PREPARATION AND CHROMATOGRAPHIC EVALUATION OF 3,5-DIMETHYLPHENYL CARBAMOYLATED BETA-CYCLODEXTRIN STATIONARY PHASES FOR NORMAL-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SEPARATION OF ENANTIOMERS

Thirteen chiral stationary phases (CSPs) were prepared from beta-cyclodextrin (beta-CD) and their chiral recognition abilities were evaluated under normal-phase conditions by high-performance liquid chromatography. All materials were prepared by three different methods and contained 3,5-dimethylphenylcarbamate residues. The influence of different spacers, the amount of immobilized carbamoylated beta-CD and the degree of substitution on beta-CD on the enantioselectivity of the CSPs was considered. The results suggest that the enantioselectivity of the materials is favoured by high degrees of substitution of carbamate groups on beta-CD and large amounts of chemically bonded carbamoylated beta-CD. The highest selectivities were obtained on CSPs where complete carbamoylated beta-CD was immobilized on the silica surface.