Rapid Screening and Confirmation of Amphetamine, Methamphetamine, Methadone, and Methadone Metabolite in Urine by Gas/Thin Layer Chromatography

Abstract

A method suitable for large scale screening and confirmation of urine specimens for amphetamine, methamphetamine, methadone, and its primary metabolite (2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine) is described. The drugs are extracted from alkaline urine into an organic solvent. The amphetamine drugs are then back-extracted into a small volume of acid and identified by gas chromatography both as free bases on a 10% Apiezon L-10% KOH column and as their trifluoroacetamide derivatives on a 3% OV-17 column. The organic layer, which still contains methadone and its primary metabolite, is analyzed by split-sample thin-layer chromatography using two solvent systems: ethyl acetate: methylene chloride: concentrated ammonium hydroxide (90:10:0.7) and methanol: chloroform: concentrated ammonium hydroxide (74:25:0.8). These solvent systems separate methadone from its primary metabolite without interference from other drugs or urinary substances.