Determination of cocaine, its metabolites, pyrolysis products, and ethanol adducts in postmortem fluids and tissues using Zymark® automated solid-phase extraction and gas chromatography-mass spectrometry

Abstract : Cocaine (COC) is one of the most widely abused illicit drugs in America. COC abuse transcends all social, racial, and economic boundaries. Following the introduction in the mid-1980s of a new form of cocaine called crack, cocaine use has been on the rise. Because of its intense high, crack smoking has become very popular. Despite its popularity, crack smoking is a particularly dangerous form of COC use. Additionally, COC and ethanol are frequently used together, resulting in the formation of a biologically active molecule that is nearly as psycoactive as COC but produces a longer lasting and toxic effect. Demonstrating the presence or absence of COC and COC-related molecules in postmortem fluids and/or tissues can have serious legal consequences and may help determine the cause of impairment and/or death. We have developed a simple method for the simultaneous determination of COC and the COC metabolites benzoylecgonine, norbenzoylecgonine, ecgonine methyl ester, ecgonine, and norcocaine, as well as anhydroecgonine methyl ester (a unique byproduct of COC smoking), cocaethylene (a molecule formed by the concurrent use of COC and ethanol) and their related metabolites, anhydroecgonine, norcocaethylene, and ecgonine ethyl ester. This method incorporates a Zymark RapidTrace automated solid-phase extraction system, gas chromatography/mass spectrometry, and PFP/PFPA derivatives. The lower limits of detection ranged from 0.78 - 12.5 ng/mL, and the linear dynamic range for most analytes was 0.78 3200 ng/mL. The extraction efficiencies were from 26 - 84%, with the exception of anhydroecgonine and ecgonine, which were from 1 - 4%. We applied this method to 5 aviation fatalities. This method has proven to be simple, robust, and accurate for the simultaneous determination of COC and 11 COC metabolites in postmortem fluids and tissues.