Molecular interactions of glycine and L-alanine + citrate buffer solutions at different temperatures: Volumetric, viscometric, and FTIR approach

Abstract

Densities,𝜌, and viscosities,𝜂of glycine/L-alanine in water and in (0.10, 0.50, 1.00) mol∙kg−1 aqueous trisodium citratebuffer (Na3CB) solutions of pH 7.40 at T = (298.15 to 318.15) K have been measured by using vibrating tube digital density meter and suspended level Ubbelohde capillary viscometer, respectively, at atmospheric pressure i.e.101.3 kPa. Thermodynamic parameters, i.e., 𝜙𝑣𝑜, Δ𝑡𝑟𝜙𝑣, viscosity B-coefficients, and Δ𝑡𝑟𝐵 obtained from density and viscositymeasurements have been used to unravel predominant forces among glycine/L-alanine and aqueous Na3CB solutions. Activation free energies, Δ𝜇2𝑜# for the viscous flow of solutions, have been obtained by applying transition state theory to theviscosity B-coefficients values. The results are further supported by FTIR studies for glycine/L-alanine in water and aqueous Na3CB solutions of pH 7.40, revealing the intermolecular hydrogen bonding in these systems. Moreover, the results obtained from volumetric, viscometric, and spectroscopic studies provide valuable information on intermolecular interactions, influencing their efficacy in biological applications.