Simultaneous Electrochemical Determination of Ascorbic Acid, Dopamine, and Uric Acid in a Variety of Food, Pharmaceutical, and Biologic Samples Using a Modified Glassy Carbon Electrode with Sunset Yellow

The glassy carbon electrode (GCE) was modified with sunset yellow (SY) food dye to develop a simple, environmentally friendly, lowcost electrochemical sensor. The electrode's performance as a helpful sensor was demonstrated in the simultaneous and selective measurement of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The SY dye was covalently fixed on the electrode surface. The structure and morphology of the modified electrode were investigated by scanning electron microscopy (SEM), and the results showed that SY particles were located on the surface of the GC electrode. The electrochemical activity of the modified electrode was measured using cyclic voltammetry (CV), chronoamperometry, chronocoulometry, and impedance spectroscopy (EIS) techniques. The results showed that under optimal conditions, the SY/NaOH-treated-GCE has good electrocatalytic activity, a suitable linear range (7-320, 0.2-45, 0.2-50 μM), a low detection limit (4.78, 0.12, 0.12 μM) for AA, DA, and UA, respectively, and high stability. Analytical application of SY/NaOH-treated-GCE was successfully evaluated to determine AA, DA, and UA in bell pepper, grapefruit, dopamine ampoule, vitamin C tablet, tap water, and biological samples (human blood and urine). The results reported by our team show that the SY/NaOH-treated-GCE is suitable for simultaneous and selective determination of electroactive species in various biologic and pharmaceutical samples.