C 2 H 4 as a Novel Reaction Gas for Eliminating 238 U Isobaric Interference in Ultratrace Plutonium Isotope ( 238 Pu, 239 Pu, 240 Pu, and 241 Pu) Measurement by ICP-MS/MS

作者：Chenyang Peng, Xinyu Du, Hao Wang, Yiman Lu, Jie Chen, Feng Zhang, Xiaoqing Gao, Haoran Ma, Shan Xing, Xiaolin Hou, Keliang Shi · 发表于：Analytical Chemistry · 年份：2025 · DOI：10.1021/acs.analchem.5c01952 · 被引用次数：6 · 研究领域：Radioactive contamination and transfer、Radioactive element chemistry and processing、Nuclear Physics and Applications

Accurate determination of ultratrace plutonium isotopes ( 238 Pu, 239 Pu, 240 Pu, and 241 Pu) generally requires the utilization of multiple techniques. Among them, alpha spectrometry is the only way to measure ultratrace 238 Pu (<1 mBq/1.6 fg) but with a very long counting time (hours to days). The accurate and rapid analysis of ultratrace plutonium isotopes is still a challenge. In this work, a novel analytical method for the accurate determination of ultratrace plutonium isotopes ( 238 Pu, 239 Pu, 240 Pu, and 241 Pu) in the same run was developed by ICP-MS/MS in He–C 2 H 4 mode combined with a TK200 resin column. A high decontamination factor (DF) of 238 U (1.81 × 10 9 ) was achieved by only a single TK200 resin column. 238 U and its polyatomic ions ( 238 U 1 H + and 238 U 1 H 2 + ) can be further eliminated using C 2 H 4 as a reaction gas with a DF( 238 U) of 6.63 × 10 5, and the overall removal efficiency of 238 U reached 1.21 × 10 15 . The excellent measurement sensitivity of plutonium (5602 cps/(pg/g)) was achieved. Meanwhile, the investigation on the mechanism of the C 2 H 4 reaction by DFT calculations could provide a novel method for the better understanding of the improvement of Pu sensitivity and the elimination of 238 U interference. The detection limits for all plutonium isotopes were subfemtogram level, demonstrating the feasibility of ICP-MS/MS using C 2 H 4 for the accurate determination of ultralow-level plutonium isotopes containing subgram level 238 U. Thi...