Polycyclic aromatic hydrocarbons and amino acids in meteorites and ice samples from LaPaz Icefield,Antarctica |
| |
| Authors: | Oliver BOTTA Zita MARTINS Christian EMMENEGGER Jason P DWORKIN Daniel P GLAVIN Ralph P HARVEY Renato ZENOBI Jeffrey L BADA Pascale EHRENFREUND |
| |
| Institution: | 1. NASA Goddard Space Flight Center, Code 699, Greenbelt, Maryland 20771, USA;2. Goddard Earth Sciences and Technology Center, University of Maryland, 5523 Research Park Dr., Baltimore, Maryland 21228, USA;3. International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland;4. Swiss Space Office, State Secretariat for Education and Research, Hallwylstrasse 4, 3003 Bern, Switzerland;5. Astrobiology Laboratory, Leiden Institute of Chemistry, University of Leiden, Einsteinweg 55, 2300 RA Leiden, The Netherlands;6. Department of Earth Science and Engineering, South Kensington Campus, Imperial College London, SW7 2AZ London, UK;7. Department of Chemistry and Applied Biosciences, Eidgen?ssische Technische Hochschule Zürich H?nggerberg, Wolfgang‐Paulistrasse 10, 8093 Zürich, Switzerland;8. Metrohm Ltd., Oberdorfstrasse 68, 9100 Herisau, Switzerland;9. Department of Geology, Case Western Reserve University, Cleveland, Ohio 44106, USA;10. Scripps Institution of Oceanography, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093–0212, USA |
| |
| Abstract: | Abstract— –We have analyzed ice samples and meteorites from the LaPaz region of Antarctica to investigate the composition of polycyclic aromatic hydrocarbons (PAHs) and amino acids with the goal to understand whether or not there is a compositional relationship between the two reservoirs. Four LL5 ordinary chondrites (OCs) and one CK carbonaceous chondrite were collected as part of the 2003/2004 ANSMET season. Ice samples collected from directly underneath the meteorites were extracted. In addition, exhaust particles from the snowmobiles used during the expedition were collected to investigate possible contributions from this source. The meteorite samples, the particulate matter and solid‐state extracts of the ice samples and the exhaust filters were subjected to two‐step laser mass spectrometry (L2MS) to investigate the PAH composition. For amino acids analysis, the meteorites were extracted with water and acid hydrolyzed, and the extracts were analyzed with offline OPA/NAC derivatization combined with liquid chromatography with UV fluorescence detection and time of flight mass spectrometry (LC‐FD/ToF‐MS). PAHs in the particulate matter of the ice were found to be qualitatively similar to the meteorite samples, indicating that micron‐sized grains of the meteorite may be embedded in the ice samples. The concentration levels of dissolved PAHs in all the ice samples were found to be below the detection limit of the L2MS. The PAH composition of the snowmobile exhaust is significantly different to the one in particulate matter, making it an unlikely source of contamination for Antarctic meteorites. The amino acids glycine, β‐alanine and γ‐amino‐n‐butyric acid that were detected at concentrations of 3 to 19 parts per billion (ppb) are probably indigenous to the Antarctic meteorites. Some of the LaPaz ice samples were also found to contain amino acids at concentration levels of 1 to 33 parts per trillion (ppt), in particular α‐aminoisobutyric acid (AIB), an abundant non‐protein amino acid of extraterrestrial origin found in some carbonaceous chondrites. We hypothesize that this amino acid could have been extracted from Antarctic micrometeorites and the particulate matter of the meteorites during the concentration procedure of the ice samples. |
| |
| Keywords: | |
|
|
