A study of possible interferences in colorimetric determination of potassium in pharmaceutical formulations

A study of interferences in the colorimetric determination of potassium, extracted as ion-pair [K-18-crown-6]+ picrate- in the toluene-methylene chloride (80:20) solvent mixture, was carried out. The species examined were those likely to be found, together with the K ion, in typical pharmaceutical formulations, namely, organic bases and inorganic cations.