Development of an electrochemical sensor based on 2 mercaptoethansulfonate - self-assembled monolayer for detection of copper ions

Copper is micronutrient element and plays an important role in the bone formation together with certain proteins and enzymes. However, it can be considered as a dangerous contamination when not maintained at the appropriate physiological concentration. Therefore, simple, reliable, selective and sensitive methods for Cu2+ monitoring are important for environmental safety and health [1]. In this project, an electrochemical sensor based on the self assembled monolayers (SAMs) was designed to detect copper ions. The SAM electrode field in recent years has grown vastly in electrochemicals [2]. Many self assembly systems have been designed, but monolayers of thiolates on gold electrodes are probably the SAMs most studied to date. The use of SAM-modified electrodes to improve the selectivity of gold electrodes has been reported. The mercapto group (−SH group) has a high ability to adsorb heavy-metal ions, this unique characteristic reveals that the group has potential application in the removal of heavy-metal ions from industrial wastewater [3]. In this work, voltammetric behavior of Cu2+ on a gold electrode modified with the SAMs of 2-mercaptoethansulfonate has been investigated. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) was used to determine the electrode surface modification process. The anodic peak current increases linearly with the concentration of Cu2+ in the range of 2×10-8 to 2×10-6 M. The detection limit is 7.5×10-9 M. This method will be applicable to the determination of Cu2+ in industrial wastewater, and the good recovery of Cu2+ is obtained.