Analysis of drugs of abuse in urine by gas chromatography/mass spectrometry: experience and application.

This paper describes quantitative methods for determination of urinary drugs/metabolites. The analysis included indicators of opiate (morphine, codeine, 6-monoacetylmorphine) and methadone (methadone) consumption, indicator of marihuana/hashish consumption (11-nor-9-tetrahydrocannabinol-9-carboxylic acid), indicators of cocaine consumption (cocaine, benzoylecgonine, and ecgonine methyl ester) and of amphetamines consumption (amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, and 3,4-methylenedioxyethylamphetamine). The methods included solid-phase extraction of urine, concentration of eluent, derivatisation, and quantitative analysis by gas chromatography/mass spectrometry (GC/MS) on a capillary column in the electron impact and selected ion monitoring (SIM) mode. Sensitivity, reproducibility, and accuracy were determined for all analytes (limit of detection between 3 and 12 ng/ml, precision < 10%, accuracy > 92%). The accuracy was checked through analysis of standard reference materials and participation in an international quality assessment programme. The methods were used in the analysis of spot urine samples of 60 subjects suspected of drug abuse. Negative findings indicated several disadvantages of urine as a biological sample.