Comparison of two chromatographic methods for the determination of cocaineand its metabolites in blood and urine

After a solid-phase extraction, two chromatographic procedures (GC/FID and HPLC/UV detector) for the determination of cocaine and its metabolites (ben zoylecgonine and ecgonine methyl ester) in human blood and urine have been developed. Linear calibration curves were obtained in urine over the concen tration ranges of 0.16-4 mug/mL and 0.2-4 mug/mL, by GC and HPLC, respectiv ely; and, in blood, between 0.1 and 2 mug/mL, by both methods. The recoveri es ranged from 66% to 83% for GC, and from 61% to 95% for HPLC. The limit o f detection was found to be below 76ng/mL for all the analytes. Precision a nd accuracy were studied with acceptable results. The methods have been app lied simultaneously to quantitate the compounds in real samples; concentrat ions of cocaine and benzoylecgonine determined by GC/FID correlated well wi th those determined by HPLC/UV in most cases.