Insights into chiral recognition mechanism in supercritical fluid chromatography IV. Chlorinated polysaccharide stationary phases.

The chiral recognition mechanism for a successful enantioseparation on polysaccharide stationary phases are still poorly understood. In this series of papers, we aim to provide some insight into the retention and separation mechanisms occurring in enantioselective supercritical fluid chromatography (SFC). This paper presents a thorough investigation on chlorinated polysaccharide chiral stationary phases (CSP) comprising five coated and three immobilized phases from different manufacturers. The columns are also compared to four non-chlorinated phases to unravel the most significant differences brought about by the introduction of electron-withdrawing atoms on the aromatic ligands. Chemometrics are used to (i) get an overview of all columns (cluster analysis), (ii) describe retention (modified solvation parameter model) and (iii) describe enantioseparation (discriminant analysis). Sample applications are provided to support the discussion.