Analysis of Cocaine and Cocaethylene in Blood and Tissues by GC-NPD and GC-Ion Trap Mass Spectrometry

Cocaethylene, the ethyl homolog of cocaine, is an active cocaine metabolite found in cocaine users who simultaneously consume cocaine and ethanol. To study the combined incidence of cocaine and cocaethylene, an analytical method was devised that would simultaneously quantify both drugs in whole blood or tissues. The method includes a quantitative procedure by GC-NPD with a confirmation by ion trap mass spectrometry. Propylbenzoylecgonine, the propyl homolog of cocaine, was used as the internal standard. The quantitative method was linear from 0.05 to 10.0 mg/L with a limit of detection of 0.02 mg/L. Cocaethylene and propylbenzoylecgonine were synthesized in the laboratory. The complete analytical procedure and the method of synthesis are presented, along with brief descriptions of medical examiner cases where both cocaine and cocaethylene were quantified and where cocaethylene may have played a part in the cause of death. In the five cases presented, the cocaine concentration ranged from 0.03 to 1.4 mg/L and cocaethylene ranged from 0.03 to 0.53 mg/L in the blood.