Forensic Identification of Opium by Computerized Gas Chromatography/Mass Spectrometry

Abstract

Opium, the dried exudate of unripe capsules of the opium ,poppy (Papaver somniferum L.), is a complex mixture containing up to 25 different alkaloids in varying amounts [1]; yet it is a mixture whose identification is frequently demanded in forensic laboratories, Of the 25 alkaloids, only five are generally present in significant quantities in crude opium: morphine (Ia; about 10 percent); codeine (Ib),thebaine (II), papaverine (III), and narcotine (IV)—each present in amounts varying from 0.5 to 5 percent. At present forensic identification of suspected opium relies heavily upon general characteristics of the mixture, such as chemical spot tests, thin-layer chromatography, and gas chromatography. Obtaining good spectral data on the major alkaloids present in these mixtures has been precluded, however, due to the difficulty of isolating any of these compounds in reasonably pure form [2]. This difficulty can be overcome with combined gas chromatography/mass spectrometry (GC/MS), whose ability to produce spectral data from the constituents of small quantities of complex mixtures already has led to significant advances in the area of drug identification [3–7]. This paper describes a method using computerized GC/MS for the identification of suspected opium samples.