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 developed via an easy and effective enzyme immobilization method using chitosan film crosslinked with glutaraldehyde. Horseradish peroxidase was immobilized on the surface of a carbon paste electrode. Hexacyanoferrate(II) was present in the solution as a mediator. The biosensor exhibited a relatively fast response of less than 10 s and produced currents linearly related to the H2O2 concentration in the range of 4.7 x 10(-5) to 2 x 10(-3) M. The biosensor 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 film thickness and various operational parameters were optimized. The applicability of this biosensor was demonstrated with the analysis of real samples and the results obtained by this biosensor corroborated well with the classical iodometric titration method.