Nonenzymatic sensor for determination of glucose modified by gold nanoparticles

In this work we prepared a sensor for the glucose determination and we subsequently characterized surface and electrochemical performance of this sensor. We prepared this sensor by a simple electrochemical deposition of gold nanoparticles on Au microelectrode. The surface morphology of this modified electrode was studied by a scanning electron microscopy and atomic force microscopy. We observed the formation of spike-like nanostructures, which were homogeneously distributed on the surface (Fig. 1), increased the surface area of electrode, and showed the best catalytic activity. We used three different methods to study performance of electrodes: cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. Modified electrode exhibited good electrocatalytic activity toward oxidation of glucose in two linear ranges from 0.1 mM to 0.5 mM and from 0.5 mM to 30 mM, high sensitivity for both linear ranges 1.7 μA/mM and 2.4 μA/mM, and stability. Moreover, the modified electrode showed a good selectivity and suitability for use in real samples. (authors)