生物样品中超低水平^(239)Pu和^(240)Pu的分析  

Determination of Ultra-Low Levels of^(239)Pu and^(240)Pu in Biological Samples

作　　者：王永昌 张梦婷 侯小琳[1] WANG Yong-Chang;ZHANG Meng-Ting;HOU Xiao-Lin(Xi′an Accelerator Mass Spectrometry Center,State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi′an 710061,China;Xi′an Institute for Innovation Earth Environment Research,Xi′an 710061,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,西安加速器质谱中心,西安710061 [2]西安地球环境创新研究院,西安710061 [3]中国科学院大学,北京100049

出　　处：《分析化学》2024年第5期706-716,共11页Chinese Journal of Analytical Chemistry

基　　金：中国科学院重点部署项目(No.ZDBS-SSW-DQC003);中国科学院战略性先导科技专项(B类)项目(No.XDB40020104);中国科学院国际合作项目(No.132B61KYSB20180003);国家自然科学基金项目(Nos.11875261,42207313)资助。

摘　　要：建立了一种生物样品中超低水平^(239)Pu和^(240)Pu的分析方法。以碳酸钠为皂化剂、乙酸镁为助灰化剂,对大质量的生物样品进行灰化,再使用Fe(OH)_(2)-Fe(OH)_(3),通过共沉淀分离富集方法从灰化的样品中酸浸取得到钚,然后以硝酸铝为掩蔽剂消除样品中大量磷对钚在阴离子交换分离过程中的干扰,采用TEVA萃取色谱进一步除去铀等干扰组分,整个流程钚的平均回收率大于73%,对^(238)U的去污因子为3.3×10^(4)~5.4×10^(5)。利用APEX-Ω高效进样系统,使用高灵敏度的电感耦合等离子体质谱(ICP-MS/MS),以NH_(3)-He为碰撞/反应气体测定钚同位素,使用样品分离前加入的^(242)Pu标准为产率示踪剂和同位素稀释剂,计算样品中^(239)Pu和^(240)Pu的浓度。本方法有效地抑制了^(238)U峰拖尾以及^(238)U^(1)H+的干扰,并将钚的分析灵敏度从850 cps/(pg/g)(ICP-MS/MS)大幅度提升至8000 cps/(pg/g)。本方法对鱼虾样品(采样量3.5 kg鲜重)中^(239)Pu和^(240)Pu的检出限分别为2.56×10^(-4) mBq/(kg·wet)和7.33×10^(-4) mBq/(kg·wet);对海藻样品(采样量为300 g鲜重(30 g干重))中^(239)Pu和^(240)Pu的检出限分别为2.98×10^(-3) mBq/(kg·wet)和8.55×10^(-3) mBq/(kg·wet)。采用本方法分析了我国海域海洋生物样品中的^(239)Pu和^(240)Pu浓度。In this work,a reliable analytical method for ultra-low ^(239,240)Pu in biological samples was developed.Sodium carbonate and magnesium acetate were used as saponification agent and ashing aid,respectively,and then Fe(OH)_(2)-Fe(OH)_(3) was used for co-precipitation separation and enrichment of plutonium extracted from the ashing samples.Then aluminum nitrate was used as a masking agent to eliminate the interference of a large amount of phosphorus in the loading solution on plutonium during the anion exchange separation process.The results showed that the average recovery of plutonium was more than 73%and the decontamination factor for ^(238)U was 3.3×10^(4)–5.4×10^(5) in biological samples.The ultimate sample introduction technology(APEX-Ω)was used in determination of plutonium isotopes by inductively coupled plasma mass spectrometry(ICP-MS/MS)with NH_(3)-He as the collision/reaction gas.The ^(242)Pu standard added before sample separation was used as the yield tracer and isotope diluent to calculate the concentration of ^(239)Pu and ^(240)Pu in samples.This method not only effectively suppressed the ^(238)U peak tail and ^(238)U^(1)H+interference,but also greatly improved the analytical sensitivity of plutonium from 850 cps/(pg/g)(ICP-MS/MS)to 8000 cps/(pg/g)(APEX-ICP-MS/MS).The detection limits of ^(239)Pu and ^(240)Pu in 3.5 kg fresh fish samples were as low as 2.56×10^(-4) mBq/(kg·wet)and 7.33×10^(-4) mBq/(kg·wet),respectively.The detection limits of ^(239)Pu and ^(240)Pu in 300 g fresh seaweed samples(30 g dry weight)were 2.98×10^(-3) mBq/(kg·wet)and 8.55×10^(-3) mBq/(kg·wet).The concentrations of ^(239)Pu and ^(240)Pu in marine biological samples from the China Sea have been successfully analyzed by using the established analytical method.

关 键 词：钚同位素 生物样品 快速灰化 萃取色谱法 电感耦合等离子体质谱 

分 类 号：X835[环境科学与工程—环境工程] O657.63[理学—分析化学]