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| Titel |
Chemical analyses of micrometre-sized solids by a miniature laser
ablation/ionisation mass spectrometer (LMS) |
| VerfasserIn |
Marek Tulej, Reto Wiesendanger, Maike Neuland, Stefan Meyer  , Peter Wurz, Anna Neubeck, Magnus Ivarsson, Valentine Riedo, Pavel Moreno-Garcia, Andreas Riedo, Gregor Knopp |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250144971
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| Publikation (Nr.) |
 EGU/EGU2017-8859.pdf |
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| Zusammenfassung |
| Investigation of elemental and isotope compositions of planetary solids with high spatial
resolution are of considerable interest to current space research. Planetary materials are
typically highly heterogenous and such studies can deliver detailed chemical information of
individual sample components with the sizes down to a few micrometres. The results of such
investigations can yield mineralogical surface context including mineralogy of individual
grains or the elemental composition of of other objects embedded in the sample surface such
as micro-sized fossils. The identification of bio-relevant material can follow by
the detection of bio-relevant elements and their isotope fractionation effects [1,
2].
For chemical analysis of heterogenous solid surfaces we have combined a miniature laser
ablation mass spectrometer (LMS) (mass resolution (m/Dm) 400-600; dynamic range
105-108) with in situ microscope-camera system (spatial resolution ∼2um, depth 10 um).
The microscope helps to find the micrometre-sized solids across the surface sample for the
direct mass spectrometric analysis by the LMS instrument. The LMS instrument
combines an fs-laser ion source and a miniature reflectron-type time-of-flight mass
spectrometer. The mass spectrometric analysis of the selected on the sample surface objects
followed after ablation, atomisation and ionisation of the sample by a focussed laser
radiation (775 nm, 180 fs, 1 kHz; the spot size of ∼20 um) [4, 5, 6]. Mass spectra of
almost all elements (isotopes) present in the investigated location are measured
instantaneously.
A number of heterogenous rock samples containing micrometre-sized fossils and
mineralogical grains were investigated with high selectivity and sensitivity. Chemical
analyses of filamentous structures observed in carbonate veins (in harzburgite) and amygdales
in pillow basalt lava can be well characterised chemically yielding elemental and
isotope composition of these objects [7, 8]. The investigation can be prepared with
high selectivity since the host composition is typically readily different comparing
to that of the analysed objects. In depth chemical analysis (chemical profiling)
is found in particularly helpful allowing relatively easy isolation of the chemical
composition of the host from the investigated objects [6]. Hence, both he chemical
analysis of the environment and microstructures can be derived. Analysis of the
isotope compositions can be measured with high level of confidence, nevertheless,
presence of cluster of similar masses can make sometimes this analysis difficult.
Based on this work, we are confident that similar studies can be conducted in situ
planetary surfaces delivering important chemical context and evidences on bio-relevant
processes.
[1] Summons et al., Astrobiology, 11, 157, 2011. [2] Wurz et al., Sol. Sys. Res. 46, 408,
2012. [3] Riedo et al., J. Anal. Atom. Spectrom. 28, 1256, 2013. [4] Riedo et al., J. Mass
Spectrom.48, 1, 2013. [5] Tulej et al., Geostand. Geoanal. Res., 38, 423, 2014. [6] Grimaudo
et al., Anal. Chem. 87, 2041, 2015 [7] Tulej et al., Astrobiology, 15, 1, 2015. [8] Neubeck et
al., Int. J. Astrobiology, 15, 133, 2016. |
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