双通道-原子荧光光谱和固体进样-冷原子吸收光谱测定岩石中痕量汞  

Determination of Trace Mercury in Rocks by Dual-channel Atomic Fluorescence Spectrometry and Solid Sampling-Cold Atomic Absorption Spectrometry

作　　者：林建奇[1] LIN Jian-qi(Beijing Haiguang Instrument Co.,LTD,Beijing 101312,China)

机构地区：[1]北京海光仪器有限公司,北京101312

出　　处：《岩矿测试》2021年第4期512-521,共10页Rock and Mineral Analysis

基　　金：国家重大科学仪器设备开发专项基金项目(2018YFF01013900)。

摘　　要：岩石中的痕量汞检测往往因内部晶胞结构复杂,使得热水浴酸解提取不彻底、挥发损失以及接触污染等引起结果偏差和不稳定。本文在前人研究的基础上,采用中国研制的双通道-原子荧光光谱仪和固体进样-冷原子吸收光谱仪分析岩石中的痕量汞,以探索最佳检测方案。双通道-原子荧光光谱分析中,优化的实验条件为:以80%王水溶液对样品沸水浴提取50min,灯电流30mA,负高压280V,载气流速600mL/min,屏蔽气流速1000mL/min。测定痕量汞浓度范围为0.05~2μg/L,线性相关系数r>0.999,取样量为0.2g下方法检出限为0.285μg/kg,相对标准偏差为7.3%~15.3%。固体进样-冷原子吸收法光谱分析中,避免了化学消解处理直接进样测定,主要实验条件为:载气流速180mL/min,裂解程序700℃保持60s。测定痕量汞浓度范围为0.05~5ng,线性相关系数r>0.999,取样量为0.1g下方法检出限为0.046μg/kg,相对标准偏差为1.3%~4.2%。通过实验结果对比表明,固体进样-冷原子吸收光谱法的操作性、检出限以及稳定性均优于双通道-原子荧光光谱法,更适用于岩石中的痕量汞测定。BACKGROUND:The detection of trace mercury in rocks typically provides biased and non-reliable results because of the complex internal unit cell structure,incomplete hot water bath acid hydrolysis extraction,volatilization loss,and contact pollution.OBJECTIVES:To establish a more effective method for the determination of trace mercury concentrations in rocks.METHODS:Dual-channel atomic fluorescence spectrometry(AFS)and domestic solid sampling-cold atomic absorption spectrometry(AAS)were used to detect the total concentration of trace mercury in rocks.RESULTS:Under the optimized conditions of dual-channel AFS,the samples were extracted in a boiling water bath with 80%aqua regia solution for 50min.The current was 30mA,the negative high voltage was 280V,the carrier gas flow was 600mL/min,and the shielding gas flow was 1000mL/min.The concentration range was 0.05-2μg/L,and the linear correlation coefficient was greater than 0.999.The sample weight was 0.2g,method detection limit was 0.285μg/kg,and relative standard deviation was 7.3%-15.3%.For domestic solid sampling-cold AAS,the sample was determined by direct injection without chemical digestion.The carrier gas flow was 180mL/min,pyrolysis process was conducted for 60s at 700℃.The concentration range was determined to be 0.05-5ng,and the linear correlation coefficient was greater than 0.999.The sample weight was 0.1g,method detection limit was 0.046μg/kg,and relative standard deviation was 1.3%-4.2%.CONCLUSIONS:The solid sampling-cold AAS was found to be more effective than dual-channel AFS in terms of operation,detection limit,and stability.It is more suitable for the determination of trace mercury in rocks.

关 键 词：岩石 痕量汞 双通道-原子荧光光谱法 固体进样-冷原子吸收光谱法 

分 类 号：O657.31[理学—分析化学]