Effects of concentration and temperature on molar volumes of L-serine, L-isoleucine, and L-glutamine in aqueous NaCl and NaNO3 solutions

Abstract

Densities of L-serine, L-isoleucine, L-glutamine in 1.5 mol kg−1 aqueous NaCl, and NaNO3 solutions have been measured for several molal concentrations of amino acids at temperatures from 298.15 to 323.15 K. The partial molar volumes (ϕv0) of L-serine, L-isoleucine, and L-glutamine in 1.5 mol kg−1 aqueous NaCl/NaNO3 solutions have been computed using density data. The transfer partial molar volumes (Δtrϕv0) of L-serine, L-isoleucine, and L-glutamine from water to 1.5 mol kg−1 aqueous NaCl/1.5 mol kg−1 aqueous NaNO3 solutions have been determined at 298.15 K. The trends of variation of ϕv0 and Δtrϕv0 with change in temperature have been discussed in terms of ion-ion, ion-hydrophilic, and ion-hydrophobic interactions operative in solutions.