Radiation chemistry approach to the study of sedimentary microenvironments as models for the protection of bio-organic molecules on the early earth

This work examines the influence of sodium montmorillonite on the chemical transformations undergone by two nucleosides (cytidine and adenosine) in simulated primitive Earth conditions. The aim of this study is to test the hypothesis of a protective role of solid surfaces like clay for organic compounds adsorbed on them, when exposed to external sources of ionizing radiation (γ-ray). The results showed this role of protection: the decomposition of nucleosides was lower when adsorbed on a clay mineral. It was also found that a purinic nucleoside (more than pirimidinic) was quickly adsorbed on clay at low pH and desorbed in neutral or lightly basic aqueous solutions. For analysis of samples, different techniques were used: X-ray diffraction, UV-Vis spectroscopy, and HPLC. (author)