Influence of Nafion on detection of glucose on a polycrystalline gold electrode from alkaline and saline solutions

Abstract

The electrooxidation of glucose on a polycrystalline gold electrode from alkaline and saline solutions was investigated. The influence of Nafion on the oxidation of glucose under the same conditions was also studied. The presence of Nafion on the surface of a polycrystalline gold electrode decreased the rate of glucose oxidation in alkaline solution. The sensitivity of glucose determination was diminished. However, processes occurring at the electrode were clearly separated. Stable cyclic voltammogram of a polycrystalline gold electrode was obtained in saline solution. The addition of glucose to saline solution initiated the reaction of gold dissolution. The presence of Nafion on the electrode surface prevented the formation of hydrous gold oxide. The addition of glucose to saline solution led to the passivation of the Nafion-covered gold electrode. The gold electrode pretreated in alkaline solution and covered with Nafion was used for glucose detection in saline solution. The linear behavior was obtained in the concentration range from 2 to 10 mM with the slope of 0.0015 mA/mM and the coefficient of 0.95. The chronoampermetric response of the pretreated gold electrode covered with Nafion was also tested.