Mechanisms of lipid preservation in archaeological clay ceramics revealed by mass spectrometry imaging
Mechanisms of lipid preservation in archaeological clay ceramics revealed by mass spectrometry imaging
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DOI：
10.1073/pnas.1922445117
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发表时间：
2020-06-30
影响因子：
11.1
通讯作者：
Cramp, Lucy J. E.
中科院分区：
文献类型：
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作者：
Hammann, Simon;Scurr, David J.;Cramp, Lucy J. E.
在陶瓷器皿的无机基质中吸收并保存了数千年的脂质痕迹，充当分子化石，并提供有关过去人们的生存，饮食和仪式的多种信息。人们普遍认为脂质在吸附到纳米至微米尺寸的孔中后被保存下来，但直到今天，这些脂质在陶瓷中的分布实际上是未知的，这严重限制了我们对脂质保存过程的理解。在这里，我们使用二次离子质谱（西姆斯）成像直接原位分析700至2,000年前的考古陶器中吸收的脂质。在从较大碎片中切片后，将较小碎片的壁横截面用于西姆斯分析。脂质被发现在相对较大的区域5- 400 μ m的直径，这并不支持的概念，仅吸收到个人的纳米级孔，但表明，更宏观的结构中的陶瓷参与脂质保存以及。此外，发现陶瓷中的脂质集中在碳酸钙包裹体上，这表明脂肪酸以钙盐形式沉淀是考古样品中脂质保存的一个重要方面。这对基于从考古陶瓷中提取脂质的分析方法具有重要意义，需要考虑最大限度地提高每个独特样品的产量和可用信息。
Traces of lipids, absorbed and preserved for millennia within the inorganic matrix of ceramic vessels, act as molecular fossils and provide manifold information about past people's subsistence, di-et, and rituals. It is widely assumed that lipids become preserved after adsorption into nano-to micrometer-sized pores, but to this day the distribution of these lipids in the ceramics was virtu-ally unknown, which severely limits our understanding about the process of lipid preservation. Here we use secondary ion mass spectrometry (SIMS) imaging for direct in situ analysis of lipids absorbed in 700-to 2,000-y-old archaeological pottery. After sec-tioning from larger sherds, wall cross-sections of smaller frag-ments were used for SIMS analysis. Lipids were found in relatively large zones of 5-to 400-mu m diameter, which does not support the notion of absorption only into individual nanometer-scale pores but indicates that more macroscopic structures in the ceramics are involved in lipid preservation as well. Furthermore, lipids were found concentrated on calcium carbonate inclusions in the ceramics, which suggests that precipitation of fatty acids as calcium salts is an important aspect of lipid preservation in archae-ological samples. This has important implications for analytical methods based on extraction of lipids from archaeological ce-ramics and needs to be considered to maximize the yield and avail-able information from each unique sample.