Differential potentiometric titrations of binary mixtures of halides with two ion-selective indicator electrodes

Abstract

Differential potentiometric titrations with two different ion-selective indicator electrodes are described. Ion-selective electrodes for Cl -, Br -, I -, F -, S 2-, as well as glass and silver billet electrodes were used. The method was tested in the determination of binary mixtures of halides (Cl -, Br -, I -, and F -) by titration with solutions of silver nitrate, alone and mixed with lanthanum or thorium nitrate as required. Various factors influencing the determination were investigated. Results of simultaneous determinations of mixtures were in good agreement with the results of separate determinations within certain concentration limits. The method was successfully applied to the determination of a four-component halide mixture. Titrations of mixtures of fluoride with thiocyanate or hexacyanoferrate(III), and some other possibilities, are also reported.