(iso International Standard 5993 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAYHAPOAHAA OPIAHW3ALMWA IO CTAHAAPTW3AUWW-ORGANISATION INTERNATIONALE DE NORMALISATION ANsi inirrat oc Sec Sodium hydroxide for industrial use - Determination of mercury content --- Flameless atomic absorption spectrometric method Hydroxyde de sodium a usage industriel -- Dosage du mercure - Methode par spectromeétrie d'absorption atomique sans flamme First edition - 1979-09-01 SEP 2 1 1979 UDC 661.322.1 : 543.422 : 546.49 Ref. 1SO 5993-1979 (E) ISO 5993-1979 (E) Descriptors : Sodium hydroxide, chemical analysis, determination of content, mercury, spectrophotometric analysis. atomic absorption spectroscopic analysis. Price based on 6 pages Not for Resale Foreword national standards institutes (IsO member bodies). The work of developing Interna- tional Standards is carried out through ISo technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental and non- governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISO Council. International Standard ISO 5993 was developed by Technical Committee ISO/Tc 47, Chemistry, and was circulated to the member bodies in September 1977. Australia Hungary Philippines Poland Austria India Belgium Israel Romania Bulgaria Italy South Africa, Rep. of Chile Kenya Switzerland Czechoslovakia Korea, Rep. of Turkey United Kingdom Egypt, Arab Rep. of Mexico Netherlands USSR France Yugoslavia Germany. F. R. New Zealand No member body expressed disapproval of the document. This International Standard has also been approved by the International Union of Pure and Applied Chemistry (IUPAC). International Organization for Standardization, 1979 ? Printed in Switzerland Copyright International Organization for Standardization ng permitted without license from IHS Not for Resale INTERNATIONAL STANDARD ISO 5993-1979 (E) Sodium hydroxide for industrial use - Determination of mercury content --- Flameless atomic absorption spectro. metric method Scope and field of application 4.3 Potassium permanganate, 40 g/l solution. This International Standard specifies a flameless atomic ab- 4.4 Hydroxylammonium chloride (NH2OH.HCl), 100 g/l sorption spectrometric method for the determination of the solution. mercury content of sodium hydroxide for industrial use. 4.5 Tin(ll) chloride, 100 g/l solution in hydrochloric acid. The method is applicable to liquid or solid products having mer- cury (Hg) contents greater than 0,02 mg/kg. Dissolve 25 g of tin(1) chloride dihydrate (SnCl2.2H20) in 50 m! of hot hydrochloric acid solution, approximately 1,19 g/ml The alternative dithizone photometric method for the deter. NOTE mination of mercury content, specified in IS0 5992, is intended for use in laboratories where flameiess atomic absorption equipment is not volumetric flask, dilute to the mark with water and mix available. Transfer this solution to a glass flask and purge it by bubbling the nitrogen (4.1) through for 5 min, then add a few particles of granular metallic tin to assist stabilization. Discard when tur- 2 References bidity appears. ISO3195,Sodiumhydroxideforindustrialuse Sampling 4.6 lodine, 2,5 g/l solution. Preparation of the main solution for carrying Test sample out certain determinations. Dissolve 2,5 g of iodine and 30 g of potassium iodide in water, dilute to the mark in a 1 000 ml one-mark volumetric flask and iso 579o, inorganic chemical products for industrial use mix. General method for determination of chloride content -- Mer- curimetric method. 4.7 Mercury, standard solution corresponding to 1,o00 g of Hg per litre. ISO 5992, Sodium hydroxide for industrial use -- Determina- tion of mercury content -- Dithi