激光探针电感藕合等离子体质谱在位测定微量元素方法研究  

The methodology study of trace element in-situ analyses using Laser Ablation Inductively Coupled Plasma Mass Spectrometer

作　　者：徐平[1] 关鸿[2] 孙敏[2] John Malps 

机构地区：[1]中国科学院地质与地球物理研究所 [2]香港大学地球科学系

出　　处：《岩石学报》2000年第2期291-304,共14页Acta Petrologica Sinica

基　　金：国家自然科学基金! (编号 :495 73 176);香港研究资助局资助! (RGC HKU5 10 /96P和 HKU7110 /97P);香港大学研究和会议资助! (CR-CG)

摘　　要：利用 2 6 6 nm紫外激光熔融电感藕合等离子体质谱仪 ,在最优化测试条件下 ,对标准玻璃样品 NIST6 12中的 30个微量元素进行了 5天 2 5组 78次的测定。在采用最小二乘法拟合后 ,选用 44 Ca为内标计算的数据精密度为 4%左右 ;选用 2 9Si为内标计算的数据精密度为 6 %左右。以 NIST6 12为外标 ,以 44 Ca和 2 9Si为内标 ,分别测定微量元素浓度为 45 0μg/g左右的NIST6 10 ,40μg/g左右的 NIST6 12以及微量元素浓度小于 1μg/g的 NIST6 14标准玻璃样品 ,与标样的标定值比较 ,数据的准确度绝大部分小于 10 %。以 NIST6 12为外标 ,选用 44 Ca为内标 ,根据测定 NIST6 12和 NIST6 10的数据的精密度推导 ,激光探针电感藕合等离子体质谱法测定浓度为 45 0 μg/g左右的微量元素时 ,数据的精密度小于 10 % ;测定浓度为 40 μg/g左右的微量元素时 ,大部分元素的数据精密度也在 10 %以下 ;以 NIST6 12为外标 ,选用 2 9Si为内标 ,根据测定 NIST6 12和 NIST6 14的数据的精密度推导 ,激光探针电感藕合等离子体质谱法测定浓度为 40μg/g左右的微量元素时 ,绝大部分元素的数据的精密度小于 15 % ;测定浓度大约在 0 .8μg/g左右的微量元素时 ,除 Ni,Sc,Rb,Zr,Sm ,Gd,Pb七个元素的精密度较差外 ,其余 2National Institute of Standards and Technology(NIST) Standard Reference Material(SRM) 610,612,614 glasses have been measured by Laser Ablation Inductively Coupled Plasma Mass Spectrometry(LA-ICP-MS). The experiments are designed elaborately to optimal UV laser probe(266 nm) and ICP-MS operating conditions. The measurement results of 78 experiments of 25 groups in 5 days show that 30 trace elements in NIST612 have the statistic precision of about 4% when the 44Ca was chosen as internal standard, meanwhile those elements of same NIST612 standard glass have the statistic precision of about 6% when the 29Si was chosen as the internal standard. Good measurement accuracy of less than 10% which compared with certified data can also be acquired routinely when we measure the NIST610, NIST612 and NIST614 glasses using the NIST612 as the calibration reference material. The total relative statistic deviation of measurement can be deduced by two individual test statistic deviations. Choosing NIST612 as calibration reference material, we get total relative statistic deviation value of less than 10% of most trace elements both in NIST610(450μg/g) and in NIST612( 40μg/g) when we choose 44Ca as internal standard. By the contrast, we can get the total relative statistic deviation value of 15% to most of trace elements in NIST612 if we choose 29Si as internal standard. It suggests that 44Ca is better than 29Si as the internal standard mass. Except to Ni, Sc, Rb, Zr, Sm, Gd and Pb, that most of trace elements have the total relative statistic deviation value of less than 20% in NIST614(0.8μg/g) which is a little higher than in NIST610 and NIST612 show that the measurement precision will deteriorate with the decreasing of concentration of measured element. High blank accounts for the bad Sc value and the interference of CaO may account for the bad Ni value. The bad precision of Rb, Zr, Sm, Gd and Pb may result from the memory effect of whole system which will be displayed more obviously when we analysis t

关 键 词：激光探针 微量元素 电感藕合等离子体质谱 测定 

分 类 号：P575.1[天文地球—矿物学] O657.38[天文地球—地质学]