Synthesis and Characterization of Nanoporous Gold Film for the Sensitive Detection of Glucose

facile alloy-dealloy technique was employed to prepare a nanoporous gold (NPG) electrode that demonstrated high sensitivity toward glucose oxidation. The gold electrode was covered firmly with thin film of tin and subsequently heated at 300 degrees C to synthesize Sn-Au alloy. The dealloying step was performed in a mixed solution of hydrochloric acid and hydrogen peroxide, where Tin in the alloy was selectively oxidized to leave the NPG structure. X-ray powder diffraction (XRD) and scanning electronic microscopy (SEM) and electrochemical methods were used to characterize them. The direct electrocatalytic oxidation of glucose in pH 7.4 phosphorate buffer solution (PBS) at the nanoporous gold film has been investigated. It was found that the NPG exhibited electrocatalytic activity to glucose oxidation and could be used for the development of nonenzymatic glucose sensor. The sensitivity of the sensor to glucose oxidation was 0.00651 (+/- 0.00004) mu A/mu M with a detection range of 5-1000 mu M, and a detection limit of 5.0 (+/- 0.3) mu M (signal-to-noise ratio of 3). Long-term stability, high sensitivity and selectivity as well as good reproducibility and high resistivity towards electrode fouling resulted in an ideal inexpensive amperometric glucose biosensor applicable for complex biological matrices auch as blood serum.