Zastosowanie chromatografii cienkowarstwowej do oznaczania spoiw olejnych

The present work made at a scientific-research laboratory of the State Enterprise for Conservation of Art was aimed at identifying oil binders by means of thin-layer chromatographic analysis. The work presented a survey of techniques employed in the determination of lipids by means of chromatographic analysis on the painted material. The procedure o f the identification of oil binders was worked out on this basis, which made it possible to implement it in conservation practices. Samples o f oils such as linseed oil (cold-pressed), poppy-seed oil (sun-dried, made by Winsor-Newton) and oil coming from the egg yolk were hydrolyzed in the solution o f KOH in methanol at room temperature. After neutralizing, the samples were extracted with chloroform. Solutions of individual oils were then put on chromatograms. Silicon gel (Kieselgel 60) was used as an adsorbent. Gel- covered glass plates (20 x 20 cm or 20 x 50 cm in size, made by Merck), were activated thermically. A number of developing systems were examined, out of which naptha oil: ethyl ether: acetic acid (80:20:1) was considered as optimum. Iodine pairs associated with sulfuric acid proved to be the best developer. The sensitivity of such a methodical procedure was defined at 10~4 g. Basing on the results of the studies, the above procedure was used for painting techniques containing oil binders: non-yellowing medium, traditional medium, oil-casein distemper, yolk distemper, distemper with arabie gum. The effect of various siccatives and inhibiting (cinnabar) and catalyzing (white lead) agents on the results o f determinations was studied in the process o f drying after prior artificial aging of samples. The method obtained makes possible to distinguish the oil technique from yolk and oil-resin techniques.