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Within the Kunsthistorisches Museum (KHM), Vienna, three off‐line GC‐MS analytical procedures for the identification of natural organic media have been refined, tested, and validated for the use in investigating original, historic works of art. The analysis of a sample from a Greek terracotta statue suggested that the white ground layer of the polychromy, still partly present today, contained a gum‐based binding medium. Furthermore, a procedure for the simultaneous analysis of oils, waxes and resins was applied to the identification of the composition of the varnish layer from the 16th century painting “Lucretia” by Jacopo Negretti (1480–1528). In addition, in a collaboration with the Department for Conservation and Restoration, University of Applied Arts, Vienna, a series of samples from paintings on wooden panels from the Buddhist temple complex in Nako, Himachal Pradesh, India, was investigated for the presence of proteinaceous binding media.

SummaryA simple GC-MS method has been studied for the determination of aJdoses and uronic acids in polysaccharide hydrolysates. Unlike other methods, the derivatisation procedure gives a single peak for each particular monosaccharide, including uronic acids. The method has been applied to plant gums used in decorative artefacts. A sample of gum, after acid hydrolysis, is first mercaptalated with a mixture of ethanethiol and trifluoroacetic acid (2:1) and then derivatized in the same vessel. The obtained diethyldithioacetal trimethylsilylates or peracetates are separated by capillary column gas chromatography on SE-54 stationary phase. The chromatographic retention indices and El mass spectra of monosaccharide standards are reported togetherwith composition data for six plant gums.

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