Development of rapid and precise Pb isotope analytical techniques using MC-ICP-MS and new results for GSJ rock reference samples
Development of rapid and precise Pb isotope analytical techniques using MC-ICP-MS and new results for GSJ rock reference samples
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DOI：
10.2343/geochemj.40.121
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发表时间：
2006-04
影响因子：
0.8
通讯作者：
M. Tanimizu;T. Ishikawa
中科院分区：
文献类型：
--
作者：
M. Tanimizu;T. Ishikawa
采用多接收电感耦合等离子体质谱（MC-ICP-MS）技术，建立了一种快速、准确的岩石样品铅同位素分析方法。用加入样品中的Tl同位素参考物质（NIST SRM 997）的205 Tl/203 Tl比率校正Pb同位素比率的质量区分。分析参数的优化和最小化的记忆和矩阵的影响，使获得的Pb同位素数据迅速（每小时三个样品）与0.01%的再现性由150纳克铅每次分析消耗。对铅同位素标准物质NIST SRM 981的重复分析结果表明，~（206）Pb/~（204）Pb = 16.9308 ± 0.0010，~（207）Pb/~（204）Pb = 15.4839 ± 0.0011，~（208）Pb/~（204）b = 36.6743 ± 0.0030（2σ）。在阴离子交换化学分离，汞和铊从铅馏分完全去除确认。结果表明，TI归一化最大限度地减少了剩余杂质和介质引起的基质效应，JB-2的7个独立分析的重现性与NIST SRM 981相当。岩石标准样品的铅同位素比值与以前给出的结果吻合较好。
A rapid and precise routine Pb isotope analytical technique for rock samples was developed using multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The mass discrimination of the Pb isotope ratios was corrected with the 205Tl/203Tl ratio of a Tl isotope reference material (NIST SRM 997) added to samples. The optimization of the analytical parameters and the minimization of the memory and matrix effects enabled to acquire the Pb isotope data rapidly (three samples per hour) with a reproducibility of 0.01% by consumption of 150 ng Pb per analysis. Repeated analyses of a Pb isotope reference material, NIST SRM 981, gave the average values of 206Pb/204Pb = 16.9308 ± 0.0010, 207Pb/204Pb = 15.4839 ± 0.0011, and 208Pb/204b = 36.6743 ± 0.0030 (2σ).Pb isotope ratios of eleven Geological Survey of Japan rock reference samples were determined using this technique. In anion-exchange chemical separation, complete removal of Hg and Tl from the Pb fraction was confirmed. It was revealed that the Tl-normalization minimized the matrix effects caused by remaining impurities and medium, and the reproducibility of seven independent analyses of JB-2 was comparable to that of NIST SRM 981. Pb isotope ratios obtained for the rock reference samples showed a good agreement with those given previously.