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I Surowiec, W. Nowik, A. Quye, B. Lendl, M. Trojanowicz:
"New Developments in Application of HPLC in Archaeometry of Textiles";
Poster: 30th International Symposium and Exhibit on High Performance Liquid Phase Separations and Related Techniques, San Francisco; 17.06.2006 - 22.06.2006.

A nation´s past economic, social and cultural history can be revealed through the dyes used for its historical and archaeological textiles. The most common analytical technique used to identify these dyes, which, until the mid-nineteeth century, came from natural sources, is HPLC with PDA detection because it is sensitive, qualitative and quantitative. As the identification of a historical dye source relies on matching the analytical profile for the extracted sample with a known reference, a number of factors reduce the success rate, including chemical degradation by light, oxidation or water as a consequence of ageing effects, a limited reference set or an inefficient extraction process. Maximizing the amount of information from museum textiles, where sample size is restricted, is therefore essential. Investigations to improve extraction efficiency and evaluate different detection methods for such analysis are presented in this paper.

The detection limits for several flavonoids, anthraquinoids and dye degradation products could be reduced by FLD HPLC with post-column complexation using aluminium, gallium or zirconyl salts. This method also gave additonal structural characteristics for the analytes which may benefit identification of unknowns in extracts from archaeological samples. Detection limits were decreased even further for some compounds by mass spectrometry detection, which also enabled structure elucidation of interesting unknowns so that conclusions about the dye composition and its degree of decomposition could be made. An example is the detection of chloroalizarin in an extract from an early medieval Coptic textile and identification of unique dyes in a fifteenth century sample from a Polish king´s grave. The method also proved helpful in dating a Japanese tapestry from the collection of Academy of Fine Arts in Warsaw through the detection of synthetic dye methylene blue. Such information also aided conservation since the dye is soluble in aqueous solutions.

HPLC-IR, using a microdispenser as a solvent elimination interfece coupled to a narrow bore HPLC separation system with the subsequent application of an IR and Raman microscopes was a novel technique for detecting and identifying degradation products of flavonoid dyes. The method also proved to be promising for the comprehensive analysis of extracts from archaeological textiles.

A widely-used methanolic acidified method for extracting dye components (anthraquinones, flavonoids and indigoids) from historical fibres was improved with an additional methanol/DMF step. By increasing the extraction efficiences for the majority of main dye components and minimising the number of sample handling steps, better analytical sensitivity was achieved.

http://publik.tuwien.ac.at/files/pub-tch_6391.pdf