ISO 6920:1984
ISO 6920:1984


The calcium content is determined by titration of an aliquot portion of the test solution with ethyleneglycol-bis-(2-aminoethyl)-N,N,N',N'-tetra acetic acid, disodium salt (EGTA) solution using 2-carboxy-2'-carboxy-2'-hydroxy-5'-sulphoformazylbenzene (Zincon) as indicator. The combined magnesium and calcium contents are determined by titration of a further aliquot portion of the test solution with ethylenediaminetetra-acetic acid, disodium salt (EDTA) solution, using Mordant black 11/potassium chloride as indicator, after addition of triethanolamine solution and buffer solution. The magnesium content is calculated by difference.

General information 

  •  :  Withdrawn
     : 1984-11
  •  : 1
     : 6
  •  : ISO/TC 47 Chemistry
  •  :
    71.060.50 Salts

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