Simple extraction of toxicologically relevant psychotropic compounds and metabolites from whole blood using...

The determination of psychotropic drugs and metabolites in blood is relevant in the context of both therapeutic drug monitoring and clinical and forensic toxicology. LC-MS/MS is the preferred method for these assays. However, LC-MS/MS is particularly susceptible to matrix ionization effects and appropriate sample preparation is required to minimize these effects. In this study, a simple, single-step, mini-QuEchERS extraction procedure, coupled to UPLC-MS/MS, was developed and validated for the determination of 15 toxicologically relevant compounds in whole blood, including psychoactive drugs and some metabolites. The assay was linear in the range of 25-1,000 ng ml^-1 , fulfilling criteria for accuracy and precision. Extraction yields (71.9-87.7%) and matrix effects (-3.3 to +4.4%, with the exception of codeine, which had matrix effects of -35.36 to -28.14%) were acceptable for the majority of the evaluated compounds, using a single internal standard. The assay was applied to 238 clinical specimens from patients admitted to an emergency service, with 22 samples presenting quantifiable concentrations of 11 different compounds. The developed assay is a simple and efficient strategy for determination of target psychotropic drugs and metabolites in forensic and clinical toxicology.