A glassy carbon electrode modified with nitrogen-doped reduced graphene oxide and melamine for ultra-sensitive voltammetric determination of bisphenol A

A composite was prepared at room temperature from nitrogen-doped reduced graphene oxide (N-rGO) and melamine via π-interaction. An ultra-sensitive electrochemical sensor for the determination of trace levels of bisphenol A (BPA) was obtained by coating a glassy carbon electrode (GCE) with the composite. The structure and morphology of composite were characterized by FTIR, Raman, XRD, XPS, SEM and TEM. Because of the synergetic effects of N-rGO and melamine, the modified GCE displays considerably enhanced sensitivity to BPA. The voltammetric response, typically measured at a peak of 0.48 V (vs. SCE) is linear in the 0.05 to 20 μM BPA concentration range, and the detection limit is 0.8 nM (at S/N = 3). The sensor is reproducible, stable and selective. It was applied to analyze baby bottles, drinking cups, mineral water bottles and shopping receipts that were spiked with BPA, and the recoveries reached 99.1–101.4%.