Amperometric hydrogen peroxide biosensor based on immobilization of peroxidase in chitosan matrix crosslinked with glutaraldehyde

A new enzymatic amperometric biosensor for hydrogen peroxide (H2O2) was dev eloped via an easy and effective enzyme immobilization method using chitosa n film crosslinked with glutaraldehyde. Horseradish peroxidase was immobili zed on the surface of a carbon paste electrode. Hexacyanoferrate(II) was pr esent in the solution as a mediator. The biosensor exhibited a relatively f ast response of less than 10 s and produced currents linearly related to th e H2O2 concentration in the range of 4.7 x 10(-5) to 2 x 10(-3) M. The bios ensor had very good stability as it retained ca. 85% activity after 30 d of storage in a phosphate buffer at 4 degrees C. The effect of the chitosan f ilm thickness and various operational parameters were optimized. The applic ability of this biosensor was demonstrated with the analysis of real sample s and the results obtained by this biosensor corroborated well with the cla ssical iodometric titration method.