A new multi-analyte LC-MS/MS screening method for detection of 120 NPS and 49 drugs in hair.

Liquid chromatography coupled to mass spectrometry (LC/MS) has been increasingly used for screening purposes in forensic toxicology. High versatility and low time/resource consuming are the main advantages of this technology. Numerous multi-analytes methods have been validated in order to face the analytical challenge of the new psychoactive substances (NPS). However, forensic toxicologists must keep the attention also on "classical" psychoactive substances and medicines, such as benzodiazepines (BDZ) and prescription opioids. In this paper, a new method for simultaneous detection of 169 substances (120 NPS and 49 other drugs) in hair by LC-MS/MS was described. After decontamination of hair sample with dichloromethane, a 20-mg aliquot was added with 1 mL of methanol (0.1% of formic acid) and then sonicated at room temperature for 2 h. The mixture was then dried under nitrogen stream and reconstituted with 100 µL of methanol. The LC separation was achieved with a 100-mm long C18 column in 35 min and the mass acquisition was performed in dynamic MRM mode and in positive ionization. The analysis resulted very sensitive, with limits of quantification from 0.07 to 10.0 pg/mg. Accuracy and precisions were always within the acceptable criteria. Matrix effect and recovery rate ranges were -21.3 - +21.9% and 75.0 - 99.3%, respectively. The new method was successfully applied in a preliminary study on the prevalence of NPS, BDZ and other substances in case on driving licence issues. In 14% of cases, BDZ/antidepressants (mainly trazodone, diazepam/nordiazepam and flunitrazepam) were found. Codeine, ketamine, methylone and mephedrone were also detected.