Controlled potential coulometry: sequential determination of uranium and plutonium using platinum working electrode (Paper No. RA-17)

A controlled potential coulometric method for the sequential determination of U and Pu using Pt working electrode was developed. The method consists of reduction of U and Pu to U(IV) and PU(III) in 8-10 M H2SO4 using Ti(III) followed by destruction of excess Ti(III) along with selective oxidation of PU(III) to Pu(IV) by adding a few drops of 7-8 M HNO3. The aliquot was then diluted to about 2-3 M H2SO4 and U was determined by quantitative oxidation of U(IV) to U(VI) via Pu(IV)/Pu(III) couple at Pt working electrode. Plutonium was subsequently determined in the same aliquot using Pu(IV)/Pu(III) couple. The method was employed for the determination of U and Pu in synthetic mixtures containing varying percentages of Pu and the precision obtained was ∼± 0.2%. The method has an advantage of determination of U and Pu individually and sequentially. (author). 1 tab