Octadecylamine-functionalized graphene vesicles based voltammetric sensing of hydroquinone

The study reports one strategy for synthesis of octadecylamine-functionalized graphene vesicles (OA-GV). Firstly, citric acid was mixed with octadecylamine and subsequently heated at 180 degrees C for 4 h to form a graphene oxide that consists of small graphene sheets with a good amphiphilic structure. The graphene oxide was dispersed in water and strongly mixed with toluene to produce a toluene-in-water Pickering emulsion. The graphene oxide sheets in the emulsion were orderly self-assembled into graphene oxide micro-gel in the toluene/water interface. Followed by freeze-drying and thermal reduction in H-2 at 400 degrees C for 5 h. The as-synthesized OA-GV shows a vesicle-like architecture constructed by ultrathin graphene sheets. The use of small graphene oxide sheets and their self-assembly effectively avoid the serious agglomeration of graphene sheets and leads to a large specific surface area (1853.2 m(2) g(-1)). The introduction of octadecylamine creates highly electrochemical activity and helps to achieve a significant synergy in electrochemistry between OA-GV and hydroquinone. The sensor based on OA-GV exhibits an ultrahigh sensitivity towards hydroquinone. The differential pulse voltammetric peak current linearly increases with the increase of hydroquinone in the range of 0.01-1.0 nM with the detection limit of 0.0049 nM (S/N=3). The method has been successfully applied to determination of hydroquinone in water samples.