Preliminary Investigation on the Rapid and Direct AMS Measurement of 129I in Environmental Samples without Chemical Separation
Preliminary Investigation on the Rapid and Direct AMS Measurement of 129I in Environmental Samples without Chemical Separation
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DOI：
10.1017/rdc.2015.13
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发表时间：
2016-01
期刊：
影响因子：
8.3
通讯作者：
Qi Liu;Xiaolei Zhao;X. Hou;G. Burr;Weijian Zhou;Yunchong Fu;Ning Chen;Luyuan Zhang
中科院分区：
文献类型：
--
作者：
Qi Liu;Xiaolei Zhao;X. Hou;G. Burr;Weijian Zhou;Yunchong Fu;Ning Chen;Luyuan Zhang
摘要加速器质谱法（AMS）是目前测量环境样品中129 I最灵敏的方法，129 I/127 I的检出限约为10-15。该技术的一个缺点是从原始样品制备AMS靶所需的耗时的化学分离。这一步骤大大限制了需要快速分析和大量样本的应用，例如与核事故有关的监测研究。本工作介绍了一种不需要化学分离的AMS直接测量129 I的方法。在这种方法中，将稳定的碘（127 I）添加到铌（Nb）粉末基质中，并与干燥的原始样品混合。将该混合物直接压入溅射靶中用于AMS分析。在这项工作中测试了两种类型的环境样品，海藻和沉积物。在由这些材料制备的靶的Cs+溅射行为中没有注意到异常行为。发现通过这种快速方法测量的129 I/127 I比率和129 I浓度与使用常规AMS方法对相同材料的报道值一致。根据我们的研究结果，我们预计，这种快速测量可以应用于各种各样的材料，除了海藻和沉积物，只要消毒引起的不利影响不妨碍离子源的稳定运行。该方法对于在进行更精确的分析之前筛选大量样品特别有用。
Abstract Accelerator mass spectrometry (AMS) is the most sensitive method for measuring 129I in environmental samples available today, with a detection limit of about 10–15 for 129I/127I. A drawback of the technique is the time-consuming chemical separation required to prepare AMS targets from raw samples. This step significantly limits applications requiring rapid analyses and large numbers of samples, for example, in monitoring studies associated with nuclear accidents. This work introduces a direct method for 129I measurements by AMS that does not require chemical separation. In this approach, stable iodine (127I) is added to a matrix of niobium (Nb) powder and mixed with dried raw sample. This mixture is pressed directly into a sputter target for AMS analysis. Two types of environmental samples have been tested in this work, seaweed and sediment. No anomalous behavior was noted in the Cs+ sputtering behavior of the targets prepared from these materials. The 129I/127I ratios and 129I concentrations measured by this rapid method were found to be in agreement with reported values that used a conventional AMS method for the same material. Based on our findings, we expect that such rapid measurements can be applied to a wide variety of materials, in addition to seaweed and sediment, as long as the sputtering-induced adverse effects do not prevent the stable operation of the ion source. The method is especially useful for screening large numbers of samples before more precise analyses are made.