巯基棉富集分离-原子荧光光谱法测定高碳高硫地质样品中痕量硒  

Determination of Trace Selenium in High-Carbon and High-Sulfur Geological Samples by Thiol Cotton Fiber Separation-Atomic Fluorescence Spectrometry

作　　者：马万平 温汉捷 叶琴 赵越 杨季华 MA Wan-ping;WEN Han-jie;YE Qin;ZHAO Yue;YANG Ji-hua(School of Earth Sciences,East China University of Technology,Nanchang 330013,China;College of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]长安大学地球科学与资源学院,陕西西安710054 [3]中国科学院大学地球与行星科学学院,北京100049

出　　处：《岩矿测试》2021年第4期550-560,共11页Rock and Mineral Analysis

基　　金：国家重点研发计划项目“稀散矿产资源基地深部探测技术示范”(2017YFC0602500)。

摘　　要：氢化物发生-原子荧光光谱法(HG-AFS)应用于测定地质样品中的痕量硒具有较高的灵敏度,但复杂的基质仍会增加分析难度,尤其是富含有机质样品与硫化物样品中的有机碳、复杂配合物和共存离子等带来的干扰,故样品前处理十分重要。采用常规的巯基棉(thiol cotton fibre,TCF)富集分离方法处理富含有机质样品与硫化物样品时,常会出现回收率不稳定、TCF过早饱和的现象。因此,本文针对富含有机质样品,使用双TCF柱法,通过两次吸附可以有效减少有机质的干扰;针对硫化物样品,可通过增加TCF的用量或者减少称样量来提高硒的回收率。标准物质和实际样品的测定结果表明优化的方法可满足分析要求,对富有机质样品,硒的回收率大于95.1%±0.37%;对硫化物样品,硒的回收率大于95.5%±1.92%。同时,研究也表明,采用微波消解处理样品,能够有效地避免硒在消解过程中的损失。改进后的方法提升了富集分离效果,适用于有机质和硫化物地质样品中的痕量硒(ng/g~μg/g级)分析要求。BACKGROUND:Hydride generation-atomic fluorescence spectroscopy(HG-AFS)is highly sensitive for the determination of trace selenium in geological samples.However,the complex matrix increases the analysis difficulty,especially owing to interference caused by organic carbon,complicated complexes,and coexisting ions in samples rich in organic matter and sulfides.Therefore,sample pretreatment is important.The use of conventional thiol cotton fiber(TCF)to enrich and separate selenium often leads to unstable recovery and premature saturation of the TCF when dealing with samples rich in organic matter and sulfides.OBJECTIVES:To establish a method suitable for the determination of trace selenium in geological samples rich in organic matter and sulfides.METHODS:For samples rich in organic matter,a double TCF column(m TCF=0.15g)was used to carry out adsorption twice.The recovery for high-sulfur geological samples could be increased either by increasing the amount of TCF(m TCF≤0.2g)or reducing the sample amount.RESULTS:The measurement results for the reference materials and actual samples showed that the optimized method satisfied the analysis requirements as selenium recoveries of>95.1%and>95.5%were achieved for the organic-rich and sulfide samples,respectively.Microwave digestion can effectively avoid the loss of selenium during digestion;the measured selenium content was consistent with that reported in the literature.CONCLUSIONS:The improved method is suitable for geological samples rich in organic matter and sulfides,which can be used to determine trace selenium(ng/g toμg/g levels)in geological samples.

关 键 词：高碳高硫地质样品 硒 微波消解 巯基棉 氢化物发生-原子荧光光谱法 

分 类 号：O657.31[理学—分析化学]