Sensitive electrochemical detection of copper ions based on the copper(II) ion assisted etching of Au@Ag nanoparticles.

A new sensitive electrochemical sensor for the detection of copper ions based on the copper ion assisted etching of Au@Ag nanoparticles was developed in this work. Since copper ions could greatly catalyze the etching process of the silver shell of Au@Ag nanoparticles in the presence of thiosulfate solutions, leading to an obvious decrease of the linear sweep voltammetry (LSV) signals of silver, the concentration of the copper ions, therefore, can be measured. Under the optimized conditions, the electrochemical sensor exhibited excellent sensitivity and selectivity for Cu(2+), with wide linear ranges of 1 nM to 100 μM, and the detection limit of 0.3 nM. In addition, this method was successfully applied for the analysis of Cu(2+) in river water and exhibited good analytical performance.