Cometary glycine detected in samples returned by Stardust

available online at http://meteoritics.org Cometary glycine detected in samples returned by Stardust Jamie E. ELSILA*, Daniel P. GLAVIN, and Jason P. DWORKIN NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA *Corresponding author: [email protected] (Received 05 June 2009; revision accepted 24 July 2009) Abstract–Our previous analysis of cometary samples returned to Earth by NASA’s Stardust spacecraft showed several amines and amino acids, but the origin of these compounds could not be firmly established. Here, we present the stable carbon isotopic ratios of glycine and ε-aminon-caproic acid (EACA), the two most abundant amino acids identified in Stardust-returned foil samples measured by gas chromatography–mass spectrometry coupled with isotope ratio mass spectrometry. The δ13C value for glycine of +29 ± 6‰ strongly suggests an extraterrestrial origin for glycine, while the δ13C value for EACA of −25 ± 2‰ indicates terrestrial contamination by Nylon-6 during curation. This represents the first detection of a cometary amino acid.Our previous analysis of cometary samples returned to Earth by NASA’s Stardust spacecraft showed several amines and amino acids, but the origin of these compounds could not be firmly established. Here, we present the stable carbon isotopic ratios of glycine and ε-aminon-caproic acid (EACA), the two most abundant amino acids identified in Stardust-returned foil samples measured by gas chromatography–mass spectrometry coupled with isotope ratio mass spectrometry. The δ13C value for glycine of +29 ± 6‰ strongly suggests an extraterrestrial origin for glycine, while the δ13C value for EACA of −25 ± 2‰ indicates terrestrial contamination by Nylon-6 during curation. This represents the first detection of a cometary amino acid.