Different types of voltametric techniques for selective and sensitive detection of heavy metal ions in wastewater...

Heavy metal contamination in wastewater poses serious environmental and health risks, for which highly selective and sensitive detection methods are required. Voltametric techniques, such as DPASV, SWASV, ASV, CV, and DPV, offer simultaneous detection of multiple elements with quick analysis, accuracy and exceptional sensitivity, good selectivity, and least sample requirements. These techniques determine one or more analytes are measured by observing the current with potential. Among them, those that introduce a preconcentration step have been proven to be powerful electroanalytical techniques for detecting trace metals such as SWASV and DPASV. The outcome of experimental parameters, supporting electrolytes, and working electrodes and their impact on analytical performance are key focuses of this review. Numerous studies have explored voltammetric techniques for detecting heavy metals; however, a thorough comparison of their experimental parameters and analytical performance is uncommon. Operational conditions such as preconcentration voltage, deposition time, scan rate, pH, pulse amplitude, and supporting electrolyte play a crucial role in the magnification of the sensitivity and selectivity of the method. The optimal operational conditions were found to significantly improve the efficiency and analytical performance of the methods. Among the voltammetric techniques, SWASV offers enhanced sensitivity and reduced background noise, making it suitable for trace analysis. Results indicate that SWASV exhibits the lowest LOD in the ng L^-1 range (e.g., 0.001 µg L^-1 for Pb²⁺). DPASV and ASV are also commonly used for heavy metal detection. SWASV and DPASV are the most widely used methods for HMIs determination, while CV is more suitable for qualitative electrochemical characterization rather than trace-level quantification. This review serves as a valuable resource for researchers optimising voltammetric parameters for real-world wastewater applications.