Huiles essentielles — Détermination de l'indice d'ester des huiles contenant des esters difficilement saponifiables

The method consists in hydrolysis of the esters present in a test portion by heating in the presence of a standard volumetric solution of potassium hydroxide in dimethylsulfoxide, and back-titration of the excess potassium hydroxide with a standard volumetric solution of sulfuric acid or hydrochloric acid.