No número 4, volume 402, da revista Analytical and Bioanalytical Chemistry foram publicados vários artigos dedicados
ao tema Analytical Techniques in Art, Archaeology and Conservation Science (pp.
1411-1592). Quatro desses artigos são sobre o estudo de pergaminho através de
diferentes técnicas analíticas. Os autores, títulos e os respectivas resumos são os seguintes:
- T. Wolff, I. Rabin, I. Mantouvalou, B. Kanngießer, W. Malzer, E. Kindzorra
and O. Hahn; “Provenance studies on Dead Sea scrolls parchment by means of quantitative
micro-XRF”, pp. 1493-1503
Abstract:
In this study, we address the question of the provenance and origin
of the Dead Sea Scrolls manuscripts. A characteristic low ratio of chlorine to
bromine, corresponding to that of the Dead Sea water, may serve as an indicator
for local production. For this aim we developed a non-destructive procedure to
determine the Cl/Br ratio in the parchment of these manuscripts. Micro-X-ray
fluorescence (μ-XRF) measurements of a large number of parchment and leather
fragments from the Dead Sea Scrolls were analyzed with a routine we developed
based on fundamental parameter quantification. This routine takes into account
the absorption of the collagen matrix and the influence of the different sample
thicknesses. To calculate the representative Cl/Br ratio for each fragment, we
investigated the lateral homogeneity and determined the total mass deposition
using the intensity of the inelastically scattered, characteristic tube
radiation. The distribution of the Cl/Br ratios thus obtained from the μ-XRF
measurements make it possible to distinguish fragments whose origin lies within
the Dead Sea region from those produced in other locations.
- F. Pinzari, P. Colaizzi, O. Maggi, A. M. Persiani, R. Schütz and I.
Rabin; “Fungal bioleaching of mineral components in a twentieth-century
illuminated parchment”, pp. 1541-1550
Abstract:
In this work, we applied scanning electron microscopy (SEM),
microanalysis and Raman spectroscopy to study the fungi inhabiting a richly
illuminated parchment document and the damage induced by their activity. To
that aim, we collected samples of fungal mycelium from the deteriorated areas
on a removable adhesive tape specifically intended for lifting fungi without
damaging the support. SEM analysis of the adhesive tape samples showed the
co-occurrence of several species of fungi. One strain closely resembling Acremonium
species was observed only in the tape micrographs but no agar cultures were
obtained. Its fungal structures showed the production of abundant oxalates with
an outstanding leaching of the calcium-based materials of parchment (typically
manufactured with gypsum and lime). Needle-like crystals of calcium oxalate
produced by the fungus forming a uniform and quite regular grid around conidial
slimy heads were documented. As a result, the areas affected by moulds were
weakened, stained and characterised by a powdery patina rich in calcium.
Confocal μ-Raman confirmed the presence of oxalates while EDS showed the
presence of calcium in crystals. We conclude that the defacement of the
parchment was due to both collagenolytic activity, and to the biotransformation
of calcium-based minerals by fungi.
- A. Masic, M. R. Chierotti, R. Gobetto, G. Martra,I.
Rabin and S. Coluccia; “Solid-state
and unilateral NMR study of deterioration of a Dead Sea Scroll fragment”, pp. 1551-1557
Abstract:
Unilateral and solid-state nuclear
magnetic resonance (NMR) analyses were performed on a parchment fragment of the
Dead Sea Scroll (DSS). The analyzed sample belongs to the collection of
non-inscribed and non treated fragments of known archaeological provenance from
the John Rylands University Library in Manchester. Therefore, it can be
considered as original DSS material free from any contamination related to the
post-discovery period. Considering the paramount significance of the DSS, non invasive
approaches and portable in situ non destructive methods are of fundamental
importance for the determination of composition, structure, and
chemical–physical properties of the materials under study. NMR studies reveal
low amounts of water content associated with very short proton relaxation
times, T 1, indicating a high level of deterioration of collagen molecules
within scroll fragments. In addition, 13C cross-polarization
magic-angle-spinning (CPMAS) NMR spectroscopy shows characteristic peaks of
lipids whose presence we attribute to the production technology that did not
involve liming. Extraction with chloroform led to the reduction of both lipid
and protein signals in the 13C CPMAS spectrum indicating probable involvement of
lipids in parchment degradation processes. NMR absorption and relaxation
measurements provide non destructive, discriminative, and sensitive tools for
studying the deterioration effects on the organization and properties of water
and collagen within ancient manuscripts.
- A. Možir, L. Gonzalez, I. Kralj
Cigić, T. J. Wess, I. Rabin, O. Hahn and M. Strlič; “A study of degradation of
historic parchment using small-angle X-ray scattering, synchrotron-IR and
multivariate data analysis”, pp.
Abstract:
Parchment has
been in use for thousands of years and has been used as the writing or drawing
support for many important historic works. A variety of analytical techniques
is currently used for routine assessment of the degree of denaturation of
historic parchment; however, because parchment has a heterogeneous nature,
analytical methods with high spatial resolution are desirable. In this work,
the use of small-angle X-ray scattering (SAXS) and synchrotron-IR (SR-IR) was
examined in conjunction with multivariate data analysis to study degradation of
an extended set of historic parchment samples, and particularly to investigate
the effect of lipids and the presence of iron gall ink on the degradation
processes. In the data analysis, shrinkage temperature, lipid content, sample
age, presence of ink and accelerated degradation were included. The analysis of
loading factors in partial least-squares regression and principal component
analyses based on SAXS, SR-IR and other analytical and descriptive data reveals
the effect of lipid removal on diffraction patterns, and lipids are found to
cause the degradation process in parchment to accelerate. The effect of iron
gall ink is also evident, although the mechanism of ageing is different to that
of natural ageing in the absence of ink. In addition, a historic parchment
score from ca. 1750 is examined, demonstrating the significant effect of iron
gall ink, and lipids and inorganic soiling on its increased degradation.
