Voltammetric detection of Cu2+ using poly(azure A) modified glassy carbon electrode based on mimic peroxidase behavior of copper

Poly(azure A) (PAA) modified glassy carbon electrode was prepared by cyclic voltammetry and it was characterized by scanning electron microscopy and electrochemical analysis. The organic dye polymer on an electrode surface exhibited a limited catalytic ability for the reduction of H2O2. As a mimic peroxidase, copper ion induced the decomposition of H2O2 due to Fenton-type reaction. The generated hydroxyl radical could effectively oxidize PAA and lead to the great increase of the reduction current of the dye polymer in the cyclic voltammetric scan. An indirect and sensitive method for the trace Cu2+ detection was developed. Under the optimized conditions, the fabricated sensor displayed a linear response in the Cu2+ concentration range from 50 nM to 10 μM and that from 10 μM to 100 μM with a detection limit of 8.4 nM estimated at a signal-to-noise ratio of 3. The interference experiments show that some common metal cations had little influence on the electrochemical measurement. The proposed method was successfully applied to the determination of copper ions in water samples by standard addition method and the recovery values were found to vary from 95.4% to 108%.