Coulometric titration by a controlled-potential pulsed-charge potentiometric technique-II Acid-base, precipitation and homogeneous redox systems.

An unconventional coulometric method, based on electrolysis at controlled potential by means of discrete charge-pulses, with end-point detection obtained by mathematical linearization of potentiometric data, has been applied to various systems. The results appear very satisfactory: very weak acids can be determined with high accuracy; in the case of precipitation reactions the selectivity is high enough to allow titration of the components of halide mixtures; for homogeneous redox systems some problems caused by irreversibility at the indicator electrode are overcome.

Coulometric titration by means of a controlled-potential-pulsed-current potentiometric technique-I Metal ions by electro-deposition.

A new method for electrochemical titrations is proposed, based on the redox transformation of the test species by means of a controlled-potential pulsed current, followed by measurement of the potential in the intervals between the current pulses: the end-point is found by means of Sörensen's linearization technique. Investigations on various metal ions (Ag(+), Cu(2+), Cd(2+), Pb(2+)) have shown that the accuracy and sensitivity, which depend on the nature of the species titrated, are comparable with those of other titration techniques. The method permits analytical separations and determinations of metal ions in mixtures.