TSO NTERNATIONAL STANDARD 2227 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXKIYHAPOIHAI OPIAHI3ALIMG IIO CTAHAAPTH3ALIWI·ORGANISATION INTERNATIONALE DE NORMALISATION Formaldehyde solutions for industrial use Determination of formaldehyde content First edition -- 1972-12-01 NOV15 AnsT Itemnmt o Sec ISO 2227-1972 (E) UDC 661.727.1 : 542.61 : 547.281 Ref. No. 1SO 2227-1972 (E) Descriptors : formaldehyde, chemical analysis, determination of content, volumetric analysis. Price based on 2 pages nsefrom IHS 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, 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 2227 was drawn up by Technical Committee ISO/TC 47, Chemistry. It was approved in July 1971 by the Member Bodies of the following countries : Austria Ireland Sweden Belgium Israel Switzerland Czechoslovakia Italy Turkey Egypt, Arab Rep. of Netherlands United Kingdom U.S.A. France New Zealand Germany Romania U.S.S.R. Hungary South Africa, Rep. of No Member Body expressed disapproval of the document. @ International Organization for Standardization,1972 PrintedinSwitzerland Copyright International Organization for Standardization e from IHS Not for Resale INTERNATIONAL STANDARD ISO 2227-1972 (E) Formaldehyde solutions for industrial use Determination of formaldehyde content WARNING 4.4 Hydrochloric acid, N standard volumetric solution. Formaldehyde is toxic. It is therefore necessary to avoid 4.5 Thymolphthalein, 2 g/l ethanolic solution. inhaling its vapour during sampling and testing. Dissolve 0,2 g of thymolphthalein in 60 ml of 95 % (V/V) ethanol, add the sodium hydroxide solution (4.2). until a 1 SCOPE pale blue coloration is produced and then dilute to 100 ml with water. This international Standard specifies a volumetric method for the determination of the formaldehyde content of 5 APPARATUS formaldehyde solutions for industrial use. Ordinary laboratory apparatus and 2 FIELD OF APPLICATION 5.1 Weighing pipette, capacity approximately 3 ml. The method as described is applicable to formaldehyde solutions with formaldehyde contents between 25 % and 6 SAMPLING 45 %, but the field of application may be extended by Follow the principles given in ISO . . .1). suitably modifying the mass of the test portion. Attention is drawn to the following recommendation. Place NOTE Thismethodoftestisapplicabletosamplesthatareclea the laboratory sample, representative of the material taken or only slightly cloudy. If the test sample contains a precipitate, then even if it is thoroughty mixed the results obtained by this from the bulk, in a clean, dry, and air-tight glass bottle method will not be correct, the amount of error being dependent fitted with a ground giass stopper, of such a size that it is upon the amount of precipitate present. nearly fitled by the sample. If it is necessary to seal this bottle care shall be taken to 3 PRINCIPLE avoid the risk of contamination. Reaction of the formaldehyde present with a neutral Owing to polymerization, paraformaldehyde will tend to be sodium sulphite solution, and acidimetric titration of the deposited on standing and this will occur more rapidly if liberated sodium hydroxide using thymolphthalein as the temperature is allowed to fall below 25 °c. Accordingly indicator. the material shall be sampted as soon as possible after receipt. 4 REAGENTS 7 PROCEDURE Distilled water, or water of