Tracing Organic Contamination from Collection to Curation: Contamination Mitigation of Meteorites and Implications for Advanced Curation Methods of Astromaterials
Creators: Tunney, Libby Donna
Publisher: name: University of Alberta Library
Year: 2022

<p>Meteorites are the most primitive materials in the solar system and can provide important information about the early earth, planetary processes, and possibly yield insights to the building blocks of life. All meteoritic astromaterials are exposed to both organic compound and microbial terrestrial contamination when such materials enter the Earth’s atmosphere and inevitably land on the surface. Documentation of the types and sources of terrestrial organic compounds is important for discerning extraterrestrial organic compounds from terrestrially sourced contaminants. In order to determine various sources of contamination it is critical to understand what influences the interactions astromaterials have with the Earth; these factors will hereafter be referred to as contamination controls. Contamination controls that are addressed in this thesis study include environmental aspects, transportation materials, laboratory processes, meteorite characteristics (composition, fractures, fusion crust, etc.), and a time factor. How and where the specimens are collected, transported, and stored has an influence on contamination as there can be a transfer of organics from the surroundings to the meteorite itself. Rate of build up or degradation of organic compounds is also of concern in contamination analysis and when interpreting intrinsic organic compounds from meteorites as it possible to gain and lose organic signatures through time. Gas chromatography – mass spectrometry will be the primary instrumental method used throughout this project to identify organic compounds in processing and storage materials as well as DCM and water extracts of meteorites with varying characteristics and collection circumstances to investigate how contamination is influenced by these controls. Each contamination control will play a role in how terrestrial organic compounds interact with the meteorite and governs what is detectable. In addition, next generation sequencing will be used to characterize the 16S rRNA of microbial communities contaminating meteorites within the University of Alberta Meteorite Curation Facility.<br>
The sources and controls of terrestrial contamination as well as their time and location dependencies are poorly constrained in the field of astromaterials thus far. Exploration of the advantages of cold curation and the development of clean rooms to process astromaterials are newly emerging techniques to mitigate contamination; however, a deeper understanding of contamination is needed to take preventative measures to against it. Here, we use a selection of different meteorites including, Aguas Zarcas and Tarda for organic compound extractions as well as Peace River, Redwater, and Bruderheim for microbial extractions. Suitable handling procedures and materials when working with astromaterials should be chosen under the criterion that they contain minimal concentrations and abundances of organic compounds available for transfer. This thesis will be aimed at documenting contamination and investigating their sources and controls, as described above, both of which are critical in protecting the scientific integrity of astromaterials. From this, procedures will be proposed to mitigate and reduce any potential organic contamination during their fall, collection, transportation, storage, and processing to preserve astromaterials in the most pristine states as possible. Being mindful of the terrestrial – extraterrestrial interaction complexities greatly influence the interpretations deduced from organic compound studies on astromaterials. In addressing contamination concerns, analyses on samples will provide increased accuracy and in turn a more comprehensive picture of processes in our solar system. Not only is this significant in planetary science, but assessing contamination is consequential in analytical studies in any scientific field.</p>