Evaluating possibilities for the determination of novel psychoactive substances in human saliva using capillary electrophoresis with UV detection and mass spectrometry

Abstract

Novel psychoactive substances are an emerging threat in the field of illegally consumed compounds. The subgroup of synthetic cathinones increased in popularity due to their great variety and the lack of powerful instrumental methods for their efficient monitoring. In the context of detecting drug-related crimes, saliva is a promising sample due to the presence of significant amounts of the respective species and easy and non-invasive accessibility compared to blood or urine samples. Herein, we report two powerful instrumental approaches based on the high separation efficiency and low sample consumption of capillary electrophoresis, combined with commonly used detection principles, namely mass spectrometry and UV detection. Mass spectrometry offers high selectivity and the possibility to identify comigrating analytes but comes with some instrumental challenges and high investment costs, while UV detection provides simple coupling to capillary electrophoresis and cost-efficiency. Moreover, we developed a simple and fast pretreatment protocol for the handling of directly collected human saliva samples for subsequent injection into capillary electrophoretic systems. In this study, we successfully detected butylone and clephedrone, part of the synthetic cathinone family, and 2-aminoindane, which are all listed as psychoactive substances. Furthermore, the methods were characterized in terms of detectability, reproducibility, and limits of detection (6–15 μM). Based on this, an application in the forensic context using CE-UV was simulated for 2-aminoindane and butylone at a concentration of 10 μM (20 μM).