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Zastosowanie cienkowarstwowej analizy chromatograficznej do identyfikacji spoiw malarskich

100%

Wawrzeńczak A.

Ochrona Zabytków

1974

issue 3

218-224

In the above article reported are the results of investigations carried out in research laboratory of the state-owned Ateliers for Conservation of Cultural Property, Warsaw wiiith the purpose to adapt the thin- Layer partition chromatography to identification of binders used in paintings. These investigations, preliminary as to their character, were confined to problems connected chiefly with protein and to some extent also with polysaccharide binders. No investigations have been conducted of plant gums, gum resins or oil-based binders. All these problems will be included to the other part of the present work. As the analyses using partition chromatography are conducted more and more often, to make the phrenomena occurring during the process more easily understandable, dealt with briefly within the article are also the theoretical backgrounds of partition chromatography and discussed the results obtained until recently from investigations carried out in several conservation laboratories. The methods adopted in investigations dealt with were based on those typical for thin-layer chromatography with the use of the manufacturer’s set “CAMAG” for coating the glass plates with a carrier layer of Swiss make, then with the use of ex-works glass plates coated with silica gel (Kieselgel 60 F25/,) layer 0.25 mm thick and “Cellulose F” layer 0.1 mm thick. The above plates manufactured by MERCK Co. (West Germany) and having standard size of 20X20 cm can be readily cut to measure, according to the size of chromatographic chamber. The samples were subjected to acid hydrolysis at 105°C with simultaneous changes of both sulphuric acid concentration and duration of hydrolysis. The hydrolytic residue was neutralized with ВаСОз to pH = 7 then filtered with precipitation of deposit and, finally, the filtrate was evaporated at 50°C. To have settled the limits of detectability of amino acids and saccharides a certain number of model binders was prepared 'containing, in addition to chalk playing the role of a filler, the protein and polysaccharide binders as, e.g. hige glue, egg yolk, egg white, isinglass and honey. Proportion of the binder proper to filler in the above binders varied within a comparatively wide range. While identifying the protein binders were chiefly utilized the results of experiments carried out by M. Hey who based her methods on the fact that nor in casein neither in egg-based binders can be found hydroxyproline being a natural amino ao:d present exclusively in g lutin containing glues. Also the model monochromatic samples were prepared containing, in addition to protein binders, quite negligible admixture of honey. The results of 'investigations carried out have shown that in view of its high sensitivity, the speed with which it can be carried out and quite negligible amount of samples required for analysis the method basing on the thin-layer chromatography should find its as wide as possible application in technological tests. However, to obtain the entirely satisfactory results the above method should necessarily be supported by densiitometric technique whose results are fully satisfying the needs.

Zastosowanie chromatografii cienkowarstwowej do oznaczania spoiw olejnych

63%

Baczko K.

Ochrona Zabytków

1981

issue 1-2

86-92

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.

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2 Ochrona Zabytków

1 1981

1 1974

1 Baczko K.

1 Wawrzeńczak A.

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Zastosowanie cienkowarstwowej analizy chromatograficznej do identyfikacji spoiw malarskich

Zastosowanie chromatografii cienkowarstwowej do oznaczania spoiw olejnych