Enantiomeric separation of neutral hydrophobic dihydrofuroflavones by cyclodextrin-modified micellar capillary electrophoresis.

The enantiomeric separations of several very hydrophobic dihydrofuroflavones were performed and optimized using cyclodextrin-modified micellar capillary electrophoresis. Overall, the greatest enantiomeric peak-to-peak separations for the greatest number of flavones were obtained with hydroxypropyl-gamma-cyclodextrin. The effects of cyclodextrin and sodium dodecyl sulfate concentration and pH were examined in order to optimize the separation conditions. The ratio of surfactant-to-cyclodextrin concentration affected the chiral discrimination of the system significantly, with increases in the derivatized cyclodextrin concentration generally enhancing resolution. Higher efficiencies were obtained with lower concentrations of surfactant and cyclodextrin, although enantioseparation optimization often required higher concentrations to be used. A highly acidic pH was necessary to effectively suppress the electroosmotic flow when operating in the reversed polarity mode. Experiments utilizing the normal polarity mode and higher pH produced no separations.