Precision in analytical methods

One of the results of contamination of bleach with transition metals is the accumulation of oxygen in pipelines and storage tanks. This has become a safety issue for suppliers and utilities. Many utilities have revised their specifications for transition metal ions in bleach into the ppb range. This requires more sensitivity and precision in analytical methods. Pham [81 ] has studied a number of methods and reported results obtained by chloroform extraction colorimetry and ion chromatography. The latter is the preferred analytical method. 

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