Au–Fe(III) nanoparticle modified glassy carbon electrode for electrochemical nitrite sensor

An electrochemical sensor for the detection of nitrite was prepared by electrochemical co-deposition of Au and Fe(III) nanoparticles on glassy carbon electrode (GCE). X-ray photoelectron spectroscopy (XPS) techniques were used for characterization of the surface structure. Scanning electron micrograph (SEM) demonstrates that the films are uniform and the nanoclusters are homogeneously distributed on the GCE surface. The electrochemical behaviour of nitrite at the Au and Fe(III) nanoparticle modified electrode (Au–Fe(III)/GCE) was investigated. The chemical modified electrodes exhibited substantial electrocatalytic effect on the oxidation of nitrite anions. The current of differential pulse voltammetric peak of nitrite at the modified electrode is proportional to the concentration of nitrite over the range of 3.0 × 10−7–1.5 × 10−4 M with a detection limit of 2.0 × 10−7 M in weak acid solution. Based on a series of differential pulse amperometry experiments, a linear relationship between anodic current and nitrite concentration was attained over the range of 2.0 × 10−7–1.5 × 10−4 M with a detection limit of 1.0 × 10−7 M. The proposed method exhibited high sensitivity, good reproducibility and recovery.