Electrochemical determination of nitrofurantoin using a self-templated NiFeCo layered double oxide-carbon composite...

To achieve trace-level detection of antibiotics in food matrices, a NiFeCo layered double oxide supported N,S co-doped collagen-derived porous carbon (NiFeCo LDO-C) composite was rationally designed by integrating a dynamic metal active-site regeneration mechanism with a self-template/self-etching strategy for highly sensitive and stable electrochemical sensing of nitrofurantoin (NFT). The introduction of Co enables dynamic regeneration of Fe active sites, improving catalytic stability. This template-free strategy exploits the structural evolution of NiFeCo layered double hydroxides (LDH) during calcination: the decomposition process not only defines hierarchical pore channels through self-templating but also collaboratively promotes self-etching of the collagen-derived carbon matrix via the release of gases, enabling precise pore regulation. Benefiting from synergistic effects between heteroatom-doped carbon and mixed-valence Ni/Fe/Co centers, the sensor exhibits a wide linear range (0.05-350 μM), a low detection limit of 5.3 nM, and excellent selectivity. Satisfactory recoveries were obtained in milk and honey samples, while river water analysis further demonstrated broader applicability. Electrochemical analysis indicates that NFT reduction follows an irreversible, diffusion-controlled process. This work offers a promising strategy for developing self-regenerating electrochemical sensors for antibiotic residue detection in food safety monitoring.