Temperature-Dependent Physicochemical Properties of Di and Tri-Peptides of Glycine in Aqueous Myo-Inositol

Abstract

The present study investigates the temperature-dependent physicochemical properties of glycylglycine and glycylglycylglycine in pure water and aqueous myo-inositol solutions of varying molal concentrations (0.05, 0.10, and 0.15 mol·kg^–1) over the temperature range 293.15–318.15 K under a constant pressure of 101.3 kPa. Measurements of density, ultrasonic velocity, and viscosity served as the basis for calculating a range of volumetric, acoustic, and viscometric parameters, such as apparent molar volume (V_ϕ), partial molar volume at infinite dilution (V_ϕ⁰), limiting apparent molar expansibility (E_ϕ⁰), apparent molar isentropic compressibility (K_ϕ,s⁰), transfer parameters, and viscosity B-coefficients. Analysis of these thermodynamic and transport properties enabled the assessment of the dominant molecular interactions between glycylglycine and myo-inositol, as well as between glycylglycylglycine and myo-inositol, in aqueous media. The collective findings indicate the prevalence of hydrophilic–hydrophilic interactions, demonstrating the cooperative role of inositol in enhancing solvation dynamics and the structuring of water molecules around the solutes.