Separation of Isomers of JWH-122 on Porous Graphitic Carbon Stationary Phase with Non-Aqueous Mobile Phase Using Intelligent Software

Abstract

Cannabimimetic compounds have gained an increasing attention from the forensic community during the past few years. The present study was aimed to develop a liquid chromatographic separation method for the analysis of JWH-122 and its methyl isomers. In Hungary, JWH-122 is scheduled as a narcotic compound and its methyl isomers fall into the new psychoactive substance category, attracting significantly milder punishment than JWH-122 does. According to our best knowledge, gas chromatography or reversed phase liquid chromatography coupled with mass spectrometry could not be applied for separation and selective determination of methyl-naphthoyl indol isomers. In this study, we aimed to develop a high performance liquid chromatography method with UV and mass spectrometric detection for the separation of JWH-122 and all its possible isomers, depending on the position of methyl group on the naphthyl frame. Different reversed phase columns were used. Alkyl-modified silica with different selectivity and morphology with different mobile phase composition cannot be applied for separation of JWH-122 isomers. Porous graphitic carbon (PGC) column was used for separation of banned JWH-122 and each of its methyl isomers. In method development, a Quality by Design approach is presented for modeling the retention of the compounds. According to our knowledge, this is the first time reporting the use of intelligent software to estimate the retention on PGC material and using non-aqueous conditions. Retention times predicted by two program packages (STATISTICA and DryLab) are compared. The possibilities and limitations of the software modeling in the conditions described above are also evaluated.