ISO 9388:1992
ISO 9388:1992

Status : Published (Under review)

This standard was last reviewed and confirmed in 2020. Therefore this version remains current.
Format Language
std 1 42 PDF
std 2 42 Paper
  • CHF42
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Phosphorus content can be determined in the range of 0,001 % (m/m) to 0,025 % (m/m). Cr(III) and silica cause interference which is eliminated. The principle is dissolution of a test portion in a mixture of nitric and hydrochloric acids, fuming with sulfuric acid, oxidation of Cr(III) to Cr(VI), precipitation of Fe(III) phosphate and redissolution of the precipitate, addition of boric, tartaric and sulfamic acids, formation and extraction of molybdophosphoric acid, reduction of the heteropoly acid to molybdenum blue and back-extraction into an aqueous phase, measurement of the absorbance of the aqueous solution at 700 nm.

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General information

  •  : Published
     : 1992-08
    : International Standard confirmed [90.93]
  •  : 1
     : 6
  • ISO/TC 155
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