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ATR/FTIR spectra of historical parchments - damage category III

figure
posted on 2023-08-08, 10:36 authored by Charis TheodorakopoulosCharis Theodorakopoulos

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ATR/FTIR spectra from historical samples analysed for the EC-IDAP project showed differences between flesh and grain sides.

The historical parchments analysed were provided from the following archives:

  • School of Conservation, Copenhagen, Denmark: SC15 - SC80
  • National Archives, Scotland, UK: SC114 - SC125
  • Municipal Archive, Segovia, Spain: SC162
  • Archivio di Stato, Florence, Italy: SC163 - SC175

Most of the historical parchments had a broad band with a peak at 1450-1400cm-1 due to the presence of calcium carbonate in the flesh side, which interfered with the amide II band at 1536 cm-1. Thus, damage assessment was based on the spectra from the grain side and restricted to evaluation of the amide I peak. In particular, the amide I carbonyl stretching region (1690-1625cm-1), is sensitive to subtle changes to the triple helical structure of collagen [1]. The amide I carbonyls in the triple helix can be intramolecularly linked with weak hydrogen bonds and absorb at about 1660cm-1. At about 1630cm-1 the amide carbonyls are directed outwards in the triple helix and form relatively strong intermolecular hydrogen bonds with water molecules. In line with studies of collagen in calcified aortic cusps in which the 1660:1630 ratio was employed to indicate significant changes suggesting degeneration of the triple helix [2], collagen denaturation in parchment was also indicated with the same 1660:1630 ratio of peak intensity. Historical parchments have been classified to 4 damage categories as follows:

Damage category I (not damaged): freshly 1660:1630 ratio up to 5% change compared to the control (new (unaged) parchments)

Damage category II (slightly damaged): 1660:1630 ratio of 5-12% change compared to the control (new parchments)

Damage category III (considerably damaged): 1660:1630 ratio of 12-20% change compared to the control (new parchments)

Damage category IV (very damaged): 1660:1630 ratio of >>20% change compared to the control (new parchments)

Damage category III spectra are presented here

References

[1] M. Odlyha, C. Theodorakopoulos, J. de Groot, L. Bozec, M. Horton, e-Preservation Science 2009, 6, 138-144 - download

[2] N.R. Vyavahare, D. Hirsch, E. Lerner, J.Z. Baskin, R. Zand, F.J. Schoen and R.J. Levy, J Biomed Mater Res 1998, 40 577-585 DOI:10.1002/(SICI)1097-4636(19980615)40:4<577::AID-JBM9>3.0.CO;2-C

This dataset is part of:

Theodorakopoulos, Charis (2023). Infrared spectra database - Depository of FTIR spectra of IDAP parchments. Northumbria University. Collection. https://doi.org/10.25398/rd.northumbria.c.6742791

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