title: Chemical Composition of Micrometer-Sized Filaments in an Aragonite Host by a Miniature Laser Ablation/Ionization Mass Spectrometer.
abstract: Detection of extraterrestrial life is an ongoing goal in space exploration, and there is a need for advanced instruments and methods for the detection of signatures of life based on chemical and isotopic composition. Here, we present the first investigation of chemical composition of putative microfossils in natural samples using a miniature laser ablation/ionization time-of-flight mass spectrometer (LMS). The studies were conducted with high lateral (∼15 μm) and vertical (∼20-200 nm) resolution. The primary aim of the study was to investigate the instrument performance on micrometer-sized samples both in terms of isotope abundance and element composition. The following objectives had to be achieved: (1) Consider the detection and calculation of single stable isotope ratios in natural rock samples with techniques compatible with their employment of space instrumentation for biomarker detection in future planetary missions. (2) Achieve a highly accurate chemical compositional map of rock samples with embedded structures at the micrometer scale in which the rock matrix is easily distinguished from the micrometer structures. Our results indicate that chemical mapping of strongly heterogeneous rock samples can be obtained with a high accuracy, whereas the requirements for isotope ratios need to be improved to reach sufficiently large signal-to-noise ratio (SNR).
authors.affiliation: 1 Physics Institute, Space Research and Planetary Sciences, University of Bern , Bern, Switzerland .
authors.forename: Marek
authors.initials: M
authors.lastname: Tulej
authors.affiliation: 2 Department of Geological Sciences, Stockholm University , Stockholm, Sweden .
authors.forename: Anna
authors.initials: A
authors.lastname: Neubeck
authors.affiliation: 3 Department of Palaeobiology and Nordic Centre for Earth Evolution (NordCEE), Swedish Museum of Natural History , Stockholm, Sweden .
authors.forename: Magnus
authors.initials: M
authors.lastname: Ivarsson
authors.affiliation: 1 Physics Institute, Space Research and Planetary Sciences, University of Bern , Bern, Switzerland .
authors.forename: Andreas
authors.initials: A
authors.lastname: Riedo
authors.affiliation: 1 Physics Institute, Space Research and Planetary Sciences, University of Bern , Bern, Switzerland .
authors.forename: Maike B
authors.initials: MB
authors.lastname: Neuland
authors.affiliation: 1 Physics Institute, Space Research and Planetary Sciences, University of Bern , Bern, Switzerland .
authors.forename: Stefan
authors.initials: S
authors.lastname: Meyer
authors.affiliation: 1 Physics Institute, Space Research and Planetary Sciences, University of Bern , Bern, Switzerland .
authors.forename: Peter
authors.initials: P
authors.lastname: Wurz
mesh_terms: D015415:Biomarkers / Q000032:analysis; D002119:Calcium Carbonate / Q000737:chemistry*; D018559:Exobiology; D005118:Extraterrestrial Environment; D005580:Fossils / Q000382:microbiology*; D007554:Isotopes / Q000032:analysis; D008904:Miniaturization / Q000295:instrumentation; D059629:Signal-To-Noise Ratio; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*
chemical_list: D015415:Biomarkers; D007554:Isotopes; D002119:Calcium Carbonate