Confirmatory analysis for drugs of abuse in plasma and urine by high-performance liquid chromatography-tandem mass spectrometry with respect to criteria for compound identification

Recently, high-performance liquid chromatography-tandem mass spectrometry (LC/MS/MS) has become a powerful tool for quantitative confirmatory analysis of drugs of abuse and has begun to spread in the field of forensic toxicology. Guidelines for confirmatory analysis by GC/MS and LC/MS/MS have been published recently by several organizations (WADA, IOC, SOFT, GTFCh, EU). However, these guidelines have not yet been included in procedures for drug analysis with LC/MS/MS. The prerequisites for forensic confirmatory analysis by LC/MS/MS with respect to EU guidelines are chromatographic separation, a minimum number of two MS/MS transitions to obtain the required identification points and predefined thresholds for the variability of the relative intensities of the MS/MS transitions (MRM transitions) in samples and reference standards. LC/MS/MS methods for determination of several classes of drugs of abuse including some basic drugs (opiates, stimulants), cannabinoids and some of their phase-I- and phase-II-metabolites (especially glucuronides) in urine and serum of drug abusers and/or crime offenders or victims have been developed and validated following current recommendations and are presented in this paper. At least two MRM transitions for each substance were monitored to provide sufficient identification of drugs, deuterated analogues of analytes were used as internal standards for quantitation where possible and chromatographic separation has been performed on reversed-phase columns with gradient elution. Validation data obtained and the application to real samples show that the requested criteria for confirmatory analysis of drugs of abuse by EU guidelines can be fulfilled with a total number of four identification points by LC/MS/MS methods using a triple-quadrupole mass spectrometer. Furthermore, the methods are sufficiently sensitive to meet current requirements for confirmatory analysis of drugs of abuse in driving under the influence of drugs (DUID) cases established by the Society of Toxicological and Forensic Chemistry (GTFCh). (C) 2004 Elsevier B.V. All rights reserved.