DERIVATIVE ANALYSIS OF POTENTIOMETRIC TITRATION DATA TO OBTAIN PROTONATION CONSTANTS

A methodology is described to calibrate glass electrodes and to analyz e potentiometric titration data to calculate protonation constants, Th e analysis uses the variation of dV/dpH with titrant addition in terms of two physical parameters which involve the concentrations of H+, OH -, and H(m)A. The data for titration of acetic acid and 8-hydroxyquino line in 0.10-5.0 m NaCl media ape analyzed by this method to obtain th e stoichiometric protonation constants of the acids, the ionization co nstants of water, and the parameters s and b in the pH electrode calib ration equation, pcH = spH(m) + b, where pcH = -log [H+], and pH(m) is the pH meter reading.