Guilty by dissociation: Part B: evaluation of Supercritical Fluid Chromatography (SFC-UV) for the analysis of regioisomeric diphenidine-derived Novel Psychoactive Substances (NPS).
Journal of pharmaceutical and biomedical analysis July 15, 2022 Graeme Cochrane, Jennifer K Field, Matthew C Hulme et al. 9 citations
Supercritical fluid chromatography (SFC) with a carbon dioxide and ammonium acetate gradient separates 31 novel diphenidine-derived psychoactive substances, including regioisomers, in under 10 minutes. Different stationary phases (acidic, neutral, basic) produce medium to large selectivity differences between isomers. Acidic silica phases retain diphenidines longer via electrostatic attraction, while basic phases reduce retention via repulsion. Baseline separation is achieved for six of eight substituted groups on a simple silica column. As halo-substituent size increases, resolution between ortho- and meta-isomers decreases, causing co-elution of ortho- and meta-bromodiphenidines. Elution orders differ from reversed-phase UHPLC, providing orthogonal separation, with hydrophilic compounds better retained on SFC columns.