Matrix effects of calcium on high-precision sulfur isotope measurement by multiple-collector inductively coupled plasma mass spectrometry
Matrix effects of calcium on high-precision sulfur isotope measurement by multiple-collector inductively coupled plasma mass spectrometry
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钙对多接收器电感耦合等离子体质谱高精度硫同位素测量的基质效应
DOI：
10.1016/j.talanta.2016.01.013
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发表时间：
2016
期刊：
影响因子：
6.1
通讯作者：
Jiang Shao-Yong
中科院分区：
文献类型：
--
作者：
Liu Chenhui;Bian Xiao-Peng;Yang Tao;Lin An-Jun;Jiang Shao-Yong
多接收电感耦合等离子体质谱（MC-ICP-MS）是近年来发展起来的一种快速、高精度的硫同位素比值测定方法。在测量过程中，基体元素的存在会影响仪器对硫的质量偏差，这些基体诱导效应引起了许多研究者的兴趣。然而，这些研究更加重视强调其提出的纠正方案的必要性（例如，化学纯化和基质匹配），而对基质元素的关键性质关注较少引起基质效应。在这项研究中，四组硫酸盐溶液，其中有不同浓度的硫（0.05-0.60 mM），但一个恒定的序列的原子钙/硫比（0.1-50），在湿（溶液）和干（去溶剂化）等离子体条件下进行了研究，以详细评估从钙对硫同位素测量的基质效应。通过一系列的对比分析，我们发现，钙对硫同位素比值和32 S信号强度的基体效应主要取决于钙的绝对浓度，而不是钙与硫的相对浓度比（即，原子钙/硫比）。同样，对于同一组样品，干血浆条件下钙的基质效应比湿血浆条件下显著得多。该研究为实现蒸发岩石膏硫同位素的直接、相对精确测量提供了可能，并为沉积孔隙水硫同位素分析方法提供了参考。
Multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has been successfully applied in the rapid and high-precision measurement for sulfur isotope ratios in recent years. During the measurement, the presence of matrix elements would affect the instrumental mass bias for sulfur and these matrix-induced effects have aroused a lot of researchers’ interest. However, these studies have placed more weight on highlighting the necessity for their proposed correction protocols (e.g., chemical purification and matrix-matching) while less attention on the key property of the matrix element gives rise to the matrix effects. In this study, four groups of sulfate solutions, which have different concentrations of sulfur (0.05–0.60 mM) but a constant sequence of atomic calcium/sulfur ratios (0.1–50), are investigated under wet (solution) and dry (desolvation) plasma conditions to make a detailed evaluation on the matrix effects from calcium on sulfur isotope measurement. Based on a series of comparative analyses, we indicated that, the matrix effects of calcium on both measured sulfur isotope ratios and detected32S signal intensities are dependent mainly on the absolute calcium concentration rather than its relative concentration ratio to sulfur (i.e., atomic calcium/sulfur ratio). Also, for the same group of samples, the matrix effects of calcium under dry plasma condition are much more significant than that of wet plasma. This research affords the opportunity to realize direct and relatively precise sulfur isotope measurement for evaporite gypsum, and further provides some suggestions with regard to sulfur isotope analytical protocols for sedimentary pore water.