Selective Detection of Dopamine in the Presence of Ascorbic and Uric Acids through its Covalent Immobilization on Gold Mercaptopropionic Acid Self-assembled Monolayer

A simple, stable and recoverable sensor is developed based on selective and covalent immobilization of dopamine (DA) on the gold (Au) electrode modified by mercaptopropionic acid (MPA) self-assembled mono-layers and then, activated with 1-ethyl-3(3-(dimethylamino) propyl)-carbodiimide hydrochloride (EDC)/n-hydroxysuccinimide (NHS) activators. Fabrication steps and analytical application of this modified electrode toward quantitative determination of DA in the presence of ascorbic and uric acids are verified by cyclic and differential pulse voltammetry (CV and DPV) methods in the absence of any redox probe. The oxidation peak current of adsorbed DA changed linearly with the concentration of DA in the range of 0.5 to 600.0 mu M with a detection limit of 0.064 mu M, and the RSDs varied from 1.4 to 3.5% for n = 3 at each point. Finally, the fabricated sensor is used successfully for electroanalytical determination of DA in human blood plasma and pharmaceutical injection real samples.