Solutions properties and solute–solvent interactions in ternary sugar–salt–water solutions

Viscometric constants were used to provide information on solute–solvent interactions in ternary water–sugar–salt solutions. Comparison was made between pure water and aqueous salt solution as solvents affecting the behaviour of small carbohydrates. The determination of intrinsic viscosity was made more accurate by applying triple extrapolation of the three equations (Huggins, Kramer and Meffroy-Biget). Results obtained with this triple extrapolation method were compared to that obtained with the Jones–Dole equation usually used. The B coefficient of the Jones–Dole equation was interpreted in terms of its components (Bsize) and (Bstructure), respectively assigned to the hydrodynamic volume and the contribution to solvent structural change. The determination of the apparent molar volumes in pure water enabled calculation of the hydration numbers. The determined apparent molar volumes of the studied sugars in aqueous salt solutions suggested a dehydration of the sugars explained by sugar–salt interactions. The most important perturbations observed in LiCl solutions compared to those in NaCl solutions were explained by LiCl being surrounded with more water molecules.