ISO 5442:1980
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ISO 5442:1980
11487

Abstract 

Applicable to products having contents, expressed as sulphate2- , between 0.03 % (m/m) and 0.5 % (m/m). Reduction of the compounds to hydrogen sulphide by heating with a mixture of hydriodic and hypophosphorus acids in the presence of hydrochloric acid. Entrainment of the hydrogen sulphide in a flow of nitrogen and absorption in an excess of ammoniacal cadmium acetate solution. Liberation of the absorbed hydrogen sulphide in the presence of an excess of standard volumetric iodate/iodide solution. Back-titration of the excess iodine with standard volumetric sodium thiosulphate solution using starch as the indicator. An apparatus for reduction, entrainment and absorption is shown in a figure. Has also been approved by the IUPAC.


General information 

  •  :  Withdrawn
     : 1980-10
  •  : 1
     : 5
  •  : ISO/TC 47 Chemistry
  •  :
    71.060.50 Salts

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