Search for Organic Material on Mars with the Thermochemolysis Derivatization Technique Onboard the MOMA Experiment

Abstract

International audienceAfter the SAM experiment onboard the Curiosity rover, the Mars Organic Molecule Analyzer (MOMA) experiment onboard the future ExoMars mission will be the continuation of the search for the organic composition of the Mars surface. MOMA will have the advantage of extracting the sample from as deep as 2 meters below the martian surface to minimize effects of radiation and oxidation on organic materials. To analyse the wide range of organic compounds (volatile and non volatils compounds) penten-tially present in the martian soil MOMA includes two operational modes: UV laser desorption / ionization ion trap mass spectrometry (LDI-ITMS) and pyrolysis gas chromatography ion trap mass spectrometry (pyr-GC-ITMS). In order to analyse refractory organic compounds and chirality samples which undergo GC-ITMS analysis may be submitted to a derivatization process, consisting in the reaction of the sample components with specific reactants (MTBSTFA [1], DMF-DMA [2] or TMAH [3]). To prove the feasibility of the derivatization within the MOMA conditions we have adapated our laboratory procedure to the space conditions (temperature, time, pressure and size) in order to decrease our detection limits and increase the range of the organic compounds that MOMA will be able to detect. Here, we only discuss the optimization of the thermochemiolysis technique