Determination of Ultralow Level 129I/127I in Natural Samples by Separation of Microgram Carrier Free Iodine and Accelerator Mass Spectrometry Detection

Xiaolin Hou, Weijian Zhou, Ning Chen, Luyuan Zhang, Qi Liu, Maoyi Luo, Yukun Fan, Wangguo Liang, Yunchong Fu

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    Separation of carrier free iodine from low iodine level samples and accurate measurement of ultralow level 129I in micrograms of iodine target are essential but a bottleneck in geological dating of terrestrial system and tracer research using naturally produced 129I. In this work, we present a carrier free method using coprecipitation of AgI with AgCl for preparing micrograms of iodine target, associated with combustion using a tube furnace for separating iodine from solid samples and anion exchange chromatography for preconcentrating iodine from a large volume of water. An accelerator mass spectrometry was used to measure ultralow level 129I in micrograms of iodine target. The recovery of iodine in the entire separation procedure is higher than 80% and 65% for solid and water samples, respectively. One microgram iodine in the target (AgI−AgCl) can produce a stable 127I signal for AMS measurement of 129I/127I, and a detection limit of this method for 129I is calculated to be 105 atoms. This will allow us to accurately determine 129I in prenuclear geological samples of low iodine concentration with 129I/127I of 10−12, such as loess, soil, coral, rock, sediment, and groundwater. Some samples with low iodine content have been successfully analyzed, and the lowest value of the 129I/127I ratio of 2 × 10−11 was observed in 23.5 and 63.5 m loess samples collected in the Loess Plateau, China. The developed method sheds light on a wide application in earth science
    Original languageEnglish
    JournalAnalytical Chemistry
    Volume82
    Issue number18
    Pages (from-to)7713-7721
    ISSN0003-2700
    DOIs
    Publication statusPublished - 2010

    Keywords

    • Radiation research and nuclear technologies
    • Radio ecology and tracers

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