THERMODYNAMIC PARAMETERS OF WATER RELATED PROPERTIES OF AMINO ACIDS AT LOW TEMPERATURE RANGES

摘要

We have developed a method to measure thermodynamic parameters of partition coefficients for relevant low molecular weight precursors, such as the naturally occurring amino acids. The experimental set up allows the determination of K_d of relevant solutes in conditions akin to gel permeation chromatography experiments. This information is useful to ascertain the characteristics of the interaction of these molecules with organized, structured water layers, such as the ice surface of interstellar dust or comets. The ranking of the temperature dependence of such interactions is not related to their hydrophilic-hydrophobic character but gives rise to an unique experimentally derived scale for the twenty naturally occurring amino acids. This information may well contribute to our understanding of the chemistry and physics of biochemical compounds at surfaces and at temperatures corresponding to extreme environments.