| Chemically modified electrodes (CME) are paied more and more attention to by the researchers in environmental chemistry and life sciences. Electro-catalysis of CME is important application and widely applied in analytic chemistry. Electrocatalysis studies of small molecular inorganic, organic and biologic matters based on chemically modified electrodes are valuable in clinical diagnosis, bromatology, and environmental monitoring and biochemical analysis. This thesis involves the following subjects relating to electrocatalysis oxidation of catechol, hydrogen peroxide, dopamine and ascorbic acid.(1) In chapter 1, gold nanoparticle-modified glassy carbon electrodes (NG/GCE) were prepared by two different methods. (a) Prepared gold colloid was modified on glassy carbon electrode by potential static deposition methode, and modified electrode was denoted as NG/GCE1. (b) HAuCl4 was reduced as gold nanoparticles on glassy carbon electrode directly based on under potential deposition technique (UPD) and modified electrode was denoted as NG/GCE2. These modified electrodes were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The resulting electrodes showed excellent electrocatalytic activity towards the oxidation of catechol, making oxidation peak potential negatively shift greatly and oxidation peak current increase obviously. The catalytic oxidation current of catechol at NG/GCE1 and NG/GCE2 vs their concentrations have good linear relations in the range of 2.0 × 10-61.2× 10-2 mol·L-1 and 5.0 × 10-6 4.2 × 10-3 mol·L-1 under the optimal operations, respectively. Moreover, the studied electrode exhibited high sensitivity and good reproducibility.(2) In chapter 2, a modified electrode was fabricated based the electropolymerization of a thin indigo carmine (IC) film on glassy carbon electrode (GCE). The activity of the modified electrode towards dopamine (DA) and ascorbic acid (AA) was characterized with electrochemical methods.
|
PDF Full Text Request