Determination of the R- and S-enantiomers of methylone and ethylone in seized drugs by enantioselective liquid chromatography tandem mass spectrometry analysis

Synthetic cathinones constitute a major class of the new psychoactive substances (NPS) that have come to dominate recreational drug abuse in recent years. As synthetic cathinones are all chiral molecules, the use of chiral analysis to determine their enantiomeric ratios (ER) in seized drug samples can assist in the identification of the precursor chemicals and manufacturing processes used in production, thereby contributing to drug intelligence. In addition, as different enantiomers of synthetic cathinones vary in biological activity and toxicology, chiral analysis can support research into the physiological properties and side effects of seized drugs, thus enabling better treatment for overdose or addiction. Therefore, suitable methods for chiral separation and quantitative analysis of synthetic cathinones in forensic laboratories are needed. This study describes the separation of R- and S-enantiomers of methylone and ethylone, two of the most commonly abused synthetic cathinones, by liquid chromatography (LC) using a Lux AMP polysaccharide-based chiral column, followed by tandem mass spectrometry analysis. Enantiomeric separation was achieved in 13.4 min, and the precision, accuracy, carryover, detection limit, and quantification limit of this method were determined. A total of 39 seized drug samples were analyzed in this study, and the results yielded ER of 0.97–1.09 for methylone and 0.87–1.17 for ethylone. The purity of methylone or ethylone was lower in instant coffee bags than in other package types. The ER and purity profiles can be useful for forensic science and drug intelligence.