Direct electrocatalytic oxidation of nitric oxide and reduction of hydrogen peroxide based on alpha-Fe2O3 nanoparticles-chitosan composite.

alpha-Fe(2)O(3) nanoparticles prepared using a simple solution-combusting method have been dispersed in chitosan (CH) solution to fabricate nanocomposite film on glass carbon electrode (GCE). The as-prepared alpha-Fe(2)O(3) nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM). The nanocomposite film exhibits high electrocatalytic oxidation for nitric oxide (NO) and reduction for hydrogen peroxide (H(2)O(2)). The electrocatalytic oxidation peak is observed at +0.82 V (vs. Ag/AgCl) and controlled by diffusion process. The electrocatalytic reduction peak is observed at -0.45 V (vs. Ag/AgCl) and controlled by diffusion process. This alpha-Fe(2)O(3)-CH/GCE nanocomposite bioelectrode has response time of 5 s, linearity as 5.0 x 10(-7) to 15.0 x 10(-6) M of NO with a detection limit of 8.0 x 10(-8) M and a sensitivity of -283.6 microA/mM. This alpha-Fe(2)O(3)-CH/GCE nanocomposite bioelectrode was further utilized in detection of H(2)O(2) with a detection limit of 4.0 x 10(-7) M, linearity as 1.0 x 10(-6) to 44.0 x 10(-6) M and with a sensitivity of 21.62 microA/mM. The shelf life of this bioelectrode is about 6 weeks under room temperature conditions. Copyright 2010 Elsevier B.V. All rights reserved.