Development, validation and evaluation of a quantitative method for the analysis of twenty-four new psychoactive substances in oral fluid by LC–MS/MS

Abstract

The use of new psychoactive substances (NPS) has been recognized worldwide at an alarming rate. Oral fluid collection is becoming more prevalent as a matrix for evaluating drug consumption. In this study, a specific, quick and non-invasive method for detection and quantitation of twenty-four synthetic cannabinoids and cathinone derivatives, including ten not previously reported NPS in oral fluid was performed. A quantitative method was developed on a liquid chromatography coupled to a triple quadrupole mass spectrometer system operated in dynamic multiple reaction monitoring (dMRM) mode using solid phase extraction (SPE) as pre-concentration step. Analytical separation of the target drugs was reached in a total elution time of 10 min. The developed method was validated according to the ASB standard 036. Overall bias and precision of the method were within ±20% for twenty-three compounds. All drugs showed acceptable linearity with R2 values greater than 0.98, and LLOQ values of 0.25 ng/mL and 1.0 ng/mL for selected NPS. The overall bias for a performed blind verification study was 7%. Our results demonstrate the method is suitable for quantifying NPS in oral fluid through solid phase extraction and analysis using LC–MS/MS.