Nonenzymatic glucose sensor based on glassy carbon electrode modified with a nanocomposite composed of nickel hydroxide and graphene

We report on a nonenzymatic glucose sensor based on a glassy carbon electrode that was electrochemically modified with a nanocomposite prepared from nickel hydroxide and graphene. Scanning electron microscopy revealed that the nickel hydroxide in the nanocomposite was present in the form of a nanostructure of three-dimensional spheres that were assembled by many densely arranged nanosheets. The electrocatalytic activity of the electrode toward the oxidation of glucose was investigated by chronoamperometry. The current response was linearly related to the glucose concentration in the range from 1 to 10 mu M, with a sensitivity of 494 mu A mM(-1) cm(-2) and a correlation coefficient of 0.9990, and a second range (from 10 to 1000 mu M with a sensitivity of 328 mu A mM(-1) cm(-2) and a correlation coefficient of 0.9990). The detection limit was 0.6 mu M at a signal-to-noise ratio of 3, and the response time was as short as 2 s.