Mars Organic Carbon Analyzer (MOCA)


The recent discovery by the Phoenix MECA Wet Chemistry Lab (WCL) of close to 1% perchlorate in the martian soil at the landing site [1,2], emphasizes the need for an organics detection/quantification instrument that will be free from perchlorate interferences.  We are developing a new type of electrochemically-based total organic carbon analyzer for detecting and quantifying organics in martian soils that contain percent levels of Mg- or other perchlorates [3]. 

The Mars Organic Carbon Analyzer (MOCA) utilizes a unique boron-doped diamond electrode system [4] that quantitatively oxidizes organic compounds in an aqueous solution to produce CO2, which can subsequently be quantified by a mass spec or tunable laser diode.  The released CO2 can also be directed to a detector to provide
13C/12C isotope ratios.  A prototype MOCA device has been demonstrated using eight low-molecular-weight (1 to 5 carbon) organics and shown to be capable of detecting all of them at or below the 10 ppm level depending on detector and methodology. 

The effort undertaken in this research will result in the development and demonstration of the MOCA at a sufficiently mature “brassboard” level so that it may be proposed for future flight opportunities to provide for the identification and quantification of organics in surface materials on Mars, or in melted ice on Mars and other planetary bodies. This research will further NASA's mission and Astrobiology program goals by addressing detection and quantification of organic carbon, and thus perform an assessment of habitability and biological potential that does not depend on the presence of any specific organic molecules. 

In addition, integration of MOCA with an existing instrument capable of providing the
13C/12C ratio will provide an indication of potential biotic depletion and insight into the evolution of martian organics.  Even though MOCA is focused on Mars, it would also be applicable to other planetary bodies (e.g., comets, Europa, etc) for seeking chemical precursors of life or potential habitats.  Earth-based benefits can also be realized by its adaptation to monitoring total organic carbon (TOC) in municipal water systems and as an on-site system for environmental research.

moca-1

MOCA-2

 

[1] "Wet Chemistry Experiments on the 2007 Phoenix Mars Scout Lander: Data Analysis and Results"
S. P. Kounaves, M. H. Hecht, J. Kapit, K. Gospodinova, L. DeFlores, R. C. Quinn,
W. V. Boynton, B. C. Clark, D. C. Catling, P. Hredzak, D. W. Ming, Q. Moore, J. Shusterman,
S. Stroble, S. J. West, and S. M. Young,
.
J. Geophys. Res., 2010, 115, E00E10, doi:10.1029/2008JE003084 Abstract.- Full Text PDF

[2] "Detection of Perchlorate and the Soluble Chemistry of Martian Soil at the Phoenix Lander Site"
M. H. Hecht, S. P. Kounaves, R. C. Quinn, S. J. West, S. M. M. Young, D. W. Ming, D. C. Catling, B. C. Clark, W. V. Boynton, J. Hoffman, L. P. DeFlores, K. Gospodinova, J. Kapit, and P. H. Smith
Science, 2009, 325, 64-67. Abstract - Full Text PDF

[3] "An Electrochemically Based Total Organic Carbon Analyzer for Planetary and Terrestrial On-Site Applications" S. T. Stroble & S. P. Kounaves, Anal. Chem., 2012, 84, 6271–6276. Abstract - Full Text PDF

[4] Total Organic Carbon Analyzer (TOC), S. P. Kounaves, International Patent WO-03104765 Issued 12/18/2003, US Patent No. 7,632,393 Issued 12/15/2009, US Patent No. 8,216,447 Issued 7/10/2012

 



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Last Updated: 07/29/2015