Chemical derivatization of amino acids for in situ analysis of Martian samples by gas chromatography.

Three different methods of derivatization are tested in order to select and optimize one for the in situ analysis of amino acids in Martian samples. The silylation procedure can easily be automated with a high yield and a linear response in a large range of concentrations. The alkylation method is simple and easily automated, but irreproducible data are obtained for the reaction in the GC liner at quite a high temperature (300 degrees C). Moreover by-products of the reaction interfere in the GC chromatograms and mass spectrometry detection is needed for product identification. The chloroformate derivatization has several advantages such as one-step reaction and short time analysis. The main problem of this procedure is the shaking step which difficult to develop in space application.