The amino acid and polycyclic aromatic hydrocarbon compositions of the promptly recovered CM2 Winchcombe carbonaceous chondrite
The amino acid and polycyclic aromatic hydrocarbon compositions of the promptly recovered CM2 Winchcombe carbonaceous chondrite
复制标题
DOI：
10.1111/maps.13936
复制
发表时间：
2023-01-09
影响因子：
2.2
通讯作者：
Hallis, Lydia J.
中科院分区：
文献类型：
--
作者：
Chan, Queenie H. S.;Watson, Jonathan S.;Hallis, Lydia J.
温奇康贝陨石的快速回收提供了一个宝贵的机会，研究原始碳质天体材料中的可溶性有机质（SOM）的配置文件。我们的兴趣，在生物相关的分子，氨基酸单体的蛋白质，和最普遍的陨石有机物-多环芳烃（PAHs）的解决，通过分析溶剂提取物的温奇康贝陨石使用气相色谱质谱。温奇康贝陨石样本中的氨基酸丰度约为1132 ppm，比其他CM 2陨石低10倍。地球上罕见的氨基酸的检测，包括α-氨基异丁酸（AIB）;异缬氨酸; β-丙氨酸; α-，β-和γ-氨基-正丁酸;和5-氨基戊酸，和外消旋对映体的比例（D/L = 1）观察丙氨酸和异缬氨酸表明，这些氨基酸是本土的陨石，而不是陆地污染物。主要α-AIB和异缬氨酸的存在与其通过Strecker-氰醇合成途径形成一致。之前观察到的含水蚀变陨石中异缬氨酸的L-对映体过量被视为母体含水处理的指标;因此，观察到温奇康贝的异缬氨酸外消旋比，以及整体高游离：总氨基酸比，和低氨基酸浓度表明，分析的石头是来自经历了短暂的含水蚀变的岩性。温奇康贝还含有2- 6环烷基化和非烷基化的多环芳烃。低的总多环芳烃丰度（6177 ppb）和高的非烷基化：烷基化的比例是不同的，观察到的严重含水蚀变CM。弱的岩相学性质的温奇康贝，以及观察到的差异为温奇康贝SOM含量低的总氨基酸丰度相比，严重改变的CM，但高的游离：总氨基酸和非烷基化：烷基化PAH的比例是与较少改变CM的建议，温奇康贝可以代表一类弱，不良锂化陨石没有以前研究。
The rapid recovery of the Winchcombe meteorite offers a valuable opportunity to study the soluble organic matter (SOM) profile in pristine carbonaceous astromaterials. Our interests in the biologically relevant molecules, amino acids-monomers of protein, and the most prevalent meteoritic organics-polycyclic aromatic hydrocarbons (PAHs) are addressed by analyzing the solvent extracts of a Winchcombe meteorite stone using gas chromatography mass spectrometry. The Winchcombe sample contains an amino acid abundance of similar to 1132 parts-per-billion that is about 10 times lower than other CM2 meteorites. The detection of terrestrially rare amino acids, including alpha-aminoisobutyric acid (AIB); isovaline; beta-alanine; alpha-, beta-, and gamma-amino-n-butyric acids; and 5-aminopentanoic acid, and the racemic enantiomeric ratios (D/L = 1) observed for alanine and isovaline indicate that these amino acids are indigenous to the meteorite and not terrestrial contaminants. The presence of predominantly alpha-AIB and isovaline is consistent with their formation via the Strecker-cyanohydrin synthetic pathway. The L-enantiomeric excesses in isovaline previously observed for aqueously altered meteorites were viewed as an indicator of parent body aqueous processing; thus, the racemic ratio of isovaline observed for Winchcombe, alongside the overall high free:total amino acid ratio, and the low amino acid concentration suggest that the analyzed stone is derived from a lithology that has experienced brief episode(s) of aqueous alteration. Winchcombe also contains 2- to 6-ring alkylated and nonalkylated PAHs. The low total PAHs abundance (6177 ppb) and high nonalkylated:alkylated ratio are distinct from that observed for heavily aqueously altered CMs. The weak petrographic properties of Winchcombe, as well as the discrepancies observed for the Winchcombe SOM content-a low total amino acid abundance comparable to heavily altered CMs, and yet the high free:total amino acid and nonalkylated:alkylated PAH ratios are on par with the less altered CMs-suggest that Winchcombe could represent a class of weak, poorly lithified meteorite not been previously studied.