Chiral ligand exchange countercurrent chromatography: Equilibrium model study on enantioseparation of mandelic acid

• An equilibrium model was proposed for chiral ligand exchange countercurrent chromatography.
• The model predictions was in good conformity with the experimental values.
• The model can be used for optimization of the enantioseparation conditions.

The equilibrium model in enantioseparation of mandelic acid by chiral ligand exchange countercurrent chromatography was investigated using N-n-dodecyl-l-proline as chiral ligand and cupric ion as central metal. Important parameters, including physical partition coefficient and formation constants of binary and ternary coordination complexes in the two-phase solvent system, were determined. This equilibrium model could give an excellent prediction of distribution ratio and enantioseparation factor of the analyte in the biphasic solvent system, which was further verified by experiments. All the average relative deviations were less than 12%, indicating that the established model could provide a simple computational approach for optimization of enantioseparation conditions in chiral ligand exchange countercurrent chromatography.