Natural Resources Institute Finland, Latokartanonkaari 9, Helsinki, 00790, Finland.
Laboratory of Chronology, Finnish Museum of Natural History, Gustaf Hällstömin katu 2a, Helsinki, Finland.
Rapid Commun Mass Spectrom. 2020 Nov 15;34(21):e8877. doi: 10.1002/rcm.8877.
Stable isotope analyses are used on precious archeological and paleontological materials despite their destructive nature, because the information gained by these methods on, for example, feeding habits, migration and health of individuals cannot otherwise be obtained. We approached this issue by devising a new sequential extraction scheme aimed at producing multiple (O, C, N) isotope proxies from small amounts of sample.
The new extraction scheme includes dissolution of the bone in dilute HNO followed by separate treatments of the collagenous and phosphate fractions. The collagen fraction is treated further adopting the methods presented in the literature for collagen extraction, modified to accommodate small sample sizes. The phosphate-containing fraction is purified from organic contaminants by H O and the phosphate is precipitated as Ag PO following methods presented in the literature. The use of HF as demineralization agent is also tested.
A starting amount of ca 2 mg produced enough material for meaurement by isotope ratio mass spectrometry of the collagen C and N isotope compositions and bone phosphate O isotope composition. We show that the isotopic data obtained from the sequential extraction scheme are comparable with the isotopic composition measured following conventional methodologies that are usually based on 100-500 mg sample sizes.
The new sequential extraction scheme combines the preparation for stable isotope analysis of bone mineral and organic phases, thus minimizing the amounts of sample needed and damage caused on a sample piece. The method may allow analysis of skeletal samples previously excluded from isotope analysis due to material limitations.
尽管具有破坏性，但稳定同位素分析仍被用于珍贵的考古学和古生物学材料，因为这些方法可以提供有关个体的饮食习惯、迁徙和健康等信息，而这些信息无法通过其他方法获得。我们通过设计一种新的连续提取方案来解决这个问题，该方案旨在从小量样品中产生多种（O、C、N）同位素代用指标。
新的提取方案包括在稀 HNO 中溶解骨骼，然后分别处理胶原和磷酸盐部分。胶原部分进一步采用文献中提出的胶原提取方法进行处理，方法经过修改以适应小样本量。含磷酸盐部分通过 H O 从有机污染物中纯化，磷酸盐沉淀为 Ag PO 采用文献中提出的方法。还测试了 HF 作为脱矿剂的用途。
起始量约为 2mg 即可产生足够的材料，用于通过同位素比质谱法测量胶原 C 和 N 同位素组成以及骨磷酸盐 O 同位素组成。我们表明，从连续提取方案获得的同位素数据与通常基于 100-500mg 样品量的常规方法测量的同位素组成相当。
新的连续提取方案结合了骨矿物质和有机相的稳定同位素分析准备工作，从而最大限度地减少了所需的样品量和对样品的破坏。该方法可能允许分析由于材料限制而以前被排除在同位素分析之外的骨骼样品。
