Comparison of soluble and insoluble organic matter in analogues of Titan's aerosols
Comparison of soluble and insoluble organic matter in analogues of Titan's aerosols
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DOI：
10.1016/j.epsl.2018.05.014
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发表时间：
2018-08-01
影响因子：
5.3
通讯作者：
Afonso, Carlos
中科院分区：
文献类型：
--
作者：
Maillard, Julien;Carrasco, Nathalie;Afonso, Carlos
土卫六是土星最大的卫星，它有一个厚厚的大气层，与地球上最初被认为的大气层相似。因此，对土卫六光化学烟雾的研究是了解地球原始大气的宝贵工具。土卫六大气中发生的化学反应以及形成烟雾的确切过程在很大程度上仍然未知。在地球上生产类似物样品已被证明是一种有用的工具，可以提高我们对土卫六上气溶胶形成的认识。这种固体有机类似物样品，命名为托林，是用PAMPRE实验（通过反应等离子体产生气溶胶微重力的法语首字母缩写）产生的。发现PAMPRE托林大部分是不溶的，只有三分之一的本体样品可以溶解在甲醇中。这种部分溶解度限制了质谱法中先前的研究，这些研究仅对可溶性级分进行。本研究的目的是比较两个馏分的PAMPRE的托林（不溶性和可溶性）使用超高分辨率傅里叶变换离子回旋共振质谱仪（FTICR）配备了激光解吸/电离源。利用改进的货车Krevelen图，我们根据氢/碳比和氮/碳比比较了样品中分子的全局分布。在可溶性和不溶性部分的分子组成中观察到主要差异。托林的可溶部分先前被鉴定为一组平均分子式为（C2 H3 N）（n）的聚合物。在这项工作中，我们观察到的不溶性部分的托林是由一个显着不同的一组聚合物的平均组成（C4 H3 N2）（n）。(C)2018爱思唯尔B. V.保留所有权利。
Titan, the biggest moon of Saturn, has a thick atmosphere which presents similarities with the one thought to be on Earth at its beginning. The study of Titan's photochemical haze is thus a precious tool in gaining knowledge of the primitive atmosphere of Earth. The chemistry occurring in Titan's atmosphere and the exact processes at act in the formation of the hazes remain largely unknown. The production of analogs samples on Earth has proved to be a useful tool to improve our knowledge of the aerosols formation on Titan. Such solid organic analogs samples, named tholins, were produced with the PAMPRE experiment (French acronym for Aerosols Microgravity Production by Reactive Plasma). PAMPRE tholins were found to be mostly insoluble, with only one-third of the bulk sample that can be dissolved in methanol. This partial solubility limited the previous studies in mass spectrometry, which were done only on the soluble fraction. The goal of the present study is to compare the two fractions of PAMPRE's tholins (insoluble and soluble) using a ultra-high resolution Fourier transform ion cyclotron resonance mass spectrometer (FTICR) equipped with a laser desorption/ionization source. Using modified Van Krevelen diagrams, we compare the global distribution of the molecules within the samples according to their Hydrogen/Carbon ratio and Nitrogen/Carbon ratio. Major differences are observed in the molecular composition of the soluble and the insoluble fraction. The soluble fraction of tholins was previously identified as a set of polymers of average formula (C2H3N)(n). In this work we observe that the insoluble fraction of tholins is comprised of a significantly different set of polymers with an average composition of (C4H3N2)(n). (C) 2018 Elsevier B.V. All rights reserved.