Nanostructured α-Fe2O3 platform for the electrochemical sensing of folic acid

Abstract

α-Fe₂O₃ nanofibers are synthesized by a simple and efficient electrospinning method and the selective determination of folic acid (FA) is demonstrated in the presence of an important physiological interferent, ascorbic acid (AA), using the α-Fe₂O₃ nanofiber modified glassy carbon (GC) electrode at physiological pH. Bare GC electrode fails to determine the concentration of FA in the presence of a higher concentration of AA due to the surface fouling caused by the oxidized products of AA and FA. However, modification with α-Fe₂O₃ nanofibers not only separates the voltammetric signals of AA and FA by 420 mV between AA and FA, but also enhances higher oxidation current. The amperometric current response is linearly dependent on FA concentration in the range of 60–60 000 nM, and the α-Fe₂O₃ nanofiber modified electrode displayed an excellent sensitivity for FA detection with an experimental detection limit of 60 nM (1.12 × 10⁻¹⁰ M (S/N = 3)). Furthermore, the α-Fe₂O₃ nanofiber modified electrode showed an admirable selectivity towards the determination of FA even in the presence of a 1000-fold excess of AA and other common interferents. This modified electrode has been successfully applied for determination of FA in human blood serum samples.