Highly improved electrooxidation of glucose at a nickel(II) oxide/multi-walled carbon nanotube modified glassy carbon electrode

Electrochemical oxidation of glucose on a glassy carbon disc electrode modified with multi-walled carbon nanotubes and nickel(H) oxide (GC/MWCNT/NiO) was examined by cyclic voltammetry and chronoamperometry in alkaline aqueous solutions. The results were compared with those obtained on a nickel(II) oxide modified glassy carbon electrode (GC/NiO). Both electrodes conditioned by potential cycling in a limited potential range (0.1-0.6 V vs. Ag/AgCl) in 0.10 M NaOH solution. It was found that the multi-walled carbon nanotubes improve remarkably the reactivity of nickel(II) oxide for glucose oxidation. The GC/MWCNT/NiO electrode exhibited good linear behavior in the concentration range from 2.0 x 10(-4) mol/L to 1.2 x 10(-2) mol/L for the quantitative analysis of glucose with a limit of detection of 1.6 x 10(-4) mol/L (3 sigma). The prepared electrode exhibits satisfactory stability and long life if stored at ambient conditions. Finally, it has been demonstrated that the proposed modified electrode can be successfully used for the assay of glucose in serum samples. (c) 2009 Elsevier B.V. All rights reserved.