The anatomy of a cocaine comparison case: a prosecutorial and chemistry perspective

Methodology used for the comparative chemical analyses of two illicit cocaine seizures, and its application in a successful criminal prosecution, is described. A description of events leading to the arrest of the defendant and an overview of the jury trial are provided. Illicit cocaine, found in the defendant's suitcase and wallet, was subjected to chemical derivatization and three distinct gas chromatographic methods for the detection and relative quantitation of cocaine manufacturing impurities/by-products. The cocaine impurities included cis- and trans-cinnamoylcocaine, the isomeric truxillines and the hydroxycocaines. Among the cocaine manufacturing byproducts detected were benzoylecgonine, ecgonine methyl ester, ecgonine, N-benzoylnorecgonine methyl ester and N-norcocaine. Chemical derivatization of the cocaine samples was accomplished using heptafluorobutyric anhydride and N,O-bis(trimethylsilyl)acetamide. The derivatized impurities/by-products were subjected to capillary gas chromatographic analysis using both flame ionization and electron-capture detectors. The comparative chemical analyses provided a positive correlation between the suitcase and wallet cocaine samples.