Simultaneous determination of ultra-trace level 237Np and Pu isotopes in soil and sediment samples by SF-ICP-MS with a single column chromatographic separation

• DOI: 10.1016/j.microc.2019.05.044
• Publication Date: 2019-05-18T14:07:45Z
• Authors: Zhaoya Huang; Youyi Ni; Hai Wang; Jian Zheng; Shinnosuke Yamazaki; Aya Sakaguchi; Xinggui Long; Shigeo Uchida
• Keywords: Soil test

Abstract This work presents a method developed for simultaneous analysis of ultra-trace level 237Np and Pu isotopes in soil and sediment samples by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). 242Pu was used as a yield tracer for 237Np as well as for Pu isotopes. A simple single chromatographic column packed with anion exchange resin (AG MP-1M) was used for the separation of 237Np and Pu isotopes from the matrix elements and other potential interferences. The SF-ICP-MS measurement precision of the 237Np/242Pu atom ratio for sub-fg/mL level 237Np and 242Pu was 0.97%, and the overall fractionation between 237Np and 242Pu for the whole analysis procedure was 1.010 ± 0.038. Besides, the single column chromatographic separation realized high decontamination factor of U (1.8 × 106 to 1.7 × 107), and that ensured the interference effect of 238U to the 237Np, 239Pu and 240Pu measurements was negligible or could be easily corrected. Four standard reference materials were analyzed for method validation, and the results illustrated 242Pu was an effective non-isotopic tracer for 237Np determination. Finally, the developed method was successfully employed in the analysis of the global fallout level of 237Np and Pu isotopes in Japanese paddy soil samples to study their environmental behaviors.