Publications

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2005
Skelley, AM, Scherer JR, Aubrey AD, Grover WH, Ivester RHC, Ehrenfreund P, Grunthaner FJ, Bada JL, Mathies RA.  2005.  Development and evaluation of a microdevice for amino acid biomarker detection and analysis on Mars. Proceedings of the National Academy of Sciences of the United States of America. 102:1041-1046.   10.1073/pnas.0406798102   AbstractWebsite

The Mars Organic Analyzer (MOA), a microfabricated capillary electrophoresis (CE) instrument for sensitive amino acid biomarker analysis, has been developed and evaluated. The microdevice consists of a four-wafer sandwich combining glass CE separation channels, microfabricated pneumatic membrane valves and pumps, and a nanoliter fluidic network. The portable MOA instrument integrates high voltage CE power supplies, pneumatic controls, and fluorescence detection optics necessary for field operation. The amino acid concentration sensitivities range from micromolar to 0.1 nM, corresponding to part-per-trillion sensitivity. The MOA was first used in the lab to analyze soil extracts from the Atacama Desert, Chile, detecting amino acids ranging from 10-600 parts per billion. Field tests of the MOA in the Panoche Valley, CA, successfully detected amino acids at 70 parts per trillion to 100 parts per billion in jarosite, a sulfate-rich mineral associated with liquid water that was recently detected on Mars. These results demonstrate the feasibility of using the MOA to perform sensitive in situ amino acid biomarker analysis on soil samples representative of a Mars-like environment.

1991
Wing, MR, Bada JL.  1991.  Geochromatography on the Parent Body of the Carbonaceous Chondrite Ivuna. Geochimica Et Cosmochimica Acta. 55:2937-2942.   10.1016/0016-7037(91)90458-h   AbstractWebsite

Ivuna, a CI carbonaceous chondrite, has been found to contain abundant amounts of the three-ring polycyclic aromatic hydrocarbons (PAHs) phenanthrene/anthracene, but no detectable levels of the two- and four-ring PAHs naphthalene and pyrene/fluoranthene. Either the three-ring PAHs in Ivuna were synthesized in a process that did not produce the two- or four-ring PAHs, or all these compounds were synthesized together and subsequently separated. Thermodynamical considerations and studies of hydrocarbon pyrolysis and combustion do not support the former possibility. Ivuna and other CI carbonaceous chondrites are known to have been extensively altered by water. The aqueous solubilities suggest that some PAHs would have been mobilized during the aqueous alteration phase in carbonaceous meteorite parent bodies. In a model geochromatography experiment, naphthalene, phenanthrene, and pyrene were partially resolved at a low pressure and flow rate utilizing columns containing crushed serpentine or beach sand, and water for elution. This laboratory geochromatography experiment suggests that complete separation of PAHs could be expected to occur in the parent body of CI carbonaceous chondrites. Such processes on Earth are known to lead to the formation of hydrothermal PAH minerals such as pendletonite. It is proposed that aqueous fluids driven by heat in the parent body of Ivuna migrated from the interior to the surface, in the process transporting, separating, and concentrating PAHs at various zones in the parent body.