ISO 5993:1979Published

Sodium hydroxide for industrial use — Determination of mercury content — Flameless atomic absorption spectrometric method

Hydroxyde de sodium à usage industriel — Dosage du mercure — Méthode par spectrométrie d'absorption atomique sans flamme

Abstract / scope

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.