Indium–tin oxide film electrode as catalytic amperometric sensor for hydrogen peroxide

Abstract

A commercial indium–tin oxide (ITO) film, deposited on a glass substrate, was investigated for its potential use as a disposable amperometric sensor for hydrogen peroxide determination in aqueous solutions. After a very simple, yet crucial, electrochemical pre-treatment of a fresh ITO film electrode, a stable and sensitive electrocatalytic response to hydrogen peroxide was exhibited. The electrocatalytic character and factors influencing hydrodynamic amperometric performance of the ITO film electrode were examined and discussed. Under optimized conditions, the amperometric signal was linearly proportional to the hydrogen peroxide concentration over the range 8.4 × 10^–5–2.1 × 10^–3 mol l^–1(2.9–71.4 mg l^–1) with a detection limit of 5.6 × 10^–1 mol l^–5 mol l^–1(1.9 mg l^–1). The electrode also displayed good reproducibility with an s_r value of 1.5% for 20 consecutive chronoamperometric measurements of 2.8 × 10^–4 mol l^–1 hydrogen peroxide.