Simultaneous quantification of methamphetamine, cocaine, codeine, and metabolites in skin by positive chemical ionization gas chromatography–mass spectrometry

A positive chemical ionization gas chromatography–mass spectrometric method was validated to simultaneously quantify drugs and metabolites in skin collected after controlled administration of methamphetamine, cocaine, and codeine. Calibration curves (2.5–100 ng/skin biopsy) for methamphetamine, amphetamine, cocaine, norcocaine, benzoylecgonine, cocaethylene, norcocaethylene, anhydroecgonine methyl ester, morphine, codeine, and 6-acetylmorphine (5–100 ng/skin biopsy for ecgonine methyl ester and ecgonine ethyl ester) exhibited correlation coefficients >0.999 and concentrations ±20% of target. Intra- and inter-run precisions were <10%. This procedure should be useful for postmortem analysis; data are included on drug concentrations in skin after controlled drug administration.