ABSTRACT
Among the separation modes of liquid chromatography, ligand exchange chromatography (LEC) is a particularly useful technique in many applications:
1. Chiral separation of optical isomers in chiral ligand exchange chromatography (CLEC).[1] In this method, complexes of transition metal ions and enantiomeric molecules are formed. Chiral separation is a result of the differences between the free energies of the intermediate diastereomeric complexes formed. For the separation to be successful, the sample molecule must have two polar functional groups with the correct spacing, which can simultaneously act as ligand for the divalent transition metal ion. For this reason, the underivatized racemic amino acids with their amino and carboxyl groups and other similar compounds, such as amino alcohols, hydroxy acids, and diamines, can be resolved with CLEC.
