Electrochemical determination of ascorbic acid at p-phenylenediamine film–holes modified glassy carbon electrodes

Abstract

In this work, the determination of ascorbic acid (AA) at a glassy carbon electrode (GCE) modified with a perforated film produced by reduction of diazonium generated in situ from p-phenylenediamine (PD) is reported. Holes were intentionally created in the modifier film by stripping pre-deposited gold nanoparticles. The modified electrodes were electrochemically characterized using common redox probes: hydroquinone, ferrocyanide and hexamineruthenium(III). The cyclic voltammetric and amperometric responses of AA using the modified electrodes were compared with those of a bare GCE. The bare GCE showed a linear response to AA in the concentration range of 5 mM to 45 mM with detection limit of 1.656 mM and the modified GCE showed a linear response to AA in the concentration range from 5 to 45 µM with detection limit of 0.123 μM. The effects of potential interferents on amperometric signal of AA at the modified GCE were examined and found to be minimal. The inter-electrode reproducibility, stability, and accuracy were determined. The modified electrode showed excellent inter-electrode reproducibility, accuracy and stability. The modified electrode reported is a promising candidate for use in the electro-analysis of AA.