title: Determination of plutonium isotopes in seawater reference materials using isotope-dilution ICP-MS.
abstract: We analyzed the activities of (239)Pu, (240)Pu, (239+240)Pu, (241)Pu, the ratio of number of atoms (atom ratio) for (240)Pu/(239)Pu, and the activity ratio of (241)Pu/(239+240)Pu in seawater reference materials, IAEA-443 and IAEA-381, using a highly sensitive isotope dilution sector field inductively coupled plasma mass spectrometry method. With a mean chemical yield of 65% determined with (242)Pu as a tracer, we found that the experimentally established values in IAEA-443 for (239)Pu, (240)Pu, (241)Pu and (239+240)Pu activities are almost the same as those in IAEA-381. Regarding the (239+240)Pu activity, we provided the most precise and accurate result among the twelve laboratories, which participated in the interlaboratory comparison. In addition, for the (240)Pu/(239)Pu atom ratio, our results for IAEA-381 (0.2315±0.0008) and IAEA-443 (0.2325±0.0008) are in good agreement with the IAEA information value (0.229±0.006), but have much smaller uncertainty. Since the new seawater reference material, IAEA-443, is commercially available, it can be used not only for method validation for seawater plutonium isotope ratio and activity analysis, but also for more general use as a plutonium isotope standard for mass discrimination correction for other environmental samples.
authors.affiliation: Office of Biospheric Assessment for Waste Disposal, National Institute of Radiological Sciences, 491 Anagawa, Chiba 263-8555, Japan. jzheng@nirs.go.jp
authors.forename: Jian
authors.initials: J
authors.lastname: Zheng
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yamada
mesh_terms: D006207:Half-Life; D038622:Internationality; D007564:Japan; D011005:Plutonium / Q000032:analysis / Q000737:chemistry* / Q000592:standards*; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation / Q000592:standards*; D012015:Reference Standards; D012016:Reference Values; D012623:Seawater / Q000032:analysis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry* / Q000592:standards*
chemical_list: D014874:Water Pollutants, Chemical; D011005:Plutonium