Determination of the heroin metabolite 6-acetylmorphine by high-performance liquid chromatography using automated pre-column derivatization and fluorescence detection

An improved method for the determination of 6-acetylmorphine in the urine of drug addicts receiving morphine was developed. A newly introduced reversed-phase high-performance liquid chromatographic system proved to be more sensitive than a normal-phase system used previously. By replacing the earlier manual derivatization procedure with an automated on-line pre-column method, both the reproducibility and efficiency were considerably improved. Coefficients of variation for repeated analyses typically ranged from 6 to 10% in the 1-100 micrograms/l concentration range. The detection limit was 1 microgram/l and the correction for recovery by calibration with blank urine samples spiked with 6-acetylmorphine was satisfactory. The analytical improvements achieved, however, did not increase the chance of detecting heroin use by drug addicts.