Development of a gas chromatography compatible Sample Processing System (SPS) for the in-situ analysis of refractory organic matter in martian soil: preliminary results

In the frame of the 2009 Mars Science Laboratory (MSL) mission a new sample preparation system (SPS) compatible with gas chromatography–mass spectrometry (GC–MS) has been developed for the in situ analysis of complex organic molecules in the Martian soil. The goal is to detect, if they exist, some of the key compounds that play an important role in life on Earth including carboxylic acids, amino acids and nucleobases.Before analysis by GC–MS, all the targeted refractory compounds trapped in the soil sample must be extracted and chemically transformed (derivatization). The extraction is carried out in a two step process which requires the separation and evaporation of the extraction solvent in order to concentrate the organic compounds of interest. To improve the compatibility of the technique for spaceflight a one step procedure is performed using only a thermal processing for the extraction step.These two extraction methods are followed by a derivatization step which uses MTBSTFA (N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide).The sample preparation methods have been tested on “spiked” soil and on Atacama Desert soil coming from the aridest part of the desert located in Chile. All the targeted compounds have been detected by these two procedures, demonstrating the applicability of the technique for in-situ analysis. The one step procedure has been successfully tested on Atacama soil samples with a laboratory pilot reactor, developed for this study, within representative space operating conditions.