Gas chromatography/electron impact mass fragmentometric determination of urinary 6-acetylmorphine, a metabolite of heroin.

A procedure for detection and quantification of urinary 6-acetylmorphine (6-AM), a metabolite of heroin, is described. After initial solvent extraction from urine, the 6-AM was purified either by acid-base liquid-liquid extraction or by solid-phase extraction techniques. The 6-AM was then derivatized to its propionyl ester, which was characterized by gas chromatography/mass spectrometry in the electron impact mode. Confirmation of 6-AM was accomplished by comparing retention times and relative abundances of selected ions with that of a standard. Quantification was based on 6-[2H3]acetyl-N-[2H3]methylnormophine (6-[2H6]AM) as internal standard. Excellent linearity was obtained in the concentration range 1-100 ng/mL. The overall yield after solvent extraction and acid-base purification ranged from 79 to 82%; for solvent extraction and solid-phase purification, it was 92 to 95%. The limit of detection was 810 pg/mL. Within-run and between-run CVs for 6-AM at concentrations in the range 1-100 ng/mL were generally less than 5% and less than 10%, respectively.