| China is a large country for agricultural, and it is also a large country for pesticideproduction and use. With the development of agriculture, people pay more attention tothe environmental pollution and food safety problems caused by pesticide residues. Ithas important significance to develop the detection technology, especially the rapiddetection technology for monitoring pesticide residues in environment and foodtimely.Electrochemical sensing technology is an important method for rapid detection ofpesticide residues. According to different detection principle, electrochemical sensorcan be divided into chemical sensor, biosensor and immunosensor, etc. In recent years,with the development of nanoscience and nanotechnology, it has become the directionof research to construct the electrochemical sensor interface with the characteristics offast, efficient, sensitive and suitable for field detection pesticide residues by nanomaterials. In this paper, the electrochemical sensors with the character of highsensitivity, selective, fast response, good stability were constructed by selecting theappropriate nano materials. The sensor interface was fabricated through theinvestigation of the electrochemical catalytic of graphene, carbon nanotubes, noblemetal nanoparticles and magnetic nanoparticles. The main research contents are asfollows:(1) A graphene-Nafion matrix which was used as solid-phase adsorbents modifiedglassy carbon electrode (Graphene-Nafion/GCE) was developed for the determinationof organophosphorus pesticides. Graphene nanosheets was synthesized chemically byHummers method, and characterized by X-ray photoelectron spectroscopy. Thesurface morphology and electrochemical properties of the Graphene-Nafion/GCEwere investigated by means of scanning electron microscopy, cyclic voltammetry, andsquare-wave voltammetry, respectively. Under the optimized experimental conditions,took methyl parathion as a model compound, the linear range and the detection limitof the electrochemical sensor were investigated. Furthermore, theGraphene-Nafion/GCE was applied in the determination of real samples.(2) An amperometric biosensor for the determination of organophosphate andcarbamate pesticides was developed based on the immobilization ofacetylcholinesterase(AChE) on regenerated silk fibroin(SF) matrix by non-covalentadsorption. The obtained biosensor was denoted as AChE-SF/MWNTs/GCE. Thesurface morphology of biosensor was characterized by the atomic force microscopyimages. The electrochemical behavior of acetylthiocholine was investigated byamperometry. Under the optimized experimental conditions, a new method was established and applied in the determination of methyl parathion in vegetable samples.(3) An amperometric biosensor for the rapid determination of organophosphoruspesticide was developed based on layer by layer self-assembly both AChE and goldnanoparticles(AuNPs) on GCE in the presence of poly(diallyldimethylammoniumchloride)(PDDA). The morphological characteristics and electrochemical propertiesof the biosensor were investigated by scanning electron microscope, electrochemicalimpedance spectroscopy and differential pulse voltammetry. Took methyl parathion asa model compound, the linear range and the detection limit of the biosensor wereinvestigated. The biosensor was applied in the determination of real samples.(4) An amperometric biosensor for the rapid detection of organophosphoruspesticide was developed based on magnetic nanoparticle complexes Fe3O4-AuNPsprepared by chemical co-precipitation. These magnetic nanoparticle complexes wereimmobilized on a homemade magnetic glassy carbon electrode and served as matrixfor immobilizing AChE. The chemical composition of magnetic properties andmorphology of magnetic nanoparticles composite Fe3O4-AuNPs were characterizedby X-ray diffraction, vibrating sample magnetometry and transmission electronmicroscopy. The electrochemical characteristics of home-made magnetic glassycarbon electrode and enzyme biosensor were characterized by electrochemicalimpedance spectroscopy and cyclic voltammetery, differential pulse voltammetry. Byparaoxon as an example, the detection linear range and detection limit of the pesticideon enzyme biosensor were investigated. This biosensor was also applied to thedetermination of the pesticide in real samples.(5) A fast, simple and sensitive electrochemical competitive immunosensingmethod was developed to monitor herbicide,2,4-dichlorophenoxyacetic acid(2,4-D)based on the specific recognition between hapten and labeled antibody. The hapten2,4-D self-assembled on the alkylation GCE competed with analyte forenzyme-labeled antibody binding. The analyte concentration was dependent on theelectrochemical signal of enzyme-labeled antibody adsorbed on the GCE by hapten.The performance of the immunosensor was evaluated on river water samples spikedwith2,4-D. |
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