The Volumetric Determination of Potassium by Heterometric Titration

Abstract

Heterometric procedures for the volumetric determination of potassium are proposed. The use of direct and reverse titrations, precipitate‐forming ligands as titrants, and the addition of solvents like ethanol make possible the determination of a large number of cations and anions as their insoluble compounds. Two procedures are described: one uses direct heterometric titrations for the formation of the potassium tetraphenylboron precipitate (K‐TPB) for samples of concentrations between 40 and 60 ppm K+; the second uses indirect titrations for the formation of K2Na[Co(NO2)6] in acetic acid ‐ ethanol media, for samples containing 4–10 mg K+. The end point of the heterometric titration is obtained by photometric measurement of the optical absorption of suspensions.