Construction Of Nitrofurantoin Electrochemical Sensors Based On Metal-Organic Skeleton-Derived Nanomaterials

Nitrofurantoin（NFT）is a nitrofuran antibiotic often used as a veterinary drug to treat bacterial infections in animals,but its low solubility and bioaccumulation properties make it highly susceptible to excessive residues in animal-derived food and water systems.Long-term consumption of food containing NFT residues can cause diarrhea,hepatotoxicity,neuropathy,and"trichothecene"toxicities.Therefore,the development of nitrofurantoin detection technology is of high importance to achieve efficient monitoring of nitrofurantoin residues and to ensure food safety.Electrochemical sensor technology has the advantages of rapid response,low cost,high sensitivity,portable devices and more suitable for field analysis,and is gradually becoming one of the most dynamic means of antibiotic residue detection.In this study,two electrochemical sensors were constructed based on metal-organic framework-derived materials with nitrofurantoin as the target analyte to achieve the rapid detection of nitrofurantoin in animal-derived foods,and the main research results are as follows.（1）Construction and performance evaluation of nitrofurantoin electrochemical sensors based on cobalt-based metal-organic framework（ZIF-67）-derived nitrogen-doped carbon nanotube composites（N/Co@CNTs）.The fine hollow structure in N/Co@CNTs provides abundant electron transfer channels,the encapsulated Co nanoparticles act as active metal oxidation sites to enhance the diffusive adsorption of electrolytes,and the nitrogen doping improves the electrocatalytic performance of the electrochemical sensor,which lays a good foundation for the determination of NFT.Under the optimal optimized conditions,the linear range of the sensor for NFT detection was 0.05～550μM,the detection limit was 18.4 n M,and the sensitivity was 8.19μAμM^-1 cm^-2.Meanwhile,the detection recoveries of the sensor in milk and water samples were 94.59～103.71%,which indicated that N/Co@CNTs@CC has good practical applicability.（2）Construction and performance evaluation of a nitrofurantoin electrochemical sensor based on cobalt-molybdenum bimetallic doped molybdenum disulfide composites（Co₂Mo₃O₈/MoS₂）derived from cobalt-based metal-organic framework（Co-MOFs）.To further improve the electrical conductivity and electrochemical detection sensitivity of metal organic frameworks（MOFs）-derived materials,a transition metal（molybdenum-based sulfide）was introduced on the basis of high-temperature calcination MOFs materials to form a hybrid composite with bimetallic oxides（Co₂Mo₃O₈/MoS₂）,which was then designed as a novel electrochemical senor for NFT detection.During the synthesis of the hybrid materials,Co-MOF modulates the molybdenum disulfide interfacial microenvironment,which in turn induces the formation of molybdenum disulfide nanoflowers;the carbon matrix in Co-MOF is reduced to uniformly interconnected cobalt-molybdenum bimetallic nanosheets（Co₂Mo₃O₈）by carbon thermal reduction,and the highly electroactive metal nanosheets synergistically interact with the molybdenum-based components to significantly enhance the NFT electrochemical activity for NFT detection.The sensitivity of the sensor for NFT detection was 27.6μAμМ^-1 cm^-2,the linear detection range was 100～700μM,and the detection limit was 11.9 n M.Compared with N/Co@CNTs@CC,the Co₂Mo₃O₈/MoS₂@CC sensor showed a 3.37-fold increase in sensitivity,an extended linear detection range,and a 1.55-fold lower detection limit.In addition,the sensor could be used for NFT determination of milk,honey and tap water with recoveries of 97.73%～103.36%,which is consistent with the high-performance liquid chromatography（HPLC）results,favorably confirming its capability in practical detection and also providing a promising candidate electrode material for future NFT monitoring.