Browsing by Author "Huang, Yongsong"
Now showing 1 - 3 of 3
Results Per Page
ItemCarboxylic acid abundances in the Tagish Lake meteorite: lithological differences and implications for formic acid abundances in carbonaceous chondrites(2009) Hilts, Robert; Herd, Christopher D. K.; Morgan, Don; Edwards, LeAnne; Huang, YongsongThe most abundant soluble organic compounds in carbonaceous chondrites are typically carboxylic acids (Pizzarello et al 2001). Strait-chain monocarboxylic acids up to C-12 have been the focus of considerable attention owing to the exciting possibility that they may have been incorporated into the molecular architecture of prebiotic protomembranes on the ancient Earth (e.g., Silva et al 2004.) The most abundant monocarboxylic acid in interstellar space is formic acid (e.g. Remigen et al. 2003; Snyder 2008). It is generally accepted that the organic material in carbonaceous chondrites such as the Tagish Lake meteorite, which includes carboxylic acids, is derived from interstellar or nebular sources (Cronin et al 1988 and Cronin et al 1993). It is somewhat surprising, therefore, that up until now only what have been described as small or moderate formic acid concentrations have been found in aqueous extracts of carbonaceous chondrites (Huang et al 2005, Naraoka et al 1999, Yuen et al 1973, Shimoyama et al 1986, Yuen et al 1984 and Krishnamurthy et al 1992). Previous reports have ascribed the unexpectedly low formic acid abundances to either compound loss during extraction and subsequent work up, or to depletion caused by evaporation and/or aqueous leaching of the compound from the meteorite upon its exposure to the Earth's hydrosphere (Huang et al 2005 and Naraoka et al 1999). Here we present our analysis of the water-soluble monocarboxylic acids in two different lithologies within the Tagish Lake meteorite using the SPME-GCMS procedures recently developed by Huang et al 2005 to compare the two lithologies in this respect. Our results conclusively show that formic acid is, by a wide margin, the most abundant monocarboxylic acid in both of the Tagish Lake lithologies investigated thus far. This is in stark contrast to all previous studies of other meteorites in which it was concluded that the formic acid concentration was the lowest or one of the lowest of those monocarboxylic acids present in the extract (Huang et al 2005, Naraoka et al 1999, Yuen et al 1973, Shimoyama et al 1986, Yuen et al 1984 and Krishnamurthy et al 1992). Moreover, our serendipitous discovery that formic acid has a very low response factor when run on either GCMS(quadrupole) or GC-FID (Allen et al 1987) instruments suggests that previous studies on carbonaceous chondrites may have dramatically underestimated the quantities of formic acid present. Also, a close inspection of the relative abundances for the straight-chain monocarboxylic acids in each Tagish Lake lithology has led us to conclude that the overall oxidation levels for the water soluble organics from the two lithologies are different. Lastly, we have found that the monocarboxylic acids within the Tagish Lake meteorite are enriched in deuterium compared to terrestrial organics, with delta D values ranging from + 247 to + 581%o. These results confirm that the acids originate from interstellar space and that terrestrial contamination has been largely avoided. ItemCarboxylic acid abundances in the Tagish Lake meteorite: lithological differences and implications for formic acid abundances in carbonaceous chondrites(2009) Hilts, Robert; Herd, Christopher D. K.; Morgan, Don; Edwards, LeAnne; Huang, YongsongAnalysis of two different Tagish Lake rocks found: 1) a very low GCMS response for formic acid, 2) formic acid concns above 100 ppm and 3) that formic acid to higher homologue ratios indicate the average level of oxidation for the soluble organics. ItemOrigin and evolution of prebiotic organic matter as inferred from the Tagish Lake meteorite(2011) Hilts, Robert; Herd, Christopher D. K.; Blinova, Alexanda; Simkus, Danielle N.; Huang, Yongsong; Tarozo, Rafael; Alexander, Conel M. O.; Gyngard, Frank; Nittler, Larry R.; Cody, George D.; Fogel, Marilyn L.; Kebukawa, Yoko; Kilcoyne, A. L. DavidThe complex suite of organic materials in carbonaceous chondrite meteorites probably originally formed in the interstellar medium and/or the solar protoplanetary disk, but was subsequently modified in the meteorites’ asteroidal parent bodies. The mechanisms of formation and modification are still very poorly understood. We carried out a systematic study of variations in the mineralogy, petrology, and soluble and insoluble organic matter in distinct fragments of the Tagish Lake meteorite. The variations correlate with indicators of parent body aqueous alteration. At least some molecules of prebiotic importance formed during the alteration.