Electrochemical Behavior of Cu Electrode and Its Application in CE Determination of Polyols

The electrochemical behavior of a copper (Cu) electrode and its application in capillary electrophoresis determination of polyols was investigated in order to understand the redox property of Cu and achieve better separation efficiency. Electrochemical measurements were performed using a Cu electrode (fresh or oxidized) in buffer solutions having different pH values (7.8–13.0) by cyclic voltammetry. The Cu electrode showed higher electroactivity under stronger alkaline conditions. Further, the Cu electrode was found suitable for detecting weak oxidizing or reducing polyhydroxy compounds because of the redox reactions among Cu, Cu(I), and Cu(II) species. Thus, the Cu electrode was used in capillary zone electrophoresis (CZE) for separation and determination of propanediol and glycerol, weak electroactive polyols, using different separation (pH 8.7) and detection (pH 11.04) buffers. Separation and detection buffers with different pH values in CZE technology could offer efficient separation efficiency and detection limits at the same time.