Stony chondrite meteorites are the most common type of meteorites that fall to Earth. Of those, three percent are carbonaceous chondrites, which contain the highest concentration of organic material of all classifications of meteorites. Previous studies on their composition have primarily focused on bulk elemental composition and targeted analysis of specific compounds such as amino acids, carbohydrates, and other precursors to molecules essential to life. Non-targeted analysis is rarely performed because meteorites are complex mixtures of presumably tens of thousands of molecular formulas and thus require ultrahigh-resolution techniques for characterization. Here, we utilize 21 tesla Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to characterize the soluble organic material from two meteorites, Murchison and Aguas Zarcas. In 1969, the Murchison chondrite fell in Murchison, Australia and has since become one of the most studied meteorites to date. Its rapid collection after impact minimized terrestrial contamination, with over 100 kilograms of material recovered. Aguas Zarcas chondrite is a relatively recent meteorite that hit a doghouse in rural Costa Rica in 2019, and as such, very little is known about it. A range of solvents with diverse eluent strengths was used to extract the organic material from the two meteorites. Analysis was performed by positive- and negative-ion electrospray ionization (ESI) coupled to 21T FT-ICR MS. Formic acid and tetramethylammonium hydroxide were used as solvent modifiers to aid during the ionization process. Over 30,000 peaks were detected in each mass spectrum, of which &gt;60% could each be assigned a unique molecular formula, and collectively sorted into heteroatom classes, such as CHNOS, CHOMg, and CHO, among others. As previously seen for terrestrial complex mixtures, the more polar, protic solvents extracted more material, and oxygenated compounds were detected in high relative abundances. More specifically, acidic O2 species were observed in high abundance: up to fifteen percent of assigned peaks when the analysis was performed in negative-ion ESI assisted by a modifier. Conversely, positive-ion ESI revealed a higher relative abundance of NOx and SOx species. Overall, detected compounds reveal species with low aromaticity (double bond equivalents of 1-10) with carbon numbers that range from C10 – C60, as well as high oxygen content (up to O16 in some molecular formulas).

Molecular characterization of soluble organic material from meteorites by 21T FT-ICR MS

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