Fe-Doped ZnMOF-Derived Heterocarbon Nanotubes for Electrochemical Sensing of Carbendazim Residues in Food

Background Carbendazim (CBZ), is a benzimidazole fungicide and widely used for controlling fruit and vegetable diseases, which poses significant risks to human health due to its neurotoxicity, endocrine disruption, and reproductive toxicity. Sensitive and rapid monitoring of carbendazim residues in food is essential for ensuring food safety. Among the numerous developed methods, electrochemical sensing stands out due to its simplicity of operation, low cost, and capability for on-site detection. Its key point is to construct a high-performance sensing interface. Nevertheless, these interfaces still face some limitations, such as inadequate conductivity, relatively low sensitivity, and narrow linear range. Results Herein, graphene supported iron nanoparticles encapsulated nitrogen-doped carbon nanotubes (Fe@N-CNTs) were constructed. The MOF-derived “tube-bridge” CNTs architecture, enhanced by N-doping, ensures high conductivity and optimized electron transfer pathways. Encapsulated iron nanoparticles act as shielded yet accessible redox-active centers, enhancing catalytic specificity. Graphene prevents CNTs stacking, maximizing active site exposure and interfacial charge transfer. This synergistic design significantly boosts the electrochemical active surface area, electron transfer kinetics, and electrocatalytic activity. As a result, a highly sensitive electrochemical sensing platform for CBZ has been successfully constructed. An irreversible two-electron and two-proton process takes place on the surface of Fe@N-CNTs/Graphene/GCE. The composite demonstrated exceptional performance for CBZ detection, achieving a broad linear range (0.001-7.0 μM), and an ultralow detection limit (0.56 nM). Furthermore, the sensor exhibited superior repeatability, stability, and selectivity. Its practical applicability was successfully validated through the accurate quantification of CBZ residues in medicinal herbs and vegetables ( recoveries of 98.58%-101.7%). Significance This work offering a robust solution for monitoring ultra-low concentrations CBZ residues in complex food matrices. This innovative technology provides essential support for combating pesticide misuse while safeguarding public health and preserving ecological integrity related to CBZ contamination.