Volumetric, Compressibility and UV Spectral Studies on Interactions of Amino Acids with Aqueous Solutions of Potassium Dihydrogen Phosphate at Different Temperatures

Abstract

Densities, ρ, and speeds of sound, u, for glycine, l-alanine and l-valine have been measured in (0.2, 0.4, 0.6 and 0.8) mol · kg−1 aqueous solutions of potassium dihydrogen phosphate at temperatures T = (288.15, 293.15, 298.15, 303.15, and 308.15) K. Values of the apparent molar volumes, limiting apparent molar volumes, and transfer volumes have been calculated from the density data. The experimental speeds of sound were used to estimate apparent molar adiabatic compressibilities. The variation of these parameters with temperature is discussed in terms of the role of amino acid and salt in solute–solvent interactions. The UV–visible spectrum has also been used to analyze the results.