A hydrogen peroxide sensor based on colloidal MnO 2/Na-montmorillonite

Abstract

A novel amperometric sensor for the determination of hydrogen peroxide was prepared based on the enhanced oxidation of H 2O 2 at a glassy carbon electrode modified with colloidal MnO 2–Na-montmorillonite (nano-MnO 2/Na-Mont/GCE). The montmorillonite has been devised to support and dispense the MnO 2 nanoparticles. Scanning electron microscopy images (SEM) showed that the MnO 2 nanoparticles were homogeneously dispersed in the colloidal Na-montmorillonite. This colloidal dispersion was dried to form a uniform film when added to the surface of GCE. The voltammetric results showed that MnO 2 nanoparticles could effectively catalyze the oxidation of H 2O 2. The dependence of the response current on H 2O 2 concentration was explored under optimal conditions, and an excellent linear relationship was obtained in the range from 5 × 10 − 7 to 7.5 × 10 − 3 M with a minimum detectable concentration of 1.5 × 10 − 7 M. This sensor has been applied to measure trace concentration of hydrogen peroxide in samples of hair dye.