ENANTIOSELECTIVE CAPILLARY GAS-CHROMATOGRAPHY AND CAPILLARY SUPERCRITICAL-FLUID CHROMATOGRAPHY ON AN IMMOBILIZED GAMMA-CYCLODEXTRIN DERIVATIVE

3-O-butanoyl-2,6-di-O-n-pentyl)-gamma-cyclodextrin (3-bu-2,6-pe-gamma- CD) was chemically linked to a polysiloxane via an octamethylene space r, yielding a chiral stationary phase called Chirasil-gamma-Dex. Its i mmobilization onto the surface of capillary columns is possible by the rmal treatment. The influence of the percentage of 3-bu-2,6-pe-gamma-C D in the stationary phase was systematically investigated. With an inc reasing percentage of cyclodextrin, chiral separation factors, alpha, and retention factors, k', increased, whereas the degree of immobiliza tion decreased. A value of 40% (w/w) 3-bu-2,6-pe-gamma-CD was found to be optimal, since high separation factors are combined with a good de gree of immobilization. Besides applications in enantioselective gas c hromatography, some enantiomer separations by capillary supercritical fluid chromatography are presented.