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Study On Hydrogen Peroxide Biosensor

Posted on:2008-07-05Degree:MasterType:Thesis
Country:ChinaCandidate:Y XieFull Text:PDF
GTID:2178360215466111Subject:Inorganic Chemistry
Abstract/Summary:PDF Full Text Request
Enzyme sensor is a sensor assembled by immobilizing electrochemistry electrode such as enzyme and ion selectivity electrode, gas sense electrode, redox electrode et al. So it has the functions of molecule recoganation and selective catalysis. As slso, this electrode responds to H2O2 fastly, prepare simplly, and need little sample when detect a compound. H2O2 is an outgrowth of catalase's reaction, the content of H2O2 is important to foodstuff, medicine and enviorenment. At present, the methods of detecting H2O2 are titration, spectral, chemicradiation, electrochemistry et al. electrochemistry hydrogen peroxide electrode has been developed for it's low cost, high sensitivity and facility. In the process of preparing electrode, the technique and material of immobilizing enzyme is pivotal.In this thesis we prepared a series of hydrogen peroxide biosensors by electrochemistry.1. A new hydrogen peroxide (H2O2) biosensor based on DNA-hemoglobin (DNA-Hb) and zirconia (ZrO2) thin films modified gold electrode was presented. In this modified electrode, we confim both ZrO2 and DNA could accelerate the electron transfer between Hb and the electrode and the immobilized Hb could retain its natural structure. Firstly, ZrO2 thin films were electro-deposited on the bare gold electrode. Then DNA -Hb was immobilized on the ZrO2/Au surface. The electrode showed a high thermal stability, offering an excellent electrochemical response for determination of H2O2 concentration with high sensitivity and selectivity. The linear range for H2O2 determination was from 1.7×10-7 to 3.0×10-3 mol.L-1 with a detection limit of 8.0×10-8 mol-L-1 (S/N=3).2. We report a hydrogen peroxide (H2O2) biosensor based on DNA-HRP and Poly-L- cysteine modified Pt electrode in this paper. L-cysteine was polymerized on the bare Pt electrode by cyclic voltammetry (CV). Then DNA-HRP was immobilized on the L-Cys/Pt surface by the method of layer by layer.The electrode offers an excellent electrochemical response for determination of H2O2 concentration below micromole level with high sensitivity and selectivity. The linear range for H2O2 determination was from 1.2×10-6~9.0×10-3 mol·L-1 with a detection limit of 8.0×10-7 mol·L-1 (S/N=3).3. A novel hydrogen peroxide (H2O2) biosensor based on DNA-HRP and Poly-L- Tyrosine modified Pt electrode was presented in this paper. Firstly, L- Tyrosine was polymerized on the bare Pt electrode by cyclic voltammetry (CV). Then DNA-HRP was immobilized on the L-Tyr/Pt surface. The electrode offers an excellent electrochemical response for determination of H2O2 concentration below micromole level with high sensitivity and selectivity. The linear range for H2O2 determination was from 2.0×10-6~1.1×10-2 mol·L-1 with a detection limit of 8.0×10-7 mol·L-1 (S/N=3).4.Immobilizing hemoglobin to L-cysteine modified gold electrode by electrodeposited to develop a new hydrogen peroxide biosensor. It's uppermost virtue is produce easily and preparing periods short. This electrode presents an excellent electrochemical response for determination of H2O2 concentration with high sensitivity, linear scope is 8.21×10-8~4.83×-6mol·L-1and 4.83×10-6~8.22×10-3 mol·L-1, it's detection limit is 8.24×10-9 mol·L-1.
Keywords/Search Tags:biosensor, horseradish peroxidase, DNA, Hemoglobin
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