The Lewis acid sites present on the underlying zirconium oxide particles are responsible for the unusual elution sequence for amino acids on copper(II) loaded, phosphated zirconium oxide supports reported in an earlier study. To more thoroughly examine the effect of these strong Lewis acid sites, we have studied ligand exchange chromatography on copper(II) loaded zirconium oxide particles. It is shown here that carboxylate functional groups on amino acid solutes strongly interact with surface Lewis acid sites. Addition of competing hard Lewis bases to the eluent attenuates these specific interactions. The result is a chromatographic system with high selectivity which is also suitable for ligand exchange chromatography of proteins.
Bibliographical noteFunding Information:
The authors would like to acknowledge financial support from NIH and NSF for these studies. JAB also acknowledges financial support from the Leading Edge Academic Program at 3M.