1.1 Application range
This International Standard specifies a titration method for the determination of dissolved chloride in water. The method is applicable to the direct determination of dissolved chloride in concentrations between 5 mg/l and 150 mg/l. The working range may be extended to 400 mg/l by using a burette of larger capacity or by sample dilution. Due to many interferences the method is not applicable to heavily polluted waters of low chloride content.
1.2 Interferences
Normal concentrations of common constituents of ground water, surface water and potable water do not interfere with the determination.
The following substances interfere with the method
- Substances forming insoluble silver compounds, such as bromides, iodides, sulfides, cyanides, hexacyanoferrates(II) and hexacyanoferrates(III). If necessary, bromide and iodide ions shall be determined separately, and the result of the chloride determination corrected accordingly.
- Compounds forming complexes with silver ions, such as ammonium and thiosulfate ions.
- Compounds which will reduce chromate ions, including iron(II) and sulfite ions.
The interferences mentioned above will lead to high chloride values.
Highly coloured or turbid solutions may obscure the end point, for example hydrated iron oxide.