通过与在氯化羟胺和氢氧化钾混合物中释放的游离羟胺反应，将羰基化合物转化为肟来进行测定。用盐酸溶液滴定过量的碱，无论是比色法还是电位法。本方法适用于含有羰基化合物（尤其是酮，不包括甲基酮）的精油，这些化合物很难通过ISO 1279中规定的方法转化为肟。该方法不适用于含有大量其他碱敏感成分酯的精油。

The determination is carried out by converting the carbonyl compounds to oximes by reaction with free hydroxylamine liberated in a mixture of hydroxylammoniumchloride and potassium hydroxide. The excess alkali is titrated with hydrochloric acid solution, either colorimetrically or potentiometrically. The method is applicable to essential oils which contain carbonyl compounds (especially ketones, excluding methylketones) which are difficult to convert to oximes by the method specified in ISO 1279. The method is not applicable to essential oils which contain substantial amounts of esters of other alkali-sensitive constituents.