Sensitive and Selective Determination of Cu2+ Using Self-Assembly of 4-Mercaptobenzoic Acid on Gold Nanoparticles
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Cu2+ is a bio-accumulative and toxic environmental pollutant, so its sensitive and selective detection is of great importance. In this work, gold nanoparticles were electrochemically deposited on fluorine-doped tin oxide and characterized by scanning electron microscope and cyclic voltammetry. 4-Mercaptobenzoic acid (4-MBA), which contained carboxyl chelator, was self-assembled on the surface of gold nanoparticles through S–Au bond. The strong chelation of Cu2+ with 4-MBA formed a stable Cu2+-4-MBA complex, which was confirmed by energy-dispersive X-ray spectroscopy. Square wave voltammetry was applied to determine the concentration of Cu2+. Under optimized condition, the oxidation peak current was proportional to the concentration of Cu2+ in the range of 10–1500 nM with limit detection of 8 nM. The proposed electrochemical sensor showed excellent selectivity towards Cu2+. In addition,the applicability of the developed sensor was evaluated by determining the concentrations of Cu2+ in river water samples, which were consistent with the results of inductively coupled plasma mass spectroscopy.
Keywords4-Mercaptobenzoic acid Self-assembly Electrochemical sensor Cu2+
This research is supported by the National Natural Science Foundation of China (Nos. 61571278, 61571280).
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