Electrochemical behavior of dopamine at a 3,3'-dithiodipropionic acid self-assembled monolayers.

Lucia Codognoto, Eduardo Winter, Jonas A R Paschoal, Hugo B Suffredini, Murilo F Cabral, Sergio A S Machado, Susanne Rath, Lucia Codognoto, Eduardo Winter, Jonas A.R. Paschoal, Hugo B. Suffredini, Murilo F. Cabral, Sergio A.S. Machado, Susanne Rath

Index: Talanta 72(2) , 427-33, (2007)

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Abstract

Monolayers of 3,3'-dithiodipropionic acid (DTDPA) were prepared on a polycrystalline gold electrode through a self-assembly procedure to produce a gold 3,3'-dithiodipropionic acid self-assembled monolayer (AuDTDPA) modified electrode. The characterization of the AuDTDPA electrode was investigated by cyclic voltammetry and ac impedance using the [Fe(CN)(6)](3-/4-) redox couple. The electrochemical behavior of DA on the modified electrode AuDTDPA was studied by cyclic and square-wave voltammetries, using phosphate buffer as supporting electrolyte. The oxidation peak current for DA increases linearly with concentration in the range of 0.35x10(-5) to 3.4x10(-5)molL(-1). The performance of the AuDTDPA modified electrode was evaluated for the electroanalytical determination of dopamine (DA) in a pharmaceutical formulation. The AuDTDPA modified electrode showed a stable behavior and the presence of surface-COOH groups avoided the passivation of the electrode surface during the dopamine oxidation.