Amperometric enzyme biosensor for hydrogen peroxide via Ugi multicomponent reaction

A novel strategy based on the Ugi multicomponent reaction was employed for immobilizing horseradish peroxidase on sodium alginate-coated gold electrode. The electrode was employed for constructing an amperometric biosensor device using I mM hydroquinone as electrochemical mediator. The electrode showed linear response (poised at -300 mV vs Ag/AgCl) toward H2O2 concentration between 70 mu M and 8.8 mM at pH 7.0. The biosensor reached 95% of steady-state current in about 12 s and its sensitivity was 33.8 mA/M cm(2). The electrode retained full initial activity after 30 days of storage at 4 degrees C in 50 mM sodium phosphate buffer, pH 7.0. (C) 2007 Elsevier B.V. All rights reserved.