The development of highly selective modifies glassy carbon electrode on activated carbon-iron oxide/graphene foam for electrocatalytic oxidation of uric acid and dopamine

Abstract

This research study explores the application of nanomaterial-modified glassy carbon electrodes (GCE) for the voltammetric determination of dopamine and uric acid. The GCE was fabricated with iron oxide, activated carbon, and graphene foam. Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction Spectroscopy (XRD), and Scanning Electron Microscopy (SEM) were used to examine the microporous activated carbon, iron oxide spherical structure (Fe3O4) particles that were attached to the graphene foam sheets. A drop-dry method was used for electrode modification. AC-Fe3O4/GF/GCE was electrochemically interrogated in the ferrocyanide redox probe using cyclic voltammetry. The current intensity and the reversibility of the redox probe were enhanced in the presence of the electrochemical sensor. Differential pulse voltammetry technique (DPV) was employed for individual determination of uric acid under the optimized experimental conditions; pH 6, scan rate 50 mV s-1, pulse width 0.05 s, pulse amplitude 0.05 V, and supporting electrolyte 0.1 M phosphate buffer solution. A detection limit of 2.55 µM was obtained with an analytical linear range of 5 - 1630 µM. All selected foreign species showed no significant interference with the electrochemical determination of uric acid. Furthermore, dopamine analysis was carried out on AC-Fe3O4/GF/GCE using DPV. The electrochemical sensing was also optimized at various analytical conditions and a detection limit of 1.47 µM was obtained in the linear dynamic range of 2.5 to 450 µM. Glucose, glutamic acid, l-lysine, and ascorbic acid are a few of the interfering species that exhibited almost no impact on dopamine detection. In addition, the simultaneous determination of uric acid and dopamine was conducted successfully. They have been determined by differential pulse voltammetry, and the modified electrode exhibited a linearity relationship over a wide range of uric acid concentrations from 2.5 to 450 μM, with a detection limit of 1.75 μM, (s/n = 3). A linear trend for the current response for dopamine concentrations ranging from 5 to 400 μM, with a detection limit of 2.7 μM, has also been obtained. The results, therefore, demonstrated the sensor’s superior electrocatalytic activity and its high selectivity for dopamine and uric acid even when some foreign species were present. The average recoveries from the real sample analyses of the urine samples showed that the proposed sensor could be put to use in the real sample analysis. The developed electrode was generally found to be highly selective and sensitive toward uric acid and dopamine. It has achieved better sensing performances with a very low detection limit, wider linear ranges, and short analysis times as compared to most previously reported modified electrodes for the same analytes. Furthermore, the developed electrode was validated successfully for real sample analysis in biological fluids. The proposed methods have many attractive features, such as low cost, simplistic electrode preparation procedure, easy renewability, long-term usability, and rapid analysis. The developed electrode also displayed good repeatability and selectivity towards interfering substances. It is a promising modified electrode for the electrochemical detection of other electroactive important compounds in biological systems.