HPLC Determination of Cocaine and Benzoylecgonine in Plasma and Urine from Drug Abusers

Reversed-phase high-performance liquid chromatography (HPLC) was used for the determination of cocaine and its metabolite, benzoylecgonine (BZE), in plasma and urine. Following a solid-liquid extraction with Bond-Elut Certify cartridges and using methaqualone as reference compound, chromatography was performed with a Lichrospher RP 18 (125 x 4-mm i.d.) reversed-phase column, ultraviolet (UV) detection at 235 nm, and methanol (pH 7)-phosphate buffer (70:30 v/v) as mobile phase. Linearity was obtained from 0.1 to 20 micrograms/mL with a good correlation coefficient. Recoveries ranged from 76.9 to 96.5%, and coefficients of variation were always less than 5.0%. Urine samples from live, cocaine-intoxicated patients contained concentrations of 0.21-75.55 micrograms/mL BZE and less than 4.14 micrograms/mL cocaine, whereas postmortem urine analyses gave concentrations of 5.86-198.76 micrograms/mL for BZE and 1.56-33.24 micrograms/mL for its parent compound. Finally, postmortem blood samples were all negative for cocaine and gave BZE concentrations of 0.040-0.53 micrograms/mL.