The volatile fingerprints of life - a new method to indicate the biological or non-biological sources of gas

生命的挥发性指纹——指示气体的生物或非生物来源的新方法

• 批准号: 2759212
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2759212
• 关键词: volatile; fingerprints; life; new; method

Hydrocarbon gases are common in the Cosmos and the geosphere. The biological or non-biological source of hydrocarbon gases is often the subject of debate, the intensity of which depends on the location of the hydrocarbon gas and the amount of information available to settle any uncertainty. Unfortunately, hydrocarbon gases can be relatively information poor compounds. Their small size makes their molecular architecture undiagnostic of source. Patterns of gases with different numbers of carbon atoms do provide some information but the most information rich part of these compounds is within the atoms themselves.The carbon atoms that make up the skeleton of hydrocarbons contain two stable isotopes, carbon-12 and carbon-13. The lighter carbon isotope is more reactive than its heavier counterpart and takes part in reactions more readily. The preferential incorporation of the lighter carbon isotope in reaction product leads to isotope fractionation and can reveal synthetic mechanisms. Non-biological hydrocarbons generally reveal an increase in carbon-12 with carbon number in accord with the kinetically controlled synthesis of higher molecular weight homologues from simpler precursors. By contrast the thermal cracking of high molecular weight biologically-derived hydrocarbons produces the opposite trend where a decrease in carbon-12 with carbon number is observed.This project will explore the compositions and patterns in hydrocarbon gases associated with abiological processes such as adsorption and desorption and compare these to patterns typically associated with life. The product should be improved criteria for distinguishing gas compositional signatures associated with biological or abiological origins. At Imperial College London we have developed a custom-built desorption cell into which powders or plugs of representative samples can be loaded. Known volumes and compositions of gas can be introduced and adsorbed onto the contents and then released by depressurization. Measurement of the gas recovered from the desorption cell is performed using coupled online gas chromatography - flame ionising detector (GC-FID) and online gas chromatography - isotope ratio mass spectrometry (GC-C-IRMS) systems to study molecular weight and stable carbon isotopic fractionation respectively.The results of the project will have implications for the evolution of volatiles and atmospheres in the early solar system, the recognition of gases from any life on Mars and theories of abiotic formation of petroleum deposits on Earth.

烃类气体在宇宙和地质圈中很常见。碳氢化合物气体的生物学或非生物学来源通常是争论的主题，其强度取决于碳氢化合物的位置以及可用于解决任何不确定性的信息量。不幸的是，碳氢化合物气体可能是相对信息较差的化合物。它们的小尺寸使他们的分子体系结构无诊断。具有不同数量的碳原子的气体的模式确实提供了一些信息，但是这些化合物的最丰富部分在原子本身内。构成碳氢化合物骨骼的碳原子包含两个稳定的同位素，Carbon-12和Carbon-13。较轻的碳同位素比其重的同位素更具反应性，并且更容易参与反应。较轻的碳同位素在反应产物中的优先掺入会导致同位素分馏，并可以揭示合成机制。非生物学碳氢化合物通常揭示了碳数量增加，碳数与动力学控制的较简单前体的较高分子量同源物的合成一致。相比之下，高分子量生物学衍生的碳氢化合物的热开裂产生相反的趋势，在观察到碳-12随碳数量下降时。该项目将探索与诸如吸附和脱水及其与模式相比，与生命相关的碳氢化合物中的组合物和模式。该产品应改进与生物学或原始起源相关的气体组成标志的标准。在伦敦帝国学院，我们开发了一个定制的解吸细胞，可以在其中加载粉末或插头。可以将已知的气体和气体组成引入并吸附到内容上，然后通过降压释放。使用耦合的在线气体色谱 - 火焰电离探测器（GC-FID）和在线气相色谱 - 同位素比率质谱（GC-C-rigns）系统分别研究分子量和稳定的碳同位素分数的测量结果。识别火星上任何生命的气体和地球上石油沉积物的非生物形成理论。