▎ 摘　　要

In this paper, a novel graphene/cobalt phthalocyanine composite film was prepared by layer-by-layer (LBL) technique which for the first time used the activated positively charged glassy carbon electrode (A-GCE) as the substrate. The surface morphology of graphene/cobalt phthalocyanine composite film was characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). It is found that graphene/cobalt phthalocyanine composite film modified GCE exhibits good catalytic activity toward the oxidation of nitrite. The oxidation current barely decreases in consecutive CV test. Furthermore, the modified GCE shows long-term stability after 70 days. The super good stability can be attributed to the immobilization and dispersion of electroactive cobalt phthalocyanine by graphene, and using A-GCE as substrate which can enhance the interaction force between GCE and electroactive cobalt phthalocyanine. The nitrite sensor shows rather low detection limit of 0.084 mu M at a signal-to-noise ratio = 3 (S/N = 3). (C) 2012 Elsevier Ltd. All rights reserved.