Probing solute–solute and solute–solvent interactions in (l-arginine + d-xylose/l-arabinose + water) solutions at different temperatures by using volumetric and viscometric methods

Abstract

Densities, ρ of l-arginine in water and in aqueous–d-xylose/l-arabinose (2.5% and 5% of d-xylose/l-arabinose, w/w in water) mixed solvents were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15 and 318.15)K, and viscosities, η of these solutions at temperatures (298.15, 303.15, 308.15, 313.15 and 318.15)K were measured at atmospheric pressure. From the density values, the apparent molar volume, Vϕ, limiting apparent molar volume, Vϕ°, slope, Sv and transfer volume, Vϕ,tr° and hydration number, nH were calculated. The viscosity values have been analysed on the basis of the Jones–Dole equation; and Falkenhagen Coefficient, A and Jones–Dole coefficient, B were calculated. The Gibbs energies of activation of viscous flow per mole of solvent, Δμ1°# and per mole of solute, Δμ2°# were also calculated. The results indicate that there exist strong solute–solvent interactions in these systems, which increase with increase in carbohydrate concentration in both the solvents. It is observed that l-arginine act as a structure-maker in both these solvent systems.