nai

Project Progress

Dworkin has been active in the lab section of the GCA Astrobiology Team by operating the Astrobiology Analytical Laboratory and collaborating with numerous other laboratories. This involves the creation and maintenance of a world-class organic analytical laboratory. In the last year he developed the methodology for the detection of chiral amino acids at the femtomole level in a variety of laboratory and natural samples. He has used this technique to study the amino acid content of the CM2 meteorites Murchison, LEW90500, and ALH83100. Murchison and LEW90500 are similar in their amino acid distribution and the content of ALH83100 is severely depressed with the exception of very large quantities of ε-amino-n-caproic acid (EACA), which is derived from the Nylon-6 bag used for collection in Antarctica (Fig. 1.).

{{ 1 }}

He has also employed Mr. James Doty III, a high school senior, to study the nucleobase distribution in these three meteorites. He will be presenting his results at the 2006 Gordon Research Graduate Student Conference on the Origin of Life.

He has collaborated with several laboratories in the analysis of lab simulations of various space environments for amino acids and various other compounds. He has collaborated with Drs. Elsila and Bernstein at the NASA Ames NAI team in studying the mechanism of amino acid synthesis in 10 K ices, with Hudson and Moore at the GCA in detecting a CI-like suite of amino acids from the irradiation of acetonitrile ices, with Johnson and Nuth at of the GCA team to investigate the amino acid and volatile organic production from Fisher Tropsch type reactions on grain surfaces, and with Pask and Lauretta (associated with the UA NAI team) for the formation of organo- and poly-phosphates from FeP corrosion. Dworkin has used his laboratory equipment to characterize the physical properties and reactivity of the silylating agent for the SAM suite on the MSL rover and to study the reactivity of hydrazine thruster plumes with amino acids, alcohols, ketones, and aerogel in association with the Mahaffy and Glavin of the GCA. With Matrajt and Brownlee (UW NAI team) he has analyzed three sets of fifteen 20 µm Murchison grains in preparation for developing the methods to analyze a single IDP or Stardust particle (~10 attomoles of amino acid).

Also with Glavin at the GCA, he became a member of the Stardust Organics Preliminary Examination Team. In this role he has characterized the amine inventory of aerogel flight-spares, mud from the Genesis and Stardust recovery sites, a comet-exposed foil, a comet-exposed trackless aerogel, and collaborated with the JSC Toxicology lab to characterize the gasses collected at the landing site and clean-room. He has also used these techniques in collaboration with Glavin, Botta (GSFC), and Martins and Ehrenfreund (Leiden University) to study the amino acid content of several meteorites (CM, CR, and ordinary chondrites), and the Antarctic ices or Sahara soils on which some of them were collected. With the above collaborators and Fogel (CIW NAI team), he determined the carbon isotope ratios of indigenous nucleobases and carboxylic acids in the Murchison meteorite.

These results of some of these meteorite studies recently appeared (MAPS, June 2006), others have been submitted (Science and OLEB), or in preparation (MAPS) and were presented at the 2006 LPSC (4) and 2006 AbSciCon (7) meetings.