Selective Determination of Dopamine in the Presence of Ascorbic Acid and Uric Acid at Neutral pH Using a Silver Nanoparticles-modified Carbon Paste Electrode

Developing simple, sensitive and selective sensing systems for dopamine is important due to its biological significance. In this work, a silver nanoparticles-modified carbon paste electrode (AgNPs-CPE) has been constructed and used to detect of dopamine (DA) in the simultaneous presence of ascorbic acid (AA) and uric acid (UA) at neutral pH 7.0 by cyclic voltammetry. The modified electrode showed good performance toward the oxidation and determination of DA in the presence of AA and UA. In a mixture of the three compounds, DA showed a pair of redox peaks at about 182.0 and 116.0 mV for anodic and cathodic peaks potential, respectively, while AA and UA exhibited an oxidation peak at about 320.0 mV. Under these circumstances DA more easily oxidized than AA and UA at the surface of modified electrode and precisely determined by differential pulse voltammetry. A sensitivity of 0.074 μA/μM with a wide linear range of 12.5-300.0 μM and detection limit of 0.61 μM were obtained. The modified electrode was applied successfully for DA quantification in dopamine hydrochloride injection sample in the presence of AA and UA (100 μM).