Voltammetric procedure for trace metal analysis in polluted natural waters using homemade bare gold-disk microelectrodes

Abstract

To cite this version:Cédric Garnier, Lesven Ludovic, Billon Gabriel, Magnier Aurélie, Mikkelsen Øyvind, et al.. Voltammetric procedure for trace metal analysis in polluted natural waters using homemade bare gold-disk microelectrodes. Analytical and Bioanalytical Chemistry, Springer Verlag, 2006, 386 (2) Abstract Voltammetric procedures for trace metals analysis in polluted natural waters using homemade bare golddisk microelectrodes of 25-and 125-μm diameters have been determined. In filtered seawater samples, square wave anodic stripping voltammetry (SWASV) with a frequency of 25 Hz is applied for analysis, whereas in unfiltered contaminated river samples, differential pulse anodic stripping voltammetry (DPASV) gave more reliable results. . These microelectrodes have been validated for natural sample analysis by use in an on-site system to monitor Cu, Pb and Zn labile concentrations in the Deûle River (France), polluted by industrial activities. First results obtained on sediment core issued from the same location have shown the ability of this type of microelectrode for in situ measurements of Pb and Mn concentrations in anoxic sediments.

Voltammetric Quantification of Zn and Cu, Together with Hg and Pb, Based on a Gold Microwire Electrode, in a Wider Spectrum of Surface Waters

“…This process was described as an example of UPD on gold microelectrodes, with a positive shift of the Zn oxidation peak potential compared to mercury electrodes. This shift to more positive potential values allowed easier analysis of Zn at natural pH [17,18]. Moreover, literature reports that the addition of acid improves the determination of Pb [27,28], Cd [27,28], Cu [22] and Hg [29,30] at gold electrodes.…”

“…The determination of Zn in natural waters at bare gold electrodes has seldom been described and is usually performed at natural pH [17,18] because the peak potential of this metal in acid medium is located on the cathodic limit of the potential window for gold electrodes. This process was described as an example of UPD on gold microelectrodes, with a positive shift of the Zn oxidation peak potential compared to mercury electrodes.…”

“…However, as a result of underpotential deposition (UPD), peak potentials for metals deposited on gold microelectrodes are shifted to more positive potential compared to mercury electrodes; due to this reason, it is possible to quantify Zn at gold electrodes. Nevertheless, the determination of this metal at natural pH required sample deoxygenation to eliminate background current [17,18]. On the other hand, in a previous work [19], we have shown that ASV at a vibrating gold microwire electrode allowed a simple, quick and reliable simultaneous determination of As, Cu, Hg and Pb in unpolluted river waters.…”

“…Both gold disk [17] and wire [18] microelectrodes have been recently proposed as good electrode materials to measure Zn in fresh and sea waters. These determinations were made at natural pH because the hydrogen wave on the gold electrode is more positive than on the mercury electrode; thus, the reduction potential for Zn is close to the hydrogen wave.…”

Voltammetric Study of the Redox Current Peaks of Pb(II) Mediated by GCE in Normal Saline

“…These microelectrodes have been validated for natural sample analysis by use in an on-site system to monitor Cu, Pb and Zn, polluted by industrial activities. First results obtained on sediment core issued from the same location have shown the ability of this type of microelectrode for in situ measurements of Pb and Mn concentrations in anoxic sediments [11].…”