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.

碳氢化合物气体在宇宙和地圈中很常见。碳氢化合物气体的生物或非生物来源往往是辩论的主题，其强度取决于碳氢化合物气体的位置和可用于解决任何不确定性的信息量。不幸的是，烃类气体可能是相对信息贫乏的化合物。它们的小尺寸使得它们的分子结构无法诊断来源。不同碳原子数的气体模式确实提供了一些信息，但这些化合物中信息最丰富的部分是原子本身。构成碳氢化合物骨架的碳原子含有两种稳定的同位素，碳12和碳13。较轻的碳同位素比较重的碳同位素反应性更强，更容易参与反应。反应产物中较轻碳同位素的优先掺入导致同位素分馏，并且可以揭示合成机理。非生物烃通常显示碳-12随碳数的增加，这与从较简单的前体动力学控制合成较高分子量同系物一致雅阁。相反，高分子量生物衍生烃的热裂解产生相反的趋势，即碳-12随碳数减少。本项目将探索与非生物过程（如吸附和解吸）相关的烃类气体的组成和模式，并将其与通常与生命相关的模式进行比较。该产品应改进标准，区分与生物或非生物起源的气体成分的签名。在伦敦帝国理工学院，我们开发了一种定制的解吸池，可以将代表性样品的粉末或塞子装入其中。已知体积和成分的气体可以被引入并吸附到内容物上，然后通过减压释放。使用耦合的在线气相色谱-火焰离子化检测器（GC-FID）和在线气相色谱-同位素比质谱法对从解吸单元回收的气体进行测量（GC-C-IRMS）系统，分别研究分子量和稳定碳同位素分馏。该项目的结果将对早期太阳系挥发物和大气的演化产生影响，对火星上任何生命产生的气体的认识，以及地球上石油矿床的非生物形成理论。