Emerging inorganic nanomaterial-based electrochemical sensors for heavy metal detection in food: Advances, challenges, and prospects

The review focuses on the application of inorganic nanomaterial-based electrochemical sensors in heavy metal detection in food, systematically outlining their technical principles, performance challenges, and development prospects. Heavy metals are among the most concerning food contaminants due to their high toxicity at trace levels, persistence, and bioaccumulation, creating an urgent need for rapid and reliable screening in complex food matrices. Electrochemical sensors-particularly stripping voltammetry-based platforms-offer high sensitivity, low detection limits, and fast response, but their practical performance is frequently constrained by matrix-induced fouling, ion interference, and inconsistent validation protocols. This review focuses on inorganic nanomaterial-engineered working electrodes (metals, metal oxides, carbon nanomaterials, and their composites) for food-related heavy-metal analysis, and provides a food-matrix-oriented structure-function-performance framework that links material roles (selective preconcentration, catalytic signal amplification, and antifouling interfaces) to analytical outcomes (sensitivity, selectivity, stability, and recovery). Representative electrode fabrication routes and commonly used testing settings are summarized together with essential material/electrode characterizations and electrochemical diagnostics. Importantly, we derive actionable conclusions for food-safety deployment: accurate quantification in real foods is dominated by antifouling and selective enrichment rather than sensitivity alone; performance claims should be benchmarked by standardized sample pretreatment, interference panels, and recovery in representative foods; and electrochemical results require cross-validation against reference methods (e.g., inductively coupled plasma mass spectrometry (ICP-MS)/atomic absorption spectroscopy (AAS)). Finally, we propose a practical reporting checklist and highlight scalable pathways toward portable, multiplexed, and regulation-aligned heavy-metal monitoring in diverse food products.