Numéro de référence
ISO 3709:1976
ISO 3709:1976
© ISO 2024
ISO 3709:1976
Acide phosphorique à usage industriel (y compris les industries alimentaires) — dosage des oxydes d'azote — Méthode spectrophotométrique au xylénol-3,4
Edition 1
1976-11
1976-11
Annulée
Résumé
Applicable to products having a content, expressed as N, equal to or more than 0.2 mg/kg. Consists in oxidation of nitrous nitrogen to nitric nitrogen by potassium permanganate and reaction of nitrogen(V) with 3,4-xylenol under specified conditions to form a nitrate derivative. Subsequent destillation of the nitrate derivative and absorption in sodium hydroxide solution. Spectrophotometric measurement of the yellow nitrophenol at a wavelength of about 435 nm.