Amperometric hydrogen peroxide biosensor with silica sol-gel/chitosan film as immobilization matrix

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 muM 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.