Simultaneous detection of cocaine and heroin metabolites in urine by solid-phase extraction and gas chromatography-mass spectrometry

The present paper reports a method for the simultaneous extraction of cocaine, heroin and their metabolites from small amounts of urine (0.5 ml), using deuterated internal standards. Solid-phase extraction (SPE) on Cls columns followed by chromatographic separation coupled with mass spectrometry allowed the detection of all the substances after their derivatization. Mass spectrometry was performed in the electron-impact selected-ion monitoring (EI-SIM) mode. The limit of detection was found to be as low as 50 ng/ml for all the analytes; for reproducibility the C.V. was always better than 7%; the method was found to be linear with correlation coefficients between 0.989 and 1.00