@misc{oai:repo.qst.go.jp:00065156,
 author = {Bu, Wenting and Zheng, Jian and Guo, Qiuju and Aono, Tatsuo and Tagami, Keiko and Uchida, Shigeo and Yamada, Masatoshi and ト 文庭 and 鄭 建 and 青野 辰雄 and 田上 恵子 and 内田 滋夫 and 山田 正俊},
 month = {Sep},
 note = {Plutonium isotopes are released into the environment as a consequence of human nuclear activities including nuclear weapon testing, nuclear fuel reprocessing and nuclear accident. As the ocean covers ca. 70 % of the earth surface, it received majority of Pu isotopes released into the environment by atmospheric. For example, it has been estimated that the total global fallout 239+240Pu released into the environment was about 10.87 pBq and 6.6 pBq entered the worlds ocean[1]. Besides, a significant amount of Pu isotopes were injected directly to the worlds ocean by close-in fallout from the nuclear explosions conducted at the Pacific Proving Ground by US and the French Polynesia by France. 
Due to their radiotoxicity and long half-lives, Pu isotopes are regarded as highly hazardous pollutants in the marine environment and are of great interest. Accurate and precise determination of plutonium isotopes in marine samples is important for radioecological assessment. In addition, Pu isotopes have also been used for tracing of oceanographic processes, such as water mass circulation, transport and scavenging of particulate matter, etc. 
The concentration of Pu in seawater is extremely low (239+240Pu, 1.2-7.4 mBq/m3 in the surface seawater of the NW Pacific Ocean).[2] By the traditional alpha spectrometry method, usually large volume (~ 200 L) of seawater sample is needed for the analysis of Pu and the 240Pu/239Pu atom ratio, which is an important fingerprint for Pu source identification and for tracing of oceanographic processes, cannot be obtained.[3] Due to the low detection limit and the relatively simple sample preparing procedures, ICP-MS has been treated as a routine method for the analysis of Pu in environmental samples in recent years. However, when using ICP-MS, the detection of 239Pu and 240Pu can be affected by spectral interferences caused by 238UH+ and 238UH2+ formations, especially for the environmental samples with high U concentrations. The concentration of U in seawater in Pacific Ocean is about several ng/mL and the atom ratio of 238U/239Pu can be up to 1011.[4] Thus, complex procedures for the preconcentration of Pu and separation of Pu from U were employed for the determination of Pu in seawater prior to the analysis by ICP-MS, which somehow may lead to low Pu recovery.
In this work, we presented a simple method for the analysis of Pu concentration and its isotopic composition in seawater samples by sector field ICP-MS combined with classical chromatographic separation. High precision and accuracy were achieved by using this method. The detailed analysis procedures and the merits of this method will be discussed at the conference., ５th Asia-Pacific Symposium on Radiochemistry (APSORC 13)},
 title = {Determination of Pu isotopes at ultratrace level in seawater samples by sector-field ICP-MS combined with chromatographic separation},
 year = {2013}
}