This is an updated version of the SAIEUS_pK program earlier operated on the Excel VBA platform. SAIEUS_pK has been mentioned in a number of studies involving the surface acid-base properties.
This program calculates the pK distribution of acid-base systems from the potentiometric titration data . The solution method of the integral equation was adopted from the earlier work on the surface energy distribution . The proton binding isotherm derived from the potentiometric titration curve is used as data input to the program. The meaningful and stable results are obtained by employing a regularization method combined with non-negativity constraints .
The program is operated interactively. It is equipped with several controls and diagnostic tools  that facilitate the user in selecting the optimal pK distribution as a solution for the analyzed data.
Titration data may be entered in a form of the proton binding isotherm, Q (pH), or the titration curve pH (V). The titration curve is converted to binding isotherm using the internal procedure based on the work of Contescu et al. .
 J. Jagiello, T. J. Bandosz, K. Putyera and J. A. Schwarz, J. Colloid and Interface Sci. (1995) 172, 341-346. Determination of Proton Affinity Distributions for Chemical Systems in Aqueous Environments Using Stable Numerical Solution of the Adsorption Integral Equation.
 J. Jagiello, Stable Numerical Solution of the Adsorption Integral Equation Using Splines. Langmuir (1994) 10, 2778-2785.
 C. L. Lawson and R. J. Hanson, Solving Least Squares Problems. Prentice-Hall, Englewood Cliffs, NJ, 1974.
 C. Hansen and D. P. O’Leary, The Use of the L-Curve in the Regularization of Discrete Ill-Posed Problems. Siam J. Sci. Comput. (1993) 14, 1487-1503.
 C. Contescu, J. Jagiello, and J. A. Schwarz, Heterogeneity of Proton Binding Sites at
the Oxide/ Solution Interface. Langmuir (1993) 9 , 1754-1765.