THE IONIZATION CONSTANTS OF α-ALANINE IN NaCl AT 25°. EFFECT OF THE IONIC STRENGTH BASED ON THREE MODELS

摘要

In the present work we obtained the experimental pKs of the amino acid ot-alanine in NaCl at 25° and different ionic strengths. The equilibrium constants have been potentiometrically determined with a commerical glass electrode and the results analysed through three models: two directly based on the Pitzer and Scatchard approaches to the ion specific interaction theory and the other based on a simpler modification of the Debye-Huckel equation. The three models fit the data reasonably well and the extrapolated pK values obtained show a good agreement. The'goodness of the ridge regression method cannot be probed in this case.