Journal of Chromatography, 573 (1992) 3 13-3 1 I Biomedical Applications Elsevier Science Publishers B.V., Amsterdam CHROMBIO. 6130 Short Communication Electron-capture gas chromatographic procedure for simultaneous determination of amphetamine and N- methylamphetamine Paul R. Paetsch*, Glen B. Baker, Leslie E. Caffaro, Andrew J. Greenshaw, Gail A. Rauw and Ronald T. Coutts Neurochemical Research Unit, Department of Psychiatry, University of Alberta, Edmonton, Alberta T6G 2B7 (Canada) (First received July 2nd, 1991; revised manuscript received August 21st, 1991) ABSTRACT An electron-capture gas chromatographic procedure for the simultaneous determination of amphetamine and N-methylampheta- mine in biological samples is described. The method employs extraction with the ion-pairing reagent bis(2-ethylhexyl)phosphoric acid, and back-extraction with 0.5 M hydrochloric acid. The hydrochloric acid phase is basified, and the amphetamines and the internal standard benzylamine are derivatized with pentalluorobenzenesulfonyl chloride prior to analysis on a gas chromatograph equipped with a capillary column. Levels of amphetamine and N-methylamphetamine have been determined in the urine and liver of rats treated chronically with (- )-deprenyl. INTRODUCTION Amphetamine and N-methylamphetamine (methamphetamine) are drugs of abuse. In addi- tion these drugs are metabolites of other drugs such as the anti-parkinsonian agent ( -)-depre- nyl [l-3]. In the present report we describe a rap- id and simple procedure for the simultaneous de- termination of amphetamine and N-methylam- phetamine using pentafluorobenzenesulfonyl chloride (PFBSCl) for extractive derivatization of these drugs for subsequent analysis by gas chromatography with electron-capture detection (GC-ECD). PFBSCl has proved to be a useful reagent for the derivatization of tyrosyl peptides [4], nucleic acid pyrimidine bases [5], tranylcypro- mine [6], p-chloroamphetamine [7] and 2-phenyl- 037%4347/92/$05.00 0 1992 Elsevier Science Publishers B.V All rights reserved ethylamine [g] for GC-ECD analysis. In the past, several procedures have been developed for quantitating amphetamine and its analogues, in- cluding immunoassay techniques (for a review see ref. 9) GC with nitrogen-phosphorus detec- tion [IO], GC with mass spectrometric (MS) de- tection [ 111, high-performance liquid chromatog- raphy [12], as well as a variety of derivatizing procedures for GC-ECD (e.g. refs. 13 and 14). Many of the methods previously employed for amphetamine analysis involve time-consuming and tedious extraction procedures or have insuffi- cient selectivity and/or sensitivity for analysis in tissues and body fluids. MS procedures, although highly sensitive and specific, are often outside the financial limits of small laboratories and require highly trained personnel. The present procedure