Spectroscopic Characterization Of Ancient Matrices

Since a decade our research group deals with the analysis of ancient cosmetics and drugs, starting from the Roman founds 1-3. Actually, this kind of study involves other research groups supported by a national Fund (PRIN: Colours and ointments in antiquity). Firstly the analysis protocol provides non-destructive analyses and then the more expensive and destructive analyses, such as gas-chromatography-mass spectrometry (GC-MS) methods. The samples analyzed in this study were collected from the Egyptian Museum of Turin, Italy. The discovery of the studied archaeological finds was made by Ernesto Schiaparelli (1906 until 1913) and the archaeological founds were dated from the late III millenium b.C. to early II millenium b.C. The sites of finding were in Assiut (at about 400 Km from Cairo on the bank of the Nile) and Gebelein (south of Assiut), near the southern border with Nubia. In the sarcophagus usually it is possible to find weapons, like bows and arrows, textiles and also ointments. Here the results of the vibrational spectroscopy techniques, such as Raman microscopy (laser 632 nm), FT-Raman spectroscopy (laser 1064 nm) and FT-IR/ATR with a golden gate accessory are reported. These techniques are identified as the most suitable ones for the first approach to ancient samples analysis. Raman microscopy is in fact the most suitable technique in order to identify minor inorganic components and contaminants at the micrometric scale inside these complex matrices4. This technique can easily identify compounds like lead oxide, vermillion, rare minerals, (etc.) that could give interesting informations about the provenance of the raw materials and the original composition of the formulate. In the present study some data are reported concerning the composition of five ancient Egyptian samples. It can be observed that Titanite is present, a mineral possibly coming from mines in Southern Egypt5.Concerning to organic materials, their possibility of identification, is very different from that of inorganic ones. Some compounds were rapidly degraded, some others persisted till to present day, often unchanged (e.g. wax). Historical samples give a chemical variability due to the natural products, in addiction, ageing and degradation processes make very difficult to recognize raw materials originally present. For understanding the possible changes undergone by materials in ageing, a specific database of spectra must be available. Some thirty raw materials were chosen among oils, gums, animal fats and waxes commonly employed in the ancient preparations. The reference materials were in laboratory artificially aged by heating, photo-oxidation and enzymatic degradation. Some artificial materials aged produced different alterations according to the type of ageing. The comparison to one remain sample and our database spectrum showed a correspondence with the enzymatically degraded palm oil spectrum. This indicates the importance of this database in recognising the organic materials into archaeological holders.