Sequential atomic absorption spectrometric determination of chloride and iodide in a flow system using an on-line preconcentration technique

A flow injection method is described for the sequential determination of chloride and iodide in a mixture of the two. The chloride–iodide mixture is precipitated from solution by silver nitrate and the precipitated silver chloride is dissolved by ammonia solution to determine chloride after which the precipitated silver iodide is dissolved by potassium cyanide solution to determine iodide. The method allows the analysis of about 15 samples h–1 and mixtures with different chloride : iodide ratios can be analysed at the µmol dm–3 level.