The Influence of the Cathodic Pretreatment on the Electrochemical Detection of Dopamine by Poly(1-aminoanthracene) Modified Electrode

In this study we demonstrated the influence of the cathodic pretreatment of poly(1-aminoanthracene) (FAA) electropolymerized on a platinum electrode for determination of dopamine (DA). The DA electrochemical response was obtained after a cathodic pretreatment of the FAA electrode which consisted of applying a potential of -0.7 V (vs. Ag/AgCl) for 3 s before each measurement. The pretreatment of the electrode changed the PAA electrocatalytic properties so that the electrode began to present electrochemical response to DA without interference of ascorbic acid (AA). The anodic peak currents determined by differential pulse voltammetry using pretreated FAA showed a linear dependence on the DA concentration from 0.56 to 100 mu M with a detection limit of 0.13 mu M and a correlation coefficient of 0.9986. The electrode exhibits a relative standard deviation of 1.2% for ten successive measurements of a 0.5 mM DA solution. The analysis by scanning electron microscopy and atomic force microscopy show a homogeneous and nanostructured film with globular structures with diameter of about 20 nm. The analytical results obtained for DA determination at a pretreated FAA electrode in pharmaceutical formulation sample were in good agreement with those obtained by a comparative procedure at a 95% confidence level. FAA electrode after the pretreatment showed electrochemical responses to DA with excellent selectivity, sensitivity, and high stability without interference of AA.