Analytical Sciences

Precise Determination of Pu Isotopes in a Seawater Reference Material Using ID-SF-ICP-MS Combined with Two-stage Anion-Exchange Chromatography

Jian ZHENG and Masatoshi YAMADA

Nakaminato Laboratory for Marine Radioecology, Environmental Radiation Effects Research Group, National Institute of Radiological Sciences, 3609 Isozaki-cho, Hitachinaka, Ibaraki 311-1202, Japan

In order to obtain the precise Pu isotope composition of Irish Sea water reference material issued by the International Atomic Energy Agency (IAEA-381), we analyzed the activities of ²³⁹Pu, ²⁴⁰Pu and the atom ratio of ²⁴⁰Pu/²³⁹Pu by a highly sensitive isotope dilution SF-ICP-MS method combined with two-stage chromatographic separation and purification. With a mean chemical yield of 65% for ²⁴²Pu tracer, the experimentally established values for ²³⁹Pu, ²⁴⁰Pu and ^239+240Pu activities are in good agreement with the certified ones. For the ²⁴⁰Pu/²³⁹Pu atom ratio, we obtain a value of 0.2315 ± 0.0008 with a high precision (RSD, 0.35%), which is much more precise than the information value of 0.22 ± 0.03 (RSD, 13.6%) provided by the IAEA certification report. The precise determination of Pu isotopes in this seawater reference material will be useful for the validation of analytical methods for the study of radionuclides in the marine environment.

J-STAGE: View this article in J-STAGE