Adsorção de ftalocianina de Fe (II) sobre 3-n-propilimidazol sílica-gel: caracterização e aplicações

Abstract

In this work, the iron (II) phthalocyanine was immobilized on the 3-n-propylimidazole groups grafted on a porous SiO2 surface and, through UV-Vis electronic spectroscopy, it was found that the immobilization occurred by the coordination of the free electron-pair of nitrogen (present in the imidazole group) to the iron atom of phthalocyanine. The synthesized material (SiFePc, iron (II) phthalocyanine coordinated to 3-n-propylimidazol silica gel) was incorporated into a carbon paste electrode (CPE) and its electrochemical properties were studied by cyclic voltammetry technique. The CPE modified with SiFePc (CPE/ SiFePc) presented an E½ at 0.22 V vs Ag/AgCl, which is attributed to the redox pair Fe(II)/ Fe(III). The electrocatalytical properties of the obtained electrode were verified in presence of ascorbic acid (AA) and dopamine (DA). In this case, it was observed that the CPE/ SiFePc catalyzed the electrooxidation reaction of AA at 0.27 V vs Ag/AgCl and for DA at 0.33V vs Ag/AgCl. In the study of influence of analyte concentration at the produced current, it was observed a linear relationship, which enables the utilization of the obtained electrode in the construction of an electrochemical sensor for AA and DA.