▎ 摘　　要

An electrochemical biosensor was designed by using Fe3O4@reduced graphene oxide (Fe3O4@rGO) composite as the electrode modifier. Hemoglobin (Hb) could achieve direct electron transfer on the modified electrode due to the advantages of Fe3O4@rGO such as remarkable conductivity, excellent biocompatibility and big surface area. In addition, this electrochemical biosensor (Nafion/Hb/Fe3O4@rGO/CILE) also displayed electrocatalytic performance to different substrates such as trichloroacetic acid (TCA) and sodium nitrite (NaNO2) with the detection limit as 1.67 mmol/L and 13.33 mu mol/L (3 sigma). The apparent Michaelis-Menten constant (K-M(app)) were calculated as 33.89 mmol/L and 0.44 mmol/L, respectively. Furthermore, real samples (medical facial peel solution and pickle juice solution) were analyzed by this electrochemical sensor with acceptable recoveries. Therefore, Fe3O4@rGO modified electrode was used for the construction of electrochemical sensing device with the ability to accelerate the electron communication of Hb.