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Batch Analysis (batch + analysis)
Selected AbstractsAnalysis of urinary biomarkers for exposure to alkyl benzenes by isotope dilution gas chromatography-mass spectrometryJOURNAL OF SEPARATION SCIENCE, JSS, Issue 18 2005Adriaan A. S. Marais Abstract A validated GC-MS method for the analysis of urinary metabolites of alkyl benzenes is reported. Metabolites for exposure to toluene, xylene and ethylbenzene were analyzed simultaneously using stable isotope substituted internal standards. The method entailed acidic deconjugation of urine samples followed by extractive alkylation with pentafluorobenzyl bromide as alkylating agent. The resulting pentafluorobenzyl derivatives of ortho -, meta -, para -cresol, mandelic acid (MA), hippuric acid (HA) and ortho -, meta -, para -methylhippuric acid (MHA) were then quantified by SIM. Optimized reaction conditions for the extractive alkylation step are reported. The derivatives were found to be sufficiently stable for overnight batch analysis. The LODs were below 0.1 ,mol/L for the cresols and below 1 ,mol/L for MA and the HAs. Within-batch precision for o -MHA was 7%, for m -MHA 5%, for p -MHA 5.2% and below 5% for the rest of the analytes. [source] Fast GC for the analysis of fats and oilsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 17 2003Luigi Mondello Abstract Fast and conventional GC techniques were both applied to ten different lipidic matrices and the results then compared. The fats and oils were of fish, animal, and vegetable origin and were all simultaneously transesterified with acidic methanol before performing batch analysis of the fatty acid methyl esters (FAMEs) obtained. All FAMEs samples were consecutively analyzed three times by each method. The fast method significantly reduced the time required for analysis by a factor of 5 while maintaining a similar resolution. Furthermore, the reproducibility of relative quantitative data was measured on going from one method to the other. Peak identification was achieved through conventional GC-MS in combination with linear retention index values contained in a home library and information derived from comprehensive 2D GC group patterns. [source] Gas chromatography/negative-ion chemical ionisation mass spectrometry for the quantitative analysis of morphine in human plasma using pentafluorobenzyl carbonate derivativesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 7 2002H. J. Leis A sensitive and specific method for the quantitative determination of morphine in human plasma is presented. Morphine was extracted from plasma by solid phase extraction on C18 and converted to its pentafluorobenzyl carbonate trimethylsilyl derivative. The derivatives were analysed without further purification. Using gas chromatography/negative ion chemical ionisation mass spectrometry, a useful diagnostic fragment ion at m/z 356 is obtained at high relative abundance. Deuterated morphine was used as internal standard. Calibration graphs were linear within the range 1.25 to 320,nmol/L. Intra-day precision was 3.82% (15,nmol/L), 2.85% (75,nmol/L) and 4.13% (225,nmol/L), inter-day variability was found to be 1.77% (15,nmol/L), 4.95% (75,nmol/L) and 9.88% (225,nmol/L). Inter-day accuracy showed deviations of 2.18% (15,nmol/L), ,0.72% (75,nmol/L) and ,0.13% (225,nmol/L). The method is rugged and robust and has been applied to the batch analysis of morphine during pharmacokinetic profiling of the drug. Copyright © 2002 John Wiley & Sons, Ltd. [source] Comparison of Vaginal Cytokine Collection MethodsAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2006Constance J. Faro Objective The objective of our study was to correlate the interleukin-6 (IL-6) concentrations detected in patient-collected specimens with provider-collected specimens and compare the reproducibility of the methods. Study design All enrolled participants underwent pelvic examination with collection of cytokine samples by the provider and also collected samples themselves using vaginal swabs. The order of sample collection was randomly assigned. All samples were frozen at ,80°C for batch analysis. A commercial enzyme-linked immunosorbent assay was used to determine the concentrations of IL-6 in all samples. Results IL-6 concentrations from wicks and swabs were correlated in a linear fashion (r = 0.67, P < 0.001). IL-6 concentrations in the two swabs (r = 0.94, P < 0.001) and the two wicks (r = 0.71, P < 0.001) were correlated in a linear fashion, although there was more variability in wick specimens. Conclusion IL-6 concentrations can be reproducibly measured using either method. The ease of patient swab collection and the correlation with provider-collected specimens may make frequent assessment of the vaginal cytokine environment more acceptable to patients. [source] | ||||||||||