This work is concerned with lipidic substances, in particular vegetable oils, used as pigment binders or as a protective varnishes for finishing artwork. The introduction reviews the recent knowledge of this subject, in particular with respect to the identification of the most used drying oils, and of the methods to study their changes in the course of time. Both can be achieved using determination of the relative representation of fatty acids, most characteristic being the ratio of stearic/palmitic a oleic/palmitic acids. This parameter is changing as the artwork is getting older and the oils are drying. Because of the availability of the instrumentation needed, we have chosen the high- performance liquid chromatography method for further experimental work. The first step was optimalization of the analytical method by standards of fatty acids. For derivatization of fatty acids, reagents 2,4-dinitrophenylhydrazine and 2-nitrophenylhydrazine were examined. Whereas we were unable to get any results with the first one (the method based on the article: Bravo, B. et al., Talanta 64, 1329-1334, 2004) for unknown reasons, good results were obtained with the second one. Derivates of fatty acids have been analyzed by high performance liquid chromatography (HPLC) on column with revesed phase (C18). The...