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Importance of the interaction between sodium silicate and organic materials to astrobiology: alcohol-based organo-silicates as potential biosignatures
Author(s): Patrick J. Liesch; Vera M. Kolb
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Paper Abstract

We have found that alcohols catalyze a rapid polymerization of silicic acid to silica gel upon the addition of alcohols. Like amino acids, alcohols could be preserved in the silica gel by two mechanisms. In the first mechanism, the alcohols become entombed in the silica gel. In this case, only Si-O-Si bonds would be observed in the infrared (IR) spectra. In the second mechanism, the alcohols make chemical bonds with the silicic acid, to create organo-silicates. In this case, Si-O-C bonds would be observed in the IR. We have found that steric hindrance plays a major role in the volume of an alcohol required. Amino alcohols are more effective in creating a viscous gel than the alcohols, and appeared to form covalent Si-O-C bonds in some cases. Characteristic shifts in the Si-O-Si bands of over 50 cm-1 towards lower IR frequencies can be observed in the alcohol gels. The hydrolysis of known organo-silicates has led to the identification of the Si-O-C band in the region of 1225-1150 cm-1, and the Si-O-Si band in the region of 1125-1000 cm-1. Alcohols play an important role in many biological pathways, and could serve as biosignatures in extreme environments including meteorites and other planets.

Paper Details

Date Published: 1 October 2007
PDF: 10 pages
Proc. SPIE 6694, Instruments, Methods, and Missions for Astrobiology X, 669405 (1 October 2007); doi: 10.1117/12.731345
Show Author Affiliations
Patrick J. Liesch, Univ. of Wisconsin-Parkside (United States)
Vera M. Kolb, Univ. of Wisconsin-Parkside (United States)

Published in SPIE Proceedings Vol. 6694:
Instruments, Methods, and Missions for Astrobiology X
Richard B. Hoover; Gilbert V. Levin; Alexei Y. Rozanov; Paul C. W. Davies, Editor(s)

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