ACTIVITY COEFFICIENTS MEASUREMENTS IN AQUEOUS MIXED ELECTROLYTE SOLUTIONS OF NaCl IN NaCl- MgCl2 – GLUTAMIC ACID - H2O AT 450C.

Abstract

The perturbed-chain statistical association theory (PC-SAFT) is applied to simultaneously
describe various thermodynamic properties (density, vapor-pressure depression, activity
coefficient, solubility) of aqueous solutions containing an amino acid or an oligopeptide. The
28 organic compounds considered within this work are glycine, alanine, serine, proline,
hydroxyproline, valine, leucine, arginine, lysine, threonine, asparagine, tyrosine, histidine,
cysteine, methionine, aspartic acid, glutamic acid, R-ABA, R-isoABA, _-ABA, γ-ABA, R-
AVA, γ-AVA, diglycine, triglycine, dialanine, Gly-Ala, and Ala-Gly. If not yet available in
literature, amino-acid solubility data and activity coefficients were determined experimentally.
To prove the predictivity of PC-SAFT, osmotic coefficients in aqueous solutions containing two
amino acids (glycine/valine and alanine/ valine) were measured and predicted without applying
any additional model parameters.