Separation of iodide and iodate by anion exchange resin and determination of their ions in surface water

Abstract

Analytical methods for the determination of iodide and iodate ions in surface water were investigated. Iodide in water was adsorbed on an anion exchange resin column and eluted as iodate which was then oxidized with permanganate. For the colorimetric determination of iodide, the Leuco Crystal Violet method was adopted. To obtain the concentration of iodate in surface water, total iodine was determined by a similar analytical method after reducing iodate to iodide with sulfurous acid. The concentration of iodate was calculated by subtracdng the concentration of iodide from that of total iodine. The concentration of total iodine was 2.5 fxg/l in rain water and 5~7 µg/l in river and tap waters. The analytical results of iodide and iodate in rain and river waters showed that the rado of iodate to iodide in river water was higher than that in rain water. On the other hand, the analytical results for tap water showed that its ratio of iodate to iodide was conspicuously higher than that of river water. © 1992, The Japan Society for Analytical Chemistry. All rights reserved.