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