Electrochemical sensors for melamine and clenbuterol in food

Food safety remains a critical global concern as escalating demand and intensified market competition continue to drive economically motivated adulteration (EMA). The unauthorized inclusion of substances such as melamine (MEL) and clenbuterol (CLB) poses a severe public health risk, necessitating the development of rapid, sensitive, and reliable analytical strategies. This review critically examines advancements in electrochemical sensors for MEL and CLB detection, with a primary focus on interfacial electrode design, sensing mechanisms, and analytical performance. For MEL, both direct and indirect electrochemical strategies are evaluated. Direct detection is predominantly facilitated through metal-MEL coordination, particularly with Cu2+, while morphology-controlled nanomaterials, such as hierarchical CuO nanostructures, significantly enhance sensitivity, achieving limits of detection (LODs) as low as 0.01 nM. Indirect approaches leveraging molecularly imprinted polymers (MIPs) and quaternary nanocomposites demonstrate superior performance with LODs extending into the femtomolar range (9.6 × 10− 7 nM). In contrast, CLB detection relies on its inherent electroactivity through proton-coupled electrooxidation, with analytical performance largely governed by electrode design. Synergistic nanocomposites incorporating graphene-based materials, metal nanoparticles, and emerging two-dimensional (2D) materials such as black and violet phosphorene enable ultra-trace detection (LODs < 6 nM). These sensors demonstrate potential for practical applicability, achieving recoveries exceeding 90% in complex food matrices such as pork, beef, and milk. Graphical Abstract