Comparison of liquid and supercritical fluid chromatography using naphthylethylcarbamoylated-β-cyclodextrin chiral stationary phases

A comparison of liquid (LC) and sub- or supercritical fluid chromatography (SFC) was performed using naphthylethylcarbamoylated-β-cyclodextrin chiral stationary phases (NEC-CD CSPs). Compounds resolved in the normal-phase, reversed-phase and polar organic modes on the NEC-CD CSPs in LC were also separated on the same columns in SFC with a carbon dioxide-alcohol eluent. Advantages of SFC for chiral separations on these CSPs included simple eluents, rapid optimization of selectivity and improved resolution compared to LC results for the same columns. The effect of alcohol modifier was also investigated and the results provided insights into the chiral recognition mechanisms in SFC. The versatility of the NEC-CD CSPs in SFC was demonstrated by performing separations representative of the three distinct mobile phase modes in LC in a single analysis in SFC.