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Selected Ion Monitoring (selected + ion_monitoring)

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Chemistry100%

Terms modified by Selected Ion Monitoring

  • selected ion monitoring mode
    		•

    Selected Abstracts

    A validated method for the determination of nicotine, cotinine, trans -3,-hydroxycotinine, and norcotinine in human plasma using solid-phase extraction and liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry

    JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2006
    Insook Kim
    Abstract A liquid chromatographic-mass spectrometric method for the simultaneous determination of nicotine, cotinine, trans -3,-hydroxycotinine, and norcotinine in human plasma was developed and validated. Analytes and deuterated internal standards were extracted from human plasma using solid-phase extraction and analyzed by liquid chromatography/atmospheric pressure chemical ionization-mass spectrometric detection with selected ion monitoring (SIM). Limits of detection and quantification were 1.0 and 2.5 ng/ml, respectively, for all analytes. Linearity ranged from 2.5 to 500 ng/ml of human plasma using a weighting factor of 1/x; correlation coefficients for the calibration curves were > 0.99. Intra- and inter-assay precision and accuracy were < 15.0%. Recoveries were 108.2,110.8% nicotine, 95.8,108.7% cotinine, 90.5,99.5% trans -3,-hydroxycotinine, and 99.5,109.5% norcotinine. The method was also partially validated in bovine serum, owing to the difficulty of obtaining nicotine-free human plasma for the preparation of calibrators and quality control (QC) samples. This method proved to be robust and accurate for the quantification of nicotine, cotinine, trans -3,-hydroxycotinine, and norcotinine in human plasma collected in clinical studies of acute nicotine effects on brain activity and on the development of neonates of maternal smokers. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Rapid determination of three anticoagulant rodenticides in whole blood by liquid chromatography coupled with electrospray ionization mass spectrometry

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2006
    Mi-cong Jin
    A rapid, sensitive and selective method for the simultaneous determination of bromadiolone, flocoumafen and brodifacoum in whole blood using warfarin as internal standard (IS) by high-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC/ESI-MS) has been developed and validated. The target compounds were extracted from the whole blood with ethyl acetate and separated on an XDB C18 column (150,mm,×,2.1,mm i.d.,×,5,µm) by using a mobile phase consisting of 0.2% acetic acid/methanol (12/88, v/v) at a constant flow rate of 0.50 mL/min. The analytes were detected using negative ESI-MS in the selected ion monitoring (SIM) mode. The molecular ions [MH], of m/z 527, 541,523 and 307 were selected for the quantification for bromadiolone, flocoumafen, brodifacoum and the IS, respectively. The calibration curves were linear (r2,>,0.995) in the concentration range of 0.50,100.00 ng/mL. The method showed a satisfactory sensitivity (0.05,0.5 ng/mL using 200 µL blood), precision (RSD,<,11.9%), accuracy (recovery: 82.0,96.1%) and selectivity. This method was successfully applied to the determination of the analytes for the diagnoses of poisoned human beings and animals. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    High-throughput determination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry: application to a bioequivalence study of two formulations in healthy volunteers

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2006
    Hui-chang Bi
    A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to determine carbocysteine in human plasma was developed and fully validated. After methanol-induced protein precipitation of the plasma samples, carbocysteine was subjected to LC/MS/MS analysis using electrospray ionization (ESI). The MS system was operated in the selected ion monitoring (SRM) mode. Chromatographic separation was performed on a Hypurity C18 column (i.d. 2.1,mm,×,50,mm, particle size 5,µm). The method had a chromatographic running time of 2.0,min and linear calibration curves over the concentration ranges of 0.1,20,µg/mL for carbocysteine. The lower limit of quantification (LLOQ) of the method was 0.1,µg/mL for carbocysteine. The intra- and inter-day precision was less than 7% for all quality control samples at concentrations of 0.5, 2.0, and 10.0,µg/mL. These results indicate that the method was efficient with a simple preparation procedure and a very short running time (2.0,min) for carbocysteine compared with methods reported in the literature and had high selectivity, acceptable accuracy, precision and sensitivity. The validated LC/MS/MS method has been successfully used to a bioequivalence study of two tablet formulations of carbocysteine in healthy volunteers. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Simultaneous determination of ten antihistamine drugs in human plasma using pipette tip solid-phase extraction and gas chromatography/mass spectrometry

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 4 2006
    Chika Hasegawa
    Ten antihistamine drugs, diphenhydramine, orphenadrine, chlorpheniramine, diphenylpyraline, triprolidine, promethazine, homochlorcyclizine, cyproheptadine, cloperastine and clemastine, have been found to be extractable from human plasma samples using MonoTip C18 tips, inside which C18 -bonded monolithic silica gel was fixed. Human plasma (0.1,mL) containing the ten antihistamines was mixed with 0.4,mL of distilled water and 25,µL of a 1,M potassium phosphate buffer (pH 8.0). After centrifugation of the mixture, the supernatant fraction was extracted to the C18 phase of the tip by 25 repeated aspirating/dispensing cycles using a manual micropipettor. The analytes retained on the C18 phase were then eluted with methanol by five repeated aspirating/dispensing cycles. The eluate was injected into a gas chromatography (GC) injector without evaporation and reconstitution steps, and was detected by a mass spectrometer with selected ion monitoring in the positive-ion electron impact mode. The separation of the ten drugs from each other and from impurities was generally satisfactory using a DB-1MS column (30,m,×,0.32,mm i.d., film thickness 0.25,µm). The recoveries of the ten antihistamines spiked into plasma were 73.8,105%. The regression equations for the ten antihistamines showed excellent linearity with detection limits of 0.02,5.0,ng/0.1,mL. The within-day and day-to-day coefficients of variation for plasma were not greater than 9.9%. The data obtained from determination of diphenhydramine and chlorpheniramine in human plasma after oral administration of the drugs are also presented. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Determination of , -tocopherol in infant foods by liquid chromatography combined with atmospheric pressure chemical ionisation mass spectrometry

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2003
    Andras Kalman
    A novel, sensitive and specific method for the quantification of , -tocopherol in two infant foods (milk and cereals) using liquid chromatography on-line with positive atmospheric pressure chemical ionisation mass spectrometry detection (LC/APCI-MS) has been developed. The samples were first saponified in order to eliminate fats and to transform tocopherol esters into free tocopherol, followed up by a liquid,liquid extraction of the analyte in petroleum benzine/diisopropyl ether (75:25, v/v) prior to injection onto the LC system. For the quantification, deuterium-labelled tocopherol was used as internal standard and the samples were monitored in selected ion monitoring (SIM) mode. Calibration curves between 1,40,,g/mL of , -tocopherol showed a good linear correlation (r2,=,0.99994), and the detection limit was determined to be 2.5,ng/mL. The within-day and between-day precision were determined for several dietetic infant formulae and certified reference samples, and found to be below 3.5%. The accuracy determined on a Nestlé reference sample (milk powder) was calculated to be 115.2,±,1.2%, which confirms the robustness of the proposed method. This study shows that single quadrupole LC/MS can be applied for the quantification of vitamins in food and the method offers better sensitivity and selectivity than traditional method such as LC-UV. This would simplify the preparation of the food samples and consequently enhance the vitamin analysis throughput in the food area. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    A rapid assay for angiotensin-converting enzyme activity using ultra-performance liquid chromatography,mass spectrometry

    BIOMEDICAL CHROMATOGRAPHY, Issue 3 2010
    Fang Geng
    Abstract Angiotensin-converting enzyme (ACE) plays an important role in the renin,angiotensin system and ACE activity is usually assayed in vitro by monitoring the transformation from a substrate to the product catalyzed by ACE. A rapid and sensitive analysis method or ACE activity by quantifying simultaneously the substrate hippuryl,histidyl,leucine and its product hippuric acid using an ultra-performance liquid chromatography coupled with electrospray ionization-mass spectrometry (UPLC-MS) was first developed and applied to assay the inhibitory activities against ACE of several natural phenolic compounds. The established UPLC-MS method showed obvious advantages over the conventional HPLC analysis in shortened running time (3.5,min), lower limit of detection (5,pg) and limit of quantification (18,pg), and high selectivity aided by MS detection in selected ion monitoring (SIM) mode. Among the six natural products screened, five compounds, caffeic acid, caffeoyl acetate, ferulic acid, chlorogenic acid and resveratrol indicated potent in vitro ACE inhibitory activity with IC50 values of 2.527 ± 0.032, 3.129 ± 0.016, 10.898 ± 0.430, 15.076 ± 1.211 and 6.359 ± 0.086,mm, respectively. A structure,activity relationship estimation suggested that the number and the situation of the hydroxyls on the benzene rings and the acrylic acid groups may play the most predominant role in their ACE inhibitory activity. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Simultaneous clinical monitoring of lactic acid, pyruvic acid and ketone bodies in plasma as methoxime/tert-butyldimethylsilyl derivatives by gas chromatography,mass spectrometry in selected ion monitoring mode

    BIOMEDICAL CHROMATOGRAPHY, Issue 5 2008
    Man-Jeong Paik
    Abstract Simultaneous determination of lactic acid, pyruvic acid, 3-hydroxybutyric acid and acetoacetic acid for clinical monitoring of lactic acidosis and ketone body formation in human plasma (20 µL) was performed by gas chromatography,mass spectrometry in selected ion monitoring (SIM) mode after generating methoxime/tert-butyldimethylsilyl derivatives. All of the targeted carboxylic acids were detected by characteristic fragment ions, which permitted sensitive and selective identification in the presence of co-extracted free fatty acids and other acidic metabolites at much higher levels. The method was linear (r , 0.9991), reproducible (% relative standard deviation = 1.2,5.8), and accurate (% relative error = ,7.2,7.6), with detection limits of 0.05,1.7 ng/mL. This rapid, accurate and selective method using minimal plasma samples (20 µL) is useful in the clinical monitoring of lactic acidosis and ketone body formation in plasma. Copyright © 2008 John Wiley & Sons, Ltd. [source]