The ionization constants of alpha-alanine in NaCl at 25 degrees. Effect of the ionic strength based on three models.
In the present work we obtained the experimental pKs of the amino acid alpha-alanine in NaCl at 25 degrees and different ionic strengths. The equilibrium constants have been potentiometrically determined with a commercial 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-Hückel 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.
Fiol
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Departamento de Quimica Fundamental e Industrial Facultad de Ciencias, Universidad de La Coruña, Campus da Zapateira s/n, La Coruña, Spain.
Brandariz
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Sastre de Vicente
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