▎ 摘　　要

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 -0.35V (versus Ag/AgCl) for 100s. The electrode, typically operated at a working potential as low as 0.06V, has a linear response in the 0.1 to 20ppb As(III) concentration range and a 0.01ppb detection limit. The electrochemical sensitivity is 52Appb(-1). The high sensitivity is assumed to be the result of various synergistic effects. The method was applied to ultratrace (0.1ppt) determination of As(III) in real water samples.