Henderson-Hasselbach titration curve

Equation [414] solved for piCintr (actually pfC for a single site) gives the standard Henderson-Hasselbach titration curve. 

Figure 10-3. Theoretical titration curves for the model compounds of Asp and His obtained from REX-CPHMD simulations [41]. Solid curves are the obtained by fitted the computed deprotonated fraction to the generalized Henderson-Hasselbach equation. The dashed lines indicate the computed pKa values...

Poly(N-vinyl-imidazole) is an essentially monofunctional polybase, as shown by the sharpness of the jump in the titration curve 89). From conductance measurements, it was found that the data fitted the Henderson-Hasselbach expression with a term for the ionic strength ... 

The titration curve of Figure 4 satisfies the Henderson-Hasselbach equation and our Equation (15). The slopes of the lines representing vs F or vs a are practically equal to the theoretical value of /2.3 kT= 17.8 V predicted by (9) and (15). The conclusion expressed by the second Equation (14) is verified e.g. the excess electrostatic partial free energy of an anionic site may then be taken as equal to ze4>Q where is the potential at the charged sites. It may be related also to the measured surface potential of the monolayer even when the distribution of the counterions is ignored. This is not allowed for polyelectrolytes membranes, solutions or gels for which neither the distribution of the fixed charged sites nor the potential shift be measured. 

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