A variation of the standard addition method. In this procedure changes in the potential resulting from the addition of a known amount of a species which reacts stoichiometrically with the ion of interest (e.g. a complexing agent) are employed to determine the original activity or concentration of the ion.
Source:
Orange Book, 2nd ed., p. 171 (https://media.iupac.org/publications/analytical_compendium/)