scope:

This standard describes a titrimetric method for the determination of the dissolved sulphate content of water. The standard applies to any kind of water with a sulphate content of at least 3 mg/l. With concentrations up to 7.5 mg/l NaCl an SO₄² content of 3 to 100 mg/l can be determined correctly. Ca²⁺ interferes; it should be removed in advance by an ion exchanger. Fe³⁺ over 5 mg/l influences the colour change of the indicator. It is also removed if an ion exchanger is used. Interference by phosphate can be corrected, provided that the phosphate content is not higher than the sulphate content.