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.