Voltammetric determination of organic nitrogen compounds in environmental samples using carbon paste electrode modified with activated carbon

Abstract

A quick and simple procedure is described to determine pyridine and quinoline using voltammetric methods and carbon paste electrodes modified with activated carbon in the proportion of 50:20:30 w/w graphite:activated carbon:silicon. Studies with cyclic voltammetry indicated that reduction of organic nitrogen molecules is irreversible in ammonium chloride solution acidified to pH 2.5 with Britton-Robinson buffer. Under the best optimum conditions for the differential pulse voltammetry for pyridine and square wave voltammetry for quinoline, the analytical curve was linear from 1.0 × 10−4 to 9.0 × 10−7 mol L−1 for both analytes with limits of detection of approximately 2.0 × 10−7 mol L−1 and limits of quantification of approximately 7.0 × 10−7 mol L−1. The proposed methods were successfully applied to determine pyridine and quinoline in samples of textile effluents and fuel with minimum sample treatment.