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For the first time a solid bismuth microelectrode was utilized for anodic stripping voltammetry in the course of Tl(I) ions determination. The proposed solid bismuth microelectrode (ϕ 25 μm) is more environmentally friendly sensor in comparison to bismuth film electrodes as bismuth ions are not added to the supporting electrolyte for bismuth film formation. Furthermore, an amount of metallic bismuth needed for fabrication of proposed sensor is significantly minimized as compared to solid bismuth electrode with a large surface area. Furthermore, the measurements may be carried out from unstirred solutions that gives possibility of performing fields analysis. The optimization of the analytical parameters of Tl(I) determination procedure was presented. A calibration graph for Tl(I) determination was linear in the range from 2 × 10−9 to 2 × 10−7 mol l−1 (deposition time of 120 s). The detection limit for thallium ions determination was 8.3 × 10−10 mol l−1 for deposition time of 120 s. Repeatability of the proposed procedure calculated as RSD% for Tl(I) at concentration of 2 × 10−8 mol l−1 was 5.2% (n = 5). The accuracy of the proposed procedure was successfully checked by analysis of a lake water certified reference material TM 25.5.

A new way of decreasing the detection limit ‐ double deposition and stripping steps was proposed to determine trace amounts of gold(III) by anodic stripping voltammetry. Two carbon composite electrodes that differed drastically in their surface areas were used for the measurements. The calibration graph was linear from 1×10−9 to 1×10−8 mol L−1 following deposition time of 300 s at the first and the second electrode. The detection limit was found to be 2.3×10−10 and 1.4×10−11 mol L−1 for deposition time 600 and 2400 s, respectively. It is the lowest detection limit obtained so far for gold(III) determination in stripping voltammetry.

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The article reports on utilization of double deposition and stripping steps for increasing sensitivity of Cu(II) determination by anodic stripping voltammetry (ASV) at two lead film working electrodes. A significant preconcentration of copper was achieved thanks to utilization of a simple design of four electrodes system that gives possibility to perform one measurement cycle consisting of two deposition and two stripping steps. Due to the fact that deposition step is doubled, the concentration of Pb(II) needed to lead film electrodes formation was significantly reduced as compared to traditional procedures using three electrodes system. The analytical procedure of Cu(II) determination was optimized. The experimental factors: supporting electrolyte's pH and its concentration, lead ions concentration, potential and time of deposition at both working electrodes were studied. The Cu(II) peak current was linearly dependent on its concentration from 5×10−10 to 2×10−8 mol L−1 (deposition time of 270 and 160 s at the first and the second working electrode, respectively). The obtained detection limit for copper ions determination was 2.1×10−10 mol L−1. The described procedure was validated by analysis of two water certified reference materials. The described procedure was also utilized for real water sample analysis.