SIMPLE AND SENSITIVE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC DETERMINATION OF METHAMPHETAMINES IN HUMAN URINE AS DERIVATIVES OF 4-(4,5-DIPHENYL-1H-IMIDAZOL-2-YL) BENZOYL CHLORIDE, A NEW FLUORESCENCE DERIVATIZATION REAGENT

A simple, rapid and highly sensitive high-performance liquid chromatog raphic method for the determination of methamphetamine and its metabol ites in human urine was developed. Without tedious pretreatment proced ures, aliquots of methamphetamine spiked or abusers urine samples were simply acidified, dried under a stream of N-2 gas, and then derivatiz ed with 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoyl chloride in acetonitr ile in the presence of traces of triethylamine. Five derivatives were isocratically separated within 33 min by an ODS column, and the efflue nt was monitored at 440 nm (lambda(ex), 330 nm). Using 1-phenylethylam ine as an internal standard calibration curves were confirmed to be li near up to at least 2 x 10(-5) M in urine with correlation coefficient s of 0.998-1.000, while the detection limits at S/N = 3 were 0.6-5.2 f mol per 5-mu l injection. The relative standard deviations (n = 5) of inter- and intra-day variations were less than 8.9%. The correlation b etween the concentrations of methamphetamine and amphetamine in urine determined by the proposed method and another currently accepted one w as satisfactory. The method was successfully applied to urine samples collected from methamphetamine addicts. (C) 1998 Elsevier Science B.V. All rights reserved.