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.