Enantiomeric separation by capillary electrochromatography - II. Chiral separation of dansyl amino acids and phenoxy acid herbicides on sulfonated silica having surface-bound hydroxypropyl-beta-cyclodextrin

A chiral silica-based stationary phase having surface-bound hydroxypropyl-b eta-cyclodextrin (HP-beta-CD) with a relatively strong electroosmotic flow (EOF) was introduced for enantioseparation by capillary electrochromatograp hy (CEC). The stationary phase contained a hydrophilic sulfonated sublayer to which a chiral top layer of HP-beta-CD was immobilized. While the sulfon ated sublayer was to provide a relatively strong EOF, the top HP-beta-CD wa s to confer the desired chiral recognition towards enantiomeric solutes. Th is HP-beta-CD sulfonated silica (CDSS) stationary phase proved useful for t he rapid separation of anionic enantiomers such as dansyl amino acids and p henoxy acid herbicides. The effects of the organic modifier content, pH, an d ionic strength of the mobile phase on enantioseparation were investigated . Under the optimized separation conditions, ten dansyl amino acids and six phenoxy acid herbicides were enantioseparated with a resolution greater th an unity.