Separation of hydroxy acid enantiomers by ligand exchange-micellar electrokinetic chromatography

Hydroxy acid enantiomers have specific bioactivity. Much attention has been paid to their analytical separation. This work investigated their separati on and behavior by ligand exchange-micellar electrokinetic chromatography u sing Cu(II)-L-OH-proline complexes as chiral selectors. Previous work showe d that D-amino acid enantiomers migrated faster than L-analogues when Cu(II )-L-proline complexes were used as chiral selectors. The enantiomer migrati on orders (EMO) of amino acids were reversed by introducing the SDS micella r phase. In the case of hydroxy acid enantiomers, however, it was observed that L-enantiomers migrated faster than the D-forms in both cases of withou t and with the SDS micellar phase. When CTAB was added to running electroly tes, D-enantiomers migrated as the first peak. Further, when the ligands we re changed, different EMOs were observed. The resolution condition, mechani sm and behaviors are discussed in this paper.