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Communication Dans Un Congrès Année : 2018

Optimization of the Sample Pre-Treatment and Wet Chemistry Experiments on Mars Organic Molecules Analyzer (moma), EXOMARS2020

Résumé

The Mars Organic Molecule Analyzer (MOMA) experiment aboard the ExoMars 2020 rover will analyze the catalog of organic molecules present in samples collected at the surface and subsurface (down to 2 meters) of Mars. MOMA has two complementary analytical modes: Laser Desorption/Ionization-Mass Spectrometry (LDI-MS) and pyrolysis-Gas Chromatography-Mass Spectrometry (Pyr-GC-MS). In addition to the pyrolysis analysis, three types of derivatization reagents are present in nine capsules (9 out of 30 total cups) and can be used to enable the analysis of refractory compounds by increasing their volatility and protecting labile chemical groups via (N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide - MTBSTFA, dimethylformamide dimethyl-acetal - DMF-DMA and tetramethylammonium hydroxide TMAH). MTBSTFA is the most versatile reagent. It is dedicated to analyze the labile compounds with a very high sensitivity. DMF-DMA preserves the chiral center of molecules and will allow for their enantiomeric separation. TMAH will be used to extract and characterize potential refractory compounds (macromolecules, kerogen, etc.) and protect polar compounds (alkylation) released from the pyrolysis experiment. In the context of the Exomars 2020 mission and the MOMA experiment, these three techniques have been optimized (volume of reagent, temperature, time of reaction) and tested on several martian analogues. The effect of the presence of perchlorate on each reagent has been examined. By using pyrolysis, DMF/DMA, MTBSTFA and TMAH derivatization chemistry, the MOMA experiment will be able to characterize the presence and the amount of key molecules indicating prebiotic chemistry and life (e.g. amino acids) as well as the enantiomeric ratio of key chiral molecules, used as a bioindicator. These measurements will also give us a first insight into the potential presence of living organisms in the soil of Mars.
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Dates et versions

insu-04505426 , version 1 (14-03-2024)

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Arnaud Buch, Francois Raulin, Harald Steininger, Cyril Szopa, Fabien Stalport, et al.. Optimization of the Sample Pre-Treatment and Wet Chemistry Experiments on Mars Organic Molecules Analyzer (moma), EXOMARS2020. 42nd COSPAR Scientific Assembly, Jul 2018, Pasadena, United States. pp.Abstract id. F3.7-14-18. ⟨insu-04505426⟩
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