Vitamin C-amino acid interactions in aqueous solutions: Volumetric and interfacial properties

Abstract

Nature of interactions occurring in aqueous solutions have been studied to understand various phenomena such as protein stabilization, drug-delivery, and food preservation. These interactions have been studied by measuring physicochemical properties of mixed aqueous solutions. Herein, we have measured the volumetric and interfacial properties of vitamin C (VC) in aqueous solutions of amino acids (Glycine, Gly; L-Leucine, Leu). Volumetric were studied at temperatures (298.15 K to 313.15 K). Transfer volumes were obtained from infinite dilution partial molar volumes of VC in aqueous Gly-and Leu-solutions. Positive transfer volumes (∆tV2° and ∆tK2) were observed, which decreases as Gly > Leu, suggesting dominance of hydrophilic-ionic interactions. Double derivative, (∂2V2° /∂T2)P suggest chaotropic nature of VC in presence of amino acids. Nature of interactions influencing interfacial properties (contact angle and surface tension) has also been evaluated at 298.15 K. Solute-co-solute interactions not much influence the interfacial properties.