Solvent extraction and chemical derivatization of organic molecules of exobiological interest for in situ analysis of the martian soil
Abstract
Mars is presently the most likely planet on which there is a possibility of finding extinct and/or extant life. The next exploratory missions to Mars will focus on key organic molecules such as carboxylic and amino acids. In the frame of the preparation of the Sample Analysis on Mars (SAM) GC/MS-based experiment aiming at performing in situ chemical analysis of the Martian soil, the development of an automated extraction process coupled to chemical derivatization is under investigation. This paper presents a solid-liquid extraction method (1) able to perform in situ extraction of organic compounds on Mars. The extraction efficiency of various organic solvents has been tested (and compared to that of water), first on standard soil samples and then, on Martian soil analogues such as the Akatama desert (Chili) soil (2). It was shown that propanol is the best solvent, allowing high extraction yields for both amino and carboxylic acids with space compatible extraction time (15 to 30 min) when the extraction procedure is assisted by sonication. A highly sensititive and quantitative single-step derivatization reaction using as N-methyl, N-tert.-butyl (dimethylsilyl) trifluoroacetamide (MTBSTFA) silylation agent was then used, prior to GC/MS analysis. The development of a miniaturized reactor, where both the extraction and the derivatization processes could take place is currently under investigation. This method is discussed for an easy automation with coupling to an in situ GC-MS space instrument. (1) A. Buch et al., J.of Chrom. A, 999 (2003) 165-174 (2) R. Navarro-Gonzàlez et al., Science 302 (2003) 1018-1021
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.1669B