The number of reported new chiral psychoactive substances (cNPSs) on the illicit market continues to rise, emphasizing the need for advanced identification and chiral separation methods to monitor them as well as their metabolites, while supporting forensic investigations [1]. In this scenario, this group of authors carried out dedicated studies, three of which are the object of this presentation. In the first study it was demonstrated - for the first time - that Lux® Cellulose-2 [cellulose tris(3- chloro-4-methylphenylcarbamate)] and Lux® Cellulose-4 [cellulose tris(4-chloro-3- methylphenylcarbamate)] chiral stationary phases (CSPs) can be successfully applied for the enantioselective analysis of fentanyl analogues under polar-ionic (PI) conditions [2]. In this study it was proved that conformationally driven enantiorecognition mechanisms strongly contribute to chiral discrimination with these selectors. A second study [3] aimed to illustrate the development of efficient enantioselective HPLC methods for five benzofuran-substituted phenethylamines, two substituted tryptamines, and three substituted cathinones using reversed-phase (RP) and PI eluents in combination with a CSP based on (+)-(18-crown-6)-tetracarboxylic acid. Enantiomeric resolution was achieved for nine analytes, with separation factor (α) and resolution (RS) values up to 1.32 and 5.12, respectively. Full stereochemical characterization — via circular dichroism (CD) detection, stopped-flow electronic circular dichroism (ECD) spectroscopy, and time-dependent density- functional theory (TD-DFT) calculations — allowed the determination of the enantiomeric elution order (EEO) on this CSP. The applicability of the optimized methods to real biological matrices was assessed on an MS-based platform by analyzing whole blood samples collected via volumetric absorptive microsampling (VAMS) and spiked with the target analytes. In a third study [4], six synthetic cannabinoid receptor agonists (SCRAs) were enantioseparated for the first time using both (R,R)- and (S,S)-Whelk-O®1 CSPs under RP conditions. Scalemic mixtures were identified for two out of six compounds, while the remaining samples appeared to contain single enantiomers. Enantiomeric purity was determined using the enantiomeric chromatographic comparison approach (ICCA). The EEO was assigned by combining ECD data with ab initio TD-DFT simulations, following a consolidated approach. Finally, as a proof of concept, the optimized enantioselective chromatographic protocols were successfully transferred — with only minor modifications — to an LC system interfaced with a triple quadrupole mass spectrometer for LC-MS/MS-based analyses.
Shafi AJ, Berry H, et al., Ther. Adv. Psychopharmacol. 10 (2020) 1-21, 10.1177/2045125320967197.
Varfaj I, Protti M, et al., J. Chromatogr. A 1643 (2021) 462088, 10.1016/j.chroma.2021.462088.
Protti M, I. Varfaj I, et al., Talanta 257 (2023) 124332, 10.1016/j.talanta.2023.124332.
Varfaj I, Protti M, et al., Anal. Chim. Acta 1317 (2024) 342901, 10.1016/j.aca.2024.342901.