Thermal treatment for immobilization of chiral polysiloxanes in capillary gas chromatography

The chiral selector L‐t‐leucine‐t‐butylamide has been anchored to a polysiloxane by nucleophilic displacement of 2,2,2‐trifluoroethyl ester‐functionalized block polysiloxanes with L‐t‐leucine‐t‐butylamide. Attempts were made to immobilize the chiral polysiloxanes inside the capillaries by thermal treatment at 300°C for 30–90 min. The polysiloxanes were found to be more resistant than Chirasil‐Val to the racemization caused by such high temperature treatment. Capillary columns coated with this type of immobilized polysiloxane have shown very high enantioselectivity and thermal stability.