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摘要: 原地宇生核素26Al/10Be埋藏测年法是最近十多年涌现的测年新技术之一，广泛应用于地貌演化、古人类等研究领域，Al回收率及其纯度很大程度上决定着年代结果的精度。美国Purdue大学现用Al分离纯化程序有一些步骤尚待完善。本文通过条件实验，对该程序提出如下修改建议：①用38~75 μm阴离子交换树脂取代原用的75~150 μm树脂，以减少淋洗液(0.05 mol/L草酸-0.5 mol/L盐酸)体积并实现Al与主要干扰元素Fe、Ti的定量分离；②用阳离子交换法从草酸-盐酸中提取Al，以规避较为冗长的化学法破坏草酸。模拟样品的分析结果表明，经改进的两步骤可实现Al近于定量的回收，全流程Al回收率达91%±5%，纯度为98%。
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关键词:
- 宇生核素 /
- 26Al/10Be埋藏测年 /
- 铝 /
- 分析程序 /
- 离子交换法
Abstract: In situ cosmogenic 26Al/10Be burial dating, one of the dating methods that has emerged over the past several years, has been widely applied in geomorphology, archaeology and other science disciplines. The chemical recovery and purity of Al is one of the key factors to yield high-precision age results. Further improvements are needed for several steps for separating and purifying Al in the current chemical procedure of Purdue University. Based on results of conditional experiments, this study proposes the following suggestions for refining the procedure: 1) 38-75 μm, instead of 75-150 μm, anion exchange resin should be used to reduce the volume of eluting solution (0.05 mol/L H2C2O4-0.5 mol/L HCl) and to separate Al from its major interference elements of Fe and Ti; 2) Cation exchange resin be used to extract Al from H2C2O4-HCl solution to avoid the time-consuming decomposition of H2C2O4 by chemical reagents. The analyses of simulating samples show that quasi quantitative recovery of Al is realized by using the above two refined steps and the whole procedure recovery of Al reached 91%±5% with a purity of 98%.-
Key words:
- cosmogenic nuclides /
- 26Al/10Be burial dating /
- Al /
- analytical procedure /
- ion exchange method
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表 1 阳离子交换树脂上分配系数
Table 1. Cation exchange distribution coefficients
介质 Al分配系数 0.05 mol/L草酸-0.5 mol/L盐酸 186.1±2.1 0.05 mol/L草酸-0.75 mol/L盐酸 95.3±1.4 
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