Solubility of glycine and DL-nor-valine in aqueous solutions of NaNO3 and KNO3 and measurements of transfer thermodynamics

Abstract

The solubility and solvation thermodynamics of the amino acids in aqueous solutions are related to their biochemical and biophysical actions in human physiology. This makes such studies to be highly relevant for academia, health and industry. In the present work solubilities of glycine and DL-nor-valine were measured under different experimental conditions by an analytical gravimetric method in aqueous NaNO3 and KNO3 solutions and the results were employed as an input in theoretical solvation investigations. Thermodynamic parameters like standard transfers Gibbs energies and entropies and other important physicochemical parameters such as molar volume, density, dipole moment, mixed solvent diameter, etc., of the experimental solutions were evaluated at 298.15K and compared with earlier values. Finally the above mentioned parameters were used to conclude ΔGt,ch0(i) i.e. chemical effects of the transfer Gibbs energies and ΤΔSt,ch0(i) i.e. chemical effects of the transfer entropy. Different factors such as nature of solute and solvent, interactions between solute and solvents, etc., which are influencing the solvation of glycine and DL-nor-valine were also characterized by different physical and analytical techniques.