Simultaneous Determination of Cadmium, Lead, Copper, and Thallium in Highly Saline Samples by Anodic Stripping Voltammetry (ASV) Using Mercury‐Film and Bismuth‐Film Electrodes

Abstract

AbstractThis paper describes a comparative study of the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in highly saline samples (seawater, hydrothermal fluids, and dialysis concentrates) by ASV using the mercury‐film electrode (MFE) and the bismuth‐film electrode (BiFE) as working electrodes. The features of MFE and BiFE as working electrodes for the single‐run ASV determinations are shown and their performances are compared with that of HMDE under similar conditions. It was observed that the stripping peak of Tl(I) was well separated from Cd(II) and Pb(II) peaks in all the studied saline samples when MFE was used. Because of the severe overlapping of Bi(III) and Cu(II) stripping peaks in the ASV using BiFE, as well as the overlapping of Pb(II) and Tl(I) stripping peaks in the ASV using HMDE, the simultaneous determination of these metals was not possible in highly saline medium using these both working electrodes. The detection limits calculated for the metals using MFE and BiFE (deposition time of 60 s) were between 0.043 and 0.070 μg L−1 for Cd(II), between 0.060 and 0.10 μg L−1 for Pb(II) and between 0.70 and 8.12 μg L−1 for Tl(I) in the saline samples studied. The detection limits calculated for Cu(II) using the MFE were 0.15 and 0.50 μg L−1 in seawater/hydrothermal fluid and dialysis concentrate samples, respectively. The methods were applied to the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in samples of seawater, hydrothermal fluids and dialysis concentrates.