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1.
F. Susanto S. Humfeld C. M. Niederau H. Reinauer 《Fresenius' Journal of Analytical Chemistry》1992,344(12):549-553
Summary A method for the determination of theophylline in human serum by the isotope dilution/mass spectrometric technique is described. As an internal standard labelled (1,3-15N2-2-13C)theophylline is added to the serum sample. The analyte and internal standard are extracted with chloroform/2-propanol (90:10) and converted to the trimethylsilyl derivatives. The extraction and silylation procedures are checked by adding theophylline and internal standard in various concentrations to blank serum and determining the recovery. The trimethylsilyl derivatives of labelled and non-labelled theophylline are separated and detected by GC-MS with the mass spectrometer set to m/z 252 and 255. The amounts of theophylline in the serum are calculated from the isotope ratios measured by selected ion monitoring. The accuracy, precision and recovery of this GC-MS method are presented and discussed. The coefficient of variation determined from duplicate samples was less than 2.5%. The detection limit was 10 ng/ml at a signal-to-noise ratio of 3:1.Part of the work was presented at the 32th Kongreß der Deutschen Gesellschaft für Laboratoriumsmedizin, Frankfurt 1991 相似文献
2.
A method is described for the separation, identification and quantification of six sulfonylureas in serum by liquid chromatography/mass
spectrometry with atmospheric-pressure chemical-ionization (APCI LC/MS). The sample pretreatment is based on single-step liquid-liquid
extraction, using the 4-methylcyclohexyl analogue of glibenclamide as internal standard. Carbutamide and tolbutamide have
been chosen as representative sulfonylureas of the first generation and glipizide, glibornuride, glibenclamide and gliquidone
as those of the second generation, widely used in the treatment of diabetes mellitus. This method allows a screening of these
sulfonylureas in serum and subsequently the quantification of the serum level in one run of measurement. Accuracy, precision,
specificity and sensitivity for each sulfonylurea are presented and discussed.
Received: 10 April 1996 / Revised: 13 September 1996 / Accepted: 17 September 1996 相似文献
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Summary A method has been developed for the determination of valproic acid, without derivatization, in human serum by isotope-dilution
mass spectrometry using labelled 2-propyl[3,3,3-d3] valeric[5,5,5-d3] acid as internal standard for accurate quantification of the concentration of valproic acid in the sample. After acidification,
the analyte and internal standard are extracted withn-hexane. The amounts of valproic acid in the serum are calculated from the isotope ratio of valproic acid to labelled valproic
acid, which is measured by electron impact (EI) and chemical ionization (CI) selected ion monitoring (SIM).
The concentrations of valproic acid in sera measured using isotope-dilution mass spectrometry are compared with results from
gas-liquid chromatography (GLC) and fluorescence polarization immunoassay (FPIA). The accuracy, precision and recovery of
the GC-MS methods are discussed. The coefficient of variation determined from duplicate samples was less than 1.5%. The detection
limit was 10 ng mL−1 at a signal-to-noise ratio of 3:1.
Part of this work was presented at the Kongre? der Deutschen Gesellschaft für Laboratoriumsmedizin, Berlin, 1994. 相似文献
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Summary A simple high-performance liquid chromatographic method for the measurement of 8-Methoxypsoralen (8-MOP) in human plasma following
a single 40mg dose has been described. After addition of phosphate-NaOH buffer, pH 12, and internal standard (trimethylpsoralen),
the sample is vortex-mixed with diisopropylether. The resulting extract is analysed on a reverse phase column using phosphoric
acid (0.05% v/v): acetonitrile (1:1) as mobile phase, and U.V. detection at 220nm. No interference from endogenous sources
has been observed. The limit of sensitivity of the assay is 5ng/ml plasma. The measuring range is between 10–700ng 8-MOP/ml
plasma, to be expected from oral doses of 0.6mg 8-MOP/kg body weight, and corresponds to the therapeutic plasma concentration.
The relative standard deviation at 50ng/ml level of 8-MOP is 3.6%. 相似文献
7.
Comparative studies of high-performance liquid chromatographic and liquid chromatographic/mass spectrometric methods for the quantitative determination of glibenclamide in patient serum are described. The 4-methylcyclohexyl analogue of glibenclamide [N-(4-(-5-chloro-2-methoxybenzamidoethyl)benzenesulfonyl-N-(4-methylcyclohexyl)-urea] is used as internal standard for both methods. After acidification of the sample, the analyte and internal standard are extracted with chloroform. For HPLC analysis, the glibenclamide and internal standard are derivatized to a highly fluorescent amine with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-chloride). The glibenclamide derivative is detected by a fluorescence detector. For APCI LC/MS assay, a derivatization of the analyte is not required and the compounds are measured by selected ion monitoring (SIM). The accuracy, precision, and recovery of the compared methods are presented and discussed. 相似文献
8.
Summary A method for the quantitative determination of oleic acid in human plasma by isotope-dilution mass spectrometric technique
is described.
For the measurement of the fatty acid concentration (1-13C) oleic acid is added to the plasma sample. The fatty acids are extracted with n-hexane. Portions of the extract are esterified
by the boron trifluoridemethanol method or stable isotope methylation. The methyl ester derivatives of the fatty acids are
separated and detected by GC-MS with the mass spectrometer set to m/z 296 and 297.
For the measurement of oleic acid after stable isotope methylation the m/z 299 and m/z 300 are monitored. The amounts of oleic
acid in the plasma are calculated from the isotope ratios measured by selected ion monitoring.
The recovery of the methylation step and the precision and accuracy of the GC-MS method are presented and discussed. 相似文献
9.
Summary Comparative studies of gas-liquid Chromatographic, mass fragmentographic methods, and isotope dilution-mass spectrometric assay for the quantitative determination of pentobarbitone in human plasma, are described. Butabarbitone is used as internal standard for the measurement of the drugs by gas-liquid chromatography and mass fragmentography, and deuterated pentobarbitone is used for quantification by the isotope dilution-mass spectrometric method.For analysis, the plasma samples are buffered to pH 4 and extracted on Clin-Elut columns with diethyletherethylacetate (11).Absolute and analytical recoveries of the drugs from plasma and reproducibility of the results are discussed.
Part of the work was presented at the 29th Kongreß der Deutschen Gesellschaft für Laboratoriumsmedizin, Hamburg 1985 相似文献
Gas-Chromatographie, Massen-Fragmentographie und Isotopen-Verdünnungs-Massenspektrometrie — Ein Methodenvergleich zur Bestimmung von Pentobarbital im Plasma
Zusammenfassung Ein Methodenvergleich zur quantitativen Bestimmung von Pentobarbital im Plasma mittels Gas-Chromatographie und GC-MS, einschließlich Isotopenverdünnung-Massenspektrometrie, wird beschrieben.Für die gas-chromatographische und massenfragmentographische Analyse wird Butabarbital als interner Standard und für die Quantifizierung bei der GC-MS-Methode mit Hilfe der Isotopen-Verdünnung, wird deuteriertes Pentobarbital verwendet. Die Plasmaproben werden auf pH 4 gepuffert und über Clin-Elut-Säulen mit Diethylether-Ethylacetat (11) extrahiert.Die absolute und analytische Wiederfindung sowie Präzision und Reproduzierbarkeit der einzelnen Verfahren werden diskutiert.
Part of the work was presented at the 29th Kongreß der Deutschen Gesellschaft für Laboratoriumsmedizin, Hamburg 1985 相似文献
10.
H. Reinauer G. Lindner und J. Oldendörp 《Fresenius' Journal of Analytical Chemistry》1980,301(2):110-112