| Thiabendazole has some excellent anti-mildew and anti-mold properties,and it is widely used in the anti-mildew preservation of fruits and vegetables,there have been reports on its application to mold prevention in food production workshops,but the abuse thiabendazole will cause the fruits,vegetables and food to be contaminated in some degrees.The excessive concentration of thiabendazole residues is harmful to the human,mainly affecting the human liver,nervous system and bone marrow.Therefore,it is significance to develop an efficient,sensitive and accurate detected method for thiabendazole.Graphene nanomaterials have been widely used in the fields of modified electrode,due to their two-dimensional planar structure,unique optical properties and excellent electrical properties.It has excellent electrical conductivity,which has a large specific surface area,it can be used as a good carrier to effectively increase the enrichment ability of the sensor,and it has attracted much attention in the field of electrochemical sensors.Therefore,the application of graphene to an electrochemical sensor by an appropriate method can significantly improve its sensitivity and response rate.Based on the excellent electrical conductivity of graphene,modified on the surface of glassy carbon electrode to prepare thiabendazole molecularly imprinted electrochemical sensor by electrochemical method in this paper.It replaces traditional biomolecule with membrane as identified component.It not only has high selectivity and sensitivity to thiabendazole,but also has the advantages of good stability and low cost,and the sensor has been successfully applied to actual sample detection.This paper mainly includes the following three parts:1.The background,significance and research contents of this experimental research work are introduced.The common analytical methods for thiabendazole are reviewed.2.Graphene oxide?GO?was prepared by the modified Hummers and Offeman's Method,the graphene oxide modified glassy carbon electrode?GO-GCE?was obtained by dropping 10?L of the suspension onto the surface of the freshly polished GCE.The electrochemically reduced GO was tested by CV.An electrochemically reduced graphene modified electrode?ERGO-GCE?was prepared by cyclic voltammetry in a 0.5 M sodium chloride solution.A novel molecularly imprinted electrochemical sensor was prepared by electrochemically in-situ polymerization to detect thiabendazole?TBZ?on ERGO-GCE.The experimental conditions were optimized,30 mL phosphate buffer solution?0.1 M,pH=9?with 20mL methanol mixture were selected as the electropolymerization solution.The molar ratio of functional monomer to template molecule was 3:1.During the potential range of-0.2+0.8V,TBZ molecularly imprinted membrane was prepared by electropolymerization for 10 cycles at a scanning rate of 40 mV/s.After the thiabendazole in the imprinted film was eluted with 0.5 M hydrochloric acid.The sensor was characterized by cyclic voltammetry?CV?,differential pulse voltammetry?DPV?,electrochemical impedance spectroscopy?EIS?,scanning electron microscopy?SEM?and Fourier transform infrared?FTIR?spectroscopy.3.The performance and application of the thiabendazole molecular imprinting electrochemical sensor were studied.Compared with non-imprinted sensor,the sensor imprinting factor was 3.61.Compared with the three analogues?carbendazol,albendazole and benomyl?,the sensor has good selectivity to thiabendazole,and the maximum current response value is 1.51,1.93 and 2.95 times than others,respectively.Under the optimal conditions,the current response of the imprinted sensor was linear to thiabendazole concentration in the ranges of 5.0×10-7-1.0×10-55 M and 1.0×10-5-1.2×10-44 M,with a limit of detection?LOD?of 1.25×10-77 M?S/N=3?.Finally,the imprinted electrochemical sensor was applied in the specific detection of TBZ in real samples with spiked recoveries of 96.3–104.9%,The average relative standard deviation was less than 5.9%.The results show that the method has high accuracy and precision. |
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