Study of Egyptian mummification balms by FT-IR spectroscopy and GC–MS

Abstract

Fourier transform infrared spectroscopy (FT-IR) and gas chromatography coupled with mass spectrometry (GC–MS) were used in order to analyse twelve mummification balms from mummy skulls of the Musée des Confluences (Lyon, France).For FT-IR analyses, a simple extraction protocol in dichloromethane and water allowed to separate the materials by their polarity. This study clearly shows that the organic fraction is the main constituent of the Egyptian balms and hides much information in the bulk analyses (made without any extraction). Infrared absorption reveals the presence of (i) several organic materials (proteins, polysaccharides), (ii) inorganic salts (CaSO4, CaCO3 and NH4Cl) possibly used as natron in ancient time, and (iii) ochre used in order to dye the bandages.GC–MS analyses were made on the organic fraction of extracted balms, previously trimethylsilylated before injection. Biomarkers and degradation products of oils, fats, resins (with oleanene, lupene, lanostane, masticadiene, and abietane compounds) and beeswax were found. These materials were often used in combination. Many identified byproducts (di and triterpenic molecules, hydroxylated fatty acids, etc) give us the opportunity to discuss the different degradation reactions taking place in such archaeological material. Furthermore, beeswax was identified in numerous samples thanks to the presence of long chain alkanes, long chain fatty acids and palmitate ester. In one balm, the co-occurrence of brassicaceae oil chemical markers and cholesterol (and its degradation products) shows the combine use of oil and fat. Finally, a great correlation and complementarity was observed between the two analytical techniques.