Amperometric enzymatic determination of bisphenol A using an ITO electrode modified with reduced graphene oxide and Mn3O4 nanoparticles in a chitosan matrix

The authors describe a nanostructured hybrid platform for amperometic determination of the plasticizer bisphenol A (BPA). It consists of two dimensional sheets of reduced graphene oxide (rGO) that are decorated with Mn3O4 nanoparticles. The enzyme tyrosinase was immobilized on the surface of the hybrid nanosheets placed on an ITO electrode. The larger surface area and enhanced charge transfer properties of the rGO/Mn3O4 nanosheets provide a synergistic effect that results in excellent sensing performance including fast electron transfer kinetics, high electroactivity, good reproducibility and selectivity compared to other electrodes of that kind. Figures of merit include a sensitivity of 93.2 μA⋅nM−1⋅cm−2, an analytical range that extends from 0.01 to 100 μM, and a 10 nM lower detection limit. Its long-term stability of 8 weeks suggests the use of such enzyme electrodes as potential tools in clinical diagnostics.