Determination of Trace Iodine in Seawater — Use of Ion Chromatography and Capillary Zone Electrophoresis —

DOI Web Site Web Site
  • ITO Kazuaki
    Faculty of Engineering, Kindai University Present address: Seawater Assessment Technologies Research Institute
  • TAKEDA Kazuhiko
    Graduate School of Biosphere Science, Hiroshima University
  • HIROKAWA Takeshi
    Emeritus Professor, Hiroshima University

Bibliographic Information

Other Title
  • 海水中の微量ヨウ素分析─イオンクロマトグラフィーとキャピラリーゾーン電気泳動法の利用─
  • 海水中の微量ヨウ素分析 : イオンクロマトグラフィーとキャピラリーゾーン電気泳動法の利用
  • カイスイチュウ ノ ビリョウ ヨウソ ブンセキ : イオンクロマトグラフィー ト キャピラリーゾーン デンキ エイドウホウ ノ リヨウ

Search this article

Abstract

<p>Inorganic iodine in seawater exists as iodide ion (I−) and iodate ion (IO3−). Measurements by ion chromatography (IC) and capillary zone electrophoresis (CZE) were investigated. In IC, direct UV measurements of I− in seawater samples were completed for the first time using a strongly basic anion exchange column of low ion-exchange capacity (0.03 meq. mL−1), and a high concentration of sodium chloride eluent. Measurements of I− using an ODS column coated with a cationic surfactant (CTA+) as a separation column were also possible. IO3− was reduced to I− offline and measured with UV. In the polymer column (> 3.7 meq. g−1) and the CTA+-coated ODS column with a high ion-exchange capacity and hydrophobic property, it was possible to detect I− with high sensitivity (below μg L−1 level) due to the concentration of I− in a large amount of sea water samples. In the IC using an ODS column coated with dodecylammonium (DA+), it was possible to measure I− and IO3− together with nitrite ion (NO2−), nitrate ion (NO3−), and bromide ion (Br−). The separation mechanism of this method was discussed. The method was applied to Seto-Inland Sea water samples, while considering the dynamics of seawater. In capillary zone electrophoresis using transient isotachophoresis (tITP-CZE), the detection limit of I− was below the μg L−1 level. The speciation of I− and IO3−, and measurement of total inorganic iodine (TII) due to an on-capillary reduction of IO3− to I− were also possible. Furthermore, it was possible to detect other anions, such as NO2− and NO3−. The measurements of total iodine (TI), including organic iodine, was possible by oxidation under UV irradiation. The methods were applied to obtain vertical profiles (0 – 5500 m) of iodine species in the North Pacific Ocean.</p>

Journal

  • BUNSEKI KAGAKU

    BUNSEKI KAGAKU 68 (4), 227-239, 2019-04-05

    The Japan Society for Analytical Chemistry

Keywords

Details 詳細情報について

Report a problem

Back to top