Preparation And Application Of Pyrite-Based Hydrogen Peroxide And Glucose Electrochemical Sensors

Electrochemical sensors have the advantages of good selectivity,high sensitivity,fast response speed,good stability and real-time online detection,which arouse great interest of researchers.In this paper,hydrogen peroxide（H₂O₂）based non-enzymatic electrochemical sensor was prepared by using pyrite as the solid electrode.H₂O₂ is an important compounds in the fields of industry,medical treatment and environment.The qualitative and quantitative determination of H₂O₂ is important.The immobilization method and supporting material are important factors in the preparation of glucose electrochemical sensors.In this paper,the bio-electrocatalytic activity of glucose oxidase（GOD）was investigated to construct the glucose electrochemical biosensor.This research not only provide a new supporting material for biosensor,but also indicate a new application for pyrite.Pyrite is one of the most abundant sulfide minerals on earth.It is a polysulfide with cubic Na Cl crystal structure.In addition,pyrite is the most stable iron sulfide minerals which can be found in nature.Pyrite is a semiconductor material which capable of conducting electricity and used as a solid electrode in this topic to detect hydrogen peroxide.After cutting and encapsulating,the pyrite was used directly as a working electrode to detect hydrogen peroxide.The pyrite electrode were characterized by scanning electron microscopy,X-ray fluorescence analyzer and electrochemical analyzer.The prepared electrochemical sensor had good stability,wide linear range and can work in mild p H environment.The linear range of this sensor for H₂O₂ was calculated as 1.0×10^-5 mol L^-1 to 1.0×10^-2 mol L^-1 with a correlation coefficient of 0.997.The detection limit（LOD）is as low as 8.6×10^-6 mol L^-1,with a sensitivity of 19.61 m A m M^-1 for hydrogen peroxide（S/N=3）.The pyrite-based electrochemical enzyme-free sensor is capable of detection of the reduction current of hydrogen peroxide at mild p H electrolyte.Glucose sensors are popular with researchers for their wide application in medical,industrial and food industries.In this part,the glucose sensor was also prepared by using glutaraldehyde（GA）as a coupling reagent to immobilize glucose oxidase（GOD）on the surface of pyrite.The concentration of pyrite,GA,GOD,the adsorption time of the three substances,and the p H value of the electrolyte solution were investigated and optimized.The best optimized concentration conditions were as follows: 30 mg/m L pyrite concentration,15% GA concentration,0.5 mg/m L GOD concentration.The best immobilization time of pyrite,GA,GOD were 1 h,0.5 h,1 h,respectively.The optimized electrolyte p H was 7.0.The linear range of glucose was measured and calculated by cyclic voltammetric method were 1.0×10^-5-2.0×10^-2 mol/L,and the detection limit is 3.8×10^-6 mol/L.