Reference number
ISO 5993:1979
ISO 5993:1979
© ISO 2025
International Standard
ISO 5993:1979
Sodium hydroxide for industrial use — Determination of mercury content — Flameless atomic absorption spectrometric method
Edition 1
1979-09
1979-09
ISO 5993:1979
12187
Published
(Edition 1, 1979)
This publication was last reviewed and confirmed in 2023.
Therefore this version remains current.
Abstract
Covers a method applicable to liquid or solid products having mercury contents greater than 0,02 mg/kg. The principle of determination is based on oxidation of the mercury contained in a test portion to mercury(II) ions by potassium permanganate in the presence of sulphuric acid, reduction of the excess oxidant by hydroxylammonium chloride, reduction of the mercury(II) ions to mercury by tin(II) chloride, entrainment of the mercury in air or nitrogen, passage of the gaseous mixture through a measuring cell, and measurement of the absorption at a wavelength of 253,7 nm.