Hydrogen peroxide biosensor based on enzyme multilayers through electrostatic adsorption

A hydrogen peroxide biosensor has been prepared, and the procedure is as follows: firstly 2, 6-pyridinedicarboxylic acid is electropolymerized onto a glassy carbon electrode to form a negatively charged surface; secondly, the positively charged polyelectrolyte poly (allylamine hydrochloride) (PAH) layer is constructed by the self-assembly technique to immobilize the negatively charged horseradish peroxidase through electrostatic adsorption; lastly, the multi-enzyme layers are fixed by the above methods and the biosensor are constructed. The effects of experimental conditions such as applied potential, mediator concentration and pH values on the electrode performance have been investigated, and the reproducibility, interferences and lifetime of the electrode are also tested. The linear response of detection of the electrode to hydrogen peroxide is in the concentration range of 4.6 x 10(-6) similar to 3.5 X 10(-3) mol/L with a detection limit of 2 X 10(-6) mol/L. The electrode was applied to the determination of recoveries of real sample with satisfactory results.