Spectrophotometric determination using chromazurol

4 Spectrophotometric determination using chromazurol S General remarks 

In the presence of pyridinium chloride, beryllium ions form with chromazurol S at pH 6.0 a metal chelate complex which after 13 min. remains stable for at least 3 hours. The absorption maximum of this complex at 373 nm is suitable for photometric determination of beryllium. The molar ratio of beryllium to chromazurol S is 1 1. 

The technique can be used to determine between 2 and 100 pg of beryllium ions per litre of water. Since such concentrations only occur in very exceptional cases, it is first necessary to concentrate the beryllium. It is usual to start with 3 litres of water sample (see Section 3.4.3.2). 

White filter strip, 12,5 cm Measuring cylinder, 100 ml Iron (III) chloride solution (3 g/1) 

Hydrochloric acid I (1.17 g/ml), reagent purity Hydrochloric acid II  

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Chromazurol S complexes have been used in the spectrophotometric determination of aluminium. 

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