Amperometric hydrogen peroxide biosensor with silica sol–gel/chitosan film as immobilization matrix Original Research Article

A new type of silica sol–gel/organic hybrid composite material was developed for the fabrication of an amperometric H2O2 biosensor. This composite consists of sol–gel and the natural polymer chitosan. The composite film was used to immobilize horseradish peroxidase on a carbon paste electrode. The fabrication procedure was systematically optimized to improve the biosensor performance. Hexacyanoferrate(II) was present in the solution as an electron donor. The biosensor had a fast response of less than 10 s and linear calibration range of 2.5×10−4 to 3.4×10−3 M, with a detection limit of 3 μM based on S/N=3. The biosensor retained ca. 85% of its original activity after 30 days of storage in a phosphate buffer at 4°C.