@misc{oai:repo.qst.go.jp:00063677,
 author = {Zheng, Jian and Yamada, Masatoshi and Pan, Shaoming and Dong, Wei and Guo, Qiuju and ZENG, Li and Zhang, Yongsan and Wu, Fengchang and 鄭 建 and 山田 正俊 and 董 微 and 曾 理 and 張 永三},
 month = {Nov},
 note = {There has been an increasing interest in the distribution and fate of natural and artificial radionuclides in the environment due to the resurgence of interest in nuclear power to deal with the global warming problem. Their existence and accumulation in the environment raises an irradiation threat to human health. On the other hand, radionuclides have served as geochemical tracers for the study of fundamental environmental issues, such as water mass movement, particle scavenging, sediment mixing processes, soil erosion and desertification. 
Recently, we developed ICP-MS based analytical techniques for ultra-trace analysis of actinides (Pu isotopes and 241Am) in various low-level environmental samples, such as seawater, sediment, settling particle, atmospheric fallout samples and soil. Using a sector-field ICP-MS combined with a high-efficiency sample introduction system (APEX/SF-ICP-MS), we achieved an extremely high sensitivity for Pu and 241Am (ca. 20M cps/ppb), which is more than 400 times higher than that of quadrupole ICP-MS. For the first time, the determination of Pu atom ratio and 241Am at femtogram levels in small environmental samples was achieved. Although ICP-MS has been widely used for the determination of long-lived radionuclides in environmental samples, due to its short half-life, the determination of 241Am (t1/2 = 433 y) in low-level environmental samples by ICP-MS has been a challenging task. With the developed APEX/SF-ICP-MS analytical system, excellent detection limit which is better than that of alpha spectrometry, was achieved. Besides the effort for improving the sensitivity for actinides analysis using ICP-MS, a simple, rapid chromatographic separation system which consisted of a two-stage anion exchange chromatography and a TRU extraction chromatography was established in our laboratory for simultaneous separation and purification of Pu isotopes and 241Am in various low-level environmental samples. In this talk, we report the application of the developed method to the studies of 241Am and Pu vertical distribution in marine sediments in Yangtze River estuary/East China Sea and the distribution of Pu isotopes in deep-sea sediments in the South Pacific. The source characterization and apportionment of Pu isotopes in Yangtze River estuary and the anomalous plutonium isotope ratios in sediments of the South Pacific will be discussed., International Workshop on Loｗ-level Measurement of Radionuclides and Its Application to Earth and Environmental Sciences},
 title = {Isotope dilution SF-ICP-MS for the determination of 241Am and Pu isotopes in low-level environmental samples},
 year = {2009}
}