Electroanalytical Quantification of Zn ²⁺ and Cd ²⁺ in Aqueous Matrices Using Low‐Cost Cork Electrodes via Anodic Stripping Voltammetry

In recent years, the development of industries has grown a lot with the increase in population and, consequently, a global concern about environmental pollution, especially by highly dangerous pollutants such as heavy metal ions. Among these potentially toxic metals are Zn 2+ and Cd 2+ . In human health, small amounts of Zn 2+ are essential for proper metabolic functioning, while excessively high concentrations will negatively affect the body's functioning. Cd 2+ , even in low concentrations, is highly toxic. This concern is particularly relevant in effluents from the oil industry, where the significant presence of organic and inorganic substances, with diverse compositions, can represent a considerable environmental challenge. Therefore, the aim of this work was to investigate the use of 50% (m/m) graphite/cork electrodes to quantify Zn 2+ and Cd 2+ ions in real samples of tap water, groundwater and produced water, using differential pulse anodic stripping voltammetry (DPASV) as an electroanalytical tool. The results obtained clearly showed that the application of this electrode was efficient in detecting the heavy metal ions Zn 2+ and Cd 2+ , with a detection limit of 0.095 µg L −1 and quantification limit of 0.317 µg L −1 for Zn 2+ and a detection limit of 56 µg L −1 and quantification limit of 120 µg L −1 for Cd 2+ . In the water recovery tests, the results for Zn 2+ and Cd 2+ ions were within the acceptable range (105%–118%), which suggests that the proposed methodology is reliable. In general, this approach highlights the ease of producing the electrode with low‐cost materials, the good sensitivity of the electrochemical method, the low consumption of reagents and the rate of analysis, thus contributing to another electroanalytical approach for monitoring the heavy metal ions (Zn 2+ and Cd 2+ )in real effluents.