▎ 摘　　要

In this work, the modified electrode based on composites of reduced graphene oxide/leucomethylene blue/platinum nanoparticles (rGO/LMB/PtNPs) was fabricated in-situ via an electron relay effect. Cationic dye of methylene blue (MB) was absorbed on the surface of graphene oxide (GO) with through pi-pi bond interactions. Then PtCl62- ions were self-assembled on the surface of the composites of GO/MB through Coulomb interactions. Using NaBH4 as the reducing agent, PtNPs were formed and GO was reduced to rGO. With the aid of PtNPs, MB was catalytically degraded to LMB and a rGO/LMB/PtNPs modified electrode was successfully prepared in situ. Due to the excellent electrochemical properties of rGO and the well-established assistant reductant of MB, as well as the catalytic amplifying effect of PtNPs, this as prepared rGO/LMB/PtNPs modified electrode showed excellent properties for the voltammetric determination of Fe(II) with the linear range of 0.01 to 2 mu m and a detection limit of 3 nM. This modified electrode was successfully applied to detect the content of Fe(II) in seawater.