Mutual interference effects during the successive determination of lodide, bromide, chloride and fluoride in a single sample using halide-selective electrodes

Abstract

The determination, using halide-selective electrodes, of iodide, bromide, chloride and fluoride in a single 100-mg sample of an orthophosphate mineral is described. Mutual halide interference does not occur if the level of iodide is less than one twentieth of that of bromide (although with care this can be extended to one tenth) and if the chloride concentration is between 50- and 200-fold in excess of that of bromide. The extent of other interferences in the determination is discussed briefly.

The method is applicable to the determination of iodide over the concentration range 5 × 10^–5 to 10^–1M, bromide from 5 × 10^–4 to 10^–1M, chloride from 3 × 10^–4 to 10^–1M and fluoride from 3 × 10^–6 to 10^–1M, provided that the described precautions are taken to limit mutual interference effects.