Studies on the electrocatalytic oxidation of dopamine at phosphotungstic acid–ZnO spun fiber-modified electrode

A novel and selective electrochemical sensor was developed for the determination of dopamine (DA) based on phosphotungstic acid (PWA)–zinc oxide (ZnO) electrospun fibers. The fibers were constructed in situ on a Pt electrode by using electrospinning technology and succedent heat treatment. The obtained fibers were characterized by SEM, FTIR, and XRD. The electrochemical properties of PWA–ZnO fibers modified electrode and its electrocatalysis for DA electro-oxidation were investigated by cyclic voltammetry and differential pulse voltammetry. The stability of PWA–ZnO fibers was excellent because PWA was embedded in the fibers, which can solve the problem of PWA loss during experiment. According to large surface area of PWA doped ZnO fibers, the modified electrode showed excellent electrocatalytic activity toward the oxidation of DA in the phosphate buffer solution (pH 5.0). A linear relationship between the current response and the concentration of DA ranging from 1.9 × 10−7 to 4.5 × 10−4 M was obtained with a detection limit of 0.089 μM at pH 5.0. The DA can be determined in the presence of ascorbic acid (AA) because two compounds were well-separated with a potential difference of 0.36 V on the modified electrode. Based on its excellent electrochemical performance and ease of preparation, the proposed electrode may provide a promising alternative in routine sensing applications.