Maximum buffer capacity.

Buffer capacity can be calculated for a given buffer at different pH values. The table and figure below show how buffer capacity,β, of a buffer solution composed from  0.2 M acetic acid (Ka = 1.75 × 10^-5 ) and 0.2 M sodium acetate changes with pH.

Accordingly, it can be seen that the maximum buffer capacity for this buffer occurs at pH = pKa = 4.76. Therefore, an equation can be derived for maximum buffer capacity, βmax, as the following:

Where, C is the total buffer concentration. According to the above equation, the maximum buffer capacity (which occurs at pH = pKa) is only dependent on the total buffer concentration.