Reference number
ISO 5440:1978
ISO 5440:1978
© ISO 2024
International Standard
ISO 5440:1978
Sodium hexafluorosilicate for industrial use — Determination of phosphate content — Molybdovanadate spectrophotometric method
Edition 1
1978-10
1978-10
ISO 5440:1978
11486
Published
(Edition 1, 1978)
This publication was last reviewed and confirmed in 2023.
Therefore this version remains current.
Abstract
Applicable to products having contents, expressed as phosphorus pentoxide, of 0.005 % (m/m) to 0.05 % (m/m). The residue from the determination of the loss of mass according to ISO 5444 is used to prepare the test sample. Dissolution in dilute hydrochloric acid and nitric acid solutions. Formation of the yellow molybdovanadate and spectrophotometric measurement at a wavelength of about 420 nm. Calculation of the content from the measured absorbance.