Analyses of dextroamphetamine and its metabolites in human urine by capillary electrophoresis with diode array and capacitively coupled contactless conductivity detection (CE-DAD-C(4)D).

内容摘要

Dextroamphetamine is a psychostimulant widely used in the treatment of attention-deficit/hyperactivity disorder and as a model compound in clinical toxicology and pharmacokinetic studies, and some studies report its use in cocaine dependence treatment. The present work describes the development and validation of a capillary electrophoresis (CE) method coupled with diode array (DAD) and capacitively coupled contactless conductivity (C4D) detectors for the simultaneous analysis of dextroamphetamine and its main urinary metabolites. Although phenylacetone is a key intermediate in the oxidative deamination pathway, this study focuses on the determination of 4-hydroxyamphetamine, norephedrine, hippuric acid, and benzoic acid in synthetic urine and spiked human samples. The method was optimized for background electrolyte composition, pH, and separation voltage, allowing efficient resolution and dual detection. Rapid separations were obtained, with migration times under 8 min. Linear responses were observed for all compounds within 1-200 μM (R2 ≥ 0.955), with LOD/LOQ ranging 0.32-32.2 μM and 1.07-97.6 μM, respectively. For dextroamphetamine, migration occurred at 3.64 min (DAD) and 3.41 min (C4D), with LOD/LOQ of 2.16/7.19 μM (DAD) and 8.58/28.60 μM (C4D). Intra- and inter-day repeatability tests demonstrated analytical precision with acceptable limits. The method was applied to spiked human urine samples using the standard addition technique for endogenous metabolites (hippuric acid and benzoic acid). This study demonstrates the feasibility of clinical and toxicological monitoring involving psychostimulant determination.