Isotopic composition of silicon measured by multicollector plasma source mass spectrometry in dry plasma mode
Isotopic composition of silicon measured by multicollector plasma source mass spectrometry in dry plasma mode
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DOI：
10.1039/b210109b
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发表时间：
2003-01-01
影响因子：
3.4
通讯作者：
André, L
中科院分区：
文献类型：
--
作者：
Cardinal, D;Alleman, LY;André, L
采用Nu仪器等离子体多集电极电感耦合等离子体质谱仪（MC-ICP-MS）在干等离子体模式下，使用Cetac Aridus去溶剂化雾化系统，测定了二氧化硅（石英）、蛋白石（蛋白石、海绵）和标准样品中精确的硅同位素分馏。样品Si-28/Si-29比率的变化表示为δ（29）Si单位，其表示与使用标准样品交叉技术测量的相同比率的NBS 28标准品的千分之几偏差。我们测量镁同位素的动态模式，仪器质量偏差进行充分的校正，应用分馏指数法和外部归一化。稀释HF/HCl中1 ppm Si溶液的δ（29）Si测量的重复性和内部精度优于+/-0.1%（+/-2 sigma）。通过内部标准品与激光氟化同位素比质谱（IRMS）的交叉分析评估了准确度。与湿等离子体MC-ICP-MS相比，干等离子体方法的灵敏度提高了十倍以上，因此对于环境，地球化学和地质科学具有重要意义，其中Si同位素开辟了一系列新的研究。
Precise Si isotopic fractionation in silica (quartz), opal (diatomite, sponges) and standards have been determined employing a Nu Instruments Plasma multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) in dry plasma mode, using a Cetac Aridus desolvating nebulization system. Variations in sample Si-28/Si-29 ratios are expressed as delta(29)Si units, which represent deviations in parts per thousand from the same ratio of the NBS28 standard measured using the standard-sample bracketing technique. We measured Mg isotopes in dynamic mode for adequate correction of instrumental mass bias, applying the fractionation exponential law and external normalisation. The repeatability and the internal precision on the delta(29)Si measurements of a 1 ppm Si solution in diluted HF/HCl is better than +/-0.1% (+/-2 sigma). The accuracy has been assessed by cross analyses of an in-house standard with the laser fluorination-isotope ratio mass spectrometry (IRMS). The dry plasma methodology improves the sensitivity more than ten times compared to wet plasma MC-ICP-MS and hence is of great relevance regarding environmental, biogeochemical and geological sciences where Si isotopes open up a range of new studies.