Development of sol-gel based carbon ceramic electrode modified by graphene oxide - polypyrrole nanocomposite for simultaneous determination of uric acid and dopamine in presence of ascorbic acid

In this paper a sensitive carbon ceramic electrode (CCE) based on Methyltrimethoxy Silane (MTMOS) was prepared simply by three step sol-gel process. The surface of CCE was modified with polypyrrole -electrochemically reduced graphene oxide (ERGO-PPy) nanocomposite by electro polymerization. Scanning electron microscopy, electrochemical impedance spectroscopy, XRD, FT-IR and electrochemical techniques were used to characterize the composite electrode. The cyclic voltammetry and differential pulse voltammetry results suggested that the modified electrode exhibited enhanced sensitivity and selectivity towards the oxidation of dopamine and uric acid. Differential pulse voltammetry results show that simultaneous determination of DA and UA in presence of ascorbic acid could be performed selectively and sensitively at ERGO/PPy modified sol-gel based CCE. The oxidation peak currents of DA and UA in presence of AA, presented a good linear relationship with the concentrations in the range from 0.05 to 65 μM and 0.1 to 120μM respectively with a detection limit of 0.002 μM for DA and 0.08 μM for UA. The good performance of the modified electrode provided a promising modified electrode in electrochemical determination of DA in human blood serum and urine samples.