Rapid screening of drugs of abuse and their metabolites by gas chromatography/mass spectrometry:: application to urinalysis

This paper describes a rapid gas chromatographic/mass spectrometric (GC/MS) screening method for the detection of drugs of abuse and/or their metabolites in urine. Synthetic stimulants, opiates, cocaine metabolites, cannabinoids-and specifically the acid metabolite of tetrahydrocannabinol (THC-COOH)-can be simultaneously extracted by a single liquid/liquid separation step, at alkaline pH. and assayed as trimethylsilyl derivatives by GC/MS in SIM (selected ion monitoring) mode. All the analytes show a good linearity (R-2 > 0.99 for most of the considered substances) in the range 25-1000 ng/mL, with a good reproducibility of both the retention times (CV% < 0.7) and the relative abundances of the characteristic diagnostic ions (CV% < 13). The limit of detection (LOD) of the method is 25 ng/mL of target compound in human urine for most of the substances investigated, 3 ng/mL for THC-COOH, and 10 ng/mL for norbuprenorphine. Validation of the method allows its application to different fields of forensic analytical toxicology, including antidoping analysis. Copyright (c) 2005 John Wiley & Sons, Ltd.