Reagentless Amperometric Determination of Hydrogen Peroxide by Silica Sol–Gel Modified Biosensor

Abstract

A sensitive amperometric hydrogen peroxide biosensor was developed based on the immobilization of horseradish peroxidase (HRP) enzyme by the sol–gel method on a carbon paste electrode in a ‘sandwich configuration’. The configuration of the biosensor is a carbon paste/sol–gel–ferrocene/HRP/sol–gel. The biosensor has a fast response with a linear calibration range of 3–57 µmol dm^–3 with a sensitivity of 0.067 µA µmol^–1 (correlation coefficient 0.996). Based on a signal-to-noise ratio of 3, the detection limit of the biosensor is 0.6 µmol dm^–3. The lifetime, fabrication reproducibility and measurement reproducibility were evaluated and an interference study was carried out. Recoveries measured by the biosensor in various samples were satisfactory.