltd. [source] A novel on-line solid-phase extraction approach integrated with a monolithic column and tandem mass spectrometry for direct plasma analysis of multiple drugs and metabolitesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2005Xu Zang An on-line solid-phase extraction liquid chromatography/tandem mass spectrometry (SPE LC/MS/MS) assay using a newly developed SPE column and a monolithic column was developed and validated for direct analysis of plasma samples containing multiple analytes. This assay was developed in an effort to increase bioanalysis throughput and reduce the complexity of on-line SPE LC/MS/MS systems. A simple column-switching configuration that requires only one six-port valve and one HPLC pumping system was employed for on-line plasma sample preparation and subsequent gradient chromatographic separation. The resulting analytical method couples the desired sensitivity with ease of use. The method was found to perform satisfactorily for direct plasma analysis with respect to assay linearity, specificity, sensitivity, precision, accuracy, carryover, and short-term stability of an eight-analyte mixture in plasma. A gradient LC condition was applied to separate the eight analytes that cannot be distinctly differentiated by MS/MS. With a run time for every injection of 2.8,min, a minimum of 300 direct plasma injections were made on one on-line SPE column without noticeable changes in system performance. Due to the ruggedness and simplicity of this system, generic methods can be easily developed and applied to analyze a wide variety of compounds in a high-throughput manner without laborious off-line sample preparation. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||