A Rapid Anodic Fabrication of Nanoporous Gold in NH4Cl Solution for Nonenzymatic Glucose Detection

Abstract

One-step anodic potential step treatment of pure gold electrode in HCl or KCl solution is a simple and efficient strategy to form nanoporous structures. This method has now been employed in NH4Cl solution to fast construct nanoporous gold (NPG) electrode for nonenzymatic glucose detection. The surface area of as-prepared NPG was greatly increased by adding the proper amount of NH2OH·HCl as anodic depolarizer and reducing agent, resulting in the improved sensitivity for glucose determination. In situ Raman spectroscopy confirmed the existence of gold oxides, which is vital for the formation of NPG during anodization in Cl−-containing electrolyte. The electrocatalytic oxidation of glucose on the NPG and the corresponding amperometric detection of glucose was investigated. Comparing with our prior published one (Biosens. Bioelectron., 2011, 26, 3555–3561), NPG reported here exhibited increased sensitivity and wider linear range for glucose detection in phosphate buffered saline (PBS) solution in the presence of Cl−; a broad linear relationship from 0.2 to 16 mM (corresponding to 0.036 to 2.7 g L−1) at −0.4 V and a high sensitivity of 3625 μA mM−1 cm−2 at 0.2 V was achieved in 0.1 M NaOH. The good selectivity and reproducibility make NPG a promising nonenzymatic glucose sensing platform.