Measurement of activity coefficients of amino acids in aqueous electrolyte solutions:: experimental data for the systems (H2O plus NaBr plus glycine) and (H2O plus NaBr plus L-valine) at T=298.15 K

Electrochemical cells with two ion-selective electrodes, a cation ion-selective electrode against an anion ion-selective electrode, were used to measure the activity coefficient of amino acids in aqueous electrolyte solutions. Activity coefficient data were measured for (H2O + NaBr + glycine) and (H2O + NaBr + L-valine) at T = 298.15 K. The maximum concentrations of sodium bromide, glycine, and L-valine were (1.0, 2.4, and 0.4) mol (.) kg(-1), respectively. The results show that the presence of an electrolyte and the nature of both the cation and the anion of the electrolyte have significant effects on the activity coefficients of amino acid in aqueous electrolyte solutions. (C) 2003 Elsevier Ltd. All rights reserved.