Separation of chlorophenols by cyclodextrin supported capillary zone electrophoresis - Monitoring of the electrochemical dehalogenation of pentachlorophenol

The interest in the analysis of chlorinated phenols is related to their tox icity and their widespread occurrence as pollutants. Neutral cyclodextrin d erivates as buffer additives gave excellent results in the separation of ph enol and all its chlorinated congeners. Based on the traditional counterele ctroosmotic capillary zone electrophoresis we developed an efficient and fa st separation method that requires no further organic modifier and shows a high reproducibility. The best results were obtained by the use of heptakis (2,3,6-tri-O-methyl)-beta-cyclodextrin in an alkaline phosphate buffer (pH 11.0). The analytical method was applied to the monitoring of the electroch emical dehalogenation of pentachlorophenol. Preparative electrolyses were c arried out in methanol to study the degradation pathway in terms of regiose lectivity and a mixture of partially dehalogenated chlorophenols was obtain ed. depending on the electrolysis time and the reduction potential. (C) 200 0 John Wiley & Sons, Inc.