Preparation of chiral stationary phase for HPLC based on immobilization of cellulose 3,5-dimethylphenylcarbamate derivatives on silica gel

The immobilization of cellulose 3,5-dimethylphenylcarbamate derivatives having a polymerizable vinyl group, i.e., 4-vinylphenylcarbamate or 2-methacyloyloxyethylcarbamate, on silica gel was examined under various conditions. The immobilization was basically conducted through the radical copolymerization of the derivatives with a vinyl monomer. Several factors, such as the vinyl monomer content and the type and amount of the vinyl group of cellulose derivatives, were varied. The introduction of a vinyl group onto the silica surface resulted in a more efficient immobilization of the cellulose phenylcarbamate derivatives on the silica gel. As the content of the vinyl group on the cellulose derivatives was reduced, the immobilization became more difficult, although the obtained phase exhibited higher chiral recognition abilities. These immobilized CSPs could be stably used with the eluent containing 10% chloroform, which cannot be used for the phase prepared by coating the derivatives on silica gel. Some racemates were better resolved on the immobilized CSP by using chloroform as a component of the eluent.