A direct 'touch' approach for gold nanoflowers decoration on graphene/ionic liquid composite modified electrode with good properties for sensing bisphenol A

In the present work, a direct “touch” method was developed for attaching AuNPs with clean surface on the graphene-ionic liquid modified glassy carbon electrode (G-IL GCE). The morphology and composition of the thus-prepared AuNPs on G-IL GCE were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. The results showed that AuNPs with interesting flower-like shapes are well dispersed on the G-IL film. Significantly, as it is a surfactant-free synthesis, the AuNPs are very clean and can be directly modified on a G-IL GCE without any pre-treatments. Comparing with the bare or even various AuNPs-G-IL mixtures modified GCEs, the proposed sensor exhibit better electrochemical activity with a higher peak current and a lower overpotential towards bisphenol A (BPA) oxidation. After optimization, a good linear relationship between current response and the concentration of BPA in the range of 0.01–1 and 1–60 μM were obtained, and the detection limit was as low as 4.8 nM. To testify the reliability, the thus-prepared AuNPs/G-IL GCE was used for determining the concentration of BPA in disposable paper cups, plastic bottles and noodles cups.