Studies on the effect of dry-heat ageing on parchment deterioration by vibrational spectroscopy and micro hot table method

Assessment of spatially offset Raman spectroscopy to detect differences in bone matrix quality

Since spatially offset Raman spectroscopy (SORS) can acquire biochemical measurements of tissue quality through light scattering materials, we investigated the feasibility of this technique to acquire Raman bands related to the fracture resistance of bone. Designed to maximize signals at different offsets, a SORS probe was used to acquire spectra from cadaveric bone with and without skin-like tissue phantoms attenuating the light. Autoclaving the lateral side of femur mid-shafts from 5 female and 5 male donors at 100 °C and again at 120 °C reduced the yield stress of cortical beams subjected to three-point bending. It did not affect the volumetric bone mineral density or porosity. Without tissue phantoms, autoclaving affected more Raman characteristics of the organic matrix when determined by peak intensity ratios, but fewer matrix properties depended on the three offsets (5 mm, 6 mm, and 7 mm) when determined by band area ratios. The cut-off in the thickness of the tissue phantom layers was ∼4 mm for most properties, irrespective of offset. Matching trends when spectra were acquired without phantom layers between bone and the probe, ν1PO43-/Amide III and ν1PO43-/(proline + OH-proline) were higher and lower in the non-treated bone than in the autoclaved bone, respectively, when the thickness of tissue phantom layers was 4 mm. The layers, however, caused a loss of sensitivity to autoclaving-related changes in ν3CO3/ν1PO43- and crystallinity. Without advanced post-processing of Raman spectra, SORS acquisition through turbid layers can detect changes in Raman properties of bone that accompany a loss in bone strength.

Spectral Features Differentiate Aging-Induced Changes in Parchment-A Combined Approach of UV/VIS, µ-ATR/FTIR and µ-Raman Spectroscopy with Multivariate Data Analysis

From the moment of production, artworks are constantly exposed to changing environmental factors potentially inducing degradation. Therefore, detailed knowledge of natural degradation phenomena is essential for proper damage assessment and preservation. With special focus on written cultural heritage, we present a study on the degradation of sheep parchment employing accelerated aging with light (295-3000 nm) for one month, 30/50/80% relative humidity (RH) and 50 ppm sulfur dioxide with 30/50/80%RH for one week. UV/VIS spectroscopy detected changes in the sample surface appearance, showing browning after light-aging and increased brightness after SO₂-aging. Band deconvolution of ATR/FTIR and Raman spectra and factor analysis of mixed data (FAMD) revealed characteristic changes of the main parchment components. Spectral features for degradation-induced structural changes of collagen and lipids turned out to be different for the employed aging parameters. All aging conditions induced denaturation (of different degrees) indicated by changes in the secondary structure of collagen. Light treatment resulted in the most pronounced changes for collagen fibrils in addition to backbone cleavage and side chain oxidations. Additional increased disorder for lipids was observed. Despite shorter exposure times, SO₂-aging led to a weakening of protein structures induced by transitions of stabilizing disulfide bonds and side chain oxidations.

Investigating the Properties of Folded Parchment – A Preliminary Study

Parchment manuscripts form an important part of many historic collections. They are often found folded, with some displaying multiple fold patterns resulting from changing uses over their history. Parchment is a potentially fragile medium and folding can increase its susceptibility to damage, as well as hampering access and display. Treatment to address these issues may involve the relaxation of the folded structure, using humidification or a solvent such as propanol, and gentle pressing or stretching. However, this presents a dilemma – an inappropriately folded manuscript may be more prone to damage, but treatments require invasive interventions. This preliminary study has employed infrared spectroscopy and shrinkage temperature measurements to better understand the properties of folded parchment. It demonstrates that physicochemical changes can be detected at the fold and, to a lesser extent, in adjacent areas, compared to the bulk material, and that monitoring these changes allows the impact of different treatment methods to be assessed. This provides a basis for further research into the effect of both the original folding and of potential treatment methods, to inform conservation decisions and help ensure appropriate, effective, and sympathetic outcomes.

Non-Invasive Physico-Chemical and Biological Analysis of Parchment Manuscripts – An Overview

This work will give an overview of the scientific approach used for the study of written heritage on parchment. Elemental analysis using X-ray fluorescence (XRF) together with compound-specific analytical methods such as Fourier transform infrared (FTIR) and Raman spectroscopy can be applied in a non-invasive way, without the need for sampling and without inducing changes to the object. Physico-chemical investigations are complemented and further deepened by DNA- and biological analyses for the identification of the biological origin of materials and the identification of microorganisms, insects and viruses that might be present on the object which may add valuable information about its history and conservation state.