Abstract
This study aims to develop a modified multiwalled carbon nanotubes paste electrodes based fenchone azine ligand complexes for detecting copper, nickel and mercury. The fenchone diazine ligand complexes were characterized by using nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy and transmission electron microscopy. The electrochemical properties of the modified electrodes were determined using square wave stripping voltammetry, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that under optimal conditions, the electrodes showed a linear range between 0.1 nM and 1.0 µM, 10 nM and 1.0 µM, 5.0 µM and 0.1 mM with the limit of detection of 80 pM, 7.4 nM and 3.7 µM for detection of copper, nickel and mercury respectively. The interferences from Ba2+, Ca2+, Cd2+, Ce3+, Co2+, Cu2+, Pb2+, Mn2+, Mg2+, Ni2+, Sr2+ and Zn2+ were negligible. Cyclic voltammetry and electrochemical impedance spectroscopy indicated that the charge transfer at the electrode-solution interface was excellent. The proposed electrodes were successfully applied for detection of copper, nickel, and mercury in wastewater samples, vegetables, and skin lightening creams, respectively. In conclusion, the developed modified electrodes are able to detect copper, nickel and mercury. By implication, the developed electrodes can be used as a suitable alternative for the determination of copper, nickel and mercury because it has characteristics such as sensitivity, selectivity and high reproducibility.