FTIR analysis also reveals important details about the nature of the surface and core compositions. Figure 7 shows FTIR spectra for surface and core samples from 83.AO.202.1. The saturated C-H bands at 2927 and 2869 cm-1in the spectrum of the surface sample are reduced, whereas the C-O stretching modes at 1159 cm1 in the fingerprint region are more intense. This indicates that the surface is more highly oxidized than the core. The other important peak appears at 1574 cm-1, which is due to salts of succinic acid. There is a much higher concentration of succinate salts in the surface sample, which is consistent with exposure to alkaline conditions during some period of time.18 This might have occurred during burial, or resulted from harsh cleaning with alkaline chemicals. FTIR spectra of two surface samples Figure 8 FTIR spectra for surface and core samples from 82.AO.161.7 (cat. no. and a core from 82.AO.161.7 (cat. no. 24) (figure 8) show 24). an increased O-H stretching band in the surface sample, with a shift in the C=O band to lower wavenumbers, Table 9 lists the THM-Py-GC/MS results for the treated indicating the prevalence of carboxylic acids. However, amber objects, and representative chromatograms are the succinate salt peak at 1574 cm-1 is only a slight shown infigure 9. Azelaic acid was detected in three of shoulder on the carbonyl peak, indicating that this object the objects: 77.AO.81.29 (cat. no. 16), 77.AO.81.5 (cat. no. was not exposed to the same harsh alkaline conditions as 23), and 77.AO.81.30 (cat. no. 25). This is a common 83.AO.202.1. marker compound for cross-linked drying oils, and its presence along with palmitic acid and stearic acid indicates that drying oils may have been applied to these objects in an alternative type of conservation treatment. In 77.AO.81.4 (cat. no. 14), palmitic and stearic acids were detected along with cholesterol, but azelaic acid was absent. This suggests that an animal fat could have been applied to this object as another type of alternative treatment. Three amber objects tested in this study had been previously treated with amber oil: 77.AO.84 (cat. no. 1), 77.AO.83 (cat. no. 38), and 77.AO.81.7 (cat. no. 41). Their extremely high succinate contents suggest that they were highly degraded prior to treatment. In figure 10, the FTIR spectra for selected treated samples show that treatment with drying oil or amber oil does not interfere with the identification of Baltic amber. Figure 7 FTIR spectra for surface and core samples from 83.AO.202.1 (cat. no. 12). 276 TECHNICAL ESSAY