Liquid chromatographic selectivity and retention behavior of rare-earth elements on a chelating resin having a propylenediaminetetraacetate type functional group

A new chelating resin that has a functional group such as propylenediaminet etraacetate separated from the polymer matrix by a spacer arm (PDTA resin) was synthesized. The amount of ligand in the PDTA resin was 127 mu mol g(-1 ) as the amount of copper adsorbed on the resin. The chromatographic select ivity and retention behavior of rare-earth elements (REEs) on the PDTA resi n were evaluated. A good correlation between the capacity factor for a seri es of REEs on the PDTA resin and the stability constant of the correspondin g PDTA complexes was obtained (R-2 = 0.963). The increasing flexibility of ligand caused by the spacer arm led to a good correlation between the selec tivity of PDTA resin and free PDTA with REEs. The PDTA resin was applied to the column stationary phase for the ion chromatographic separation of REEs . A favorable separation of a series of REEs was achieved within 70 min usi ng a nitric acid gradient. It was demonstrated that the chelating resin tha t has low ligand density and a spacer arm between ligand and base matrix wa s suitable as a stationary phase for liquid chromatography and ion chromato graphy.