Analysing reds in Coptic textiles: Insights from mass spectrometry

Abstract

This research investigates Coptic textiles from the first millennium, recovered from Egyptian necropolises and known for their aesthetic and cultural significance. These textiles exemplify a crucial connection between ancient and medieval artistic traditions. Using advanced analytical techniques like high-performance liquid chromatography coupled with UV–vis spectrophotometry and electrospray ionization mass spectrometry (HPLC-UV–vis-ESI MS/MS), the study investigates natural dyes in the collection of the Jagiellonian University Museum Collegium Maius, focusing on eight red wefts of textiles dating from the 3rd to 8th centuries. Preliminary results identify madder and indigo or woad, lac dye and shellfish purple (also known as Tyrian purple or royal purple), highlighting extensive trade connections. One sample contained synthetic dye, new fuchsin, suggesting an effort to enhance its appearance during the 19th or 20th century. By linking chemical profiles with historical data, the research verified hypotheses about dye sourcing, aiding in dating the fabrics. The study also revealed fragmentation pathway and the identity of a brominated indigotin derivative, a degradation product of shellfish purple. Moreover, it uncovered previously unreported dye markers, likely resulting from degradation, and demonstrated that the extractant could react with the colorants on a fibre, thereby influencing the composition of the extract mixture, as revealed using HPLC-UV–vis-ESI MS/MS.