大体积环境水样中超痕量钚同位素的分析  

Determination of Ultra-Low Level Plutonium Isotopes in Large Volume Environmental Water Samples

作　　者：高瑞勤 侯小琳[1,2,3] 张路远 张伟超[1] 张梦婷 GAO Rui-Qin;HOU Xiao-Lin;ZHANG Lu-Yuan;ZHANG Wei-Chao;ZHANG Meng-Ting(Xi'an Accelerator Mass Spectrometry Center,State Key Laboratory of Quaternary Geology,Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application,Institute of Earth Environment,Chinese Academy of Sciences,Xi'an 710061,China;Center for Excellence in Quaternary Science and Global Change,Chinese Academy of Sciences,Xi'an 710061,China;Open Studio for Oceanic-Continental Climate and Environment Changes,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266061,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地球环境研究所,黄土与第四纪地质国家重点实验室,陕西省加速器质谱技术及应用重点实验室,西安加速器质谱中心,西安710061 [2]中国科学院第四纪科学与全球变化卓越创新中心,西安710061 [3]青岛海洋科学与技术试点国家实验室海陆气候环境变化开放工作室,青岛266061 [4]中国科学院大学,北京100049

出　　处：《分析化学》2020年第6期765-773,共9页Chinese Journal of Analytical Chemistry

基　　金：科技部基础性工作专项项目(No.2015FY110800);国家自然科学基金项目(No.11875261);中国科学院国际合作项目(No.132B61KYSB20180003)资助。

摘　　要：建立了一种环境水样中痕量钚同位素的分析方法。采用Ti(OH)3作为共沉淀剂,对大体积水样中的钚进行预浓缩,通过TEVA树脂萃取色谱分离纯化钚。结果表明,对于20 L水样,在钛载体浓度为30 mg/L条件下,钚的总回收率为88.9%。萃取色谱分离对铀的去污系数达到1.3×10^5。用高灵敏度的电感耦合等离子体串联质谱(ICP-MS/MS)同时测定239Pu和240Pu含量,使用NH3-He作为反应气体,有效消除了UH+离子对239Pu测量的干扰,通过使用串联四极杆技术,将丰度灵敏度提高5个量级,从而消除了238U峰拖尾的影响,使分析本底和干扰显著降低,同时,将钚同位素的分析灵敏度提高至990 cps/(pg/g)。对20 L水样中239Pu和240Pu的检出限分别达到1.28×10^-7 Bq/L和1.38×10^-7 Bq/L。本方法被成功用于分析地表水、水库水和地下水中239Pu和240Pu浓度。A sensitive analytical method for determination of 239Pu and 240Pu in environmental water samples was developed. By co-precipitation of plutonium with Ti(OH)3 followed by separation of plutonium using extraction chromatography with TEVA resin, a recovery of more than 80% for plutonium and a decontamination factor of 1.3×10^5 for uranium were achieved. A triple quadrupole inductively coupled plasma mass spectrometry(ICP-MS) method with dynamic collision/reaction cell was used for measurement of plutonium isotopes. By using NH3-He double gasses as collision/reaction gas, 238U1H+ ion interference to 239Pu was significantly suppressed and the final abundance sensitivity of 238U to m/z=239 was reduced to <1×10^-11, meanwhile the sensitivity of 239Pu was improved to 990 cps/(pg/g). For 20 L of water sample, the detection limits of the method for 239Pu and 240Pu reached 1.28×10^-7 Bq/L and 1.38×10^-7 Bq/L, which enabled accurately determination of 239Pu and 240Pu in normal environmental water samples. The developed method was successfully applied to determine 239Pu and 240Pu in the spiked water and real environmental water samples. The results indicated this method was reliable and could be practically applied.

关 键 词：钚 环境水样 共沉淀 氢氧化钛 电感耦合等离子体质谱 

分 类 号：O657.63[理学—分析化学] X832[理学—化学]