Analysis of hydration parameter for sugars determined from viscosity and its relationship with solution parameters

Area of Science:

• Physical Chemistry
• Solution Chemistry
• Biophysical Chemistry

Background:

• Understanding solute-solvent interactions is crucial in aqueous solutions.
• Hydration dynamics influence solution properties and biological processes.

Purpose of the Study:

• To determine the hydration parameter (h) for various solutes in aqueous solutions.
• To correlate hydration parameter (h) with solute structure and water interaction.
• To elucidate the role of solutes in water structure modification.

Main Methods:

• Viscosity B-coefficients and partial molar volume (V2) were used to calculate the hydration parameter (h).
• Correlation analysis was performed with the activity coefficient of water (α) and number of equatorial-OH groups (e-OH).
• Temperature dependence (dh/dT) and activation energy (Ea) were analyzed using Arrhenius plots.

Main Results:

• Hydration parameter (h) correlated well with solute-solvent interaction (α) and sugar e-OH groups.
• Sugars exhibited negative dh/dT, indicating water-structure making activity.
• Urea showed positive dh/dT, indicating a structure-breaking effect.
• Disaccharides had low activation energy (Ea) for hydration, suggesting stable hydration structures.

Conclusions:

• The hydration parameter (h) effectively characterizes solute hydration and its influence on water structure.
• Sugar's hydration is linked to its number of equatorial-OH groups and its ability to enhance water structure.
• Urea acts as a water structure breaker.
• Activation energy (Ea) provides insights into the stability of hydration shells for sugars.