Caroline J. Rodier

DETECTION OF MARTIAN AMINO ACIDS BY CHEMICAL DERIVATIZATION COUPLED TO GAS CHROMATOGRAPHY : IN SITU AND LABORATORY ANALYSIS

If there is, or ever was, life in our solar system beyond the Earth, Mars is the most likely place to search for. Future space missions will have then to take into account the detection of prebiotic molecules or molecules of biological significance such as amino acids. Techniques of analysis used for returned samples have to be very sensitive and avoid any chemical or biological contamination whereas in situ techniques have to be automated, fast and low energy consuming. Several possible methods could be used for in situ amino acid analyses on Mars, but gas chromatography would likely be the most suitable. Returned samples could be analyzed by any method in routine laboratory use such as gas chromatography, already successfully performed for analyses of organic matter including amino acids from martian meteorites. The derivatization step, which volatilizes amino acids to perform both in situ and laboratory analysis by gas chromatography, is discussed here.

Identification of amino acids by capillary gas chromatography. Application to martian samples

SummaryIn the search for extant or extinct life on Mars, determination of amino acids and their chirality is of prime interest. For in-situ measurement the most suitable analytical method is currently gas chromatography combined with mass spectrometry (GC-MS). Derivatization, which is needed for analysis of amino acids by GC, has never been performed in space. We present here a one step-silylation method and compare the separation and the sensitivity with those of a double-step derivatization technique (N-pentafluoropropanoylisopropyl ester derivatives) performed in laboratories. The chiral separation of the fluorinated amino acids on two chiral columns shows the complementarity of the columns for resolution of the different enantiomers of α-hydrogenated and α-dialkyl amino acids.