Voltammetric performance of nanofiber structured over-oxidized poly(3,4-ethylenedioxythiophene) modified pencil graphite electrodes for dobutamine sensing

A modified electrode was developed for the electrochemical sensing of dobutamine (DBT), one of the catecholamines. For this modification process, pencil graphite electrodes (PGE) were modified with over-oxidized nanofiber structured poly (3,4-ethylenedioxythiophene) (PGE/OPEDOTNF) by electropolymerization. The electrochemical performance of PGE/OPEDOTNF was evaluated by cyclic and differential pulse voltammetry. In addition, the performances of non-nanofiber PEDOT-modified PGE electrodes were also examined for comparison. The characterization of the modified electrodes was carried out by scanning electron microscopy and electrochemical methods. The signal of the modified electrodes was observed in a linear range of 0.1-2.0 µM against DBT using the differential pulse voltammetry method. The limit of detection and quantification are calculated as 0.026 µM and 0.086 µM, respectively. The effect of the interfering species was examined. It has been shown that DBT can be detected sensitively and selectively using pencil graphite electrodes modified with nanofiber-structured poly(3,4-ethylenedioxythiophene). The repeatability of PGE/OPEDOTNF electrodes was found to be 5.2%. PGE/OPEDOTNF electrodes remained stable for 15 days without losing their electrochemical activity.