吹扫捕集-原子荧光光谱与同位素稀释质谱法结合测定海水中痕量汞  

Determination of Trace Mercury in Seawater by Purge and Trap-Atomic Fluorescence Spectrometry Combined with Isotope Dilution Mass Spectrometry

作　　者：巢静波[1] 王茜[1] 王静如 李芳缘 陈艳[1] CHAO Jingbo;WANG Qian;WANG Jingru;LI Fangyuan;CHEN Yan(Chemical Metrology and Analytical Science Division,National Institute of Metrology,Beijing 100029;College of Chemical Engineering,Beijing University of Chemical Technology,Beijing 100029)

机构地区：[1]中国计量科学研究院化学计量与分析科学研究所,北京100029 [2]北京化工大学化学工程学院,北京100029

出　　处：《分析科学学报》2021年第2期165-170,共6页Journal of Analytical Science

基　　金：原国家质量监督检验检疫总局能力提升项目(No.ANL1806)。

摘　　要：建立了吹扫捕集-原子荧光光谱,结合同位素稀释质谱法测定海水中痕量汞的高准确度的分析方法,以HNO_(3)消解样品,通过吹扫捕集、金柱吸附的方式实现痕量汞与高盐基体的分离并进一步富集,与电感耦合等离子体质谱联用,采用同位素稀释质谱法进行准确测定。对影响样品准确测定结果的消解用HNO_(3)体积、消解时间、SnCl_(2)用量、基体影响、本底控制等因素进行了选择和优化。吹扫捕集-同位素稀释质谱法的检出限为3.7 pg/g。在优化的条件下,分别对国际比对海水样品和采自渤海、舟山岛附近海水中的总汞含量进行了6次测定,国际比对样品海水测定结果的相对标准偏差为4.11%。在30 pg/g和50 pg/g加标水平上,海水样品的加标回收率分别为98.1%和104%。以国际比对海水样品测定为例进行了不确定度评定,测定结果的扩展不确定度<5%(k=2),为常规海水和国际比对、海水标准物质等样品中痕量汞的高准确度测定提供了有力的技术手段。A high accurate method for the determination of trace mercury in seawater by purge and trap-atomic fluorescence spectrometry(AFS)combined with isotope dilution mass spectrometry(IDMS)has been developed.Trace mercury was separated and enriched from high-salt matrix of seawater by purge and trap,gold column adsorption system,then determined by AFS combined with IDMS.The factors such as the volume of nitric acids,the time for digestion,the volume of stannous chloride,the influence of matrix and the control of background were optimized.The detection limit of Purge and Trap-IDMS for mercury is 3.7 pg/g.The trace mercury content in the seawater samples of the international comparison and the samples from Bohai Sea and Zhoushan island were determined,the relative standard deviation(RSD)of CCQM-K155&P196 sample was 4.11%(n=6)under the optimized conditions.At the level of 30 pg/g and 50 pg/g of Hg,the recoveries of seawater were 98.1%and 104%,respectively.The uncertainty of seawater from CCQM comparison was evaluated,the relative expanded uncertainty was less than 5%(k=2).The established method provides a powerful technical means for the high accurate determination of trace mercury in seawater,international comparison,and seawater certified reference materials.

关 键 词：同位素稀释质谱法 吹扫捕集 痕量汞 海水 

分 类 号：O657.31[理学—分析化学]