Development of rapid plutonium analysis for environmental samples by isotope dilution/inductively coupled plasma mass spectrometry with on-line column

This paper describes our development of a rapid on-line column/ID-ICP-MS technique for the analysis of plutonium (Pu) in environmental samples using an UTEVA((R)) extraction chromatograph resin (UTEVA resin) column. It took only 40 min to separate and measure Pu in the sample solution, including the time for conditioning the resin column for the next analysis. In our method, Pu in a 3 M nitric acid solution was fed to the UTEVA resin, and then eluted from the resin by reducing Pu to Pu(III) with 3 M nitric acid mixed with 0.01 M ascorbic acid after washing the resin. The outflow from the resin column was directly introduced to an ICP-MS system. The low concentration of ascorbic acid and the small volume of the eluting solution (0.6 mL) made successive stable analysis possible without any skimmer cone clogging. The chemical recovery of Pu during column operation was 70%, and typical lower detection limits for (239)Pu, (240)Pu and (242)Pu were 9.2, 4.3 and 7.5 fg (21, 36 and 1.1 mu Bq), respectively. We analyzed five international standard materials for Pu, and obtained good results.