Mass spectrometry of hyper-velocity impacts of organic micrograins Ralf Srama 1,2 * , Wolfgang Woiwode 7 , Frank Postberg 1,3 , Steven P. Armes 4 , Syuji Fujii 4 , Damien Dupin 4 , Jonathan Ormond-Prout 4 , Zoltan Sternovsky 5 , Sascha Kempf 1,6 , Georg Moragas-Klostermeyer 1 , Anna Mocker 1 and Eberhard Gru ¨n 1,5 1 Max Planck Institute Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg, Germany 2 IRS, University of Stuttgart, 70569 Stuttgart, Germany 3 Department of Chemistry and Earth Sciences, University of Heidelberg, 69120 Heidelberg, Germany 4 Department of Chemistry, University of Sheffield, Brook Hill, Sheffield S3 7HF, UK 5 LASP, University of Colorado, Boulder, CO 80309-0392, USA 6 University of Braunschweig, 38106 Braunschweig, Germany 7 Institute for Meteorology and Climate Research, KIT, 76021 Karlsruhe, Germany Received 28 June 2009; Revised 29 September 2009; Accepted 29 September 2009 The study of hyper-velocity impacts of micrometeoroids is important for the calibration of dust sensors in space applications. For this purpose, submicron-sized synthetic dust grains comprising either polystyrene or poly[bis(4-vinylthiophenyl)sulfide] were coated with an ultrathin overlayer of an electrically conductive organic polymer (either polypyrrole or polyaniline) and were accelerated to speeds between 3 and 35 km s 1 using the Heidelberg Dust Accelerator facility. Time-of-flight mass spectrometry was applied to analyse the resulting ionic impact plasma using a newly developed Large Area Mass Analyser (LAMA). Depending on the projectile type and the impact speed, both aliphatic and aromatic molecular ions and cluster species were identified in the mass spectra with masses up to 400 u. Clusters resulting from the target material (silver) and mixed clusters of target and projectile species were also observed. Impact velocities of between 10 and 35 km s 1 are suitable for a principal identification of organic materials in micrometeoroids, whereas impact speeds below 10 km s 1 allow for an even more detailed analysis. Molecular ions and fragments reflect com- ponents of the parent molecule, providing determination of even complex organic molecules embedded in a dust grain. In contrast to previous measurements with the Cosmic Dust Analyser instrument, the employed LAMA instrument has a seven times higher mass resolution – approxi- mately 200 – which allowed for a detailed analysis of the complex mass spectra. These fundamental studies are expected to enhance our understanding of cometary, interplanetary and interstellar dust grains, which travel at similar hyper-velocities and are known to contain both aliphatic and aromatic organic compounds. Copyright # 2009 John Wiley & Sons, Ltd. ASTROBIOLOGICAL BACKGROUND The current interest in the detection of organic matter in micrometeorites is coupled to major questions in astrobiol- ogy such as ‘‘What is the origin of habitable planets?’’ and ‘‘Does life exist elsewhere in the universe?’’. In this work, we provide the basis for extended calibration measures for interplanetary dust experiments. Some meteorites contain carbonaceous material and are known as chondrites. They contain up to a few percent of carbon and can contain a wide range of complex organic compounds. Amino acids have been identified in several carbonaceous meteorites in concentrations of up to 3 ppm versus total carbon content. 1 Isotopic analysis shows that certain grains found in primitive meteorites are formed in stellar atmospheres, representing samples of ancient stardust. The identification of organic compounds in micrometeoroids is expected to play a key role in our understanding of abiotic synthetic reactions, the cosmochemical carbon cycle, and the role that these two processes might play in biogenesis. The contemporary view is that some of the organic material required to initiate the Earth’s prebiotic chemistry was probably delivered by cometary and asteroidal impacts. 2 Observations of bright comets show that parts of their volatile composition are even similar to interstellar material. 3 Many simple interstellar molecules such as aldehydes, acids, ketones or sugars have important functions in terrestrial biochemistry. These molecules are also present in meteoritic organic material and thus could also have been important for prebiotic chemistry. 4 There is no doubt that a substantial amount of organic compounds was delivered to the early planets via meteorites. But to what extent can organic compounds survive the extremely high pressures and temperatures generated RAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2009; 23: 3895–3906 Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/rcm.4318 *Correspondence to: R. Srama, Max Planck Institute Nuclear Phy- sics, Saupfercheckweg 1, 69117 Heidelberg, Germany. E-mail: ralf.srama@mpi-hd.mpg.de Copyright # 2009 John Wiley & Sons, Ltd.