Evaluation of cyclodextrins modified with dichloro-, dimethyl-, and chloromethylphenylcarbamate groups as chiral stationary phases for capillary electrochromatography.

Abstract

Capillary electrochromatography using cyclodextrins modified with dichloro-, dimethyl-, and chloromethylcarbamate groups were used for the enantiomeric separation of standard analytes. The chiral selector was chemically bonded to aminopropylsilanized silica particles, and these chiral stationary phases (CSPs), mixed with aminopropylsilanized silica (1:1 wt:wt), were packed into 100-microm-i.d. fused-silica capillaries. The effect of the type of cyclodextrin, the nature and position of the substituents on the phenyl ring, and the binding mode of cyclodextrin phenylcarbamates onto the silica gel surface on the chiral recognition were studied. Experimental parameters such as organic solvent concentration were varied in order to better understand the mechanism contributing to the chiral recognition of these CSPs. Good enantioseparations were achieved for a racemic flavanone (FLA) and trans-cyclopropanedicarboxylic acid dianilide (CAD).