Dissertation > Mathematical sciences and chemical > Chemistry > Analytical Chemistry > Instrument analysis ( physics and physical chemistry ) > Electrochemical analysis

Fabrication and Study of Ionic Liquid and Nano Materials Modified Electrode

Author CaiZhiFang
Tutor GuoManDong
School Shanxi Normal University
Course Chemistry
Keywords Ionic liquids Gold electrode Chitosan Nano silver Nanogold Hemoglobin Glucose oxidase L-cysteine Ascorbic acid
CLC O657.1
Type Master's thesis
Year 2014
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Nano materials and ionic liquid have special unique physical andchemical properties. Ionic liquids that has wide electrochemicalwindows is a green solvents chemical industry, which can promotethe electron transfer, high ionic conductivity and goodbiocompatibility. Nano materials have high surface area, free energyand strong adsorption capacity. These special materials caused theelectroanalytical chemistry community interest. In this paper, Thenew type of modified electrode was constructed by using ionic liquidand nano materials as modifiers. The analysis of electrochemistry andelectroanalytical chemistry research is one of the hotspots in the fieldof chemical research. The main works are described as follows:1. The electrochemical behavior of hydrogen peroxide(H2O2)wasstudied by cyclic voltammetry and Linear scanning at a gold electrode(Au/CME) modified by hemoglobin(Hb), chitosan (CS), a gel containingNano silver (Nano-Ag) and room temperature ionic liquid (RTIL) of1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6). A good micro environment has been set up for Hb,due to the fine conductivityof ionic liquid BMIMPF6, the high surface activity and strongadsorption of Nano-Ag, which increased the adsorption and electriccatalytic activity of Hb. This paper studies the characteristics of themodified electrodes, optimize the experimental conditions ofmodified electrodes, detailed discussion the mechanism of Hbelectron transfer on the surface of modified electrode and theelectrochemical behavior of H2O2. The modified electrode testedactual sample of H2O2with the satisfactory result.2. A sensitive glucose biosensor was fabricated by coating glucoseoxidase (GOD),1-butyl-3-methyl imidazole six fluoride phosphate(BMIMPF6), chitosan (CS), gold nanoparticles (nano-Au) compositematerials on gold electrode(Au) surface. The biosensor wascharacterized using cyclic voltammetry and scanning electronmicroscope (SEM). The preparation conditions and electrochemicalproperties of modified electrode were discussed in detailed. Theresult show that this composite materials provides a good microenvironment for GOD, and makes GOD keeps the high biologicalelectrochemical activity. Moreover through nano-size effect ofnano-Au and the high conductive of ionic liquid BMIMPF6, promote theelectron transfer. The modified electrode can be used as a glucosebiosensor, and the study is important to life science and clinical medicine. Under the optimal conditions, the reduction peak currenthas a good linear relationship to glucose concentration in the rangedbetween1.0×10-4~1.0×10-6mol·L-1, the linear equation wasy=0.0871x+37.889(r=0.9995)and the detection limit was3.85×10-8mol·L-1.3. The polymer film of gold nanocrystalline-chitosan-ionic liquid-L-cysteine was prepared as a thin film covered the gold electrodesurface by a simple and fast drop coating and electrodepositedmethod.In PBS solution, The electrochemical behavior of ascorbicacid (AA) was investigated using cyclic voltammetry and differentialpulse voltammetry.The results show that the modified electrode canenhance the adsorption of AA on the electrode surface, andaccelerates the rate of electron transfer when react with AA.In theprocess of reaction,the electrochemical response is obviouslyboosted,and the detection sensitivity can be greatly improved.Theproperties of modified electrode is excellent stability andreproducibility.Finally,this shortcutly analytical method is employedfor the determination of biological samples of AA.

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