Kinetic-potentiometric determination of aluminium in acidic solution using a fluoride ion-selective electrode

Abstract

A kinetic-potentiometric method is described for the determination of aluminium(III) based on monitoring its reaction with hydrofluoric acid using a fluoride ion-selective electrode at pH 2. At that pH the reaction Al³⁺+ HF AlF²⁺+ H⁺ is the predominant path for the initial consumption of aluminium in a complex with fluoride. The initial rate of the complex formation reaction was used to construct calibration graphs. There is a linear relationship between the initial rate of reaction and the amount of aluminium added. The method is rapid and can be used for the determination of aluminium down to 0.5 µmol with satisfactory precision (relative standard deviation < 6%).