CONFIRMATION AND QUANTITATION OF COCAINE, BENZOYLECGONINE, ECGONINE METHYL-ESTER, AND COCAETHYLENE BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY - USE OF MICROWAVE IRRADIATION FOR RAPID PREPARATION OF TRIMETHYLSILYLAND T-BUTYLDIMETHYLSILYL DERIVATIVES

The authors developed a technique by which cocaine metabolites as well as cocaethylene can be identified and quantitated using gas chromatog raphy/mass spectrometry (GC/MS), and deuterated standards of benzoylec gonine, cocaine, ecgonine methyl ester, and cocaethylene as internal s tandards, The authors used a solid phase extraction (Clean Screen, Wor ldwide Monitoring Corporation, (Horsham, PA)) technique, and rapid der ivatization of metabolites using microwave irradiation before GC/MS an alysis. The t-butyldimethylsilyl derivatives (prepared by microwave ir radiation in 2.5 minutes, 640 Watts [W]) offered better baseline separ ation and chromatography than conventional trimethylsilyl derivatives. The assay was linear between 0.87-17.3 mu mol/L of benzoylecgonine (2 50-5,000 ng/mL) concentration, 0.83-16.6 mu mol/L of cocaine (250-5,00 0 ng/mL), 0.79-15.8 mu mol/L of cocaethylene (250-5,000 ng/mL) and 1.2 5-25.1 mu mol/L of ecgonine methyl ester (250-5,000 ng/mL). The yields are comparable between the microwave technique and conventional heati ng.