The Rancimat method is an accelerated ageing test. Air is conducted through the sample in the reaction vessel at a constantly increased temperature. The fatty acids are oxidized during this process. Volatile secondary reaction products are formed at the end of the test that are conducted by air flow into a measuring vessel, where they are absorbed by a measuring solution (distilled water). The continually recorded electrical conductivity increases as a result of the absorption of the ionic reaction products. The time up to which the secondary reaction products arise is called the induction time. It characterizes the oxidation stability of oils and fats.
This Application Bulletin provides a detailed description of the method, in particular also of the required sample preparation.