Non-enzymatic detection of hydrogen peroxide based on Fenton-type reaction on poly(azure A)-chitosan/Cu modified electrode

Highlights: • The PAA-CS modified GCE was prepared using cyclic voltammetry. • Copper ions were strongly bound to the PAA-CS composites by complexation. • ·OH derived from the reaction between Cu²⁺ and H₂O₂ effectively oxidized PAA. • An electrochemical sensor of H₂O₂ with good analytical performance was developed. - Abstract: In this work, a sensitive electrochemical method for the detection of H₂O₂ was proposed based on Fenton-type reaction on the electrode surface. A glassy carbon electrode modified with poly(azure A) (PAA), chitosan (CS) and copper ions, displaying a good electrochemical activity, was fabricated by cyclic voltammetry and the adsorption of Cu²⁺. Scanning electron microscopy-Energy dispersive spectroscopy analysis, infrared and Raman spectral characterization and XPS measurement showed the stable complexation of Cu²⁺ with the PAA-CS film. Hydroxyl radicals derived from the Fenton-type reaction between Cu²⁺ and H₂O₂ could effectively oxidize poly(azure A), leading to the great reduction-current change of the dye polymer in the electrode process. Under the optimized conditions, the fabricated electrode displayed a linear response in the H₂O₂ concentration range from 0.002 to 0.5 mM and that from 2.56 to 25.0 mM with a detection limit of 0.7 μM estimated at a signal-to-noise ratio of 3. The good analytical performance including low detection limit, fast response time, low cost, good anti-interference performance, satisfying stability, acceptable repeatability and reliable reproducibility were found from the proposed amperometric sensor, suggesting that the current work could provide a feasible approach for the non-enzymatic H₂O₂ detection.