Amperometrically indicated "pseudotitrations"--I. Complexometric determination of chromium(III)

In the pseudotitration no reaction takes place between titrand and titrant in the bulk of the solution. An amperometric indicating system, which generates a small amount of redox catalyst in the vicinity of the electrode, does enable an end-point to be found. Bulk concentrations and diffusion constants are the controlling parameters. This method allows to utilize slow, thermodynamically favourable reactions for titrating purposes. The principle is demonstrated by the direct titration of chromium(III) with EDTA at room temperature.