The Preparation And Its Application Of Carbon Nanomaterials Chemically Modified Carbon Paste Electrode

In recent years, the development, preparation, characterization, future and application in food analysis, life science, environmental monitoring of carbon paste electrodes (CPE) were summed up. More and more applications of CPE were reported in analytical chemistry, especially electrochemical due to its low current background, easy fabrication, high sensitivity, renewable surface and low cost. Carbon is one of the exceptional familys in the periodic table. In addition to the previous years, lots of heated discussions of carbon nanotube (CNT), the scientists also found another "Wizards" of the family-graphene (Ge). As popular carbon nanometer materials in recent years, it also possesses the properties of good conductivity property, electricity catalytic performance, large surface area and low cost. Thus, it has incomparable advantages in electrode materials.In this thesis, on the basis of previous studies, carbonaceous nanomaterials was used as the mainmodifier doped in carbon paste electrode. The main contents of this thesis are shown below:(1) Three paste electrodes based on graphite powder (GP), CNT and Ge respectively, was prepared in the same way. And used to examine the electrochemical oxidation of Maltol. It was found that the addition of CNT or Ge and did not play a catalytic role for the reaction of maltol, CPE maltol showed the best electrochemical response. Then a new method for voltammetry detection of maltol was established by differential pulse voltammetry and exhibited a wide linear range response for Maltol with a low detection limit.(2) A Carbon Nanotubes-doped Carbon Paste Electrodes (CNT/CPE) was developed through a mixture of certain proportion CNT and GP. The optimization of the CNT/GP composite rate was Optimized and determined ultimately. Successfully applied to the analysis detection of baicalein which belonging to flavonoid compounds. Optimized the experimental conditions, then the peak currents increased linely with baicalein concentrations changing in the range of2×10-8mol L-1and1×10-5mol L-1, the detection limit was4.2×10-9mol L-1. Successfully used the method in the quantitative determination of baicalein in Shuanghuanglian oral liquid and Spiked human blood serum samples with satisfactory results. Also, a possible oxidation mechanism of baicalein was obtained on the CNT/CPE on the basis of experimental results and the literature report.(3) Firstly the Gold Nanoparticles (AuNPs) were synthesized according to a method reported by G Tsutsui with slight modifications and characterized by atomic force microscope (AFM) and UV-spectrum respectively. A nano-Au monolayer was formed by self-assembly on the surface of the modified electrode fabricated previously, then a new voltammetric sensor for rutin was fabricated. Experiment results show that the modified electrodes showed good catalytic capacity to the oxidation reaction of rutin. In order to further explored the mechanism of electrode reaction, some electrochemical reaction parameters,(such as the number of electron transfer, the saturated adsorption quantity) was calculated. Under the optimal experimental conditions, a new voltammetry method was established for the determination of rutin, the detection sensitivity is the highest in the known method.