α-Fe2O3 nanorod arrays for bioanalytical applications: nitrite and hydrogen peroxide detection

A novel biosensor was fabricated by the anodic electrochemical deposition of alpha-Fe2O3 nanorod (NR) arrays onto an iron substrate in an aqueous (NH4)(2)Fe(SO4)(2) solution. The NR array electrode exhibits superior electroactivity for the oxidation of nitrite and the reduction of hydrogen peroxide. A wide linear response range (2 x 10(-7)-5 x 10(-3) M), high sensitivity (135.36 mu A mM(-1) cm(-2)) and low detection limit (1 x 10(-7) M) were obtained for the oxidation of nitrite. This alpha-Fe2O3 NR array electrode was further utilized in the detection of H2O2 with a detection limit of 2 x 10(-7) M, linearity of 5 x 10(-7)-3 x 10(-3) M and a sensitivity of 77.30 mu A mM(-1) cm(-2). The stability and selectivity of the biosensor were also evaluated. The results indicate that the alpha-Fe2O3 NR arrays are efficient bifunctional sensors, with potential applications in biological and medical systems.