Evaluation of Electrochemical Techniques for Heavy Metal Detection in Aqueous Media

Abstract

Electrochemical techniques have emerged as promising analytical tools for detecting trace metal ions due to their high sensitivity, selectivity, rapid response, portability, and cost-effectiveness. These methods are particularly valuable for real-time and on-site monitoring of toxic heavy metals such as Hg2+, Cd2+, Cu2+, and Pb2+, which pose significant environmental and health risks. In response to the growing demand for low-cost and reliable monitoring systems, substantial research efforts have focused on developing advanced electrode materials and modification strategies. This survey provides a comprehensive analysis of recent advancements in electrochemical detection of trace metals, emphasizing the role of chemically modified electrodes. Various modification techniques are explored, including the use of functionalized metallic surfaces, polymeric coatings, and nanomaterials like metal nanoparticles and carbon-based structures. The potential of clay-based materials is also highlighted for improving sensor performance. These modifications aim to enhance electrochemical response through increased surface area, improved electron transfer, better analyte preconcentration, and reduced noise. Nanomaterials contribute significantly to signal amplification and selectivity, facilitating lower detection limits and broader detection capabilities. However, challenges such as matrix interferences, sensor stability, reproducibility, and environmental concerns related to some nanomaterials remain. The review addresses these limitations and examines mitigation strategies including anti-fouling coatings, surface regeneration, and hybrid materials. Looking ahead, integrating electrochemical sensors with microfluidic platforms and wireless technologies is seen as a crucial step toward creating portable, user-friendly, and sustainable systems. The future of these techniques lies in their miniaturization and applicability in remote and resource- limited settings. This study offers researchers and practitioners an in-depth overview of current progress, technological challenges, and emerging directions in electrochemical trace metal ion detection.