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Negative ion chemical ionization for the determination of methylphenidate in human plasma by stable isotope dilution gas chromatography/mass spectrometry
Author(s) -
Leis Hans Jörg,
Fauler Günter,
Raspotnig Günther,
Windischhofer Werner
Publication year - 2000
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/1096-9888(200009)35:9<1100::aid-jms32>3.0.co;2-9
Subject(s) - chemistry , chromatography , mass spectrometry , chemical ionization , isotope dilution , selected ion monitoring , gas chromatography–mass spectrometry , gas chromatography , detection limit , calibration curve , derivative (finance) , analytical chemistry (journal) , ionization , ion , organic chemistry , financial economics , economics
A sensitive and specific method for the determination of methylphenidate in human plasma is presented. Methylphenidate was extracted from plasma by solvent extraction with hexane at pH 9.3 and derivatized to its heptafluorobutyrate derivative. The derivative was measured by gas chromatography/negative ion chemical ionization mass spectrometry without any further purification. Using this detection mode, a diagnostically useful fragment ion at m / z 369 was obtained at high relative abundance. 18 O 2 ‐labelled methylphenidate was used as an internal standard and its rapid and facile preparation from the unlabeled compound is described. Calibration graphs were linear within the range 0.14–18.25 ng ml −1 . The inter‐assay precision was 8.7% (0.14 ng ml −1 ) and 3.1% (4.56 ng ml −1 ) and the intra‐assay variability was 1.3% (0.14 ng ml −1 ) and 0.4% (4.56 ng ml −1 ). Accuracy determinations showed deviations of +0.7% (0.14 ng ml −1 ) and −2.5% (4.56 ng ml −1 ). The method is rugged, rapid and robust and has been applied to the batch analysis of methylphenidate during pharmacokinetic profiling of the drug. Copyright © 2000 John Wiley & Sons, Ltd.