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Ion Transitions (ion + transition)

Distribution by Scientific Domains
Chemistry100%

Kinds of Ion Transitions

  • product ion transition
    		•

    Selected Abstracts

    Development and validation of a sensitive assay for the quantification of imatinib using LC/LC-MS/MS in human whole blood and cell culture

    BIOMEDICAL CHROMATOGRAPHY, Issue 12 2009
    Jelena Klawitter
    Abstract We developed and validated a semi-automated LC/LC-MS/MS assay for the quantification of imatinib in human whole blood and leukemia cells. After protein precipitation, samples were injected into the HPLC system and trapped onto the enrichment column (flow 5 mL/min); extracts were back-flushed onto the analytical column. Ion transitions [M + H]+ of imatinib (m/z = 494.3 , 394.3) and its internal standard trazodone (372.5 , 176.3) were monitored. The range of reliable response was 0.03,75 ng/mL. The inter-day precisions were: 8.4% (0.03 ng/mL), 7.2% (0.1 ng/mL), 6.5% (1 ng/mL), 8.2% (10 ng/mL) and 4.3% (75 ng/mL) with no interference from ion suppression. Autosampler stability was 24 hs and samples were stable over three freeze,thaw cycles. This semi-automated method is simple with only one manual step, uses a commercially available internal standard, and has proven to be robust in larger studies. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Simultaneous determination of morphine, codeine, 6-acetylmorphine, cocaine and benzoylecgonine in hair by liquid chromatography/electrospray ionization tandem mass spectrometry

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2009
    Da-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]

    Simple, sensitive and rapid liquid chromatographic/electrospray ionization tandem mass spectrometric method for the quantification of lacidipine in human plasma

    JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 7 2004
    N. V. S. Ramakrishna
    Abstract A simple, sensitive and rapid liquid chromatographic/electrospray ionization tandem mass spectrometric method was developed and validated for the quantification of lacidipine in human plasma using its structural analogue, amlodipine, as internal standard (IS). The method involves a simple single-step liquid,liquid extraction with tert -butyl methyl ether. The analyte was chromatographed on an Xterra MS C18 reversed-phase chromatographic column by isocratic elution with 20 mM ammonium acetate buffer,acetonitrile (10 : 90, v/v; pH 6) and analyzed by mass spectrometry in the multiple reaction monitoring mode. The precursor to product ion transitions of m/z 456.4 , 354.4 and m/z 409.3 , 238.3 were used to measure the analyte and the I.S., respectively. The chromatographic run time was 1.5 min and the weighted (1/x2) calibration curves were linear over the range 0.1,25 ng ml,1. Lacidipine was sensitive to temperature in addition to light. The method was validated in terms of accuracy, precision, absolute recovery, freeze,thaw stability, bench-top stability and re-injection reproducibility. The limit of detection and lower limit of quantification in human plasma were 50 and 100 pg ml,1, respectively. The within- and between-batch accuracy and precision were found to be well within acceptable limits (<15%). The analyte was stable after three freeze,thaw cycles (deviation <15%). The average absolute recoveries of lacidipine and amlodipine (IS) from spiked plasma samples were 51.1 ± 1.3 and 50.3 ± 4.9%, respectively. The assay method described here could be applied to study the pharmacokinetics of lacidipine. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Determination of aminoglycoside and macrolide antibiotics in meat by pressurized liquid extraction and LC-ESI-MS

    JOURNAL OF SEPARATION SCIENCE, JSS, Issue 4-5 2010
    Houda Berrada
    Abstract A simple method for the simultaneous determination of dihydrostreptomycin, spectinomycin, spiramycin, streptomycin, tilmicosin, and tylosin in meat has been developed using pressurized liquid extraction and LC-triple quadrupole MS (LC-ESI-MS/MS). The pressurized liquid extraction operational parameters were optimized and no protein precipitating and fat removing steps were required. A gradient HPLC separation was developed with ion-pair mobile phases consisting of aqueous 1,mM heptafluorobutyric acid water and methanol. Protonated molecules were used as precursor ions for CID. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of three fragment ion transitions to provide a high degree of sensitivity and specificity. Dirithromycin and sisomycin were selected as internal standards. A validation study was conducted for these antibiotics in poultry meat samples. All selected compounds could be detected (monitoring ions by multiple reaction monitoring) in meat samples at amounts below the regulatory level of concern. Using the internal standards, pressurized liquid extraction recovery rates were from 70 to 96% (RSD 12,25%). LC-ESI-MS/MS method detection limits of the selected antibiotics were 1,6,,g/kg. Good method reproducibility was found by intra- and inter-day precisions at maximum residue level, yielding the RSDs less than 15 and 16%, respectively. [source]

    Reduction of in-source collision-induced dissociation and thermolysis of sulopenem prodrugs for quantitative liquid chromatography/electrospray ionization mass spectrometric analysis by promoting sodium adduct formation

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 20 2008
    Chad E. Wujcik
    Six chromatographically resolved sulopenem prodrugs were monitored for their potential to undergo both in-source collision-induced dissociation (CID) and thermolysis. Initial Q1 scans for each prodrug revealed the formation of intense [Prodrug2,+,H]+, [Prodrug2,+,Na]+, [Prodrug,+,Na]+, and [Sulopenem,+,Na]+ ions. Non-adduct-associated sulopenem ([Sulopenem,+,H]+) along with several additional lower mass ions were also observed. Product ion scans of [Prodrug3,+,Na]+ showed the retention of the sodium adduct in the collision cell continuing down to opening of the , -lactam ring. In-source CID and temperature experiments were conducted under chromatographic conditions while monitoring several of the latter ion transitions (i.e., adducts, dimers and degradants/fragments) for a given prodrug. The resulting ion profiles indicated the regions of greatest stability for temperature and declustering potential (DP) that provided the highest signal intensity for each prodrug and minimized in-source degradation. The heightened stability of adduct ions, relative to their appropriate counterpart (i.e., dimer to dimer adduct and prodrug to prodrug adduct ions), was observed under elevated temperature and DP conditions. The addition of 100,µM sodium to the mobile phase further enhanced the formation of these more stable adduct ions, yielding an optimal [Prodrug,+,Na]+ ion signal at temperatures from 400 to 600°C. A clinical liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay for sulopenem prodrug PF-04064900 in buffered whole blood was successfully validated using sodium-fortified mobile phase and the [PF-04064900,+,Na]+ ion for quantitation. A conservative five-fold increase in sensitivity from previously validated preclinical assays using the [PF-04064900,+,H]+ precursor ion was achieved. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Application of ion trap technology to liquid chromatography/mass spectrometry quantitation of large peptides

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2008
    Petia Shipkova
    Triple quadrupole mass spectrometers are generally considered the instrument of choice for quantitative analysis. However, for the analysis of large peptides we have encountered some cases where, as the data presented here would indicate, ion trap mass spectrometers may be a good alternative. In general, specificity and sensitivity in bioanalytical liquid chromatography/mass spectrometry (LC/MS) assays are achieved via tandem MS (MS/MS) utilizing collision-induced dissociation (CID) while monitoring unique precursor to product ion transitions (i.e. selected reaction monitoring, SRM). Due to the difference in CID processes, triple quadrupoles and ion traps often generate significantly different fragmentation spectra of product ion species and intensities. The large peptidic analytes investigated here generated fewer fragments with higher relative abundance on the ion trap as compared to those generated on the triple quadrupole, resulting in lower limits of detection on the ion trap. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    A mass spectrometric method to simultaneously measure a biomarker and dilution marker in exhaled breath condensate

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 5 2008
    Charles R. Esther Jr
    Exhaled breath condensate (EBC) collection is a simple and non-invasive method to sample airway secretions, but analysis is limited by extensive and variable dilution of airway secretions within the condensate. To overcome this limitation, we developed a sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to simultaneously detect adenyl purines as biomarkers of inflammation and urea as a dilution marker in EBC. Separation prior to mass spectrometry was achieved using a C18 column with methanol and formic acid as the mobile phase, and characteristic precursor to product ion transitions of m/z 268 to 136 (for adenosine), m/z 348 to 136 (for AMP), and m/z 61 to 44 (for urea) were monitored for quantification. To correct for matrix effects, isotopically labeled adenosine, AMP, and urea were used as internal standards. Using these methods, we detected urea and the adenyl purines adenosine and AMP in EBC from seven subjects with cystic fibrosis (CF) and seven healthy controls and found that the AMP/urea ratio was elevated in the CF samples. These results demonstrate that mass spectrometry can be used successfully in EBC analysis to simultaneously detect a biomarker for airway inflammation and control for variable dilution. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Quantification of montelukast, a selective cysteinyl leukotriene receptor (CysLT1) antagonist in human plasma by liquid chromatography,mass spectrometry: validation and its application to a human pharmacokinetic study

    BIOMEDICAL CHROMATOGRAPHY, Issue 8 2009
    D. Vijaya Bharathi
    Abstract A highly sensitive, rapid assay method has been developed and validated for the estimation of montelukast (MTK) in human plasma with liquid chromatography coupled to tandem mass spectrometry with electro spray ionization in the positive-ion mode. Liquid,liquid extraction was used to extract MTK and amlodipine (internal standard, IS) from human plasma. Chromatographic separation was achieved with 10 mm ammonium acetate (pH 6.4): acetonitrile (15:85, v/v) at a flow rate of 0.50 mL/min on a Discovery HS C18 column with a total run time of 3.5 min. The MS/MS ion transitions monitored were 586.10 , 422.10 for MTK and 409.20 , 238.30 for IS. Method validation and clinical sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.25 ng/mL and linearity was observed from 0.25 to 800 ng/mL. The intra-day and inter-day precisions were 5.97,8.33 and 7.09,10.13%, respectively. This novel method has been applied to a pharmacokinetic study of MTK in humans. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Highly sensitive method for the determination of ropinirole with a lower limit of quantitation of 3.45 pg/mL in human plasma by LC-ESI-MS/MS: application to a clinical pharmacokinetic study

    BIOMEDICAL CHROMATOGRAPHY, Issue 5 2009
    D. Vijaya Bharathi
    Abstract A highly sensitive, rapid assay method has been developed and validated for the estimation of ropinirole (RPR) in human plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. A solid-phase process was used to extract RPR and citalopram (internal standard, IS) from human plasma. Chromatographic separation was operated with 0.2% ammonia solution:acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on a Hypurity C18 column with a total run time of 3.2 min. The MS/MS ion transitions monitored were 261.2 , 114.2 for RPR and 325.1 , 209.0 for IS. Method validation and clinical sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 3.45 pg/mL and the linearity was observed from 3.45 to 1200 pg/mL. The intra-day and inter-day precisions were in the range of 4.71,7.98 and 6.56,8.31%, respectively. This novel method has been applied to a pharmacokinetic study of RPR in humans. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Highly sensitive method for the determination of omeprazole in human plasma by liquid chromatography,electrospray ionization tandem mass spectrometry: application to a clinical pharmacokinetic study

    BIOMEDICAL CHROMATOGRAPHY, Issue 4 2009
    Shivva Vittal
    Abstract A highly sensitive, rapid assay method has been developed and validated for the estimation of omeprazole (OPZ) in human plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves alkalinization of plasma followed by simple liquid,liquid extraction of OPZ and lansoprazole (internal standard, IS) from human plasma with acetonitrile. Chromatographic separation was achieved with 0.01 m ammonium acetate:acetonitrile (40:60, v/v) at a flow rate of 0.25 mL/min on an Inertsil ODS 3 column with a total run time 2.5 min. The MS/MS ion transitions monitored were 346.1 , 198.1 for OPZ and 370.1 , 252.1 for IS. Method validation and clinical sample analysis were performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.05 ng/mL and the linearity was observed from 0.05 to 10.0 ng/mL. The intra-day and inter-day precisions were in the ranges 2.09,8.56 and 5.29,8.19%, respectively. This novel method has been applied to a pharmacokinetic study of OPZ in humans. Copyright © 2008 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 study

    BIOMEDICAL CHROMATOGRAPHY, Issue 2 2009
    D. 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 study

    BIOMEDICAL CHROMATOGRAPHY, Issue 6 2008
    D. 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 study

    BIOMEDICAL CHROMATOGRAPHY, Issue 6 2008
    Nimmagadda 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]