土壤中^(238)Pu、^(239)Pu、^(240)Pu和^(241)Pu的同步分离和电感耦合等离子体串联质谱分析  

Determination of^(238)Pu,^(239)Pu,^(240)Pu and^(241)Pu in Soil by Tandem Quadrupole Inductively Coupled Plasmon-Mass Spectrometry

作　　者：郭毅超 彭晨阳 杜心雨 张峰 周浩林 史克亮[1,2] 邢闪 侯小琳 GUO Yi-Chao;PENG Chen-Yang;DU Xin-Yu;ZHANG Feng;ZHOU Hao-Lin;SHI Ke-Liang;XING Shan;HOU Xiao-Lin(School of Nuclear Science and Technology,Lanzhou University,Lanzhou 730000,China;Frontiers Science Center for Rare Isotopes,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]兰州大学核科学与技术学院,兰州730000 [2]兰州大学稀有同位素前沿科学中心,兰州730000

出　　处：《分析化学》2025年第3期397-406,共10页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.12175201);兰州大学学生创新创业行动计划项目;国民核生化灾害防护国家重点实验室开放基金项目(No.SKLNBC2024-07)资助。

摘　　要：环境中的钚同位素(^(238)Pu、^(239)Pu、^(240)Pu和^(241)Pu)是核活动溯源研究的重要“指纹”核素。环境介质中钚同位素含量通常极低,且钚同位素尤其是^(238)Pu的质谱测量会受到共存的^(238)U严重干扰。分析土壤样品中的4种钚同位素通常需要联合多种测量技术,导致分析时间较长,且同位素比值分析不确定度较大。本研究采用二氯氧钛(TiOCl_(2))在近中性条件下产生的水合氧化钛(HTiO)沉淀对土壤消解液中的钚进行高效预富集,使用单一TK200树脂柱实现了样品中^(238)U的高效去污,其去污系数达到10^(8)。通过密度泛函理论(DFT)计算,发现U^(+)和Pu^(+)与碰撞反应气体NH_(3)的反应活性差异显著,因此可将NH_(3)作为消除^(238)U的反应气体。研究结果表明,通过优化碰撞气体(He)和反应气体(NH_(3))流速,^(238)U的干扰可被高效抑制,其去污系数达到10^(4)。结合化学分离,本方法对总^(238)U的去污系数可达10^(12)。采用化学分离结合电感耦合等离子体串联质谱技术,实现了对土壤中4种痕量钚同位素的准确分析,通过流程空白计算出钚同位素的检出限可达fg量级。采用本方法对国际标准参考物质(NIST-SRM-4357和IAEA-384)进行分析,结果表明,本方法可用于土壤样品中超微量的4种钚同位素的同时准确分析。Plutonium isotopes(^(238)Pu,^(239)Pu,^(240)Pu and^(241)Pu)in the environment are important“fingerprint”nuclides in the study of nuclear activity traceability.The content of plutonium isotopes in the environmental metrics is usually very low,and the measurement of these isotopes,especially^(238)Pu,using mass spectrometry is seriously interfered with by the coexisting^(238)U.The analysis of several plutonium isotopes in soil usuallyrequires combination of multiple measurement techniques,which leads to a long analysis time and large uncertainty in the isotope ratio.In this work,the hydrous titanium oxide(HTiO)precipitated by the hydrolysis of titanium oxydichloride(TiOCl_(2))under near-neutral condition was used to preconcentrate plutonium from the soil digestion solution,and the highly efficient decontamination of^(238)U in the sample was achieved by TK200 resin column chromatography with a decontamination factor of 10^(8).Simulation resuts of density functional theory(DFT)showed that NH_(3)was considered as a promising reaction gas to eliminate the interference of^(238)U from^(238)Pu measurement using mass spectrometry due to the significant discrepancy of the chemical reactivity of U^(+)and Pu^(+)with the reactive gas NH_(3).Experiments confirmed that by optimizing the flow rates of collision gas(He)and reaction gas(NH_(3)),the interference of^(238)U could be effectively suppressed,and the decontamination factor of^(238)U was 10^(4).Combined with chemical separation,the overall decontamination factor of^(238)U could reach 10^(12) by using the developed method.By combining chemical separation and tandem quadrupole inductively coupled plasmon-mass spectrometry(ICP-MS/MS)measurement,the simultaneous determination of four ultra-trace plutonium isotopes in soil was realized,and the detection limit of plutonium isotopes was at the femtogram level.Analysis of the international standard reference materials(NISTSRM-4357 and IAEA-384)showed that the established method could be successfully used for the accurate analysi

关 键 词：钚同位素 电感耦合等离子体串联质谱 He-NH_(3) TK200树脂 土壤 

分 类 号：O657.63[理学—分析化学]