Influence of Natural Polysaccharides on the Redox Processes of CuTsPc Thin Films and Dopamine Sensing

Abstract

Abstract:Energy diagrams have been obtained for copper tetrasulfonated phthalocyanine (CuTsPc) from electrochemical and electronic absorption measurements in layer-by-layer (LbL) films with cashew (Anacardium occidentale L.) and angico branco (Anadenanthera colubrina) natural polysaccharides in the anionic layers. In this study, LbL films were produced with either copper tetrasulfonated phthalocyanine or polysaccharides (cashew or angico branco). Since CuTsPc and the gums are polyanions, the multilayer deposition was carried out in a tetralayer fashion, in which a conventional cationic polyelectrolyte, namely poly (allylamine hydrochloride) (PAH), was interposed between the polyanionic layers. An alternative for the simultaneous determination of electrochemical signals was using the deconvolution procedure. Mathematical deconvolution of the peaks followed Gaussian analysis. The presence of the gum led to increased adsorption of the phthalocyanine, and enhanced the UV-VIS absorption and electrochemical response of the films. Furthermore, modified electrodes based on polysaccharides/phthalocyanine films were able to detect dopamine at concentrations as low as 10 -5 mol/L.