The method is applicable to products having carbonyl compounds contents equal to or greater than 0.01 % (m/m). The method only allows determination of those carbonyl compounds which react under the specified conditions. The principle is based on the reaction of hydroxylammonium chloride with the carbonyl compounds in a test portion and titration of the hydrochloric acid formed with standard volumetric sodium hydroxide solution, in the presence of bromophenol blue as indicator. - International Standards ISO 1388/1 to ISO 1377/12 cancel and replace ISO Recommendation R 1388-1970 of which they constitute a technical revision.