Fast GC-MS method for the simultaneous screening of THC-COOH, cocaine, opiates and analogues including buprenorphine and fentanyl, and their metabolites in urine.

A fast GC-MS method has been developed and validated for the simultaneous screening of different classes of drugs of abuse in urine. Tetrahydrocannabinol metabolite (THC-COOH), cocaine, opiates such as morphine, monoacetylmorphine (O-6-MAM), codeine, opioids such as buprenorphine, methadone, pentazocine, fentanyl and analogues, and their main metabolites can be detected and quantified after a simple liquid-liquid extraction in alkaline conditions and derivatisation to obtain the corresponding trimethyl-silyl derivatives. The chromatographic separation is performed in a total time of 6 minutes, using a short GC column (5% phenyl methyl silicone, 10m length x 0.18mm internal diameter). The Limits of Detection are satisfactory for forensic purposes for all the substances; the repeatability of concentrations (% coefficients of variation %CVs) are always lower than 15% at a high and a low concentration levels, and accuracy, intended as % error on the true value, is always lower than 15% for all the analytes. The method can successfully be applied for screening analyses in many fields of forensic toxicology.