Ligand-exchange chromatography of racemates : VII. Separation of optical isomers of amino acids on a polystyrene resin containing l-allo-hydroxyproline as the fixed ligand

Abstract

An asymmetric sorbent has been synthesized containing l-allo-hydroxyproline groupins in a macronet polyestyrene matrix. The γ-hydroxy group in allo-hydroxyproline, like the carboxylic and the amino group, is capable of coordinating copper(II) ions. The sorbent thus forms more stable bis-chelate complexes with copper(II) than the analogous sorbent containing l-hydroxyproline residues. The sorption selectivity of proline enantiomers on the copper(II) forms of the two resins has been studied as a function of copper ion content. Enantioselectivity and the retention parameters for various amino acids on the sorbent containing allohydroxyproline have been evaluted using ligand-exchange chromatography. The resolving power of this sorbent with respect to racemates of acidic and basic amino acids, as well as methionine and phenylalanine, is higher than that of similar resins described earlier.