α-Fe2O3nanorod arrays for bioanalytical applications: nitrite and hydrogen peroxide detection

Abstract

A novel biosensor was fabricated by the anodic electrochemical deposition of α-Fe₂O₃ nanorod (NR) arrays onto an iron substrate in an aqueous (NH₄)₂Fe(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 × 10⁻⁷–5 × 10⁻³ M), high sensitivity (135.36 μA mM⁻¹ cm⁻²) and low detection limit (1 × 10⁻⁷ M) were obtained for the oxidation of nitrite. This α-Fe₂O₃ NR array electrode was further utilized in the detection of H₂O₂ with a detection limit of 2 × 10⁻⁷ M, linearity of 5 × 10⁻⁷–3 × 10⁻³ M and a sensitivity of 77.30 μA mM⁻¹ cm⁻². The stability and selectivity of the biosensor were also evaluated. The results indicate that the α-Fe₂O₃ NR arrays are efficient bifunctional sensors, with potential applications in biological and medical systems.