碱熔-电感耦合等离子体质谱法测定地质样品中铍铯镓铊铌钽锆铪铀钍

采用氢氧化钾碱熔法处理样品,以铑校正铍、铯、铊、铪、铀、钍,以铼校正镓、铌、钽、锆,建立了电感耦合等离子体质谱法测定铍、铯、镓、铊、铌、钽、锆、铪、铀、钍10种元素的方法。分别选用银坩埚、镍坩埚、刚玉坩埚熔融空白样品进行试验,结果表明,采用银坩埚时各元素的空白响应信号值与镍坩埚和刚玉坩埚相比均较低。对熔融条件进行了优化,确定熔融温度为600℃、熔融时间为8min。分别采用去离子水、2%(体积分数)硝酸上机测量,并记录各元素的响应信号值,与测定地质实际样品中各元素的响应信号值进行对比,结果表明,其对测定结果的影响可以忽略不计。在优化的实验条件下,各元素校准曲线线性相关系数均在0.9990以上,方法的检出限为0.023~0.049μg/g,测定下限为0.078~0.16μg/g。采用实验方法对岩石成分分析标准物质中铍、铯、镓、铊、铌、钽、锆、铪、铀、钍10种元素进行测定,测定结果与认定值基本一致,相对误差(RE)在-8.3%~9.6%之间,相对标准偏差(RSD,n=11)均不大于4.2%。采用实验方法对2个从野外采回的地质实际样品进行测定,并加入岩石成分分析标准物质进行加标回收试验,上述10种元素的回收率在96%~102%之间。

Determination of beryllium,cesium, gallium,thallium, niobium,tantalum, zirconium,hafnium, uranium and thorium in geological sample by inductively coupled plasma mass spectrometry with alkali fusion

After geological sample was treated by alkali fusion method with potassium hydroxide, a determination method of ten elements (including beryllium, cesium, gallium, thallium, niobium, tantalum, zirconium, hafnium, uranium and thorium) was established with beryllium, cesium, thallium, hafnium, uranium and thorium corrected by rhodium, gallium, niobium, tantalum and zirconium corrected byrhenium. The silver crucible, nickel crucible and corundum crucible were selected for melting of blank sample, respectively. The results showed that the blank response signals of elements in silver crucible were lower compared to the nickel crucible and corundum crucible. The fusion conditions were also optimized as follows: the melting temperature was 600℃ and the melting time was 8min. The deionized water and 2% (volume fraction) nitric acid were used as blank solution for test respectively, and the response signal values of elements were recorded and compared with those obtained by actual geological samples. The results showed that their influence could be ignored. Under the optimized experimental conditions, the linear correlation coefficients of calibration curves of elements were all higher than 0.9990. The detection limits of the method were 0.023-0.049μg/g, and the low limits of determination limit were 0.078-0.16μg/g. Ten elements including beryllium, cesium, gallium, thallium, niobium, tantalum, zirconium, hafnium, uranium and thorium in the certified reference materials for the chemical composition of rock were determined according to the experimental method. The results were basically consistent with the certified values. The relative errors (RE) were between -8.3% and 9.6%, and the relative standard deviations (RSD, n=11) were all not more than 4.2%. The proposed method was applied for the determination of two actual geological samples from the field and the certified reference materials for the chemical composition of rock were added for the spiked recovery test. The recoveries of these ten elements were between 96% and 102%.