| Ionic liquids (ILs), a new kind of soft material, are widely applied in various fields and have attracted much attention in electroanalytical chemistry in recent years. In this thesis, cyclic voltammetry, alternating current impedence technique and chronoamperometry are used to investigate the electrochemical behaviors of several compounds in IL and on two types of the modified carbon paste electrodes with ILs as binder. The thesis may provide theoretical and practical basis for developing sensors and enriching the content of electrochemistry. There are four chapters in this thesis. The main contributes of author are summarized as follows,1. The electrochemical behavior of m-nitroaniline was investigated in [BMIM][BF4] by cyclic voltammetry and chronopotentiometry. The experimental results showed that -NH2 group of m-nitroaniline molecular lost one electron at Pt electrode, and formed into the cation radical which participated in subsequent reaction to yield the polymer. At the same time, the diffusions coefficient was calculated to be2. The electrochemical behavior of tanshinone IIA and benzaldehyde were investigated in ethanol-[BMIM][BF4] solution by cyclic voltammetry and pulse differential voltammetry. The experimental results indicated that a cathodic peak of tanshinone IIA in the presence of dissolved oxygen was observed at - 0.87 V on the cyclic voltammogram, and the linear range for the determination of tanshinone IIA was 3.4×10-6 to 3.7×10-5 mol·L-1 (r = 0.9965) with a detection limit of 1×10-6 mol·L-1. The proposed method was used to determine the total content of tanshinone in Tanshinone Tablet. The electrode reaction of benzaldehyde at glassy carbon electrode (GCE) was a total irreversible and diffusion controlled process, involving the transfer of two electrons. The peak current of square wave voltammogram versus the concentration of benzaldehyde showed a good linear relationship in the range of 0.037 to 0.485 mol L-1, with the detection limit of 0.01 mol·L-1.3. [BuPy][PF6] was used to fabricate the modified carbon paste electrode. Cyclic voltammetry and pulse differential voltammetry was used to investigate the electrochemical behavior of NO2- in pH 3.78 Britton-Robinson buffer. The experimental results indicated that the peak current was proportional to the concentration of NO2- in the range from 1.0×10-5 to 1.5×10-3 (r = 0.9959). The detection limit was 4×10-6 mol·L-1. The relative standard deviation (RSD) was calculated to be 3.2% for 11 independent determinations of 1.0×10-4 mol·L-1 NO2-solution. The modified electrode could be applied to the determination of NO2- in water. Comparing to traditional carbon paste electrode, a sensitive oxidation peak of NO2- at the modified electrode was observed.The glucose oxidase (GOx) was immobilized on the modified carbon paste electrode with [BMIM][PF6] as the binder (ILCPE), to fabricate the GOx/ILCPE. Electrochemical characteristics of the modified electrode were investigated by cyclic voltammetry and electrochemical impendence technology. The experimental results indicated that the direct electron transfer of GOx occurred at the surface of ILCPE, with the oxidation peak and reduction peak at - 0.44 and - 0.55 V on cyclic voltammogram, respectively. The electron transfer rate constant (Ks) and the surface concentration of GOx on ILCPE were estimated to be 0.35 and 5.62×10-9 mol·cm-2, respectively. At the same time, GOx/ILCPE showed the eletrocatalytic oxidization behavior for glucose. Furtherly, it was also shown that [BMIM][PF6] possess the good conductivity and biocompatibility. The study may provide a promising platform for the development for the novel enzyme electrodes.
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