Voltammetric Behavior of Carbon Paste Electrodes with Native and Chemical Modified Porphyrans

Abstract

Porphyran is a sulfated polysaccharide obtained from Porphyra genus. Carbon paste electrodes (CPEs) containing natural ionic polysaccharides have been studied. This study describes the voltammetric behavior of porphyran modified CPE obtained before and after chemical desulfation of the polysaccharides by alkaline treatment ( PA ) and solvolysis ( PD ) from the native fraction ( PN ). The cyclic voltammograms for all porphyran modified electrodes indicated a redox current peaks increase in the same potential range when compared to the unmodified CPEs. The CPEs were modified with different amounts of porphyran and those which showed the most intense anodic peaks were: 10 ( EN ), 20 ( EA ) and 40 µg ( ED ). In addition, the anodic peak current increased linearly with the square root of the scan rate, indicating that the redox process was diffusion-controlled. In conclusion, the electrochemical experiments demonstrated that electron transfer on the porphyran-modified CPEs surface is more efficient, conducting higher current and offering lower resistivity.