AMPHETAMINE AND METHAMPHETAMINE DETERMINATION IN URINE BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH SIMULTANEOUS SAMPLE CLEANUP AND DERIVATIZATION WITH 1,2-NAPHTHOQUINONE 4-SULFONATE ON SOLID-PHASE CARTRIDGES

A liquid-solid procedure is proposed for sample clean-up and derivatiz ation of amphetamine and methamphetamine in urine samples. The reagent was 1,2-naphthoquinone 4-sulphonate, and a commercial C-18 packing ca rtridge was used. The samples derivatized at room temperature were chr omatographed on a 5-mu m Hypersil ODS (250X4 mm I.D.) with an elution gradient of acetonitrile-water containing propylamine. Under these con ditions, the amines were eluted with short retention times. The proced ure was used to determine amphetamine, or methamphetamine with its met abolite amphetamine, in spiked urine samples. The detection limit (at a signal-to-noise ratio of 3) for amphetamine (0.1 mu g/ml) was simila r to that obtained with liquid-liquid derivatization and to those obta ined with immobilized reagents on a polymeric solid support. The detec tion limit for methamphetamine (0.4 mu g/ml) was higher than with the liquid-liquid procedure because of the lower reactivity on the cartrid ge. The precision and accuracy of the method were also studied.