Effect of the Mobile Phase Composition on Selectivity in Supercritical Fluid Chromatography in the Separation of Salbutamol Enantiomers

Three chiral chromatography stationary phases based on amylose and cellulose were tested for the supercritical fluid chromatography separation of antiasthmatic drug salbutamol enantiomers. A cellulose tris- 3-chloro-4-methylphenylcarbamate stationary phase provided the highest selectivity for this separation. The optimization of mobile phase composition allowed us to maximize the selectivity coefficient and to minimize the peak asymmetry factors. A successful salbutamol enantiomer separation is achieved at moderate modifier fraction (10-15 vol %) in the mobile phase on this column. Amine additives are necessary to suppress peak tailing. Among three tested amines isopropylamine gives the most symmetrical peaks along with the highest enantioselectivity.