Capillary electrophoretic separation of chlorophenols using amperometric detection

A simple end-column amperometric detector, without a porous junction, was designed and attached to a capillary electrophoresis instrument to analyze eight mono-, di- and tri-chlorophenols. The platinum detecting electrode was modified by electrodeposition of tin, to enhance sensitivity as well as reduce electrode fouling owing to phenol oxidation. The modified electrode (0.127 mm in diameter) in combination with a 70 mu m I.D. separation capillary yielded sharp peaks and enabled us to detect phenol at levels as low as 0.10 mu M. Satisfactory separation of the eight chlorophenols was achieved by using a mixed buffer of phosphate-borate.