ISO 3329:1975
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ISO 3329:1975
8594

Abstract 

Applicable to products the content of which, expressed as sulphate, is equal to or more than 0.0005 % (m/m). Heating of a test portion in the presence of sodium carbonate, in a fume-cupboard, until the ammonium salts have been eliminated (about 300 °C). Reduction of the sulphureous residue to sulphides by a mixture of hydriodic acid and hypophosphorus acid. Absorption of the hydrogen sulphide evolved in a mixture of sodium hydroxide solution and acetone. Titration of the sulphide with standard volumetric mercury(II) acetate solution in the presence of dithizone as indicator. A typical apparatus for reduction and distillation is shown in a figure.


General information 

  •  :  Withdrawn
     : 1975-07
  •  : 1
     : 4
  •  : ISO/TC 47 Chemistry
  •  :
    71.060.50 Salts

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