水中14C的样品制备与分析方法研究

摘要

14C是广泛存在于环境中的主要放射性核素,由于14C半衰期很长(5 730年)且参与地质系统中的迁移及食物链碳循环,因此14C受到人们的日益关注,建立可靠的14C测量方法成为环境监测中的一项重要工作内容.由于水中含碳量较低,且14C是低能纯β辐射体,给水中的14C测量带来一定困难.综合调研国内外水中14C分析方法,在详细阐述水中无机14C和有机14C的各种样品制备及测量方法的基础上,对鼓泡法和沉淀法、高温氧化法和加热过硫酸盐氧化法、CaCO3沉淀法、直接吸收法、苯合成法和加速器质谱法的原理及优缺点进行了分析评述,并讨论了方法中可能存在的问题,有助于实验室选用最佳的方法.%There is an increasing concern with the radiological impact associated with the discharge of long-lived radionuclides.Carbon-14 is one of the most significant radionuclides in the group because of its long half-life(5730yr) and the ease with which it assimilates into biological system.There are some difficulties in determining radiocarbon because of its low concentration and low beta radiation.After the analysis of sample preparation methods, this study lists and compares the characteristics of bubbling and sediment method, high temperature oxidation and wet oxidation, precipitate, direct absorption, benzene synthesis and AMS, contributing to choose the proper method for lab-use.