TMAH Thermochemolysis of a Martian Regolith Simulant: Optimization of an Analytical Method for the Detection of Trace Organic Matter by the MOMA-Pyr-GC-MS Experiment Onboard the ExoMars-2020 Rover

The Mars Organic Molecule Analyzer (MOMA) experiment onboard the ExoMars 2020 rover is mainly dedicated to the search for organic material in the Martian surface and subsurface (down to 2 meters). MOMA has two operational modes: Laser Desorp-tion/Ionization-Mass Spectrometry (LDI-MS) and Pyrolysis Gas Chromatography-Mass Spectrometry (Pyr-GC-MS). Two derivatization reagents onboard the MOMA experiment will allow the chiral separation (DMF-DMA) and the analysis of refractory compounds (MTBSTFA), making them more volatile and protecting the labile chemical groups. In order to improve the Pyr-GC-MS analysis, TMAH (tetramethylammonium hydroxide) will be used on MOMA to extract refracto-ry compounds (macromolecules, kerogen, etc.) and protect polar compounds released from the pyrolysis experiment. We performed pyrolysis and TMAH-thermochemolysis of a Martian regolith simulant within operating conditions similar to the MOMA ones with the aim of optimizing the analytical parameters, especially the thermochemolysis temperature, and ensuring the success of the future in situ molecular analysis on Mars.