THERMAL-TREATMENT FOR IMMOBILIZATION OF CHIRAL POLYSILOXANES IN CAPILLARY GAS-CHROMATOGRAPHY

The chiral selector L-t-leucine-t-butylamide has been anchored to a po lysiloxane by nucleophilic displacement of 2,2,2-trifluoroethyl ester- functionalized block polysiloxanes with L-t-leucine-t-butylamide. Atte mpts were made to immobilize the chiral polysiloxanes inside the capil laries by thermal treatment at 300 degrees C for 30-90 min. The polysi loxanes were found to be more resistant than Chirasil-Val to the racem ization caused by such high temperature treatment. Capillary columns c oated with this type of immobilized polysiloxane have shown very high enantioselectivity and thermal stability.