1271 International Standard (ISO INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEKAYHAPOAHAA OPFAHM3AUWR HO CTAHAAPTW3AUWMORGANISATION INTERNATIONALE DE NORMALISATION Ansr Internet Doa sc Essential oils - Determination of carbonyl value -- Free hydroxylamine method Huiles essentielles -- Détermination de I'indice de carbonyle -Methode a I'hydroxylamine libre Second edition - 1983-12-01 Corrected and reprinted - 1985-08-01 UDC 668.5 : 547.28 : 543.86 Ref.No.1SO1271-1983(E) Descriptors : essential oils, chemical analysis, determination of content, carbonyl compounds. Price based on 4 pages Not for Resale Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental 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. They are approved in accordance with IsO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 1271 was prepared by Technical Committee ISO/TC 54. Essentialoils. cancels and replaces the first edition, of which it constitutes a technical revision. International Organization for Standardization, 1983 Printed in Switzerland No reproduction or networking permited without license from IHS e with ISO Not for Resale INTERNATIONAL STANDARD ISO1271-1983 (E) Essential oils - Determination of carbonyl value Free hydroxylamine method 1 Scope and field of application Titration of the excess alkali with hydrochloric acid solution, either colorimetrically or potentiometrically This International Standard specifies a method for the deter- mination of the carbonyl value of essential oils. It is applicable to essential oils which contain carbonyl compounds (especially 5 Reagents ketones, excluding methylketones) which are difficuit to con- vert to oximes by the method specified in ISO 1279. All reagents shall be of recognized analytical grade and the The method is not applicable to essential oils which contain water used shall be distilled water or water of at least equivalent substantial amounts of esters or other alkali-sensitive consti purity. tuents. 5.1 Hydrochloric acid, standard volumetric solution, International Standards specifying requirements for individual c(HCI) ~ 0,5 mol/l. essential oils will specify whether this method or the hydrox- ylammonium chloride method specified in Iso 12791) is ap- plicable. 5.2 Potassium hydroxide solution, c(KOH) ~ 0,5 mol/l, in 95 % ( V/ V) ethanol. 2 References 5.3 Bromophenol blue, ethanolic solution. Iso 212, Essential oils - Sampling. Dissolve, by heating, 0,2 g of bromophenol blue in 3 ml of Iso 356, Essential oils - Preparation of test sample. ethanolic potassium hydroxide solution, c(KOH) = 0,1 mol/l, and 10 mi of 95 % (V/V) ethanol. After cooling, dilute to 100 ml with the same ethanoi. 3 Definition For the purpose of this International Standard, the following 5.4 Hydroxylammonium chloride, ethanolic solution. definition applies. Dissolve 50 g of hydroxylammonium chloride in approximately carbonyl value (of an essential oil) : The number of milligrams 100 ml of water, add about 800 ml of 95 % ( v/v) ethanol, of potassium hydroxide, per gram of essential oil, required to then 10 ml of the ethanolic bromophenol blue solution (5.3) neutralize the hydrochloric acid liberated in the oximation reac- and dilute to 1 000 ml with 95 % (V/V) ethanol. Add the tion with hydroxylammonium chloride. ethanolic potassium hydroxide solution (5.2) until the solution is green, if the liqu