Solvation behavior of some amino acid compounds in aqueous solutions of trilithium citrate at different temperatures

The interactions of amino adds glycine (Gly),L-alanine (Ala), and L-valine (Val) with trilithium citrate (TLC) as a function of temperature have been investigated by combination of volumetric and acoustic measurements. Densities and speeds of sound of amino acids in aqueous solutions of trilithium citrate have been measured at T = (288.15, 298.15, 308.15 and 318.15) K and experimental pressure, p = 0.1 MPa. The apparent molar volume (V-phi), the partial molar volume (V-phi(0)) and standard partial molar volumes of transfer (Delta V-phi(0)) for amino adds from water to aqueous trilithium citrate have been calculated from density data. Group contributions of amino adds to partial molar volume were determined. Partial molar isentropic compression (kappa(phi,s)) and partial molar isentropic compression of transfer (Delta kappa(0)(phi,s)) have been calculated from speed of sound data. Hydration number (n(H)) has also been calculated. The pair and triplet interaction coefficient have been calculated from both the properties. The results have been explained based on competing patterns of interactions of co-solvent and the solute. (C) 2014 Elsevier B.V. All rights reserved.