Indirect atomic absorption determination of chloride by continuous precipitation of silver chloride in a flow injection system

Abstract

A method is proposed for the determination of chloride by flow injection atomic absorption spectrometry. The chloride forms a precipitate with silver nitrate which is retained on a stainless-steel filter. Two unsegmented flow configurations involving normal and reversed flow injection are proposed. By using normal flow injection, chloride was determined in the range 3–100 µg ml^–1, with a sampling rate of 50 h^–1 and relative standard deviation of 2.0%. In reversed flow injection, chloride was determined in the range 0.3–10 µg ml^–1 with a sampling frequency of 200 h^–1 and relative standard deviation of 3.5%. Both methods have been applied to the determination of chloride in water samples, and the results have been critically compared with those obtained by the batch method.