The organic compositions of carbonaceous chondrite meteorites have been extensively studied; however, there have been fewer reports of other meteorite classes, and almost none from iron meteorites, which contain much less carbon than carbonaceous chondrites but make up ~4% of observed meteorite falls. Here, we report the bulk amino acid content of three iron meteorites (Campo del Cielo, IAB; Canyon Diablo, IAB; and Cape York, IIIAB) and both the metal and silicate portions of a pallasite (Imilac). We developed a novel method to prepare the samples for analysis, followed by hot water extraction and analysis via liquid chromatography‐mass spectrometry. Free amino acid abundances ranging from 301 to 1216 pmol g⁻¹ were observed in the meteorites, with the highest abundance in the silicate portion of the pallasite. Although some of the amino acid content could be attributed to terrestrial contamination, evidence suggests that some compounds are indigenous. A suite of C₅ amino acids was observed with a distinct distribution favoring a straight chain (n‐pentanoic acid) structure; this straight chain dominance is suggestive of that observed in thermally altered stony meteorites. Amino acids were also observed in terrestrial iron granules that were milled and analyzed in the same way as the meteorites, although the distribution of detected amino acids was different. It is possible that similar formation mechanisms existed in both the meteorites and the terrestrial iron, or that observed amino acids resulted from reactions of precursors during sample preparation. This work suggests that iron meteorites should not be overlooked for contributions of amino acids and likely other soluble organic molecules to the early Earth. Future studies of iron–nickel meteorites and asteroids, such as Psyche, may provide further insights into their potential organic inventory.

中文翻译：

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铁和石铁陨石中的氨基酸丰度和组成

碳质球粒陨石的有机组成已得到广泛研究。但是，其他陨石种类的报道却很少，铁陨石几乎没有报道，铁陨石的碳含量比碳质球粒陨石少得多，但约占陨石坠落量的4％。在这里，我们报告了三种铁陨石（Campo del Cielo，IAB； Canyon Diablo，IAB；和约克角，IIIAB）的总氨基酸含量，以及方铁矿（Imilac）的金属和硅酸盐部分。我们开发了一种新颖的方法来准备要分析的样品，然后进行热水萃取和通过液相色谱-质谱法进行分析。游离氨基酸丰度范围为301至1216 pmol g ^-1在陨石中观察到了最大的丰度，在陨石的硅酸盐部分中。尽管某些氨基酸含量可能归因于陆地污染，但证据表明某些化合物是本土的。观察到一组C ₅个氨基酸，具有明显的分布，有利于直链（n戊酸）结构; 这种直链优势暗示着在热蚀的石陨石中观察到的优势。在研磨和分析陨铁的地面铁颗粒中也观察到了氨基酸，尽管检测到的氨基酸分布不同。陨石和地球铁中可能存在相似的形成机理，或者观察到的氨基酸是由样品制备过程中前体的反应产生的。这项工作表明，不应忽略铁陨石中氨基酸和可能的其他可溶性有机分子对地球早期的贡献。铁镍陨石和小行星（如Psyche）的未来研究可能会为它们的潜在有机资源提供进一步的见解。