Determining cerium in plutonium by anion exchange and x-ray fluorescence

This report describes a procedure for determining cerium in plutonium using an anion-exchange separation and x-ray fluorescence. We add lanthanum to the plutonium solution as an internal standard, oxidize the plutonium to Pu/sup /plus/4/, and pass the solution through an anion-exchange column with 8M HCl. The Pu/sup /plus/4/ sorbs to the resin, and the cerium and lanthanum pass through the column completely. We evaporate the solution containing the cerium and the lanthanum to 0.5 mL for pipetting onto a resin paper disc. The Pu/sup /plus/4/ is eluted off the column using 0.1M HCl. We then measure the K/sub α/ x-ray line for both cerium and lanthanum. The ratio of cerium to lanthanum for the sample is then compared with those from the standards. This method has a precision of 2.8% relative standard deviation for cerium over a concentration range of 0.1 to 5% cerium. 2 refs., 2 figs., 3 tabs