A reagent for the acid value determination in oils. The reagent contains a tertiary amine, such as triethanolamine, in a water-alcohol mixture as solvent. Preferred is isopropanol/water. The reagent allows determinations of acid values in oils in a two phase system. The use of the reagent is based on a pH-metric technique with conditional pH-measurement before and after the addition of an oil sample to the reagent.
