Noncovalent nanohybrid of ferrocene with chemically reduced graphene oxide and its application to dual biosensor for hydrogen peroxide and choline

A nanoscale hybrid of chemically reduced graphene oxide (CRGO) with ferrocene (Fc) was prepared through π–π stacking interaction between Fc and CRGO. FT-IR, Raman spectroscopy, SEM and cyclic voltammetry were utilized to characterize the nanohybrid of Fc with CRGO (Fc-CRGO). Fc-CRGO exhibited good stability and greatly improved electron-transfer behavior. Fc-CRGO and HRP were casted on the surfaces of glass carbon electrode (GCE) with the aid of chitosan for determination of H2O2. The choline oxidase (CHOD) cross-linked with chitosan was further dropped on the surface of modified electrode for detection of choline. The excellent biosensor performance was obtained by combining the advantages of nanohybrid and enzymes. Amperometric determination for choline has been performed at a very low applied potential of −0.10 V. The linear response range was of 1.0 ∼ 400 μM with a detection limit of 0.35 μM. The current reached 95% of maximum response within 8 s.