Silica sol-gel immobilized amperometric biosensor for hydrogen peroxide
An amperometric enzyme electrode for hydrogen peroxide was developed via an easy and effective enzyme immobilization using the sol-gel technique. The enzyme electrode comprises horseradish peroxidase (HRP) immobilized by the silica sol-gel matrix on a carbon paste electrode. Hydrogen peroxide was detected in the presence of ferrocyanide as a mediator to transfer electrons between the electrode surface and hydrogen peroxide. The effect of operational parameters, such as operating potential of the working electrode, mediator concentration, pH, and the thermal stability, were explored for optimum analytical performance by using arnperometric method. A linear calibration curve for hydrogen peroxide measuref!lent was obtained in the range of 2x10-5 to 2.6x10-3 M under the optimized conditions. The apparent Michaelis-Menten constant (¾ app) of the enzyme electrode is 4.8 mM. The performance of this enzyme electrode was also investigated using flow-injection an~ysis (FIA). The enzyme electrode retained about 60% of its activity after 35 days of storage in a phosphate buffer at 4 degree celcius.