DETERMINATION OF FLUORIDES IN ENVIRONMENTAL-SAMPLES BY DISCONTINUOUS FLOW POTENTIOMETRY

The method of regeneration of the membrane surface of a LaF3 fluoride ion selective electrode with a solution of 0,2M Al2(SO4)3 for the dire ct potentiometric determination of fluorides in real environmental sam ples (e.g. solid waste leaches and waste water) has been proposed. The metod is most conveniently applied with the discontinous flow potenti ometry measurements (DFP). The regeneration eliminates the irreversibl e passivation of the membrane surface of a fluoride ion selective elec trode with anion fluorocomplexes like [AlF4]-, [TiF6]2- which enables the determination of fluorides even in more complicated matrices.