Fourier transform infrared spectroscopy applied to the analysis of ancientmanuscripts

Fourier transform infrared spectroscopy has been applied to the characteriz ation of manuscript degradation. Samples were small pieces or individual fi bres from paper manuscripts that dated from 1360 to the end of the eighteen th century. The pH at the surface ranged from 4 to 7.6 due to irongall ink corrosion or biological degradation. Several IR techniques were tested in order to choose the best, considering the condition of the sample and the need to minimize the damage: KBr pellet s, diamond cell using the microscope in transmission mode and diamond cell using the beam condenser, microscope using the attenuated total reflectance (ATR) objective and diffuse reflexion (DRIFT) were compared. Variations of O-H and C-O absorptions show the degree of cellulose oxidatio n. More degraded samples show more intense C-O bands and weaker O-H bands. Using this method it is also possible to measure carbonate bands, which are stronger when paper is in a good condition and not degraded. Manuscript degradation depends on the acidity of irongall inks and alkaline buffering of the paper. A decrease in alkaline buffering in degraded sampl es analyzed by SEM-EDX corroborates the measurements of carbonates obtained by infrared analysis.