10.1021/jp983666c.s001 Augusto Agostinho Neto Augusto Agostinho Neto Elso Drigo Filho Elso Drigo Filho Marcelo Andres Fossey Marcelo Andres Fossey João Ruggiero Neto João Ruggiero Neto p<i>K</i> Determination. A Mean Field, Poisson−Boltzmann Approach American Chemical Society 1999 solution concentration values p K value p K Determination pH values Poisson 1999-07-23 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/p_i_K_i_Determination_A_Mean_Field_Poisson_Boltzmann_Approach/3727437 A model describing dissociation of monoprotonic acid and a method for the determination of its p<i>K</i> value are presented. The model is based on a mean field approximation. The Poisson−Boltzmann equation, adopting spherical symmetry, is numerically solved, and the solution of its linearized form is written. By use of the pH values of a dilution experiment of galacturonic acid as the entry data, the proposed method allowed estimation of the value of p<i>K</i> = 3.25 at a temperature of 25 °C. Values for the complex dimensions and dissociation degree are calculated using experimental pH values for solution concentration values ranging from 0.1 to 60 mM. The present analysis leads to the conclusion that the Poisson−Boltzmann equation or its linear form is equally suited for the description of such systems.