||High performance method for determination of Pu isotopes in soil and sediment samples by sector field inductively coupled plasma mass spectrometry
Wang, Zhongtang ,
Zheng, Jian ,
Ni, Youyi ,
Men, Wu ,
Tagami, KeikoUchida, Shigeo
2226 , 2017-01 , ACS Publications
Artificial plutonium in the environment is extensively studied in radioecology (e.g. soil to plant transfer and radiological assessment) and geochemistry (e.g. sediment dating). In this study, a new chemical separation method was developed for rapid determination of Pu in soil and sediment samples, based on the following investigations: extraction behaviors of interfering elements (IEs, for ICPMS measurement) on TEVA resin; decontamination of U using TEVA, UTEVA and DGA resins and the impact of co-precipitation on Pu determination. The developed method consists of four steps: HNO3 leaching for Pu release; CaF2/LaF3 co-precipitation for the removal of major metals and U; the proposed TEVA+UTEVA+DGA procedure for the removal of U, Pb, Bi, Tl, Hg, Hf, Pt and Dy; and ICPMS measurement. The accuracy of this method in determining 239+240Pu activity and 239Pu/240Pu and 241Pu/239Pu atom ratios was validated by analyzing five standard reference materials (soil, fresh water sediment and ocean sediment). This method is characterized by its stable and high Pu recovery (90-97% for soil; 92-98% for sediment) and high decontamination factor of U (1.6 × 107) which is the highest reported for soil and sediment samples. In addition, the short analytical time of 12 h and the method detection limits, which are the lowest yet reported in literature, of 0.56 μBq g-1 for 239Pu, 1.2 μBq g-1 for 240Pu, and 0.34 mBq g-1 for 241Pu (calculated on the basis of a 1 g soil sample) allow the rapid determination of ultratrace level Pu in soil and sediment samples.