Electrochemistry And Electrochemiluminescence Sensing For Targeted Detection Of Pesticide And Veterinary Drug Residues In Food

The pesticide and veterinary drug residues in food are characterized by low concentration but high toxicity,which seriously endangers environmental safety and public health.The complexity of the substrate and trace content of the residue restrict the development of detection technology.It is of great significance to develop a sensitive,reliable,rapid and accurate detection method for trace pesticide and veterinary drug residues in complex food substrates.In recent years,electrochemistry and electrochemiluminescence（ECL）sensing technology has become a development frontier and research focus in the field of food safety testing,and relevant research theories and applications are also progressing and innovating.Based on the requirements of rapid and accurate detection methods for pesticide and veterinary drug residues in food,this paper relies on electrochemistry and ECL sensing technology and docking with molecular imprinting technology（MIT）to build relevant sensing detection system,aiming at realizing targeted and accurate detection of agricultural and veterinary drug residues in food.The mechanism of synergistic enhancement of basic electrical signal by bifunctional nanomaterials was studied.Multifunctional ECL luminophore were prepared and various signal enhancement strategies were developed.A preliminary exploration was made to improve the fixing method of sensing interface.The novel molecular imprinting sensor detection system was constructed and successfully applied to the accurate detection of pesticide and veterinary drug residues in food.1.Construction and evaluation of a covalent molecular imprinted electrochemical sensor with hygromycin B borate ester bonds based on co-amplifying signal of Cu-MOF and Ti₃C₂TxA novel covalent molecular imprinted electrochemical sensor（MIECS）was prepared for the specific detection of hygromycin B（HYB）in food.Cu-MOF,which provides a large specific surface area,and Ti₃C₂Tx,which provides excellent electrical conductivity,are modified to the surface of the gold electrode（GE）to collaboratively enhance the underlying electrical signal and increase the electroactive area.HYB was used as the template molecule and 3-thienylboronic acid was used as the functional monomer to prepare molecular imprinted polymer by electropolymerization on the surface of Cu-MOF/Ti₃C₂Tx/GE.A ph-sensitive reversible borate ester bonds was formed between boric acid ligand and HYB,which contributed to the controlled elution and adsorption of HYB.The construction process of MIP/Cu-MOF/Ti₃C₂Tx/GE was optimized in detail,and its electrochemical performance was fully characterized.Based on the relationship between HYB concentration and electrical signal,a method was established to achieve the selective detection of HYB in food.The linear range of the method was 5×10^-9–5×10^-6 mol L^-1,and the detection limit was 1.92×10^-9mol L^-1.Experiments showed that the proposed method has satisfactory selectivity,stability and reproducibility.The results were in good agreement with the verification method,which proved that the method has reliable practicability and accuracy.It provided a new method and theoretical support for the rapid detection of HYB in food.2.Ag NWs-Au NPs aggregation conductive network mediated by polythionine:construction of molecular imprinted electrochemiluminescence sensor for specific detection of kanamycinA molecular imprinted ECL sensor based on Ag NWs-Au NPs aggregation conductive network mediated by polythionine was developed for the specific detection of kanamycin（KAM）in food.As nano-antenna,Au NPs were electrostatically self-assembled onto Ag NWs to construct the luminophore Ag NWs-Au NPs.The nitrogen atom on the amino group of thionine（Thi）was able to bond to Au NPs to be electropolymerized onto Ag NWs-Au NPs/GCE.Polythionin（p Thi）can be used as a coreactant accelerator while promoting the formation of Ag NWs-Au NPs aggregation quasi-three-dimensional conductive network,which greatly enhanced the ECL intensity.Using KAM as template molecule and o-phenylenediamine（o PD）as functional monomer,MIP was prepared by electropolymerization on the surface of Ag NWs-Au NPs/p Thi/GCE.The construction process of Ag NWs-Au NPs/p Thi/MIP/GCE was optimized in detail and its ECL performance was comprehensively characterized.The method was established based on the relationship between KAM concentration and ECL intensity to achieve the accurate and quantitative detection of KAM.The method has satisfactory selectivity,stability and reproducibility.The linear range was 1×10^-10–1×10^-6 mol L^-1,and the detection limit was 3.14×10^-11mol L^-1.This method has been applied to KAM detection in actual samples,and the recovery rate was83.27%–94.13%,which was consistent with the detection result of verification method and had good accuracy.It provided a new method for designing ECL components and constructing a sensitive sensor platform for detecting harmful substances in food.3.A self-enhanced molecular imprinted electrochemiluminescence sensor platform was constructed for the specific detection of thiabendazole based on the dual functions of melamine-silverMelamine as a template chelated Ag⁺to prepare M-Ag by self-assembly at room temperature,which not only has excellent ECL characteristics but also can be used as a co-reactant accelerator.A molecular imprinted ECL sensor platform was constructed based on M-Ag as a self-enhanced ECL luminophore for the specificity detection of thiabendazole（TBZ）in food.Mo S₂-QDs with edge activity and electrochemical reaction catalytic activity were used to accelerate the reaction rate of microsystem and further enhance the ECL intensity.TBZ was the template molecule and o PD was the functional monomer.MIP was prepared by electropolymerization on M-Ag@Mo S₂-QDs/GCE surface by hydrogen bonding.The preparation process and ECL properties of MIP/M-Ag@Mo S₂-QDs/GCE were optimized.A specific detection method for TBZ in foods was established by researching the ECL reaction mechanism and specific recognition mechanism of MIP/M-Ag@Mo S₂-QDs/GCE.The linear range of the method was 5×10^-8–5×10^-5 mol L^-1,the detection limit was 1.42×10^-8 mol L^-1,and the method had good selectivity,stability and reproducibility.In the actual sample detection experiment,the recovery rate was 83.57%–101.03%.The test results were in good agreement with the verification method,which proved that the method has satisfactory accuracy and practicability.The study provided a new development idea for the preparation of self-enhanced ECL molecular imprinting sensor and the selective detection of TBZ in food.4.Magnetic fix molecular imprinting electrochemiluminescence sensing platform constructed based on magnetic metal organic framework material loaded carbon nitride nanosheets for specifically identify thiabendazoleA magnetically fixed bifunctional monomer molecularly imprinted ECL sensor was constructed for the selective and sensitive detection of TBZ in food.Fe₃O₄ modified with sulfonic acid group acted as a magnetic core to adsorb Co²⁺to initiate the growth of Co-based MOF（ZIF-67）.Graphite phase carbon nitride nanosheets（Gc NNs）were doped with intrinsic amino group into magnetic MOF（MMOF）to prepare the integrated magnetic ECL luminophore（MMOF-GCNNs）.The MMOF-Gc NNs was fixed to the surface of magnetic glassy carbon electrode（MGCE）with the superparamagnetic properties of Fe₃O₄,which enhanced the stability and reusability of ECL system.Sodium ascorbate（L-Aas）was used as a coreactant accelerator to enhance the ECL reaction rate and ECL intensity.TBZ was the template molecule and o PD/RS was the bifunctional monomer.MIP was prepared by multiple hydrogen bonding electropolymerization.Bifunctional monomers can effectively increase the number of imprinting sites and enhance adsorption performance.The preparation process of MIP/MMOF-Gc NNs/L-Aas/MGCE was optimized and its ECL performance was characterized.According to the relationship between TBZ concentration and ECL intensity,a method was constructed to achieve the selective quantitative detection of TBZ.The linear range was 1×10^-9–5×10^-5 mol L^-1,and the detection limit was 3.77×10^-10 mol L^-1.A good recovery rate（80.08%–96.82%）was obtained in the actual sample detection,which was basically consistent with the detection results of the verification method,with satisfactory practical application and accuracy.This study provided a new research idea for improving the fixing mode and assembly strategy of ECL sensing interface.