Determination of amphetamine-related compounds by high-performance liquid chromatography with chemiluminescence and fluorescence detections

Abstract

High-performance liquid chromatography with chemiluminescence detection has been established for the determination of trace levels of amphetamine-related compounds (APs) after fluorigenic derivatization. Bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide in acetonitrile was used as a post-column chemilumigenic reagent. As derivatization reagents, dansyl chloride (Dns-Cl), 4-fluoro-7-nitrobenzoxadiazole (NBD-F)_and naphtalene-2,3-dicarbaldehyde (NDA) were compared. Dns-Cl was the most suitable of the three for the simultaneous determination of both primary and secondary amino APs. The on-column detection limits for Dns-derivatives were 3 · 10 −15 − 4 · 10 −15 mol. NDA gave the most sensitive derivatives (cyanobenz[ f]isoindole, CBI derivatives) with only primary amino APs. The detection limits for CBI derivatives were as low as 2 · 10 −16 mol. The present method was applied to the determination of methamphetamine in human urine. Only diethyl ether extraction was necessary as a clean-up treatment before Dns derivatization, because diethyl ether extracted methamphetamine quantitatively from urine at strong alkaline pH and the extract showed few interfering peaks around the retention time of methamphetamine after the derivatization. Methamphetamine concentrations as low as 1 · 10 −7 M in urine were determined after the above treatments.