Determination of heroin, 6-acetylmorphine, and morphine in biological fluids using their propionyl derivatives with ion trap GC-MS

We present an analytical method for the determination of heroin, free 6-acetylmorphine (6-AM), and free morphine in blood, urine, and vitreous humor. This method is used in postmortem cases where heroin is the suspected cause of death. The analytical protocol includes the following steps: liquid-liquid extraction at pH 9.5, propionylation at room temperature of 6-AM, and morphine by propionic anhydride using 4-dimethylaminopyridine as catalyst. Neither heroin nor diethylnalorphine (internal standard) is transformed during this derivatization. The reaction products are analyzed using full-scan (250-405 amu) ion trap gas chromatography-mass spectrometry. This method provides a baseline separation and distinctive mass spectrum of each compound of interest. Reproducibility and an evaluation of analysis parameters are also presented.