Amperometric Biosensor For Hydrogen Peroxide Based On Hemoglobin Entrapped In Alsio4 Sol-Gel Film
An unmediated hydrogen peroxide sensor is designed by employing a hemoglobin- AlSiO4 sol-gel film modified electrode. Hemoglobin exhibits direct (unmediated) electrochemistry at the modified electrode. Both Hb and Hb entrapped AlSiO4 sol-gel films were characterized in details by scanning electron microscopy, Fourier transformation infrared spectroscopy, X-ray photoelectron spectroscopy and electrochemical techniques. The sol-gel films are uniform porous and show a very low mass transport barrier and a regular dense distribution of Hb. AlSiO4 sol-gel matrix retains the native structure and activity of entrapped Hb and prevents the enzyme from leaking out of the film. The protein also shows elegant catalytic activity towards the electrochemical reduction of hydrogen peroxide. Consequently, a prototype hydrogen peroxide sensor is prepared. Under optimumconditions, this sensor provides a linear response over the hydrogen peroxide concentrations in the range of 1×10-6～4×10-4mol/L. The detection limit is 5×10-7mol/L. This configuration is shown to be sensitive, stable and easy to be fabricated.