Direct Determination of Cu2+ Based on the Electrochemical Catalytic Reaction of Fe3+/Cu2+

Copper ion (Cu²⁺) is one of the heavy metal ions which has been considered as a severe pollutant affecting the environment and human health. Therefore, it is necessary to detect Cu²⁺ sensitively and conveniently in food and drinks. However, the gold standard method that inductively coupled plasma mass spectrometry (ICP‐MS) is expensive equipment required and time‐consuming. In this work, a highly sensitive and facile electrochemical method was studied to directly determine the concentration of Cu²⁺ without cumbersome modification on the surface of glassy carbon electrode (GCE). In the presence of ferric ion (Fe³⁺), Cu²⁺ could play a role of catalyst in the detection system, and the electrochemical signal of differential pulse voltammetry (DPV) response to Cu²⁺ could be amplified obviously. Under the optimal conditions, a good linear relationship was obtained in the range of 1 nM to 5 μM with a detection limit of 57.5 pM (S/N=3) were obtained. Besides, the proposed method has good applicability for the detection of Cu²⁺ in tap water. Furthermore, the copper complex was detected and the results were indicated the proposed method was effective and sensitive.