Use of a solution cathode glow discharge for cold vapor generation of mercury with determination by ICP-atomic emission spectrometry.
Use of a solution cathode glow discharge for cold vapor generation of mercury with determination by ICP-atomic emission spectrometry.
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DOI：
10.1021/ac8011126
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发表时间：
2008-08
影响因子：
7.4
通讯作者：
Zhenli Zhu;G. C. Chan;S. Ray;Xinrong Zhang;G. Hieftje
中科院分区：
文献类型：
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作者：
Zhenli Zhu;G. C. Chan;S. Ray;Xinrong Zhang;G. Hieftje
本文介绍了一种新的蒸气发生法测定水溶液中汞的方法。不需要化学还原剂，溶解的汞物质在溶液阴极辉光放电中转化为挥发性汞蒸气。然后将产生的汞蒸气输送到电感耦合等离子体中，通过原子发射光谱法进行测定。汞蒸气很容易从含有0.1 M HNO 3的背景电解质中产生。发现在低分子量有机酸（甲酸或乙酸）或醇（乙醇）的存在下，蒸气产生效率高2-3倍。放电诱导的蒸汽产生和减少干扰伴随无机离子的最佳条件也被确定。然而，氯离子的存在降低了汞蒸气产生的效率。在连续进样模式下，发现检测限为0.7 μ g L（-1），重复性为1.2% RSD（n = 11）为20 μ g L（-1）的标准。与其他蒸气发生法相比，该方法具有以下优点：首先，它适用于无机汞和有机汞的测定;有机汞（硫柳汞）可以直接转化为挥发性汞，而无需预先氧化。第二，蒸气发生效率高，其效率（以甲酸作为促进剂）上级常规SnCl 2-HCl还原。第三，蒸汽产生非常迅速，因此易于与流动注射耦合。该方法灵敏度高，操作简便，无需辅助试剂，可替代传统的蒸气发生法测定超痕量汞。
A novel vapor-generation technique is described for mercury determination in aqueous solutions. Without need for a chemical reducing agent, dissolved mercury species are converted to volatile Hg vapor in a solution cathode glow discharge. The generated Hg vapor is then transported to an inductively coupled plasma for determination by atomic emission spectrometry. Mercury vapor is readily generated from a background electrolyte containing 0.1 M HNO 3. Vapor generation efficiency was found to be higher by a factor of 2-3 in the presence of low molecular weight organic acids (formic or acetic acids) or alcohols (ethanol). Optimal conditions for discharge-induced vapor generation and reduced interference from concomitant inorganic ions were also identified. However, the presence of chloride ion reduces the efficiency of Hg-vapor generation. In the continuous sample introduction mode, the detection limit was found to be 0.7 microg L (-1), and repeatability was 1.2% RSD ( n = 11) for a 20 microg L (-1) standard. In comparison with other vapor generation methods, it offers several advantages: First, it is applicable to both inorganic and organic Hg determination; organic mercury (thiomersal) can be directly transformed into volatile Hg species without the need for prior oxidation. Second, the vapor-generation efficiency is high; the efficiency (with formic acid as a promoter) is superior to that of conventional SnCl 2-HCl reduction. Third, the vapor generation is extremely rapid and therefore is easy to couple with flow injection. The method is sensitive and simple in operation, requires no auxiliary reagents, and serves as a useful alternative to conventional vapor generation for ultratrace Hg determination.