Accurate Differentiation of Carotenoid Pigments Using Flight Representative Raman Spectrometers
Language English Country United States Media print
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
28418705
DOI
10.1089/ast.2016.1547
Knihovny.cz E-resources
- MeSH
- Carotenoids analysis chemistry MeSH
- Space Flight * MeSH
- Crystallization MeSH
- Lasers MeSH
- Spectrum Analysis, Raman instrumentation MeSH
- Calcium Sulfate chemistry MeSH
- Sulfates chemistry MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Carotenoids MeSH
- Calcium Sulfate MeSH
- Sulfates MeSH
Raman spectrometers will be utilized on two Mars rover missions, ExoMars and Mars 2020, in the near future, to search for evidence of life and habitable geological niches on Mars. Carotenoid pigments are recognized target biomarkers, and as they are highly active in Raman spectroscopy, they can be readily used to characterize the capabilities of space representative instrumentation. As part of the preparatory work being performed for the ExoMars mission, a gypsum crust colonized by microorganisms was interrogated with commercial portable Raman instruments and a flight representative Raman laser spectrometer. Four separate layers, each exhibiting different coloration resulting from specific halophilic microorganism activities within the gypsum crust, were studied by using two excitation wavelengths: 532 and 785 nm. Raman or fluorescence data were readily obtained during the present study. Gypsum, the main constituent of the crust, was detected with both excitation wavelengths, while the resonance Raman signal associated with carotenoid pigments was only detected with a 532 nm excitation wavelength. The fluorescence originating from bacteriochlorophyll a was found to overwhelm the Raman signal for the layer colonized by sulfur bacteria when interrogated with a 785 nm excitation wavelength. Finally, it was demonstrated that portable instruments and the prototype were capable of detecting a statistically significant difference in band positions of carotenoid signals between the sample layers. Key Words: Gypsum-Raman spectrometers-Carotenoids-ExoMars-Mars exploration-Band position shift. Astrobiology 17, 351-362.
Department of Physics University of Leicester UK
Institute of Geochemistry Mineralogy and Mineral Resources Charles University Prague Czech Republic
Laboratory of Inorganic Analytical Chemistry Department of Chemistry University of Liège Belgium
References provided by Crossref.org
Microbial colonization of gypsum: from the fossil record to the present day
