For the last four decades space exploration missions have searched for molecular life on planetary surfaces beyond Earth. Often pyrolysis gas chromatography mass spectrometry has been used as payload on such space exploration missions. These instruments have relatively low detection sensitivity and their measurements are often undermined by the presence of chloride salts and minerals. Currently, ocean worlds in the outer Solar System, such as the icy moons Europa and Enceladus, represent potentially habitable environments and are therefore prime targets for the search for biosignatures. For future space exploration missions, novel measurement concepts, capable of detecting low concentrations of biomolecules with significantly improved sensitivity and specificity are required. Here we report on a novel analytical technique for the detection of extremely low concentrations of amino acids using ORIGIN, a compact and lightweight laser desorption ionization – mass spectrometer designed and developed for in situ space exploration missions. The identified unique mass fragmentation patterns of amino acids coupled to a multi-position laser scan, allows for a robust identification and quantification of amino acids. With a detection limit of a few fmol mm−2, and the possibility for sub-fmol detection sensitivity, this measurement technique excels current space exploration systems by three orders of magnitude. Moreover, our detection method is not affected by chemical alterations through surface minerals and/or salts, such as NaCl that is expected to be present at the percent level on ocean worlds. Our results demonstrate that ORIGIN is a promising instrument for the detection of signatures of life and ready for upcoming space missions, such as the Europa Lander.
A new high-performance laser ablation and ionisation (LIMS) mass spectrometer for solid sample analysis with micrometer spatial- and up to 10 000 mass resolution is presented.
Accumulation of spectra is a common approach for improvement of the signalto-noise ratio (SNR) in mass spectrometry. However, severe degradation of the overall spectrum can occur if some individual mass spectra, affected by peak broadening, are included in the accumulation process. In this contribution, we discuss potential sources and effects of spectral distortions by using examples from mass spectra acquired by our miniature laser ablation/ionisation time-of-flight mass spectrometer. We show how recent developments in acquisition systems enable to identify individual spectra subjected to peak broadening and present a filtering method capable of systematic and reproducible exclusion of such spectra from the accumulation process. We show that the method can be used on a wide range of materials and present a detailed case study performed on a trevorite mineral sample. Using this method, improvements of the isotope accuracy of Si, Ni, and Cr by factors between 1.6 and 7.7 were achieved. Finally, we discuss the limitations of the method and provide complementary analysis of other materials in the supplementary documents provided with this contribution.
KEYWORDSfiltering method, improvement of quantitative performance, isotope accuracy, laser ablation and ionisation time-of-flight mass spectrometry (LIMS-TOF), mass resolution
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