▎ 摘　　要

Nitrogen doped graphene (NG) was prepared by thermally annealing graphite oxide and melamine mixture. After characterization by atomic force microscopy and X-ray photoelectron spectroscopy etc., the electrochemical sensor based on NG was constructed to simultaneously determine small biomolecules such as ascorbic acid (AA), dopamine (DA) and uric acid (UA). Due to its unique structure and properties originating from nitrogen doping. NC shows highly electrocatalytic activity towards the oxidation of AA, DA and UA. The electrochemical sensor shows a wide linear response for AA. DA and UA in the concentration range of 5.0 x 10(-6) to 1.3 x 10(-3) M, 5.0 x 10(-7) to 1.7 x 10(-4) M and 1.0 x 10(-7) to 2.0 x 10(-5)M with detection limit of 2.2 x 10(-6) M, 2.5 x 10(-7) M and 4.5 x 10(-8) M at S/N = 3, respectively. These results demonstrate that NC is a promising candidate of advanced electrode material in electrochemical sensing and other electrocatalytic applications. (C) 2012 Elsevier B.V. All rights reserved.