| Graphene have been widely applied in electrochemical biosensors field as a decorative material due to its high mechanical strength, excellent conductivity,specific surface area. In this paper, a water-soluble cationic cobalt phthalocyanine was used to modify the surface of reduced graphene oxide （rGO） and the obtained nanocomposite material, which showed good dispersibility in water, was further used to modify glassy carbon electrode. The electrocatalytic properties of the decorated electrode was studied in detail.The main work is as follows:（1） Nanocomposites ImCoPc/RGO were prepared by electrostatic and π-πinteraction between cobalt phthalocyanine and rGO. The structure and morphology of the obtained nanocomposite were characterized by UV-Vis absorption spectroscopy, red-infrared absorption spectroscopy and scanning electron microscopy （SEM）. Then, ImCoPc/RGO/GCE modified electrode was constructed by means of dropping the aqueous solution of the nanocomposite on the surface of the glassy carbon electrode. The electrocatalytic properties of the obtained electrode for Dopamine （DA） and nitrite were fully studied by cyclic voltammetry（CV） and differential pulse voltammetry （DPV）. The results showed that the modified electrode can selectively detect dopamine under the condition of dopamine and ascorbic acid coexistence. The minimum detection limit was 0.057μM and the detection range was 10～800 μM with a high sensitivity of 83μA·mM-1. Moreover, this electrode was also sensitive for the detection of nitrite.The detection range was 3～120μM and the sensitivity was 28.16 μA·mM-1.Moreover, the ImCoPc/RGO/GCE electrode exhibited excellent stability and reproducibility.（2） Multilayer composite films （ImCoPc/RGO）n （n=1～6） were fabricated on the surface of glassy carbon electrode by layer by layer self-assembly technique and the obtained electrode were characterized by CV and electrochemical impedance spectroscopy. Its electrocatalytic property for nitrite oxidation was investigated and the results showed that the multilayer film （ImCoPc/RGO）4 exhibited the highest catalytic activity. The minimum detection limit was 15μM and the detection range from 0.1～1.4 mM and the sensitivity was 2.787 μA·mM-1 for nitrite. In addition, the （ImCoPc/RGO）4/GCE electrode exhibited excellent stability and reproducibility. |
