2009 Volume 58 Issue 7 Pages 583-594
The present work described an attempt to apply an anodic-oxidation reaction of free chlorine for the quantitative determination. As a working electrode, polycrystalline platinum disk was mainly used. Cyclic voltammograms exhibited well-defined oxidation wave at about 1.1 V vs. Ag/AgCl. The oxidation wave showed good reproducibility and a linear relationship between the oxidation peak current versus concentration. The electro-oxidation of trace amounts of free chlorine, however, particularly amounts less than 0.028 mmol dm−3, was strongly inhibited by the initial formation of platinum oxide in a non-Faradaic reaction. Meanwhile, a reduction wave with reproducibility was observed at about 0.6 V vs. Ag/AgCl, after the sweep direction was switched from anodic to cathodic. The peak current and the concentration showed a linear relationship passed through the origin. Moreover, another reduction wave with reproducibility was observed at about 0.8 V vs. Ag/AgCl in switching potential≥1.45 V vs. Ag/AgCl, the peak current and the concentration also had a linear relationship.
