IN SITU ANALYSIS OF THE MARTIAN SOIL: DECODING COMPLEX CHROMATOGRAMS OF ORGANIC MOLECULES OF EXOBIOLOGICAL INTEREST

摘要

A chemometric method is described to interpret the gas chromatography-mass spectrometry (GC-MS) chroma-tograms of carboxylic acids. The method is suitable to the in situ analysis of prebiotic molecules in Mars exploration, in particular of amino and carboxylic acids, chemical indicators of life. The method is based on the AutoCovariance Function (ACVF) in order to extract information on the sample-number and chemical structure of the components-and on the separation performance. The procedure was applied to standard samples containing targeted compounds which are expected to be present in the Martian soil: n-alkanoic and benzenedicarboxylic acids. ACVF was computed on the obtained chromatograms and plotted vs. retention time: peaks of the ACVF plot can be related to specific molecular structures and are diagnostic for chemical identification of compounds.