1H quantitative NMR and UHPLC-MS analysis of seized MDMA/NPS mixtures and tablets from night-club venues

Abstract

3,4-Methylenedioxymethamphetamine (MDMA) in the UK has increased in purity and the contents sold as MDMA (ecstasy, E) have increased in complexity. Night-club scenes remain overall the biggest venues where such powders or tablets are consumed. HPLC and GC are the gold standard analytical methods in forensic laboratories for the quantification of seized samples of illicit drugs. However, complex mixtures of such samples may be a limiting factor for chromatographic techniques. NMR is used for the structural elucidation of newly isolated natural products or synthesized compounds, but also the inherent ability of ¹H NMR to quantify compounds is a powerful tool that is employed for quantification and purity testing in the pharmaceutical industry. In this study, a ¹H quantitative NMR (q-NMR) method is developed for the quantification of seized samples from night-clubs. These samples are shown to contain mixtures of MDMA and other NPS, e.g. ethylone, methylone, trifluoromethylpiperazine (TFMPP), N,N-dimethyl-3,4-methylenedioxyamphetamine (MDDMA), 4-bromo-2,5-dimethoxyphenethylamine (2C-B), and 4-iodo-2,5-dimethoxyphenethylamine (2C-I). The method is applied to MDMA tablets seized from similar venues, and compared with UHPLC and UHPLC-MS, resulting in a good agreement across techniques. ¹H q-NMR provides a fast (15 min) and robust analytical method for the quantification of complex seized samples without resorting to tedious sample preparation or obtaining reference standards.