| Summary: | International audience Amongst the SAM suite of instruments, SAM-GC (Gas Chromatograph) is devoted to identify and quantify volatiles evolved from the thermal/chemical treatment of any soil sample collected by the Curiosity rover. The first soil samples analyzed with SAM were composed of windblown dust and sand collected at the Rocknest site, while the second site analyzed was a basin called “Yellowknife Bay” where two holes were drilled (John Klein & Cumberland) and analysis showed these sites to be a fluvio-lacustrine sediment. For their analysis, these samples were subjected to a pyrolysis at temperatures reaching about 850°C. For SAM-GC and GCMS analyses, different fractions of pyrolysates were collected at different temperature in the ambient-900°C range in order to discriminate potential different volatile fractions present in the solid sample. With the aim to search for potential organic molecules outgassed from the samples, a SAM-GC analytical channel composed of a thermal-desorption injector and a MXT-CLP chromatographic column was used as it was designed for the separation of a wide range of volatile organic molecules. This channel is also equipped with a thermal conductivity detector (TCD) capable to detect the most abundant species (with abundances down to approximately 10-10mol). His channel is thus complementary to the mass spectrometer detection for quantification of such species, as this last instrument does not have linear response in this domain of high abundance, whereas it is significantly more sensitive than the TCD. The results obtained with this instrument first show that the performances of SAM-GC is representative of those obtained during calibrations of the instrument in laboratory, and also that results are repeatable. Hence, the instrument performs nominally, making it the first GCMS running successfully on Mars since the Viking missions (middle of the 70’s). Moreover, the complementarity of GC towards MS is also shown, both by allowing the quantification of the major species ...
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