Enantioseparation of Three Non-Steroidal Anti-Inflammatory Agents on Chiral Stationary Phase by HPLC

This paper reported the enantioseparation of Naproxen, Ketoprofen and Etodolac on tartardiamide-DMB chiral stationary phase (CHI-DMB) and (R,R)-DNB-DPEDA chiral stationary phase,using hexane as the mobile phase with various modifiers. The influence of the mobile phase composition including the type and concentration of the modifiers in hexane and the structures of the analytes on the chiral separation was studied. The results indicated that the steric structure of the solute, especially the environment of the chiral carbon, was the predominant factor for the chiral recognition. The type, the steric structure and the concentration of the modifiers also influence the retention factor and the resolution. The chiral recognition mechanism of the analytes on CHI-DMB and (R,R)-DNB-DPEDA was also discussed. The hydrogen-bonding interaction played an important role on enantioseparation on CHI-DMB, so did the π-π interaction. On (R,R)-DNB-DPEDA the π-π interaction was the key for the solutes retention and enantioseparation, while hydrogen-bonding interaction was not important. Additionally, it has been demonstrated that enantioselectivity and retention was also dependent upon the nature and functional groups on the aromatic ring of solutes and CSP.