Effect of temperature and concentration alterations on the volumetric, acoustic and hydration studies of l-threonine in aqueous lactose solutions

Abstract

The density and speed of sound in the solution of l-threonine in the concentration range (0.025 to 0.2) mol kg−1 in water and various lactose solutions (0 to 6 mass% of lactose in water) have been carried out at temperatures range of (293.15 to 313.15) K. The experimental data is used to obtain the apparent molar volume (Vϕ), limiting apparent molar volume (V0ϕ), limiting apparent molar transfer volume (V0ϕ,tr), as well as apparent molar compressibility (Ks,ϕ), limiting apparent molar compressibility (K0s,ϕ), limiting apparent molar transfer compressibility (K0s,ϕ,tr), pair and triplet interaction coefficients for volume and compressibility (VAB, VABB and KAB, KABB), limiting partial molar expansibility (ϕ0E), coefficient of thermal expansion (α) and hydration number (nH) of amino acid. The results have been interpreted in terms of solute-solute and solute-solvent interactions; and hydration characteristics of amino acid molecules in aqueous lactose solutions.