Numéro de référence
ISO 5375:1979
ISO 5375:1979
© ISO 2024
ISO 5375:1979
Phosphates condensés à usage industriel (y compris les industries alimentaires) — Dosage des oxydes d'azote — Méthode spectrophotométrique au xylénol-3,4
Edition 1
1979-02
1979-02
Annulée
Résumé
Applicable to products having contents, expressed in nitrogen, of 2 mg/kg or more. Oxidation of nitrogen(III) of a test portion to nitrogen(V) by potassium permanganate. Reaction of nitrogen(V) with 3,4-xylenol under specified conditions to form a nitrate derivative. Distillation of the nitrate derivative and absorption in a sodium hydroxide solution. Spectrophotometric measurement of the yellow coloured nitrophenol at a wavelength of about 435 nm. Has also been approved by the IUPAC.