Poly(amido amine) dendrimer and silver nanoparticle–multi-walled carbon nanotubes composite with poly(neutral red)-modified electrode for the determination of ascorbic acid

Abstract

A new film containing poly(amido amine) dendrimer, silver nanoparticles and multi-walled carbon nanotubes composite with poly(neutral red) was prepared on a paraffin wax impregnated graphite electrode. The PAMAM / AgNPs–MWCNT / PNR film exhibited promising electrocatalytic oxidation of ascorbic acid (AA) in acetate buffer solution of pH 4.0. The PAMAM / AgNPs–MWCNT / PNR film-modified electrode enhanced the sensitivity of detection of AA. The PAMAM / AgNPs–MWCNT / PNR film-modified electrode was characterized by cyclic voltammetry, chronoamperometry, hydrodynamic voltammetry (HDV) and difference pulse voltammetry. These experiments confirmed the electrocatalytic oxidation of AA by PAMAM / AgNPs–MWCNT / PNR film-modified electrode. The PAMAM / AgNPs–MWCNT / PNR-modified electrode has been found to possess good electrocatalytic activity towards AA oxidation which has been observed at a lower oxidation potential of around 0.26 V with a higher current response. The electrochemical oxidation of AA by PAMAM / AgNPs–MWCNT / PNR-modified electrode involved a two proton and two electron process. A linear relationship between the catalytic current and AA concentration was obtained in the range from 0.16 to 2500 \(\upmu \)M with a detection limit of 0.053 \(\upmu \)M.