Determination of uranium in natural groundwaters using high-performance liquid chromatography

Abstract

A procedure using high-performance liquid chromatography (HPLC) and trace enrichment techniques has been developed to measure trace levels of uranium in solutions containing high concentrations of dissolved salts. This procedure is required to support research into the feasibility of deep geological disposal of used nuclear fuel, which includes studying the leaching of uranium from fuel by natural groundwater. After conditioning, several milliliters of sample are passed through a small reversed-phase enrichment of cartridge, where the uranium is concentrated and separated from the bulk of other constituents. The uranium is then back flushed from the column onto a reversed-phase analytical column where further separation is achieved. The separated species are monitored spectrophotometrically after postcolumn reaction with the chromogenic reagent Arsenazo III. Analysis of simulated ground waters has shown the procedure to be free from major interferences. Automation of the system using automatic switching valves and an automated sample injector allows approximately 40 samples per day to be analyzed with a measurement precision of about 4%. Detection limits are in the 1-2 ng/times/mL/sup /minus/1/ range.