Comparison of the retention behaviour of uranium and thorium on high-efficiency resin substrates impregnated or dynamically coated with metal chelating compounds

Abstract

A study of the separation of trace uranium from multi element mixtures using high-performance chelating ion chromatography (HPCIC) is described. Three different chelating columns were compared in the investigations and the results are discussed. Two types of neutral polystyrene substrates were used for forming the chelating surfaces, a hypercrosslinked macronet and a standard low crosslinked polymer. Calmagite, 4-(2-pyridyl) azoresorcinol (PAR) and dipicolinic acid were the chelating compounds selected to impregnate or coat the resins. One unusual finding was the different retention orders for uranium(VI) and thorium(IV) on the three columns. The best separation of uranium(VI) was obtained on the macronet resin dynamically coated with dipicolinic acid. The column gave a uranium peak of good symmetry well separated from thorium(IV), lanthanum(III) and iron(II). The reproducibility of retention and quantitative performance for uranium(VI) was evaluated using arsenazo III post-column reaction detection.