Determination of stability constants of metal complexes with potentiometric pH titrations

The use of different cells for pH measurements for the determination of equilibrium constants of metal complexes is discussed in relation to the liquid junction potential connected with them. The effects of H+aq and OH-aq on this quantity are also considered. The literature values for the convesion factor A, representing the difference in pH value based on the calibration with NBS buffers and that defined in terms of H+ concentration, are discussed.