Enantioseparation of acidic compounds on chiral stationary phase by high performance liquid chromatography

Cellulose and cellulose derivatives are biopolymers which are often used as stationary phases for the separation of enantiomers. Describing the mechanism of such separations is a difficult task due to the complexity of these stationary phases. In this paper, the separation of six acidic compounds (cetirizine, naproxen, tropic acid, ibuprofen, ketoprofen and 2,2-biphenyl-cyclopropanecarboxylic acid) was studied on two chiral columns-trtis(3,5-dimethylpheny carbmate) (CDMPC) and (S,S)-Whelk-O1 chiral columns. The influence of the structures of the analytes on the chiral separation was investigated. The mobile phase composition including the concentration and type of the alcohol modifier and the acidic additive in hexane was varied, and the influence on the retention factor (k') for each enantiomer, the separation factor (alpha) and the resolution (R) was studied. Then the two different chiral recognition mechanism were discussed and compared.