Functional crown ether derivatives as sorbents for ligand exchange chromatography

Two kinds of macrocyclic compounds, S-TAROH18C6 and S-TAROEt12C4 derived from tartaric acid have been synthesized. The structure and conversion of functional groups on this silica gel based resin have been confirmed by IR spectral and elemental analysis. The coordination behaviour of these materials has been investigated by means of IR, EPR, potentiometry and the modification of Langmuir isotherm equation. The metal complexes have been investigated as stationary phases for the separation of amino acid mixtures. Factors affecting the retention and the sample selectivity have been examined. S-TAROEt12C4 possesses good chromatographic characteristics and a unique selectivity in separating underivatized amino acid mixtures and can be used as well for enantiomeric separations.