Preparation And Application Of Graphene Based Electrochemical Sensor In The Direction Of Bisphenol A

Graphene has been extensively investigated in the fields ofelectrochemical sensors due to its unique spatial structure, largespecific surface area, good thermal stability, excellent mechanical,electrical and other properties. However, graphene gathered easily andwas difficult to disperse in water and general solvent, which causegreat trouble to its extensive application. Therefore, thefunctionalization of graphene nanomaterials in the development ofelectrochemical biosensors was emphasized. In this paper, thefunctionalized graphene was obtained by noncovalent interactions andchemical doping methods, and then the functionalized graphenemodified electrodes were used for the direction of bisphenol A. Themain contents are as follows:(1) The functionalized graphene oxide was achieved by thehighly delocalized π-conjugated system of graphene oxide and the πelectron of melamine through π-π interaction. The layer spacing of offunctionalized graphene oxide expanded from original8.4to9.0,illustrateing that melamine is intercalated between the graphene oxidelayers. Additionally, the structure of this composite wascharacteristiced by SEM, TEM, FT-IR spectroscopy. UV-vis spectrumof melamine shift apparently as melamine functionalized grapheneoxide, proving that it’s not a simple physical mixture of melamine andgraphene oxide, the nanocomposite was formed via the π-πnoncovalent interaction.(2) Graphene/melamine (RGO/M) nanocomposite was fabricatedby anchoring melamine molecule on the surface of graphene sheets.Based on the high adsorption capacity and unique electronic properties of graphene as well as on the electrostatic attractionbetween protonated melamine and negatively charged bisphenol A(BPA), a novel electrochemical sensor for determining endocrinedisruptor BPA in water was fabricated by depositing RGO/Mnanocomposite on the surface of glassy carbon electrode (GCE). Theelectrochemical sensor exhibited a wider linearity range of0.01-200μM with a low detection limit of4nM. This fresh sensor wassuccessfully applied to the determination of BPA extracted fromreal plastic samples(3) Nitrogen doped graphene was fabricated by hightemperature calcination method, melamine was nitrogen source. Thenitrogen doped graphene/melamine (N-g/M) was fabricated by π-πstacking interactions between nitrogen doped graphene and melamine.The N-g/M nanocomposite was used to modify glassy carbonelectrode for the determination of bisphenol A. It was found that thefabricated sensor had benign electrocatalytic activity to the oxidationof BPA. The detection limit was0.8nM (S/N=3), which was superiorto some other obtained sensors. This fabricated sensor wassuccessfully applied in the determination of BPA in real plasticsamples with a recovery range of97101%. Compared with manyother reported electrochemical sensors, our new sensor possesseshigher sensitivity and faster response.