Journal of Chromatographic Science, 2019, Vol. 57, No. 4, 361–368 doi: 10.1093/chromsci/bmz008 Advance Access Publication Date: 7 February 2019 Article Article Enantioseparation of Synthetic Cathinones Enantiomers with Tertiary Amine Structure in Urine and Plasma Mohammed A. Meetani * , Rashed H. Alremeithi, and Muath K. Mousa Chemistry Department, College of science, United Arab Emirates University, PO Box 15551, Al-Ain, UAE * Author to whom correspondence should be addressed. Email: mmeetani@uaeu.ac.ae Received 17 March 2018; Revised 23 December 2018; Editorial Decision 28 December 2018 Abstract A sensitive and selective method for detection and quantitation of the enantiomers of 18 synthetic cathinones with tertiary amine structure using HPLC–UV-VIS has been developed. Two chiral col- umns, Astec Cellulose DMP and Amylose-based Chiralpak AS-H, have been examined separately. Mobile phase composed of hexane, isopropanol and triethylamine (99.0:1.0:0.1) was used under an isocratic elution mode. Three of these compounds were separated simultaneously after being spiked into urine and plasma samples. 2,3-Methylenedioxy pyrovalerone was used as an internal standard for the purpose of quantitation. The analytical method has been validated in terms of lin- earity, limits of detection (LOD), limits of quantitation (LOQ), recoveries and reproducibilities in ur- ine and plasma matrices. The calibration curves exhibited correlation coefficients better than 0.99. It was found that the LODs of these cathinone derivatives in urine were in the range of 1.00–1.47 ppm; while in plasma, the LODs were in the range of 0.14–0.67 ppm. The LOQs in urine were in the range of 3.03–4.46 ppm and in plasma they were in the range of 0.42–2.04 ppm. The method recoveries in terms of percent error averaged 2.4% and 3.2% for the spiked plasma and urine samples, respectively; while interday and intraday reproducibilities reported at three differ- ent levels, 5, 100 and 200 ppm, in terms of coefficient of variance were in the range of (0.27–5.39)% in plasma and (0.47–3.12)% in urine which lies in the acceptable range. Introduction Abuse of new psychoactive substances (NPS) has increased rapidly and raised concerns of many governments (1, 2). “Bath salts”, “plant feeders” or “plant food” are faked names to circumvent leg- islation from banning these new recreational drugs that overrun most of the world countries. The “bath salt” coined in the USA has been used to describe a new kind of design drugs termed “synthetic cathinones” (3–6). Leaves of Catha edulis which was discovered by Peter Forskal in eighteeth century, are the main source for the parent compound, S-cathinone, in nature (1, 7). Cathinone is a β-keto ana- log of amphetamine which can also be classified as a psychoactive phenethylalkylamine alkaloids (8). Synthetic cathinones have a mechanism of action that is comparable with amphetamine and 3,4- methylenedioxymethamphetamine (MDMA), since they share a sim- ilar chemical structure. Synthetic cathinones contain a chiral carbon center and occur as a racemic mixture of two enantiomers that may have different metabolic pathway in the biological system. For instance, in terms of potency, S(-) methcathinone and S(+) amphet- amine have higher stimulatory effect than their R(-) and R(+) enan- tiomers, respectively (9–14). Enantiomer composition determination of synthetic cathinones is important since it can provide information about the starting materials that are used to synthesis these kinds of recreational drugs. For instance, the starting materials could possess a stereogenic center or they could be achiral which will lead to non- equimolar mixtures of enantiomers. In general, chiral separation can be carried out using one of the following techniques: directly on a chiral stationary phase (CSP) and chiral additives in mobile phase (9, 15), or indirectly using derivatization with enantiomerically pure reagents that convert the enantiomers to diastereoisomers which can be separated on achiral © The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com 361 Downloaded from https://academic.oup.com/chromsci/article/57/4/361/5308448 by guest on 28 June 2022