CoFe2O4–CoFe microspheres for simultaneous electrochemical determination of trace lead(II) and cadmium(II) ions

Abstract

In this study, CoFe2O4–CoFe microspheres were synthesized using a simple hydrothermal method and treated in a furnace at a high temperature. The structure and morphology of the CoFe2O4–CoFe microspheres were well characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) pattern, and X-ray photoelectron spectroscopy (XPS). The glassy carbon electrode (GCE) modified with CoFe2O4–CoFe as an electrochemical sensor exhibited excellent electrochemical activity for the detection of both Pb(II) and Cd(II) ions via differential pulse anodic stripping voltammetry (DPASV). The related measurement conditions of the proposed electrochemical sensor were optimized by changing the deposition potential, deposition time, and pH value of the electrolyte. Under optimized conditions, the CoFe2O4–CoFe-based electrochemical sensor exhibited broad linear ranges of 5.0–400 and 5.0–320 μg L−1 with limits of detection (LODs) of 0.50 and 0.26 μg L−1 for the Cd(II) and Pb(II) ions, respectively. In addition, the results of the interference and actual water sample analyses showed that the peak currents of target ion were not strongly interfered with, by 50-times interference ions, such as Al(III), As(III/V), Ca(II), Cr(III), and Zn(II). The proposed CoFe2O4–CoFe microsphere-based electrochemical sensor can be potentially applied to detect Pb(II) and Cd(II) ions in untreated tap water and other environmental samples, simultaneously.