We here present a comparison of methods for the pretreatment of a batch of tree rings for high-precision measurement of radiocarbon at the Aarhus AMS Centre (AARAMS), Aarhus University, Denmark. The aim was to develop an efficient and high-throughput method able to pretreat ca. 50 samples at a time. We tested two methods for extracting α-cellulose from wood to find the most optimal for our use. One method used acetic acid, the other used HCl acid for the delignification. The testing was conducted on background 14C samples, in order to assess the effect of the different pretreatment methods on low-activity samples. Furthermore, the extracted wood and cellulose fractions were analyzed using Fourier transform infrared (FTIR) spectroscopy, which showed a successful extraction of α-cellulose from the samples. Cellulose samples were pretreated at AARAMS, and the graphitization and radiocarbon analysis of these samples were done at both AARAMS and the radiocarbon dating laboratory at Lund University to compare the graphitization and AMS machine performance. No significant offset was found between the two sets of measurements. Based on these tests, the pretreatment of tree rings for high-precision radiocarbon analysis at AARAMS will henceforth use HCI for the delignification.

中文翻译：

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用于放射性碳分析的树环样品的批量处理

我们在此比较了丹麦奥胡斯大学奥胡斯 AMS 中心 (ARAMS) 对一批树木年轮进行高精度测量放射性碳的预处理方法。目的是开发一种高效且高通量的方法，能够预处理 ca。一次 50 个样本。我们测试了两种从木材中提取 α-纤维素的方法，以找到最适合我们使用的方法。一种方法使用乙酸，另一种使用盐酸进行脱木质素。测试是在后台进行的14C 样品，以评估不同预处理方法对低活性样品的影响。此外，使用傅里叶变换红外 (FTIR) 光谱分析提取的木材和纤维素部分，结果表明从样品中成功提取了 α-纤维素。纤维素样品在 ARAMS 进行了预处理，这些样品的石墨化和放射性碳分析在 ARAMS 和隆德大学的放射性碳测年实验室进行，以比较石墨化和 AMS 机器的性能。两组测量值之间没有发现明显的偏移。基于这些测试，ARAMS 对树木年轮进行高精度放射性碳分析的预处理将从此使用 HCI 进行脱木质素。