A hydrogen peroxide biosensor based on peroxidase activity of hemoglobin in polymeric film.

A Hydrogen peroxide (H2O2) biosensor, based on hemoglobin (Hb) and ortho-phenylenediamine (o-PD) gold electrode, was fabricated. Hb was immobilized onto the electrode surface by electrochemical polymerize method with o-PD. The designed biosensor showed a well defined redox peak which was attributed to the direct electrochemical response of Hb. The immobilized Hb exhibited an excellent electrocatalytical response to the reduction of hydrogen peroxide, enabling the sensitivity determination of H2O2. Factors and performances such as pH, potential, influencing the designed biosensor, were studied carefully. The amperometric detection of H2O2 was carried out at -300 mV in phosphate buffer solution (PBS) (0.1 M) with pH 6.0. This biosensor showed a fast amperometric response (less then 5 s) to H2O2. The levels of the (Relative standard deviation) RSDs (< 3.5%) for the entire analyses reflected a highly reproducible sensor performance. Using the optimized conditions, the detection limit of the biosensor was 1 x 10(-7) M and linear range was from 5 x 10(-6) to 1.25 x 10(-4) M. In addition, this sensor showed long-term stability and good sensitivity.