A comparative study between the behavior diffusion of α-aminobutyric acid and γ-aminobutyric acid in sodium chloride aqueous solutions

Ternary mutual diffusion coefficients measured by the Taylor dispersion method are reported for two aqueous systems, that is, DL-2-aminobutyric add (AABA) + sodium chloride, and DL-4-aminobutyric acid (GABA) + sodium chloride at 298.15 K, and at different carrier concentrations (from 0 to 0.010 mol dm(-3)). These data, complemented by NMR measurements, permit us to have a better understanding of the structure of these ternary systems, and their thermodynamic and transport behaviour. The effect of the ionic strength on the transport properties of both amino acids has been assessed. Contrary to AABA, the presence of sodium chloride does not affect the structure of GABA and its diffusion properties. This has been justified by the preferential intramolecular electrostatic interaction between ammonium and carboxylate groups. (C) 2019 Elsevier B.V. All rights reserved.