Molecular Characterization of a South American Yellow Dye Source: Cosmos Sulphureus

Determining the dye source used in ancient coloured textiles is challenging, especially if little information is available on the raw materials or traditional recipes of the geographical area. This is the case of South American dye sources and particularly of yellow ones, the widest and highest photo-sensitive class. In this work, Cosmos sulphureus, an annual plant whose flowers were used for dyeing in nuances of red to yellow, was analysed. The petal content was analysed by high-pressure liquid chromatography with a diode array detector (HPLC-DAD) and high-resolution mass spectrometer (HPLC-HRMS) and sixteen compounds were identified, some of which had never been reported in Cosmos sulphureus. Not mordanted and mordanted yarns, dyed with Cosmos sulphureus petal extract and artificially aged, were analysed to assess the role played by the mordant and ageing. The information pointed at Cosmos sulphureus as the dye source in a yellow Chimú / Chancay textile (1000-1047 AD).