Reversible Switched pH‐Responsive Hydroquinone Electrochemical Sensor Based on Composite Film of Polystyrene‐b‐Poly (Acrylic Acid) and Graphene Oxide

Abstract

AbstractThe detection of some environmental pollutants remains still a great challenge and the current methods suffer from low sensitivity, reproducibility and require sophisticated instruments. Here, a simple, sensitive and pH‐responsive electrochemical sensor for the detection of hydroquinone (HQ) was developed based on a pH‐responsive block copolymer polystyrene‐b‐poly(acrylic acid) (PS‐b‐PAA) and graphene oxide (GO) composite film (PG) modified glassy carbon electrode (GCE). The electrochemical behaviors of HQ at the modified GCE (PG/GCE) electrode were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The peak current of the PG/GCE electrode toward HQ was significantly enhanced at pH 7.0 and greatly suppressed below pH 6.0, which are caused by swelling and shrinking of pH‐responsive block copolymer and the synergistic effect with GO. The PG/GCE exhibited a reversible “On/Off” switch for the HQ electrochemical behaviors between pH 4.0 and pH 7.0. When the pH of the medium is 7.0, the PG complex film on the PG/GCE is in the “On” state, the linear detection range of HQ is from 16 μM to 104 μM with a detection limit as low as 0.34 μM. Furthermore, the PG/GCE can also successfully detect the HQ concentration of the lake water sample with satisfactory recovery, indicating that the pH‐responsive block copolymer/GO‐functionalized sensor provided a powerful avenue for simple, sensitive and convenient detection of HQ, which can be translated into practical application.