Reagentless amperometric determination of hydrogen peroxide by silica sol-gel modified biosensor

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 mu mol dm(-3) with a sensitivity of 0.067 mu A mu mol(-1) (correlation coefficient 0.996). Based on a signal-to-noise ratio of 3, the detection limit of the biosensor is 0.6 mu mol 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.