Collagen extraction depends on the state of bone preservation, and the acidity of Brazilian soils often prevents the use of this material for radiocarbon dating. When available, however, bone samples constitute very important chronological records for both archaeological sites and natural depositional sites of specific animals. The extraction of collagen was performed using two filters, the first aiming to remove insoluble contaminants, and the second, a vivaspin ultrafilter 30KD to retain large molecular weight materials. The collagen was liofilized and converted to CO2 by combustion in sealed quartz tubes with CuO and Ag. The graphite was produced by zinc reduction in independently sealed Pyrex™ tubes. In order to verify the accuracy of this protocol, we analyzed a modern bone and four previously dated fragments, including those from the Sixth International Radiocarbon Intercomparison (SIRI), and a fragment of human bone from the Amourins site, a Brazilian shellmound. The results for the known age material are in agreement with the expected and the studied sector of Amourins shellmound was dated 4100–3900 years cal BP from a chronological model performed with charcoal dating found in different stratigraphic layers. Samples were dated at the radiocarbon laboratory of Universidade Federal Fluminense (LAC-UFF) in Brazil.

中文翻译：

---

巴西 LAC-UFF 骨骼样本的初步放射性碳测年结果

胶原蛋白的提取取决于骨骼保存的状态，而巴西土壤的酸度通常会阻止使用这种材料进行放射性碳测年。然而，当可用时，骨骼样本构成了考古遗址和特定动物自然沉积地点的非常重要的年代记录。使用两个过滤器进行胶原蛋白的提取，第一个旨在去除不溶性污染物，第二个是 vivaspin 超滤器 30KD，以保留大分子量材料。胶原蛋白被液化并转化为二氧化碳2通过在装有 CuO 和 Ag 的密封石英管中燃烧。石墨是在独立密封的 Pyrex™ 管中通过锌还原生产的。为了验证该协议的准确性，我们分析了一块现代骨骼和四个以前年代的碎片，包括来自第六次国际放射性碳比对 (SIRI) 的碎片，以及来自巴西贝丘 Amourins 遗址的人类骨骼碎片。已知年龄材料的结果与预期一致，根据不同地层中发现的木炭测年进行的年代模型，所研究的 Amourins shellmound 扇区的日期为 4100-3900 年 cal BP。样品在巴西联邦弗鲁米嫩塞大学 (LAC-UFF) 的放射性碳实验室进行了测定。