Architecture of Fe3O4–graphene oxide nanocomposite and its application as a platform for amino acid biosensing

The Fe3O4–graphene oxide (Fe3O4–GO) nanocomposites were prepared by a chemical co-precipitation of FeSO4, FeCl3,·NH3·H2O and GO. The Fe3O4–GO was characterized by scanning electron microscopy, X-ray powder diffraction, thermogravimetric analysis and electrochemical method. The results showed that ultrafine Fe3O4 nanoparticles was prepared and densely assembled on GO nanosheets. The Fe3O4–GO exhibits large surface area and high catalysis towards the oxidation of cysteine and N-acetyl cysteine, which could be used for cysteine and N-acetyl cysteine sensing with a wide linear range (0.5–13.5 mM for cysteine and 0.12–13.3 mM for N-acetyl cysteine) and low detection limit (56 μM for cysteine and 25 μM for N-acetyl cysteine). The excellent catalytic activity, high sensitivity and good stability made such Fe3O4–GO nanocomposites to be promising nanomaterials for constructing nonenzymatic sensor.

► Fe3O4–GO nanocomposites are prepared.
► Fe3O4–GO exhibits high catalysis towards the oxidation of cysteine and N-acetyl cysteine.
► Mediating Fe3O4–GO on a glassy carbon electrode developed an electrochemical sensor.
► The sensor showed high selectivity and stability.