| As the electrochemical sensors have many merits such as remarkable sensitivity, good selectivity, low-cost, easy miniaturization and few sample consumption etc, they have been widely used in online detection. The production and development of various kinds of functional materials such as resorcinarene and carbon nanotubes have promoted electrochemical sensors to more sensitive, accurate, instant and miniaturized analysis without any marks. Therefore, the research into the electrochemical sensors modified by the resorcinarene and carbon nanotubes is of great significance.This dissertation detailed how to modify glassy carbon electrodes and carbon fiber electrodes with several functional materials such as resorcinarene, carbon nanotubes, polyaniline/cobalt-cobalt oxide, antimony film, trimethoprim and melamine to afford novel electrochemical sensors. The applications of the modified sensors were also discussed.The electrochemical sensors were prepared by modifying glassy carbon electrodes and carbon fiber microelectrodes with resorcinarene affording the electrochemical sensors which revealed potential response to hydrogen peroxide and glucose. The electrochemical properties of the obtained sensors were characterized by the AFM and EIS, and the response mechanism of the sensors to hydrogen peroxide and glucose was discussed. The sensors were applied in potentionmetre determination of hydrogen peroxide and glucose, and the experimental conditions for the determination were optimized. These sensors were easily prepared and possessed good reproducibility and stability. The research into chemical sensors modified with resorcinarenes together with the application of these novel sensors laid great signification on the preparation and application study of modified nanoelectrodes for potentionmetre analyses.The method and preparing condition of the pH sensors modified by polyaniline/cobalt-cobalt oxide and antimony film on glassy carbon electrodes and carbon fiber electrodes were discussed. The range of potentiometric response of these modified electrodes to pH as well as response mechanism and their specifications was studied. The response of these modified electrodes to pH was close to Nernst response and displayed a broad response range, which would overcome the acid error caused by glassy electrode. Therefore, these sensors could be applied in the determination of pH of some specific solutions.The electrochemical sensor which enjoyed a catalytic function towards hydrogen peroxide was fabricated by electrochemically modifing glassy carbon electrodes with some organic molecules with specific groups such as-NH2. The properties and response principle of the obtained sensor as well as its application were also studied. As an important substance in industry, clinical medicine and environment science, hydrogen peroxide is also the product in many reduction-oxidation enzymatic reactions. The substrate concentration in the enzymatic reactions could be indirectly detected by analyzing the concentration of hydrogen peroxide. Therefore, the study on the measurement of hydrogen peroxide with high sensitivity is of great meaningfulness.The electrochemical properties of melamine were studied on the basis of three groups of-NH2in melamine molecule as well as their electrochemical oxidization within a certain range of potential, and an easy-going method for determining the content of melamine in milk and dairy products was established. Besides, this methodology emerged with several advantages as follows:simple pretreatment of samples, low cost and no complicated equipment required. The analytical method for pesticide imidacloprid detection with electrochemistry was also established based on the electrochemical response of pesticide imidacloprid on the electrodes modified with carbon nanotubes and Prussian Blue. The establishment of these methods to detect melamine and pesticide imidacloprid is meaningful to food safety and food quality monitoring. |
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