LC-based analysis of drugs of abuse and their metabolites in urine

In the literature, many analytical methods have been described for the determination of illicit drugs in biological fluids. Urine is one of the preferred matrices for control of drugs of abuse because its analysis is considered non-invasive and the concentration of the compounds and their metabolites, as well as the volume of sample available, are higher than in other biological fluids. For the analysis of drugs of abuse in urine, liquid chromatography coupled to mass spectrometry (LC-MS) or tandem mass spectrometry (LC-MS2) has become a powerful technique. Its main advantages are its selectivity and sensitivity, reduced need for sample preparation, absence of need for derivatization and reliability of results. In addition, when two selected reaction monitoring (SRM) transitions are recorded per compound, this technique provides the four identification points required by the European Union for identification and confirmation of illicit substances. For pre-concentration or clean up of samples, specific procedures, such as those using mixed-mode solid phases, have allowed good recoveries and low limits of detection, and helped reduce ion suppression in LC-MS2.This review discusses methods published in 2000–2006 to determine the drugs of abuse consumed most (namely, amphetamines, methamphetamines, cannabinoids, cocaine, LSD and opiates) and their metabolites in urine, particularly by LC-MS2.