A HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC PROCEDURE FOR THE SEPARATION OF COCAINE AND SOME OF ITS METABOLITES FROM ACEPROMAZINE, KETAMINE, AND ATROPINE FROM SERUM

A high-performance liquid chromatographic procedure for the separation of cocaine and its metabolites from such non-test drugs as acepromazine, ketamine and atropine in serum is described. The method involves the use of a SemiPermeable Surface (SPS) C8 column with a mobile phase constituted of 3.25% tetrahydrofuran and 96.75% 0.0025 M potassium phosphate buffer, v/v, containing 0.0025% triethylamine, the final pH of the mobile phase being 2.75. The flow rate was 0.5 ml/min. A photodiode array detector equipped with a computer software was used to monitor the analyte peaks. Retention times for cocaine (COG), benzoylecgonine (BE), benzoylnorecgonine (BN), norcocaine (NOR) and bupivacaine (BV) were 15.5, 7.4, 12.25, 21.0 and 24 minutes, respectively. The non-test drugs ketamine and atropine co-eluted at 10.0 minutes while acepromazine eluted with the solvent front (3.8 min.). The sensitivity of this assay for each of COC, BE, BN and NOR, at a signal to noise (S/N) ratio of greater than 6.0, was 1.0 ng/ml while that for BV was 5ng/ml at the same S/N value.