Uranium determination at ppb levels by X-ray fluorescence after its preconcentration on polyurethane foam

A sensitive method based on the preconcentration of uranium on powdered polyurethane foam (PUF) has been developed to determinate this element in water samples by X-ray florescence. Uranium at ppb levels was sorbed as the salicylate complex on powdered PUF at pH 4.0. The resulting PUF was filtered through a filter paper and used for X-ray fluorescence measurements. For 50 μg/l of uranium the coefficient of variation for five measurements is 5% and the detection limit is 5.5 μg/l. The interference level of various ions and ligands was studied and optimum conditions were developed to determine uranium in reference materials, waste water, mine drainage, and sea water.