Flow-Injection Amperometric Method for Indirect Determination of Dopamine in the Presence of a Large Excess of Ascorbic Acid

A simple flow injection amperometric system for fast and indirect quantification of dopamine (DA) in the presence of a large excess of ascorbic acid (AA) is reported. The method consists of the application of three sequential potential pulses to an unmodified glassy carbon‐working electrode positioned in a wall‐jet cell. DA is indirectly detected at +0.35 V through the reduction of the oxidation product (o‐dopaminoquinone) electrochemically generated at +0.80 V. The third potential pulse (0.00 V) is applied for the regeneration (cleaning) of the unmodified working electrode. The limits of detection (LOD) and quantification (LOQ) were calculated as 50 and 170 nmol L−1, respectively. Considering the LOQ value, the present methodology allows DA quantification in the presence up to 5000‐fold more of AA (1.0 mmol L−1).