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The polyethylenimine (PEI) or ethanediamine (EDA) has been employed to adsorb metal ions. However, both the combination of CoFe 2 O 4 -reduced graphene oxide (rGO) with PEI or EDA for the analysis of Cu(II) determination and interaction mechanism towards copper ion by electrochemical method and X-ray photoelectron spectroscopy (XPS) are, to the best of our knowledge, unexplored. The amine functionalized rGO/CoFe 2 O 4 composite were synthesized through a one-pot method, and characterized by electrochemical method and different spectra such as FT-IR, XRD, XPS, etc. The lowest detection limit with 20 pM (3δ method) and sensitivity with 0.39 μA/nM towards Cu(II) was obtained at PEI/rGO/CoFe 2 O 4 modified electrode under optimized condition. The characteristics of Cu(II) on the amine-group functionalized CoFe 2 O 4 /rGO composite were investigated by cyclic voltammetry and XPS. The shifts of O and N peaks of PEI (or EDA)/CoFe 2 O 4 /rGO preconcentrating Cu(II) showed the synergistic effect of CoFe 2 O 4 /rGO and PEI (or EDA) to Cu(II). The analysis indicated that the interaction between the composite and Cu(II) was adsorption control process. The proposed electrode was also employed to the analysis of real soil sample. Thus, the proposed method and interaction mechanism analysis based on adsorption interaction could provide a reference for further investigate the pollution of metal ions. [ABSTRACT FROM AUTHOR]

An amine-Fe3O4modified glassy carbon (GC) electrode was constructed for detecting Pb(II) ions in wastewater. The electrode was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Square wave anodic stripping voltammetry (SWASV) was used to detect the Pb(II), and the detection limit of Pb(II) was 0.15 µM. The sensitivity of the electrode to detect Pb(II) was about 10.07 µA/µM, with a correlation coefficient of 0.991, which was approximately 10 times bigger than that of a pure Fe3O4modified electrode. The electrode also showed good selectivity and stability. This results indicated that the amine-magnetite material could have some potential applications in heavy metal ions detection in wastewater. [ABSTRACT FROM PUBLISHER]