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Published October 1993 | public
Journal Article

Molecular and isotopic analyses of the hydroxy acids, dicarboxylic acids, and hydroxydicarboxylic acids of the Murchison meteorite

Abstract

The hydroxymonocarboxylic acids, dicarboxylic acids, and hydroxydicarboxylic acids of the Murchison meteorite were analyzed as their tert-butyldimethylsilyl derivatives using combined gas chromatography-mass spectrometry. The hydroxydicarboxylic acids have not been found previously in meteorites. Each class of compounds is numerous with carbon chains up to C_8 or C_9 and many, if not all, chain and substitution position isomers represented at each carbon number. The α-hydroxycarboxylic acids and α-hydroxydicarboxylic acids correspond structurally to many of the known meteoritic α-aminocarboxylic acids and α-aminodicarboxylic acids, a fact that supports the proposal that a Strecker synthesis was involved in the formation of both classes of compounds. Isotopic analyses show these acids to be D-rich relative to terrestrial organic compounds as expected; however, the hydroxy acids appear to be isotopically lighter than the amino acids with respect to both carbon and hydrogen. The latter finding would not be expected if both classes of compounds came exclusively from common precursors as would have been the case for a Strecker synthesis.

Additional Information

© 1993 Pergamon Press Ltd. Received November 17, 1992; accepted in revised form May 12, 1993. We thank Ed Olson (Field Museum of Natural History) for providing the Murchison sample, and the National Aeronautics and Space Administration for financial support through grants NAG 9-46 and NAGW-1899 (Life Sciences Division). We are grateful to Mark Madison for calculating isomer numbers using the program ASSEMBLE (CHRISTIE and MUNK, 1987) and to Richard Becker, Sherwood Chang, and Mike Engel for thoughtful, constructive reviews. This is contribution number 125 from the Arizona State University Center for Meteorite Studies.

Additional details

Created:
August 20, 2023
Modified:
October 25, 2023