Electrochemical behavior of Azure A/gold nanoclusters modified electrode and its application as non-enzymatic hydrogen peroxide sensor

A novel non-enzymatic hydrogen peroxide sensor was developed using Azure A/gold nanoclusters modified graphite electrode. The method of preparation of Azure A/gold nanoclusters was simple and it was characterized by UV–visible spectroscopy, field emission scanning electron microscopy (FESEM) and confocal Raman microscopy. The electrochemical properties of Azure A/gold nanoclusters modified graphite electrode was characterized by cyclic voltammetry. In 0.1 M H2SO4 the modified electrode showed redox peaks which correspond to the redox behavior of gold nanoparticle. In 0.1 M PBS the modified electrode exhibited well defined redox peaks with the formal potential of −0.253 V which is analogous to the redox reaction of Azure A. The results have shown that the gold nanoclusters has reduced the formal potential of Azure A and enhanced the current due to the fast charge transfer kinetics. Also the modified electrode showed an enhanced electrocatalytic activity towards the reduction of H2O2 in the concentration range of 3.26 × 10−6 M to 3.2 × 10−3 M with a detection limit of 1.08 × 10−6 M (S/N = 3). The proposed electrode exhibited good stability and reproducibility, and it has the potential application as a sensor for other biologically significant compounds.