On the method development of immobilized polysaccharide chiral stationary phases in supercritical fluid chromatography using an extended range of modifiers

Abstract

Polysaccharide-derived selectors are often used in the separation of enantiomers by supercritical fluid chromatography (SFC). Their recognition patterns are normally investigated with alcohols and acetonitrile as modifiers. The present paper describes the results of a research program designed by Pfizer and Chiral Technologies Inc. to explore the potential of other solvents (i.e. ethyl acetate, tetrahydrofuran, dichloromethane) in SFC by using a series of polysaccharide-derived supports with broad solvent versatility (CHIRALPAK IA, IB, IC, ID, IE and IF). The contribution of such extended solvent range to the overall success rate, as well as to overcome racemization, solubility and stability issues was confirmed by using standard non-proprietary samples and research molecules. Elution patterns with such lower polarity solvents, compared to alcohols, and the role of the different additives were also investigated.

Keywords: Additive effect; Chemically immobilized polysaccharide-based chiral stationary phases; Enantiomer resolution by supercritical fluid chromatography; Mobile phase effect; SFC.