Amino acids generated from hydrated Titan tholins: Comparison with Miller–Urey electric discharge products

摘要

Various analogues of Titan haze particles (termed 'tholins') have been made in the laboratory. In certain geologic environments on Titan, these haze particles may come into contact with aqueous ammonia(NH_3) solutions, hydrolyzing them into molecules of astrobiological interest. A Titan tholin analogue hydrolyzed in aqueous NH_3 at room temperature for 2.5 years was analyzed for amino acids using highly sensitive ultra-high performance liquid chromatography coupled with fluorescence detection and timeof- flight mass spectrometry (UHPLC-FD/ToF-MS) analysis after derivatization with a fluorescent tag. We compare here the amino acids produced from this reaction sequence with those generated from room temperature Miller–Urey (MU) type electric discharge reactions. We find that most of the amino acids detected in low temperature MU CH_4/N_2/H_2O electric discharge reactions are generated in Titan simulation reactions, as well as in previous simulations of Triton chemistry. This argues that many processes provide very similar mixtures of amino acids, and possibly other types of organic compounds, in disparate environments, regardless of the order of hydration. Although it is unknown how life began, it is likely that given reducing conditions, similar materials were available throughout the early Solar System and throughout the universe to facilitate chemical evolution