Exploring the utility of natural deep eutectic solvents as additives in super/subcritical fluid chromatography- insights into chiral recognition mechanism

A push towards sustainability has led to the widespread adoption of not only green synthetic methodologies but also green analytical techniques. Supercritical fluid chromatography (SFC) is considered a greener technique compared to HPLC. In this work we investigate the utility of natural deep eutectic solvents (NADES) as green additives in chiral SFC to replace toxic additives like triethylamine and trifluoroacetic acid. A total of 33 compounds belonging to different classes were screened with four immobilized polysaccharide stationary phases, using 0.2% NADES additives in methanol modifier. A total of 25 compounds had some separation with the tested NADES. Novel selectivities were obtained using choline chloride-D-glucose when compared to commonly used additives. Other NADES were also synthesized and tested in order to shed light on chiral recognition mechanism with the new additives.