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Electrospray Ionization Technique (electrospray + ionization_technique)
Selected AbstractsForensic identification of explosive oxidizers by electrospray ionization mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2002Xiaoming Zhao The mass spectrometry of a group of inorganic oxidizers was studied using the electrospray ionization technique. It was found that a series of cluster ions were predominant in both positive- and negative-ion mode, allowing for the characterization of the investigated oxidizers. The identity of the recorded cluster ions was further confirmed by using some isotopically labeled compounds and tandem mass spectrometry with collision-induced dissociation. The use of electrospray ionization mass spectrometry for positive identification of major oxidizer components in explosive formulations was demonstrated by three samples of forensic interest. Copyright © 2002 John Wiley & Sons, Ltd. [source] Liquid chromatographic,tandem mass spectrometry assay for quantitation of a novel antidiabetic S002-853 in rat plasma and its application to pharmacokinetic study,BIOMEDICAL CHROMATOGRAPHY, Issue 7 2010N. Gautam Abstract A sensitive and selective LC-MS/MS method has been developed and validated for the estimation of novel antidiabetic synthetic flavonoid S002-853 in rat plasma using centchroman as an internal standard. The method involves a simple two-step liquid,liquid extraction with diethyl ether. The analyte was chromatographed on a Pierce Spheri-5, guard cyano column (30 × 4.6,,mm i.d., 5,,µm) with isocratic mobile phase consisting of methanol,ammonium acetate buffer (pH 4.6, 10,,mm; 90,:,10, v/v) at a flow rate of 0.75,,mL/min. The API 4000 triple-quadrupole LC,MS/MS system was operated under multiple reaction-monitoring mode. The ionization was performed by electrospray ionization technique in positive ion mode. The chromatographic run time was 6,,min and the weighted (1/x2) calibration curves were linear over the range 0.78,400,,ng/mL. The limit of detection and lower limit of quantification were 0.195 and 0.78,,ng/mL, respectively. The intra- and inter-batch accuracy (%bias) and precision (%RSD) were found to be less than 8.47 and 11.6% respectively. The average absolute recoveries of S002-853 and internal standard from spiked plasma samples were >90%. S002-853 was stable for 8,,h at ambient temperature, 4 weeks at ,60°C and after three freeze,thaw cycles. The assay was successfully applied to determine the pharmacokinetic parameters in male Sprague,Dawley rats after an oral dose administration at 25,,mg/kg. 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] Development of a novel HPLC-MS/MS method for the determination of aconitine and its application to in vitro and rat microdialysis samplesBIOMEDICAL CHROMATOGRAPHY, Issue 7 2009Quan-long Zhang Abstract A sensitive and selective LC-MS/MS method was developed and validated for the determination of aconitine in microdialysate and rat plasma. Extraction of plasma sample was conducted by use of 1% trichloracetic acid and acetonitrile solution with 10 ng/mL internal standard (propafenone) spiked. Microdialysates were analyzed without sample purification. After sample preparation, 2 µL were injected and separated with an isocratic mobile phase consisting of acetonitrile:0.1% formic acid (60:40, v/v) at a flow rate of 0.3 mL/min. The Agilent G6410A triple quadrupole LC/MS system was operated under the multiple-reaction monitoring mode (MRM) using the electrospray ionization technique in positive mode. Overall, the assay exhibited good precision and accuracy. The diffusion properties of aconitine investigated in in vitro microdialysis experiments revealed unfavourable concentration dependence avertable by keeping a constant pH 5.77 using isotonic phosphate buffer solution as perfusate. The mean relative recoveries were 48.23% [coefficient of variation (CV 4.47%)] and 55.38% (CV 2.89%) for retrodialysis and recovery experiments, respectively. The in vivo recovery of aconitine was 34.48% (CV 3.05%) and was stable over the 6 h study period. Following characterization of aconitine both in vitro and in vivo microdialysis, the developed setting is suitable for application in pharmacokinetics and pharmacodynamics studies. Copyright © 2009 John Wiley & Sons, Ltd. [source] Development and validation of a sensitive LC-MS/MS method with electrospray ionization for quantitation of pramipexole in human plasma: application to a clinical pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 2 2009D. Vijaya Bharathi Abstract A highly sensitive and specific LC-MS/MS method has been developed and validated for the estimation of pramipexole (PPX) with 500 µL human plasma using memantine as an internal standard (IS). The API-4000 was operated under multiple-reaction monitoring mode (MRM) using the electrospray ionization technique. Solid-phase extraction was used to extract PPX and IS from human plasma. The resolution of peaks was achieved with 0.01 m ammonium acetate buffer (pH 4.4):acetonitrile (30:70, v/v) on a Discovery CN column. The total chromatographic run time was 3.0 min and the elution of PPX and IS occurred at approximately 2.32 and 2.52, respectively. The MS/MS ion transitions monitored were 212.10 , 153.10 for PPX and 180.20 , 107.30 for IS. The method was proved to be accurate and precise at linearity range of 20,3540 pg/mL with a correlation coefficient (r) of ,0.999. The intra- and inter-day precision and accuracy values found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of 0.25 mg PPX tablet. Copyright © 2008 John Wiley & Sons, Ltd. [source] Development and validation of a sensitive LC-MS/MS method with electrospray ionization for quantitation of zafirlukast, a selective leukotriene antagonist in human plasma: application to a clinical pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 6 2008D. Vijaya Bharathi Abstract A highly sensitive and specific LC-MS/MS method has been developed and validated for the estimation of zafirlukast (ZFK) with 500 µL human plasma using valdecoxib as an internal standard (IS). The API-4000 LC-MS/MS was operated under multiple reaction-monitoring mode using the electrospray ionization technique. The assay procedure involved extraction of ZFK and IS from human plasma with ethyl acetate. The resolution of peaks was achieved with 10 mm ammonium acetate (pH 6.4):acetonitrile (20:80, v/v) on a Hypersil BDS C18 column. The total chromatographic run time was 2.0 min and the elution of ZFK and IS occurred at approximately 1.11 and 1.58 min, respectively. The MS/MS ion transitions monitored were 574.2 , 462.1 for ZFK and 313.3 , 118.1 for IS. The method was proved to be accurate and precise at a linearity range of 0.15,600 ng/mL with a correlation coefficient (r) of ,0.999. The method was rugged with 0.15 ng/mL as lower limit of quantitation. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of 20 mg ZFK tablet. Copyright © 2008 John Wiley & Sons, Ltd. [source] Development and validation of a sensitive LC-MS/MS method with electrospray ionization for quantitation of doxofylline in human serum: application to a clinical pharmacokinetic studyBIOMEDICAL CHROMATOGRAPHY, Issue 6 2008Nimmagadda Sreenivas Abstract A highly sensitive and specific LC-MS/MS method has been developed and validated for the estimation of doxofylline (DFL) with 300 µL human serum using imipramine as the internal standard (IS). The API-3000 LC-MS/MS was operated under multiple reaction-monitoring mode using the electrospray ionization technique. The assay procedure involved direct precipitation of DFL and IS from human serum with acetonitrile. The resolution of peaks was achieved with formic acid (pH 2.5):acetonitrile (10:90, v/v) on an Amazon C18 column. The total chromatographic run time was 3.0 min and the elution of DFL and IS occurred at approximately 1.46 and 2.15 min, respectively. The MS/MS ion transitions monitored were 267.5 , 181.1 for DFL and 281.1 , 86.2 for IS. The method was proved to be accurate and precise at linearity range of 1.00,5000 ng/mL with a correlation coefficient (r) of ,0.999. The method was rugged with 1.00 ng/mL as lower limit of quantitation. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of DFL tablet. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||