Characterization of reference lipids and their degradation products by Raman spectroscopy, nuclear magnetic resonance and gas chromatography-mass spectrometry

The study of organic residues preserved in objects and materials collected in archaeological sites can provide information on the activities of ancient societies. Degraded animal fats, plant oils, beeswax and plant resins are among the most common organic residues found within ceramic vessels or mixed with inorganic pigments in archaeological pastes. The effects of decay of these organic compounds difficult the direct comparison with modern reference data. The purpose of this work was the use of complementary analytical methods, such as GC-MS, NMR, FT-IR and FT-Raman spectroscopy for the characterization of a reference fat and the degradation products of a thermally aged mixture of a red mineral of the Patagonian region and the fat of an American ostrich (Pterocnemia pennata). Our results showed a decrease in the unsaturated fatty acids with formation of C8 and C9 dicarboxylic acids in the thermally aged fat.