Hydrogen peroxide biosensor based on the direct electrochemistry of myoglobin immobilized on silver nanoparticles doped carbon nanotubes film

A novel H2O2 biosensor has been fabricated based on the direct electrochemistry and electrocatalysis of myoglobin (Mb) immobilized on silver nanoparticles doped carbon nanotubes film with hybrid sol-gel techniques. A pair of redox peaks with peak separation of 160 mV and formal potential of -0.295 V was observed at this composite film, corresponding to the direct electrochemistry of Mb. The heterogeneous rate constant was estimated to be 0.41 s(-1). Under optimum conditions, the amperometric determination of H2O2 was performed with a linear range of 2.0 x 10(-6) -1.2 x 10(-3) mol L-1 and a detection limit of 3.6 x 10(-7) mol/L (S/N = 3). The Michealis-Menten constant was also estimated to be 1.62 mmol L-1. The proposed biosensor showed favorable reproducibility, stability, selectivity and accuracy, and has been used to determine H2O2 in real samples with favorable recoveries. (C) 2008 Elsevier B.V. All rights reserved.