Effect of NaCl and KCl on the Solubility of Amino Acids in Aqueous Solutions at 298.2 K: Measurements and Modeling

Measurements were performed to determine the solubilities at 298.2 K of four amino acids in aqueous solutions of NaCl or KCl. The amino acids studied were glycine, dl -alanine, dl -valine, and dl -serine. The results show that the solubility of amino acids is affected by the concentration of electrolyte and by the nature of both the amino acid and the cation of the electrolyte. A model has been developed to correlate the solubilities of amino acids in aqueous electrolyte solutions. The activity coefficients of amino acids in electrolyte solutions required were represented by a perturbed hard-sphere model. The model can accurately correlate the solubility of amino acids in aqueous solutions containing an electrolyte.