| Title: | Investigating the Effect of Perchlorate on Flight-like Gas Chromatography-Mass Spectrometry as Performed by MOMA on board the ExoMars 2020 Rover |
| Author(s): | Missbach H; Steininger H; Thiel V; Goetz W; |
| Address: | "Geobiology, Geoscience Centre, University of Goettingen, Goettingen, Germany. Max Planck Institute for Solar System Research, Goettingen, Germany. OHB System AG, Wessling-Oberpfaffenhofen, Germany" |
| ISSN/ISBN: | 1557-8070 (Electronic) 1557-8070 (Linking) |
| Abstract: | "The Mars Organic Molecule Analyzer (MOMA) instrument on board ESA's ExoMars 2020 rover will be essential in the search for organic matter. MOMA applies gas chromatography-mass spectrometry (GC-MS) techniques that rely on thermal volatilization. Problematically, perchlorates and chlorates in martian soils and rocks become highly reactive during heating (>200 degrees C) and can lead to oxidation and chlorination of organic compounds, potentially rendering them unidentifiable. Here, we analyzed a synthetic sample (alkanols and alkanoic acids on silica gel) and a Silurian chert with and without Mg-perchlorate to evaluate the applicability of MOMA-like GC-MS techniques to different sample types and assess the impact of perchlorate. We used a MOMA flight analog system coupled to a commercial GC-MS to perform MOMA-like pyrolysis, in situ derivatization, and in situ thermochemolysis. We show that pyrolysis can provide a sufficient overview of the organic inventory but is strongly affected by the presence of perchlorates. In situ derivatization facilitates the identification of functionalized organics but showed low efficiency for n-alkanoic acids. Thermochemolysis is shown to be an effective technique for the identification of both refractory and functional compounds. Most importantly, this technique was barely affected by perchlorates. Therefore, MOMA GC-MS analyses of martian surface/subsurface material may be less affected by perchlorates than commonly thought, in particular when applying the full range of available MOMA GC-MS techniques" |
| Keywords: | Exobiology/instrumentation/methods Extraterrestrial Environment/*chemistry Gas Chromatography-Mass Spectrometry/instrumentation/methods Hot Temperature/adverse effects *Mars Organic Chemicals/*analysis Oxidation-Reduction Perchlorates/*chemistry Soil/*che; |
| Notes: | "MedlineMissbach, Helge Steininger, Harald Thiel, Volker Goetz, Walter eng Research Support, Non-U.S. Gov't 2019/09/19 Astrobiology. 2019 Nov; 19(11):1339-1352. doi: 10.1089/ast.2018.1997. Epub 2019 Sep 18" |
