Electrochemical Detection Of H₂O₂ And Glucose Based On Electrodeposited Polydopamine Membrane

The development of simple and fast,low price,sensitive and efficient,green environmental protection detection methods have always been one of the research hotspots and breakthrough directions in the field of food safety testing,electrochemical biosensors as a comprehensive of the above advantages of the detection tool in recent years in food safety testing has been widely studied and applied.Polydopamine membrane is widely used as a binder to fix nanomaterials or enzyme molecules on the surface of the electrode due to its simple preparation process,green environmental protection,good biocompatibility,and easy to bind firmly with the substrate electrode,and to prepare electrochemical biosensors for detecting various target substances.This paper explores the new properties and applications of polydopamine membrane modified electrodes by using hydrogen Peroxide(H₂O₂)and glucose(Glucose),two small molecule substances commonly found in food safety detection:the preparation of polydopamine modified electrodes by cyclic voltammetry is used to electrode deposit polytopamine on the surface of the substrate electrode,and the selective transmittance of polypamine membranes to H₂O₂is explored,and a fast,and fast,fast,Sensitive electrochemical biosensor.The main research content of the paper is as follows.(1)Construction and application of enzyme-free hydrogen peroxide biosensor based on electrodeposited polydopamine membrane.The second part of the experiment mainly explored the effect of electrodeposition of polydopamine film by cyclic voltammetry on the selective permeability of small molecule hydrogen peroxide.It was found that the electrode modified by electrodeposited polydopamine film could effectively block the interference of ascorbic acid and uric acid in the matrix and selectively penetrate through H₂O₂.On this basis,the number of cycles of cyclic voltammetry electrodeposition and the coverage degree of polydopamine film on the electrode surface were determined by the characterization of the modified electrode and the investigation of selective permeability.The results show that the barrier performance increases with the increase of the number of coils.When the number of coils reaches 10,the modified electrode can completely block the interfering substances and specifically detect H₂O₂.On the basis of the research results,10 cycles of polydopamine were electrodeposited on the metal platinum electrode substrate with excellent electrocatalytic performance in the experiment,and an enzyme free biosensor for detecting H₂O₂was developed and constructed.In the experiment,the substrate electrode was selected,the applied potential and p H value were optimized,and the best detection conditions and performance of the sensor were obtained.The linear range of the method is 0.05-15 m M,the linear equation is:??=12.6935×[H₂O₂]/m M+5.5823(R~2=0.9937),the detection limit is 20 n M,and the recovery rate of H₂O₂detection in milk is 91%-106.6%when the sensor is applied.This study explored the selective permeability of H₂O₂through biosensor based on electrodeposition of polydopamine membrane in complex matrix,providing a new idea and method for the research and application of polydopamine membrane.(2)Construction and application of glucose oxidase biosensor based on electrodeposited polydopamine membrane.In the third part of the experiment,based on the dopamine-membrane enzyme-free biosensor designed and constructed in the second part for detecting H₂O₂,the application of dopamine-membrane modified electrode in glucose detection was further explored by utilizing the mechanism of glucose producing hydrogen peroxide under the catalytic action of glucose oxidase.An enzyme biosensor based on electrodeposited polydopamine film was designed by using a platinum electrode substrate with 10 cycles of electrodeposited polydopamine film.Glucose oxidase and bovine serum albumin(BSA)were fixed on the surface of the modified electrode by crosslinking glutaraldehyde.The results show that the sensor can effectively block the interference of various substances in complex matrix,and specifically recognize the H₂O₂catalyzed by glucose oxidase to produce?-glucose.Through the influence on the selection of the substrate electrode,the correspondence with the results of the second part of the polydopamine modified electrode detection of H₂O₂substrate electrode selection was verified.By optimizing the applied potential,p H value of buffer solution and enzyme content,the best detection conditions and performance of enzyme-modified electrode were obtained.The linear range of this method is 0.056-5.884 m M,and the linear equation is:??=2.2078×[Glucose]/m M+0.7308(R~2=0.99023),the detection limit is 30 n M,the sensor is applied to the actual sample,and the spiked recovery of Glucose detection is97.6%-113.7%.The results were compared with M-100 biosensor analyzer,and the results were basically consistent.The enzyme modified electrode based on electrodeposition of polydopamine developed in this experiment has the advantages of fast,simple,easy to operate and low cost,which has certain reference significance for the further study of glucose oxidase biosensor.