The identification of dyes of Greco-Roman period fabric in Egypt using liquid chromatography/mass spectrometry.

The red dyes of woven fabrics (I, II and III) from the Greco-Roman period, excavated at Akoris in middle Egypt, were investigated using UV-VIS absorption spectroscopy, HPLC and thermospray type liquid chromatography/mass spectrometry, selected ion monitoring (SIM) technique. UV-VIS spectrum and HPLC retention time of dyes of II and III suggested the presence of alizarin (MW 240), a natural dye from madder. Further analysis was made by LC/MS SIM using m/z 241 (MH+ ion of alizarin) as the selected ion. The presence of an ion m/z 241 peak at the identical retention time for authentic alizarin strongly suggests that fabrics II and III were dyed by madder. Fabric I, however, was not dyed by this herb, but by an unidentified weakly polar pigment.