Preparação de eletrodo contendo poli(dimetilsiloxano) funcionalizado com grupo amino para determinação de cobre

Abstract

In this work the graphite was incorporated to polydimethylsiloxane (PDMS) functionalized with amino group in order to obtain a new electrodic material to be used in copper determination. The functionalized polymeric net was prepared using PDMS, 3-aminopropyltrimethoxysilane (APTMS), tetraethylorthosilicate (TEOS) and graphite. It were prepared materials using different quantities of PDMS (0, 3, 6, 12 and 18 % weight) that were used in electrode preparation named E0, E3, E6, E12 and E18. Except for E0, in all others electrodes, the use of the binding agent was unnecessary, since the PDMS contribute to the compact and consistent paste formation. The synthesized materials were characterized using thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) to verify the polymeric net formation. The electrochemical action of the electrodes were checked using cyclic voltammetry (CV) using [Fe(CN)6]3-/4- as electroactive species. The E0 and E6 electrodes presented the better voltammetric behavior with lower difference of the anodic and cathodic current peak potential, anodic and cathodic current ratio approx. 1 and higher faradaic current. Therefore, E0 and E6 were used in the Cu2+ determination by CV and square wave voltammetry (SWV) in aqueous solution and in a handmade cachaça. Both, E0 and E6 electrode, showed satisfactory results for Cu(II) determination. These electrodes presented specificity for Cu2+ in the presence of Zn2+, Pb2+ and Ni2+ that do not showed their characteristic current peak. These results indicated that the developed electrodes, mainly E0 and E6, are conductive and are able to be used as a electrochemical sensor in Cu2+ determination in aqueous solution and in cachaça.