The innovative and accurate detection of heavy metals in foods: A critical review on electrochemical sensors

Food safety has given rise to unprecedented concern worldwide. Heavy metal contamination in foods poses serious threats to food safety and human health due to undemanding bioaccumulation and high toxicity, even at low concentrations. The high-efficiency detection of heavy metals is pivotal for ensuring food safety. The electrochemical sensor-based strategy is a promising candidate in heavy metal detection, owing to its high flexibility, selectivity, and accuracy. This review focused on the advances of electrochemical sensors (ECS) for detecting heavy metals in foods. Firstly, the basic principle of ECS was introduced. Then, research progress on ECS detection of heavy metals with various materials modified electrodes, including inorganic materials (such as metal and metal oxide nanoparticles, graphene, and carbon nanotubes), organic materials (such as metal-organic frameworks), and biomaterials (such as nucleic acid aptamer and enzymes) were introduced systematically. Finally, the challenges, applications, and prospects of ECS for detecting heavy metals in food were discussed. The advanced materials significantly push the innovative electrodes for developing sensitive and selective ECS to meet the demand for effective, simple, and rapid detection of heavy metals in the food field. Taking comprehensive consideration of economy, sensitivity, specificity, and stability, Fe3O4/graphene/nucleic acid could be proposed as the optimum materials combination for the modification of electrochemical electrodes. This review paper will attract immense attention from electrochemistry, and sensor researchers focused on heavy metal detection in foods, as well as from food activists, consumers, and businesses, not to mention from stakeholders working on food safety, food sovereignty-centered policies, public health, and agro-environmental issues.