Improvements for Analytical Procedure of Al for Cosmogenic ²⁶Al/¹⁰Be Burial Dating

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%.