Improved Carbon Paste Electrode For The Detection Of Hydrogen Peroxide And Glucose

Objective At present,with the rapid development of economy,energy,food safety and environmental issues have attracted more and more attention,so the relevant testing technology has emerged at the historic moment.And most testing methods must be various steps of pretreatment,and need complex and expensive instruments,high cost,complex operation,difficult to meet the needs of field testing.Taking this as the starting point,this experiment built an enzyme-free system to modify the carbon paste electrode,which has the characteristics of rapid response,low detection limit,high sensitivity,low cost,good stability,and combined electronic information and electrochemical principles and technology to establish a long platform suitable for field quantitative monitoring of hydrogen peroxide(H2O2)and glucose(Glu).Methods In this study,a Prussian blue(PB)nanocomposite modified carbon paste electrode(CPE)was synthesized by doping chitosan(CS)and graphene oxide(GO)with chemical precipitation and electrodeposition methods to prepare a sensitive probe for H2O2 and glucose.A home-made carbon paste electrode was used as the working electrode,Ag/Ag Cl as the reference electrode and platinum wire as the counter electrode to form a three-electrode system.A stable and exclusive catalytic sensor for the enzyme-free catalysis of hydrogen peroxide and glucose was developed.Results(1)PB/CS nanomaterials made by chemical precipitation method,PB crystal structure is dense and attached to CS,and PB/CS/r GO nanomaterials formed by electrodeposition method,the three are overlapped together,r GO is folded,increasing the surface area and speeding up the conduction speed,the effect is good and meets the experimental requirements.(2)The PB/CS/CPE in the modified electrode was pre-prepared with a PB:CS ratio of 4: 3,and subsequent experiments in PBS solution at p H 4 and temperature 20-30℃were appropriate;and the optimal preparation conditions for PB/CS/r GO/CPE were: GO volume of 18 μl,concentration of 0.8 mg/ml,CS concentration of 0.01% doped into the deposition solution,electro The number of PB turns deposited was 35 and the tests were carried out at p H 4.The current did not drop significantly and the reproducibility was good after several weeks for both modified electrodes.(3)Both methods can detect H2O2 and glucose.For comparison of the materials used in the thesis,the chemical precipitation method is more suitable for the detection of H2O2 and has a wider detection range,while the electrodeposition method is more suitable for the detection of glucose.The addition of r GO expands the current by a factor of about 10 and improves both sensitivity and stability.Conclusions In this study,the electrodes were prepared by home-made CPE,mixing GO,CS and PB,using two methods of chemical precipitation and electrodeposition.The results show that: PB improves the sensitivity of the sensor while making the sensor have a lower working potential;CS,as a common membrane material,increases the stability of the membrane;GO is reduced to r GO,which has superior mechanical strength,thermal conductivity and electrical conductivity.Supported by electrochemical technology,combined with the advantages of enzyme-free sensing,two new methods for the sensitive and rapid detection of H2O2 and glucose content are established to meet the development needs of various fields of modern pharmaceutical and food environment testing.