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Impact ionisation mass spectrometry of polypyrrole-coated pyrrhotite microparticles

Hillier, Jon K., Sternovsky, Z., Armes, S.P., Fielding, L.A., Postberg, F., Bugiel, S., Drake, K., Srama, R., Kearsley, A.T., Trieloff, M. and others. (2014) Impact ionisation mass spectrometry of polypyrrole-coated pyrrhotite microparticles. Planetary and Space Science, 97 . pp. 9-22. ISSN 0032-0633. (doi:10.1016/j.pss.2014.04.008) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://dx.doi.org/10.1016/j.pss.2014.04.008

Abstract

Cation and anion impact ionization mass spectra of polypyrrole-coated pyrrhotite cosmic dust analogue particles are analysed over a range of cosmically relevant impact speeds. Spectra with mass resolutions of 150-300 were generated by hypervelocity impacts of charged particles, accelerated to up to 37 km s-1 in a Van de Graaff electrostatic accelerator, onto a silver target plate in the Large Area Mass Analyzer (LAMA) spectrometer. Ions clearly indicative of the polypyrrole overlayer are identified at masses of 93, 105, 117, 128 and 141 u. Organic species, predominantly derived from the thin (20 nm) polypyrrole layer on the surface of the particles, dominate the anion spectra even at high (>20kms-1) impact velocities and contribute significantly to the cation spectra at velocities lower than this. Atomic species from the pyrrhotite core (Fe and S) are visible in all spectra at impact velocities above 6 km s-1 for 56Fe+, 9 km s-1 for 32S+ and 16 km s-1 for 32S- ions. Species from the pyrrhotite core are also frequently visible in cation spectra at impact speeds at which surface ionisation is believed to dominate (<10kms-1), although the large number of organic peaks complicates the identification of characteristic molecular species. A thin oxidised surface layer on the pyrrhotite particles is indicated by weak spectral features assigned to iron oxides and iron oxy-hydroxides, although the definitive identification of sulfates and hydrated sulfates from the oxidation process was not possible. Silver was confirmed as an excellent choice for the target plate of an impact ionization mass spectrometer, as it provided a unique isotope signature for many target-projectile cluster peaks at masses above 107-109 u. The affinity of Ag towards a dominant organic fragment ion (CN-) derived from fragmentation of the polypyrrole component led to molecular cluster formation. This resulted in an enhanced sensitivity to a particular particle component, which may be of great use when investigating astrobiologically relevant chemicals, such as amino acids. © 2014 Elsevier Ltd.

Item Type: Article
DOI/Identification number: 10.1016/j.pss.2014.04.008
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Planet. Space Sci. [Field not mapped to EPrints] AD - Institut für Geowissenschaften, Universität Heidelberg, 69120 Heidelberg, Germany [Field not mapped to EPrints] AD - Laboratory for Atmospheric and Space Physics, Boulder, CO 80303, United States [Field not mapped to EPrints] AD - Max Planck Institut für Kernphysik, 69117 Heidelberg, Germany [Field not mapped to EPrints] AD - Department of Chemistry, University of Sheffield, Sheffield, United Kingdom [Field not mapped to EPrints] AD - Institut für Raumfahrtsysteme, Universität Stuttgart, Germany [Field not mapped to EPrints] AD - Department of Mineralogy, Natural History Museum, London, United Kingdom [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints] M3 - Article [Field not mapped to EPrints]
Uncontrolled keywords: Interplanetary dust, Mass spectrometry, Mineralogy, Organic chemistry, Amino acids, Electrostatic accelerators, Impact ionization, Iron ores, Isotopes, Mass spectrometers, Mass spectrometry, Mineralogy, Minerals, Positive ions, Enhanced sensitivity, Hypervelocity impacts, Interplanetary dust, Iron oxyhydroxides, Isotope signatures, Large area mass analyzers, Molecular clusters, Organic Chemistry, Polypyrroles
Subjects: Q Science > QB Astronomy > QB651 Planets, Minor
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Giles Tarver
Date Deposited: 10 May 2016 11:05 UTC
Last Modified: 29 May 2019 17:19 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/55354 (The current URI for this page, for reference purposes)
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