Polypyrrole Nanowire-Modified Electrodes Doped with Hyaluronic Acid and Its Application to Determination of Vitamin C

An electrochemical sensor was developed based on hyaluronic acid (HA)-doped polypyrrole (PPy) modified glassy carbon electrode (GCE), and applied to the determination of vitamin C. The HA-PPy modified GCE was constructed by doping HA during the electropolymerization of PPy on GCE. The modified electrode was characterized by scanning electron microscope, cyclic voltammetry and electrochemical impedance spectroscopy. Several important parameters of the sensor were investigated and optimized. The results showed that doping HA in the polymerization of pyrrole could induce the linear polymerization process of pyrrole and a perfect nanowire of PPy was obtained. The results also showed that the electrochemical performance of the HA-PPy modified electrode significantly depended on the doping dose of NaHA as a dopant. Compared with bare GCE and PPy modified GCE, HA-PPy modified GCE revealed higher redox current to the electroactive compounds and smaller resistance in K3 [Fe(CN)6] solution. Under the optimal conditions, the HA-PPy modified GCE showed a wide linear range from 1.0 × 10–4 to 1.0 × 10–1 mol/L with a detection limit of 6.9 × 10–6 mol/L for the voltammetric determination of vitamin C. The HA-doped PPy modified electrodes showed significant improvement for the electrochemical characteristics, and this sensor is successfully applied to determination of vitamin C.