Support loading effects on the performance of an extraction chromatographic resin: Toward improved separation of trivalent lanthanides

Changes in the level of impregnation of an Amberchrom CG-71m support with bis(2-ethylhexyl)phosphoric acid (HDEHP) are shown to alter the column efficiency, peak tailing, and metal ion uptake capacity associated with the resulting extraction chromatographic resins. Optimum efficiency and minimum peak tailing are observed at intermediate levels (ca. 20% (w/w)) of support loading. Metal ion uptake capacity is reduced relative to a commercial (loaded to 40% (w/w)) resin under the same conditions, however. The utility of the improved ef-ficiency arising from reduced support loading is illustrated in the separation of selected trivalent lanthanide ions, including Gd(III) and Eu(III), whose resolution is unsatisfactory using commercial extraction chromatographic materials.

Automated summary

Changing the impregnation level of the support material affects the efficiency, peak tailing, and metal ion uptake capacity of extraction chromatographic resins. Optimal efficiency and minimal peak tailing are achieved at intermediate support loading levels, but the metal ion uptake capacity is reduced. The utility of reduced support loading is demonstrated in the separation of certain trivalent lanthanide ions that are not satisfactorily resolved with commercial extraction chromatographic materials.