Simultaneous determination of copper and lead in seawater using optimised thin-mercury film electrodes in situ plated in thiocyanate media.
Simultaneous determination of copper and lead in seawater using optimised thin-mercury film electrodes in situ plated in thiocyanate media.
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DOI：
10.1016/j.talanta.2004.03.018
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发表时间：
2004-10
期刊：
影响因子：
6.1
通讯作者：
H. Carapuça;Sandra C. C. Monterroso-Sandra-C.-C.-Monterroso-13881802;L. Rocha;A. Duarte
中科院分区：
文献类型：
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作者：
H. Carapuça;Sandra C. C. Monterroso-Sandra-C.-C.-Monterroso-13881802;L. Rocha;A. Duarte
在目前的工作中，重新评估了使用原位镀在硫氰酸盐介质中的薄汞膜电极的阳极溶出伏安法（ASV）方法，以便能够同时测定海水中的铜和铅。在之前建议的条件下 [6]，即使用 5 mM 的硫氰酸盐浓度，铜和铅的 ASV 峰由于形成稳定的铜 (I)-硫氰酸盐物质而重叠，限制了分析测定。因此，重新评估了硫氰酸盐浓度的最佳值：对于 0.05mM，实现了铜和铅峰的良好分辨率与汞膜形成/去除过程的高再现性之间的权衡。在该介质中，出现了 Pb 和 Cu 的 ASV 峰，其间隔为 140mV。此外，原位汞薄膜电极的制备和去除具有良好的重复性，这一点通过 ASV 测定的相对标准偏差值得到证实：Pb 为 0.5%，Cu 为 2.0%（在金属浓度为铅 1.5×10−8M 和铜 2.2×10−8M 的溶液中重复测定 10 次）。优化的方法已成功应用于经认证的海水（NASS-5）中铅存在下的铜测定。
In the present work the anodic stripping voltammetric (ASV) methodology using a thin mercury film electrode in situ plated in thiocyanate media was re-assessed in order to allow the simultaneous determination of copper and lead in seawater. Under previously suggested conditions [6], i.e. using a concentration of thiocyanate of 5mM, the ASV peaks of copper and lead overlapped due to the formation of a stable copper(I)–thiocyanate species, limiting the analytical determinations. Therefore, the best value for the thiocyanate concentration was re-evaluated: for 0.05mM a trade-off between good resolution of the copper and lead peaks and high reproducibility of the mercury film formation/removing processes was achieved. In this media, the ASV peaks for Pb and Cu occurred, separated by 140mV. Also, the in situ thin mercury film electrode was produced and removed with good repeatability, which was confirmed by the relative standard deviation values for the ASV determinations: 0.5% for Pb and 2.0% for Cu (10 replicate determinations in a solution with metal concentrations 1.5×10−8M for lead and 2.2×10−8M for copper). The optimised methodology was successfully applied to the determination of copper in the presence of lead, in certified seawater (NASS-5).