Construction Of Enzyme And Flavonoids Electrochemical Sensor Based On Novel Nanomaterials

Electrochemical sensor is composed of one or more sensor which can produce sensitive components and the measured properties of the component of a chemical or biology related signals,because of its simple-equipment,high-specificity and high-sensitivity can be applied to a wide range of food industry,environmental monitoring,biomedical and pharmaceutical research.Nanomaterials are materials that have at least one dimension(0.1-100 nm)in a three-dimensional space or are made up of them as basic units.The performance of electrochemical sensors can be excellently improved by the use of nanomaterials with good adsorption and catalytic properties.This research was designed and fabricated electrochemical sensing platform based on nanotechnology and electrochemical technology.The purpose is to improve the selectivity and sensitivity of the sensor,and realize the recognition and detection of the target molecule.The detailed materials are summarized as follows:1.Fabricating a novel luteolin electrochemical sensor based on electrochemical reduced graphene oxide / carbon nanotubeLuteolin is a natural flavonoid compound.A new electrochemical sensing method based on the sensitizing effect of carbon nano composite was established.By dropping the graphene oxide and carbon nanotube coating dispensed onto bare glassy carbon electrode,use electrochemical reduction method reducing graphene oxide to ErGO after ErGO-MWNTs dried,then use the modified electrode to investigate of the electrochemical behavior of luteolin.It'S found that the biosensor exhibits fast current response,a linear response to luteolin over the range from 2.5×10-7 to 1.3×10-5 mol /L and the oxidation peak current showed a good linear relationship with its concentration.In addition,the modified electrode showed a good response sensitivity,the detection limit(S /N = 3)up to 7×10-8 mol /L.2.Fabricating a novel uric acid electrochemical sensor based on electrochemical reduced graphene oxide / carbon nanotubeElectrochemical reduction of graphene oxide(ErGO)and multiwalled carbon nanotube(MWNTs)composite modified electrode was prepared by the method of constant potential reduction.And it was used in the voltammetric detection of uric acid.Firstly,the GO-MWNTs composite was dropped on the surface of bare glass carbon electrode,and then the ErGO-MWNTs modified electrode was prepared by electrochemical reduction of graphene oxide(GO).The experimental results show that the ErGO-MWNTs modified electrode has better electrocatalytic activity than that of the single ErGO modified electrode or MWNTs modified electrode,which is attributed to the synergistic electrocatalytic activity of ErGO and MWNTs.Subsequently,the experimental parameters for the detection of uric acid with ErGO-MWNTs modified electrode were optimized in detail.Under the selected experimental conditions,the peak current was linear with the concentration of uric acid in the range of 1.25? 10-7 to 4.5?10-5 mol / L,the correlation coefficient was0.9968 and the detection limit was 5×10-8 mol /L.3.Electrochemical reduced graphene oxide / carbon nanotubes / chitosan / nano gold modified electrode on the direct electrochemistry of horseradish peroxidase HRPIn this work,Au/CNTOH-rGO-CS modified glassy carbon electrode was used as the enzyme substrate.Then the HRP-CS/Au/CNTOH-rGO-CS modified electrode was prepared by electrochemical reduction of graphene oxide.The experimental results show that the modified electrode has ability of direct electrochemistry performance and catalytic oxidation reduction.Then the experimental conditions for the detection of hydrogen peroxide were optimized.Finally,the detection performance of hydrogen peroxide was investigated.When the concentration of H2O2 is in the range of 2.0×10-5to 1.2×10-3 mol/L,the response current is linear,and the detection limit is 5.3?10-6mol/L(S/N=3).The results show that the novel enzyme sensor is simple,low cost,and thus could exhibit fast current response.