Gordon Peter R, Sephton Mark A
Impacts and Astromaterials Research Centre, Department of Earth Science and Engineering, Imperial College London , London, UK.
Astrobiology. 2016 Nov;16(11):831-845. doi: 10.1089/ast.2016.1485.
Returning samples from Mars will require an effective method to assess and select the highest-priority geological materials. The ideal instrument for sample triage would be simple in operation, limited in its demand for resources, and rich in produced diagnostic information. Pyrolysis-Fourier infrared spectroscopy (pyrolysis-FTIR) is a potentially attractive triage instrument that considers both the past habitability of the sample depositional environment and the presence of organic matter that may reflect actual habitation. An important consideration for triage protocols is the sensitivity of the instrumental method. Experimental data indicate pyrolysis-FTIR sensitivities for organic matter at the tens of parts per million level. The mineral matrix in which the organic matter is hosted also has an influence on organic detection. To provide an insight into matrix effects, we mixed well-characterized organic matter with a variety of dry minerals, to represent the various inorganic matrices of Mars samples, prior to analysis. During pyrolysis-FTIR, serpentinites analogous to those on Mars indicative of the Phyllocian Era led to no negative effects on organic matter detection; sulfates analogous to those of the Theiikian Era led, in some instances, to the combustion of organic matter; and palagonites, which may represent samples from the Siderikian Era, led, in some instances, to the chlorination of organic matter. Any negative consequences brought about by these mineral effects can be mitigated by the correct choice of thermal extraction temperature. Our results offer an improved understanding of how pyrolysis-FTIR can perform during sample triage on Mars. Key Words: Mars-Life-detection instruments-Search for Mars' organics-Biosignatures. Astrobiology 16, 831-845.
从火星带回样本需要一种有效的方法来评估和选择优先级最高的地质材料。用于样本分类的理想仪器应操作简单、资源需求有限且能产生丰富的诊断信息。热解-傅里叶变换红外光谱法（热解-FTIR）是一种具有潜在吸引力的分类仪器，它既考虑了样本沉积环境过去的宜居性，又考虑了可能反映实际居住情况的有机物质的存在。分类方案的一个重要考虑因素是仪器方法的灵敏度。实验数据表明，热解-FTIR对百万分之几十水平的有机物质具有灵敏度。承载有机物质的矿物基质也会对有机物质的检测产生影响。为了深入了解基质效应，我们在分析之前，将特征明确的有机物质与各种干燥矿物混合，以代表火星样本的各种无机基质。在热解-FTIR过程中，类似于火星上菲洛西亚时代的蛇纹岩对有机物质检测没有负面影响；类似于西基肯时代的硫酸盐在某些情况下会导致有机物质燃烧；而可能代表西德里肯时代样本的蒙脱石在某些情况下会导致有机物质氯化。通过正确选择热萃取温度，可以减轻这些矿物效应带来的任何负面影响。我们的结果有助于更好地理解热解-FTIR在火星样本分类过程中的表现。关键词：火星-生命探测仪器-寻找火星上的有机物-生物特征。天体生物学16，831 - 845。
