【摘要】 环境样品中超微量129I的准确测定是天然129I地质定年和环境示踪应用的关键。本研究通过高温热解法分离土壤中的碘,并将其收集于碱性捕集液中,再利用AgI-AgCl共沉淀方法实现捕集液中碘的无载体分离;采用3 MV加速器质谱仪测量沉淀样品中129I/127I比值。通过优化分离和分析条件,高温热解过程中碘的分离效率达95%以上;无载体共沉淀过程碘的回收率为75%～85%;样品中碘的总分离效率大于70%。应用本方法对低碘含量土壤样品中129I/127I原子比值低至10-11的超微量129I进行了准确测定。结果表明:本方法适用于129I/127I比值低至10-12的同类样品的分析。更多还原

【Abstract】 The accurate determination of ultra low level 129I in sample is critical and essential for the application of natural 129I in geological dating and environmental tracer studies.In this work,iodine was first separated from soil by combustion at high temperature;the released iodine was collected in an alkali trap solution.AgI-AgCl coprecipitaiton was used to separate carrier free iodine from the trap solution and to prepare target.129I in the target was then measured using a 3.0 MV accelerator mass spectrometer.The recovery of iodine during the combustion is higher than 95%.An iodine recovery of about 75%-85% was obtained in the coprecipitation and the total recovery of iodine is above 70%.The developed method has been successfully used to determine 129I in soil sample with low iodine content.A 129I/127I atomic ratio as low as 10-11 in the deep soil has been determined.The determination of 129I/127I was ratio down to 10-12 in solid samples.更多还原