Rapid analysis of benzoylecgonine, cocaine, and cocaethylene in urine, serum, and saliva by isocratic high-performance liquid chromatography with diode-array detection

An isocratic high-performance liquid-chromatographic (HPLC) procedure with diode-array detection has been developed for the determination of benzoylecgonine, cocaine, and cocaethylene in urine, serum, and saliva. After solid-phase extraction with mixed-mode extraction cartridges the three solutes are separated, in less than 20 min, by HPLC on a Supelcosil ABZ+ column with 17:83 (v/v) acetonitrile-0.04 M phosphate buffer, pH 2.3, as mobile phase. Unambiguous identification of the compounds was achieved by means of their retention times and UV spectra. Satisfactory resolution was obtained between interfering compounds, benzoylecgonine, cocaine, and cocaethylene. This analytical procedure proved suitable for the determination of cocaine and its metabolites in drug addicts' urine and saliva, and rabbit serum.