In order to develop novel chiral stationary phases (CSPs)

chitosan was modified by benzoyl chlorides with various substituents

successively using methylsulfonic acid and N

N-dimethylacetamide as the solvents.In this way

new derivatives of chitosan bis(benzoate)-(benzamide)

chitosan bis(4-methylbenzoate)-(4-methylbenzamide)

chitosan bis(3

5-dimethylbenzoate)-(3

5-dimethylbenzamide) and chitosan bis(4-chlorobenzoate)-(4-chlorobenzamide) were synthesized.The corresponding CSPs were prepared by coating the chitosan derivatives on porous 3-aminopropyl silica gel employing N

N-dimethylforamide as the solvent.The chiral recognition capability of the CSPs was evaluated towards structurally various chiral compounds in normal phase conditions

and the results showed that these CSPs possessed satisfactory enantioselectivity.The CSP prepared from chitosan bis(4-methylbenzoate)-(4-methylbenzamide) with a coating ratio of 16% exhibited better chiral recognition capability than that prepared from the same derivative with a coating ratio of 20%.The CSP based on chitosan bis(3

5-dimethylbenzoate)-(3

5-dimethylbenzamide) showed stronger chiral recognition capability than the CSPs based on the other derivatives.Meanwhile

the CSP derived from chitosan bis(4-methylbenzoate)-(4-methylbenzamide) separated the chiral compounds with highest resolutions.This feature is similar to that of the CSP derived from cellulose tris(4-methylbenzoate)

and different from that of the CSP prepared from amylose tris(4-methylbenozate) that bear poor chiral recognition capability.The reason may be related to the similarity of chitosan and cellulose in which the repeating units are all connected by -1

4-glycosidic bond

other than -1

4-glycosidic bond in amylose.In addition

the CSPs generally demonstrated better resolutions in the mobile phases simultaneously containing ethanol and methanol.