NTERNATIONAL STANDARD TSO 794 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKYHAPOHA OPIAHM3ALIHA HO CTAHIAPTH3ALIMM·ORGANISATION INTERNATIONALE DE NORMALISATION Magnesium and magnesium alloys -- Determination of copper content - Oxalyldihydrazide photometric method Magnesium et alliages de magnesium -- Dosage du cuivre -- Methode photometrique a I'oxalyldihydrazide First edition - 1976-02-01 ISO 794-1976 (E) UDC 669.721 : 546.56 : 543.4 Ref. No. 1SO 794-1976 (E) Descriptors : magnesium, magnesium alloys, chemical analysis, determination of content, copper. Price based on 3 pages Not for Resale FOREWORD IsO (the International Organization for Standardization) is a worldwide federation of national standards institutes (ISO Member Bodies). The work of developing International 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, governmentat 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. Prior to 1972, the results of the work of the Technical Committees were published transformed into International Standards. As part of this process, Technical Committee 1SO/TC 79 has reviewed ISO Recommendation R 794 and found it technically suitable for transformation. International Standard IsO 794 therefore replaces 1SO Recommendation R 794-1968 to which it is technically identical. IsO Recommendation R 794 was approved by the Member Bodies of the following countries : Hungary Austria Spain Belgium Korea, Rep. of Sweden Brazil India Switzerland Bulgaria Ireland Turkey Canada Israel United Kingdom Chile Italy U.S.A. Czechoslovakia Netherlands U.S.S.R. Egypt, Arab Rep. of Norway Yugoslavia France Poland Germany South Africa, Rep. of No Member Body expressed disapproval of the Recommendation. The Member Body of the following country disapproved the transformation of ISO/R 794 into an International Standard : Switzerland @ International Organization for Standardization,1976 Printed in Switzerland Copyright International Organization for Standardization e from IHS Not for Res ISO 794-1976 (E) INTERNATIONAL STANDARD Magnesium and magnesium alloys --- Determination of copper content -. Oxalyldihydrazide photometric method 3.6 Acetaldehyde, 400 g/l solution. 1 SCOPE AND FIELD OF APPLICATION This International Standard specifies an oxalyldihydrazide In a 1 000 mi volumetric flask, place 400 g of acetaldehyde photometric method for the determination of copper (CHgCHO) and cool to approximately 5 °C; slowly add cooled distilled water (at about 5 °c) and make up the content in magnesium and magnesium alloys. volume to 1 000 ml. The method is applicable to the determination of copper content between 0,002 and 0,4 % (m/m). The method is not applicabie in the special case of NOTE --. Since heat is produced when water and acetaldehyde are mixed, and since acetaldehyde is very volatile (boiling point 21 °C) magnesium alloys containing zirconium. it is recommended that the vessel in which the mixing takes place should be cooled by cold water. 2 PRINCIPLE 3.7 Oxalyldihydrazide 2,5 g/1 solution. Attack with hydrochloric acid. Dissolve 2,5 g of oxalyidihydrazide (C2H6N402) in warm water (40 to 50 °c) and, after cooling to 20 °c, make up Formation between pH 8,8 and pH 9,3, in the presence the volume to 1 000 mi. Filter if necessary. of acetaldehyde, of the violet-coloured copper-oxalyl- dihydrazide complex, the optimum pH range being 3.8 Copper, standard solution, corresponding to 1 g of Cu obtained by adding a controlled amount of ammonia. per litre. Photometric measurement at a wavelength of about 3.8.1 In a tall-form beaker of suitable capacity (for 540 nm.1) example 400 ml), d