COMPOUND-SPECIFIC RADIOCARBON DATING OF ESSENTIAL AND NON-ESSENTIAL AMINO ACIDS: TOWARDS DETERMINATION OF DIETARY RESERVOIR EFFECTS IN HUMANS
COMPOUND-SPECIFIC RADIOCARBON DATING OF ESSENTIAL AND NON-ESSENTIAL AMINO ACIDS: TOWARDS DETERMINATION OF DIETARY RESERVOIR EFFECTS IN HUMANS
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DOI：
10.1017/s0033822200057866
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发表时间：
2013-01-01
期刊：
影响因子：
8.3
通讯作者：
Higham, Thomas
中科院分区：
文献类型：
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作者：
Nalawade-Chavan, Shweta;McCullagh, James;Higham, Thomas
当人类食用来自不同放射性碳储存库的食物时，其年龄与大气中的碳抵消，骨胶原的 C-14 日期可能会出现不准确的情况。来自多瑙河下游河谷铁门部分的中石器时代人类骨骼已经产生了长达 500 年的水库偏移。这已经通过直接测定人类骨骼中的大量胶原蛋白和嵌入其中的有蹄类动物骨骼弹射点的遗迹得到了证明（Cook 等人，2001 年）。我们对一种新型 HPLC 方法进行了改进，该方法使用不含有机或无机改性剂的纯水流动相来检测和分离未衍生化氨基酸，从而确保碳背景非常低。我们的假设是，对单一必需氨基酸和非必需氨基酸进行直接 C-14 测年可能会提高受储存库影响的人体骨骼的测年准确性。该方法有利于极性较小的氨基酸（主要是“必需”）的分离，这在最近发布的方案中目前是不可能的。我们讨论方法的发展，展示碳背景，并提出分析方法以尽量减少其影响。我们通过加速器质谱 (AMS) 测年相对现代的和 C-14 死亡、已知年龄的骨骼标准来验证该方法的精度和准确度。最后，我们将该方法应用于骨骼样本中单个氨基酸的年代测定，其结果与铁门遗址中石器时代墓葬的 500 年碳库效应类似。我们研究了必需氨基酸和非必需氨基酸的 AMS 日期是否存在差异，因为尽管是同时期的，但这些氨基酸预计源自具有不同 C-14 库的膳食来源。
When humans consume foods from different radiocarbon reservoirs offset in age to the atmosphere, inaccuracies in the C-14 date of bone collagen can occur. Mesolithic human skeletons from the Iron Gates section of the Lower Danube Valley have yielded reservoir offsets of up to similar to 500 yr. This has been demonstrated through direct dating of bulk collagen from human bones and the remains of ungulate bone projectile points that were found embedded in them (Cook et al. 2001). We present improvements to a novel HPLC method for the detection and separation of underivatized amino acids using a water-only mobile phase free of organic or inorganic modifiers, ensuring very low carbon backgrounds. Our hypothesis is that direct C-14 dating of single essential and non-essential amino acids might allow an improvement in the dating accuracy for reservoir-affected human bones. The method facilitates separation of less polar amino acids (mostly "essential"), currently not possible in the recently published protocol. We discuss methodological developments, demonstrate carbon backgrounds, and present analytical approaches to minimize their effects. We validate the precision and accuracy of the method by accelerator mass spectrometry (AMS) dating relatively modern and C-14-dead, known-age bone standards. Finally, we apply the method to the dating of single amino acids from bone samples with a proven similar to 500-yr carbon reservoir effect from Mesolithic burials at the Iron Gates sites. We investigate whether differences can be found in AMS dates for essential and non-essential amino acids since, although contemporaneous, these are expected to derive from dietary sources with differing C-14 reservoirs.