Thin-layer chromatographic screening and confirmation of methadone and its primary metabolite in urine

A thin-layer chromatographic method for the simultaneous screening and confirmation of methadone and its primary metabolite (2-ethylidene-1,5-diemthyl-3,3-diphenylpyrrolidine) in urine specimens is presented. Urine is made basic and extracted with organic solvent. After separation and concentration, the residue is spotted, half on each of two thin-layer chromatography plates. One plate is developed in an ethyl acetate:methanol:diethylamine (90:10:1.6) solvent system and the second in an ethyl acetate:methylene chloride:propylamine (85:17:1.0) solvent system. Methadone and its primary metabolite can be detected in concentration as low as 0.5 micrograms/mL without interference from other drugs and urinary substances.