Disposable Sensors for Heavy Metals Detection: A Review of Carbon and Non‐Noble Metal‐Based Receptors

Abstract

Heavy metals and metalloid pollution poses a severe threat to the environment and human health. Various anthropogenic sources are responsible for the release of these contaminants into the water and food chain of humans and animals. To protect the environment and human health, the detection of heavy metals in various environmental matrices becomes vital. Sophisticated lab-based instruments require more time, effort, and huge investments which warrants the requirement of fieldbased disposable sensors. Various optical and electrochemical sensors are reported to demonstrate good sensitivity, selectivity, and detection limits (LOD). The disposable electrodes comprised of glass, paper, plastic, and fabric are gaining importance owing to the ease of application in field analysis, reproducibility, and low cost. The majority of these sensors are based on noble/precious metals namely gold, silver, and platinum. However, limited availability and high cost of these receptors restrict wide spread applicability of these sensors. Numerous earth-abundant materials and non-noble metalbased sensors are also evolving recently due to several advantages namely large-scale availability, ease of modifications, stability, and shelf life which overcomes the limitations of noble/precious metals-based sensors. The present review provides a review of recent advances in various non-noble and earth-abundant micro and nanomaterials used as receptors in optical and electrochemical biosensors for the detection of metals/metalloids in various matrices. The review also highlights the strategies for the design and fabrication of disposable electrodes, their modification methods, detection strategy, and mechanism involved in the detection of heavy metals. Various gaps existing in the reported sensor systems and future perspectives are also delineated in the present manuscript.