QUANTITATIVE CAPILLARY ELECTROPHORESIS-ION-TRAP MASS-SPECTROMETRY DETERMINATION OF METHYLPHENIDATE IN HUMAN URINE

A quantitative capillary electrophoresis-mass spectrometry method has been demonstrated for the determination of methylphenidate in human ur ine over a dynamic range of 640. The samples were prepared by liquid-l iquid extraction using 4 ml of human urine. The extracts were analyzed using a Finnigan LCQ ion-trap mass spectrometer in a two-event, posit ive-ion full-scan MS and tandem MS selected reaction monitoring mode. The lower level of quantitation was determined to be 1.5 ng/ml methylp henidate in human urine. The intra-assay precision had a relative stan dard deviation less than 6.8%. The intra-assay accuracy was less than +/- 14.7% bias from the nominal concentration for the full-scan MS ana lysis, and less than +/- 26.5% bias for the tandem MS analysis. Six in curred human urine samples containing methylphenidate were analyzed an d a simple pharmacokinetic curve is presented. (C) 1998 Elsevier Scien ce B.V.