title: Electrochemical behavior of dopamine at a 3,3'-dithiodipropionic acid self-assembled monolayers.
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.
authors.affiliation: Institute of Chemistry, Department of Analytical Chemistry, State University of Campinas, P.O. Box 6154, 13084-971 Campinas, SP, Brazil.
authors.forename: Lucia
authors.initials: L
authors.lastname: Codognoto
authors.forename: Eduardo
authors.initials: E
authors.lastname: Winter
authors.forename: Jonas A R
authors.initials: JA
authors.lastname: Paschoal
authors.forename: Hugo B
authors.initials: HB
authors.lastname: Suffredini
authors.forename: Murilo F
authors.initials: MF
authors.lastname: Cabral
authors.forename: Sergio A S
authors.initials: SA
authors.lastname: Machado
authors.forename: Susanne
authors.initials: S
authors.lastname: Rath