摘要
地质样品中Zr、Nb、Hf、Ta和稀土元素的测定,对于开发利用稀土矿资源和研究地球化学、岩石成因等地质环境具有重要意义.采用Na2O2于750 ℃熔融8 min,沸水提取,过滤后用HCl-H2O2混合液分次溶解氢氧化物沉淀,选用He碰撞池模式和干扰校正方程克服轻稀土元素氧化物或氢氧化物对重稀土元素的干扰,以Rh校正Zr、Nb、Sc、Y、La、Ce、Pr、Nd、Sm,Re校正Hf、Ta、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu,建立了电感耦合等离子体质谱法(ICP-MS)同时测定地质样品中Zr、Nb、Hf、Ta和稀土元素的方法.在优化的实验条件下,20种元素校准曲线的线性相关系数均不小于0.999 2,检出限在0.03～2.69 μg/g之间,定量限在0.09～8.07 μg/g之间.按照实验方法对水系沉积物和岩石标准物质中Zr、Nb、Hf、Ta和稀土元素进行测定,测定值与认定值的相对误差(RE)均不大于6.7％,满足行业标准DZ/T 0130-2006的相对误差允许限要求;相对标准偏差(RSD,n=12)均不大于4.8％.将实验方法应用于土壤、水系沉积物、岩石样品中Zr、Nb、Hf、Ta和稀土元素的测定,各元素测定结果的相对标准偏差(n=6)为0.5％～4.8％.
Abstract
The determination of Zr,Nb,Hf,Ta,and rare earth elements in geological samples has important significance for exploration and utilization of rare earth mineral resources as well as the geological environ-ment researches such as geochemistry and petrogenesis.The sample was melted with Na2O2 at 750 ℃ for 8 min followed by leaching with boiling water.After filtration,the hydroxide precipitates were dissolved with HCl-H2O2 mixed solution in stages.The interferences of oxides or hydroxides of light rare earth ele-ments with heavy rare earth elements were overcome by selecting He collision cell mode and interference correction equation.Rh was used to correct Zr,Nb,Sc,Y,La,Ce,Pr,Nd and Sm,and Re was used to correct Hf,Ta,Eu,Gd,Tb,Dy,Ho,Er,Tm,Yb and Lu.Consequently,a method for simultaneous de-termination of Zr,Nb,Hf,Ta and rare earth elements in geological sample was established by inductively coupled plasma mass spectrometry(ICP-MS).Under the optimized experimental conditions,the linear cor-relation coefficients of calibration curves of 20 elements were all not less than 0.999 2.The limits of detec-tion were in range of 0.03-2.69 μg/g,and the limits of quantitation were in range of 0.09-8.07 μg/g.The contents of Zr,Nb,Hf,Ta and rare earth elements in certified reference materials of stream sediment and rock were determined according to the proposed method,and the relative errors(RE)between the results and certified values were all not more than 6.7％,which could meet the allowable limit requirements of relative error in industry standard of DZ/T 0130-2006.The relative standard deviations(RSD,n=12)were all not more than 4.8％.The proposed method was applied for determination of Zr,Nb,Hf,Ta and rare earth elements in soil,stream sediment and rock samples,and the RSDs(n=6)of determination re-sults were between 0.5％and 4.8％.
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