Large-Surface Carbon Film Electrode –– A Simple Sensor for Voltammetric Determination of Electrochemically Reducible Organic Compounds

Abstract

A newly developed large-surface carbon film electrode (LS-CFE) based on a microcrystalline natural graphi­te–polystyrene composite film was used to study the electrochemical behavior of 4-nitrophenol (4-NP) using DC voltammetry (DCV) and differential pulse voltammetry (DPV). Voltammetic behavior of 4-NP was investigated in dependence on the pH of the used Britton-Robinson buffer. As optimum pH values for the voltammetric determination of 4-NP at the LS-CFE in the cathodic potential region, the pH values 6.0 (for DCV) and 7.0 (for DPV) were chosen. The determinations of 4-NP at the LS-CFE (at a concentration of the analyte of 1·10^–4 mol l^–1) showed a good repeatability for both voltammetric techniques used (RSD 2.2 % for DCV and 0.4 % for DPV). Under optimum conditions, the calibration dependences of 4-NP were measured in the concentration range from 1 to 100 µmol l^–1, with limits of quantification (L_Qs) of 2.3 µmol l^–1 and 1.8 µmol l^–1 for DCV and DPV, respectively. The applicability of the newly developed methods for the determination of 4-NP was verified on the model samples of drinking and river water, with L_Qs in the range from 1 to 2 µmol l^–1.