Use of a boron-doped diamond electrode to assess the electrochemical response of the naphthol isomers and to attain their truly simultaneous electroanalytical determination

Abstract

Naphthol, a chemical classified as an endocrine disruptor and known to show carcinogenic activity, is found in the environment as a mixture of its isomers. For the first time, the truly simultaneous voltammetric determination of these isomeric forms of naphthol was explored in this work using a cathodically pretreated BDD electrode (CPT–BDD). The isomers 1–naphthol (1–NAP) and 2–naphthol (2–NAP) showed an irreversible oxidation process at 0.80V and 0.96V vs. Ag/AgCl (3.0molL−1 KCl), respectively, which allowed the simultaneous determination of these compounds. The electrochemical features of the 1–NAP and 2–NAP electrooxidation on CPT–BDD were investigated, including the determination of apparent diffusion coefficients and adsorption studies. Using differential pulse voltammetry under optimized experimental conditions, the analytical curves simultaneously constructed for 1–NAP and 2–NAP were both linear in the concentration range of 0.200 to 3.85μmolL−1 with limits of detection of 50 and 100nmolL−1, respectively. Because the naphthol isomers do not adsorb on CPT–BDD, an excellent repeatability of measurement was verified and the proposed electroanalytical procedure was successfully applied for a truly simultaneous quantification of 1–NAP and 2–NAP in water and synthetic urine samples.