Characterization and significance of a family of urea molecules in carbonaceous meteorites by high performance liquid chromatography with high resolution mass spectrometry

Abstract

Urea (CH4N2O), which behaves as a solid and a molten solvent, is an important carbon and nitrogen-containing precursor molecule. Due to technical limitations, a detailed analysis of urea and a family of urea molecules by on-line mass spectrometry has been untested. In this study, we aimed to clarify the distribution of urea molecules in representative carbonaceous meteorites and performed highly accurate identification and quantification of urea molecular groups by high-performance liquid chromatography with high-resolution mass spectrometry (HPLC/HRMS) with an optimized pretreatment method. Urea and its alkyl homologues were identified in the Murchison meteorite by comparison with standards, and were detected up to a maximum carbon number of C12. These diverse urea alkyl homologues are not observed in terrestrial materials, indicating an extraterrestrial origin; the abundance of urea in the Murchison meteorite is >100 g/g (several g/g for amino acids), suggesting that urea may serve as both an organic nitrogen storage and As a storage and source of organic nitrogen, urea may have played an important role in the chemical evolution of the extraterrestrial and early Earth.