Determination of trace concentration of uranium in plutonium oxide samples by ICP-AES

A method has been standardized for the determination of trace concentration of uranium (300-3000ppm) in plutonium oxide samples. The method involves the quantitative separation of U from Pu-matrix by solvent extraction with mixed solvent comprising 30% tri-n-butyl phosphate (TBP) +1% trialkyl phosphine oxide (TRPO) + 0.3M tertiary butyl hydroquinone (TBH) in n-dodecane. Uranium from the organic is stripped into the aqueous phase with 0.8M oxalic acid and determined by ICP-AES. The reliability of the method is checked by ascertaining the analytical recovery of known amount of uranium (10μg) spiked in the actual sample aliquot, which is found to be better than 99%. (author)