Use of a Bentonite-modified Carbon Paste Electrode for the Determination of Some Phenols in a Flow System by Differential-pulse Voltammetry

Abstract

The electrochemical behaviour of some phenols (methyl-, chloro- and nitrophenols) included in the US Environmental Protection Agency List of Priority Pollutants at a bentonite-modified carbon paste electrode in a flow system was studied. A fixed proportion of artificial sea-water was used in the sample solution so that the applicability of the methodology to marine environments could be tested. Amounts of bentonite from 5 to 10% were used. For methyl- and nitrophenols, a good stability of the electrode surface activity was observed after a series of repeated injections, with relative standard deviations between 0.40 and 2.98% (n = 16). Recovery studies were carried out on real sea-water samples spiked with 0.5 or 2.5 mg l ^{- 1} of the pollutants; recoveries from 95.4 to 101.1% were obtained.