Insights into chiral recognition mechanisms in supercritical fluid chromatography. I. Non-enantiospecific interactions contributing to the retention on tris-(3,5-dimethylphenylcarbamate) amylose and cellulose stationary phases

In this series of papers, we use a systematic approach to investigate the factors responsible for enantio-recognition in supercritical fluid chromatography (SFC) on chiral stationary phases (CSPs). In this first part, the interactions contributing to the retentions of the achiral solutes are measured with a modified version of the solvation parameter model. Since stereospecific interactions were not accounted for in the classical linear solvation energy relationship using Abraham descriptors, we introduce two additional descriptors, flexibility and globularity, to rationally quantify the stereochemical properties that may significantly affect enantiomeric resolutions. Two polysaccharide stationary phases presenting identical bonded groups on different polysaccharide backbones, namely tris-(3,5-dimethylphenylcarbamate) on amylose and on cellulose, are compared using 230 achiral and structurally diverse solutes. The experimental results are evaluated based on statistics and the chemical intuition of the chromatographic systems.