Reduced graphene oxide nanosheets modified with plasmonic gold-based hybrid nanostructures and with magnetite (Fe3O4) nanoparticles for cyclic voltammetric determination of arsenic(III).

The authors have fabricated reduced graphene oxide nanosheets (rGO) supported with Fe3O4 nanoparticles and Ag/Au hollow nanoshells. The material was placed on a glassy carbon electrode which is shown to enable highly sensitive determination of As(III) which is first preconcentrated from solution at a potential of -0.35 V (versus Ag/AgCl) for 100 s. The electrode, typically operated at a working potential as low as 0.06 V, has a linear response in the 0.1 to 20 ppb As(III) concentration range and a 0.01 ppb detection limit. The electrochemical sensitivity is 52 μA ppb-1. The high sensitivity is assumed to be the result of various synergistic effects. The method was applied to ultratrace (0.1 ppt) determination of As(III) in real water samples. Graphical abstract The hybrid displays a wide linear response in the 0.1 to 20 ppb As(III) concentration range and a 0.01 ppb detection limit. The high sensitivity is attributed to various synergistic effects. The method was applied to ultratrace determination of As(III) in real water samples.