Individual and Simultaneous Voltammetric Determination of Cd(II), Cu(II) and Pb(II) Applying Amino Functionalized Fe3O4@Carbon Microspheres Modified Electrode

Amino-functionalized Fe3O4@carbon microspheres (NH2-Fe3O4@C) were prepared and the electrochemical sensor was constructed using NH2-Fe3O4@C modified glassy carbon electrodes (GCE) to determine toxic heavy metals in aqueous solution. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the structure and phase of NH2-Fe3O4@C. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results indicate that NH2-Fe3O4@C modified GCE possesses large active area and excellent electron transfer. Under optimized electrochemical condition, Cd(II), Pb(II) and Cu(II) were determined using NH2-Fe3O4@C modified GCE. The electrode through amino functionalization exhibits higher sensitivity and lower detection limit toward Cd(II) and Cu(II) due to the acid-base pairing interaction between the electron-rich -NH2 ligand and the electron-deficient heavy metal ions. Compared with other similar results reported in the literature, the NH2-Fe3O4@C modified electrode exhibits wider linear response range while with comparable lower detection limit. It also exhibits excellent stability, reproducibility and anti-interference ability.