Chromatographic Investigation of Dyes Extracted from Coptic Textiles from the National Museum in Warsaw

Abstract

This work aimed to identify natural dyes in extracts from Coptic fibres. The objects examined originate from fourth- to twelfth-century AD Egypt. Chromatographic separations of all the samples were carried out using reversed-phase HPLC (high performance liquid chromatography) with UV-Vis detection and fluorescence detection. Fluorescence detection proved to be better than UV-Vis diode array detection for the determination of some compounds. Selected samples were analysed with HPLC-MS (HPLC-mass spectroscopy) which confirmed the LC-UV findings and allowed the detection and identification of additional compounds. Most of the dyes mentioned in the literature as having been used by Copts were detected: Armenian cochineal, flavonoid yellow dyes, indigotin, lac dye, madder and tannins. Some new compositions of significant colours were also discovered, which had not been reported previously in Coptic textiles. Elemental analysis using SEM-EDS (scanning electron microscopy–energy dispersive spectroscopy) was performed to identify mordants.