Enantioseparation of Synthetic Cathinones Enantiomers with Tertiary Amine Structure in Urine and Plasma

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 columns, 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 linearity, limits of detection (LOD), limits of quantitation (LOQ), recoveries and reproducibilities in urine 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 different 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.