Investigation On Electrochemical Behavior Of Some Organic Medicament At Glassy Carbon Electrode

In this thesis, the redox behavior of 3' ,5' -daidzein double sulfonic sodium (DDSS), 7-dimethoxy-3' -daidzein sulfonic sodium(DS), baicalin, dobesilate calcium 2,5-dihydroxybenzene sulfonate(DCDS) and camptotheciri at glassy carbon electrode and modified electrode were studied by many electroanalytical methods, and some new methods for quantitative determination of organic medicament above-mentioned were presented. These studies have important-significance to develop new analytical method for organic medicament, enrich the contents of electrochemistry, and it can also offer the basis for biomedicine analysis. This thesis consists of four chapters, and author's main contribution is as follows:1. Adsorptive mode of DDSS, DS, and baicalin at glassy carbon electrode was studied, and redox mechanism was suggested by combining UV-spectrum and some techniques of electrochemistry. The experimental results indicated that adsorptive mode of three compounds above-mentioned belonged to the Frumkin type isotherm. The reaction active group of DDSS and DS is hydroxide (-OH) at 4 ' position of their molecules. At glassy carbon electrode, the hydroxide is firstly oxidized to a free radical (-0*) by losing one electron and one proton, and then a subsequent chemical reaction happened. In addition, two hydroxides in 5 and 6 position of baicalin molecule could be oxidized to carbonyls involving two electrons and two protons.2. Voltammetric characteristics and oscillographic behavior of DCDS were investigated, and a differential pulse anodic voltammetry for determination of DCDS in capsule was presented. The experimental results showed that the redox reaction that DCDS is oxidized to 2-sulfo-1, 4-benzoquinone at carbon electrode or mercury electrode is completely reversible. The linear range between concentration of DCDSand pulse peak height is from 2.2 X10-8 to 3.4 X10-6 mol/L with a detection limit of 1.1 X 10-8 mol/L. Determination result for DCDS in capsule obtained by differential pulse anodic voltammetry are accordant with that obtained by HPLC.3. To study its electro-catalyzation function for camptothecin, an ascorbic acid modified electrode was successfully prepared. The experimental results indicated that the determination sensitivity for camptothecin obtained by ascorbic acid modified electrode is as 20 times as that obtained by the bare electrode.