ELECTROCATALYTIC OXIDATION OF ASCORBIC ACID AT POLYPYRROLE THIN FILM INCORPORATING PALLADIUM PARTICLES

Abstract

In this paper, we report a simple sensing strategy for electrochemical determination of ascorbic acid (AA) using a combination of polypyrrole (PPy) thin film and palladium particles composites deposited onto [Formula: see text]-doped silicon (Si) substrate. A two-step electrochemical process was employed to synthesize the composite films: At first, PPy film (average thickness 200[Formula: see text]nm) was electrogenerated on Si substrate from an organic solution of the pyrrole under galvanostatic conditions. Secondly, palladium particles were electrodeposited on PPy/Si surface from a separate solution by chronoamperometry technique. The surface morphology analysis of the obtained composites shows a uniform dispersion of palladium particles onto the polymer matrix and reveals that the electrodeposition time has a significant effect on the amount and size of the incorporated palladium particles. The electrochemical reactivity of the Pd–PPy/Si-modified electrodes towards the oxidation of AA was studied by cyclic voltammetry method in 0.1[Formula: see text]M, pH 7.0 phosphate buffer solution. The oxidation current was proportional to the concentration of AA in the range of 0.5–10[Formula: see text]mM with a detection limit of 0.2[Formula: see text]mM.