Determination of benzoylecgonine in urine from drug abusers using ion pair high performance liquid chromatography.

An ion pair reversed-phase high performance liquid chromatographic (HPLC) method for the determination of the cocaine metabolite benzoylecgonine in urine is presented. It includes sample purification with solid phase extraction (Sep-Pak C18) and ultraviolet (UV) detection at 233 nm. It is a relatively simple and sensitive method developed for confirmation of positive results from radioimmunoassay screening for benzoylecgonine in urine from drug abusers. Detection of benzoylecgonine concentrations down to 20 ng/mL is possible. Linear standard curves have been obtained from 30 ng/mL to 6 micrograms/mL.