Please use this identifier to cite or link to this item:
http://dspace.mediu.edu.my:8181/xmlui/handle/10261/5034| Title: | The limitations on organic detection in Mars-like soils by thermal volatilization–gas chromatography–MS and their implications for the Viking results |
| Authors: | Universidad Nacional Autónoma de México Consejo Nacional de Ciencia y Tecnología (México) National Aeronautics and Space Administration (US) |
| Keywords: | Astrobiology Deserts Detection of organics Search for martian life Extreme environments |
| Publisher: | National Academy of Sciences (U.S.) |
| Description: | Copyright © by National Academy of Sciences.-- La versión original está disponible en http://www.pnas.org/content/vol103/issue44/.-- Supplementary material available at: http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1621051#supplementary-material-sec The failure of Viking Lander thermal volatilization (TV) (without or with thermal degradation)–gas chromatography (GC)–MS experiments to detect organics suggests chemical rather than biological interpretations for the reactivity of the martian soil. Here, we report that TV–GC–MS may be blind to low levels of organics on Mars. A comparison between TV–GC–MS and total organics has been conducted for a variety of Mars analog soils. In the Antarctic Dry Valleys and the Atacama and Libyan Deserts we find 10–90 μg of refractory or graphitic carbon per gram of soil, which would have been undetectable by the Viking TV–GC–MS. In iron-containing soils (jarosites from Rio Tinto and Panoche Valley) and the Mars simulant (palogonite), oxidation of the organic material to carbon dioxide (CO2) by iron oxides and/or their salts drastically attenuates the detection of organics. The release of 50–700 ppm of CO2 by TV–GC–MS in the Viking analysis may indicate that an oxidation of organic material took place. Therefore, the martian surface could have several orders of magnitude more organics than the stated Viking detection limit. Because of the simplicity of sample handling, TV–GC–MS is still considered the standard method for organic detection on future Mars missions. We suggest that the design of future organic instruments for Mars should include other methods to be able to detect extinct and/or extant life. This work was supported by National Autonomous University of Mexico Grant DGAPAIN101903 and National Council of Science and Technology of Mexico Grant 45810-F and by the National Aeronautics and Space Administration Astrobiology Science and Technology for Exploring Planets program. Peer reviewed |
| URI: | http://dspace.mediu.edu.my:8181/xmlui/handle/10261/5034 |
| Other Identifiers: | Proc Natl Acad Sci U S A. 2006 October 31; 103(44): 16089–16094 1091-6490 http://hdl.handle.net/10261/5034 10.1073/pnas.0604210103 |
| Appears in Collections: | Digital Csic |
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.