Multianalytical approach to the analysis of English polychromed alabaster sculptures: μRaman, μEDXRF, and FTIR spectroscopies
Department of Analytical Chemistry, University of the Basque Country, P.O. Box. 644, 48080, Bilbao, Spain. Analytical and Bioanalytical Chemistry
(Impact Factor: 3.44).
10/2008; 392(4). DOI: 10.1007/s00216-008-2317-0
A complete study of several English polychromed alabaster sculptures is presented. The support, pigment, and binders were characterised by combining μEDXRF, μRaman, and FTIR spectroscopies. Among the pigments, minium, vermilion, lead white, carbon black, red iron oxide, and a degraded green copper pigment were determined, together with gold leaf. The presence of the rare mineral moolooite (copper oxalate) was also found as a degradation product in the green areas, where weddellite (calcium oxalate dihydrate) was also determined. These facts, together with degradation of the green copper pigment, suggest microbiological degradation of the original materials. Remains of glue and a varnish were also determined by FTIR spectroscopy and principal-components analysis (PCA) of the spectra. Finally, PCA analysis was carried out to confirm whether the pieces came from the same quarry.
Figures in this publication
Available from: Diego Garate
- "In the last decades, collaborative studies between archaeologists and chemists show a growing interest in fields such as the identification of source materials, the working technologies and dating, and so on (Edwards, 2004; Castro et al., 2008a; Proietti et al., 2011). "
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ABSTRACT: La Peña de Candamo Cave, listed as World Heritage by UNESCO in 2008, preserves one of the most important collections of parietal art in the North of Spain and there is an urgent need to evaluate the status of the cave both archaeologically and from the conservation and restoration points of view. In this work, the usefulness of non-invasive mobile instrumentation, such as Raman and EDXRF spectroscopies, is shown when this type of assessments are required under adverse experimental conditions. In addition to the rapid diagnosis that this non-invasive and mobile instrumentation provided, based on the subsequent multivariate analysis of collected spectra, it was possible the identification of the main pigments of the rock art as well as their different origins. Finally, this study also showed the biodeterioration and decalcification processes observed in some areas of the cave and revealed the damage suffered during decades. The effects of such decaying processes over pictorial layers show up the need of a continuous preventive control of paintings in order to minimise further deteriorations.
Journal of Archaeological Science 02/2013; 40(2):1354–1360. DOI:10.1016/j.jas.2012.10.008 · 2.20 Impact Factor
Available from: Janka Hradilova
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ABSTRACT: Correct identification of pigments and all accompanying phases found in colour layers of historical paintings are relevant
for searching their origin and pigment preparation pathways and for specification of their further degradation processes.
We successfully applied the analytical route combining non-destructive in situ X-ray fluorescence analyses with subsequent
laboratory investigation of micro-samples by optical microscopy, scanning electron microscopy/energy-dispersive spectroscopy
and X-ray powder micro-diffraction (micro-XRD) to obtain efficiently all the data relevant for mineralogical interpretations
of the copper pigments origin. Cu salts (carbonates, chlorides, sulphates, etc.) used as pigments exist in a range of polymorphs
with similar or identical composition. The efficiency of the micro-XRD for direct identification of such crystal phases present
in micro-samples of colour layers was demonstrated in the presented paper. A new, until now unpublished, type of copper pigment—cumengeite,
Pb21Cu20Cl42(OH)40—used as a blue pigment on a sacral wall painting in the Czech Republic was found by means of micro-XRD. Furthermore, azurite,
malachite, paratacamite, atacamite and posnjakite were identified in fragments of colour layers of selected Gothic wall paintings.
We found Cu–Zn arsenates indicating the natural origin of azurite and malachite; artificial malachite was distinguishable
according to its typical spherulitic crystals. The corrosion of blue azurite to green basic Cu chloride was clearly evidenced
on some places exposed to the action of salts and moisture—in a good agreement with the results of laboratory experiments,
which also show that oxalic acid accelerates the corrosion of Cu pigments.
Figure In situ XRF measurement of Gothic murals in the Benedictine Monastery in Sazava—here The Joseph’s Doubt scene in the capitular hall
KeywordsX-ray powder micro-diffraction-Copper pigments-Cumengeite-Wall paintings-Corrosion
Analytical and Bioanalytical Chemistry 12/2009; 395(7):2037-2050. DOI:10.1007/s00216-009-3144-7 · 3.44 Impact Factor
Available from: instrument.com.cn
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ABSTRACT: This Atomic Spectrometry Update is the latest in an annual series appearing under the title of ‘Industrial Analysis’. The structure of the review is broadly the same as in previous years. Reports on the analysis of catalysts have been moved from the ceramics and refractories section into the chemicals section of the review. It is hoped that this categorization will better reflect the interest in these materials in the petrochemicals industry.The year in which major developments in instrumental analytical chemistry begin can usually only be identified with the benefit of hindsight. It has been evident for some time that where sensitivity and selectivity are required, mass spectrometric techniques have begun to dominate the field of atomic spectrometry. Pressures on industry to improve productivity have favoured rapid multi-element techniques such as ICP-MS, and the advent of a viable solid sampling option in LA has provided a very powerful tool for product and process investigation. The identification of chemical form continues to grow in importance, and the use of atomic spectrometry coupled with chromatography has become a significant area of research in the chemicals industry. Surface analysis techniques based on MS (e.g., SIMS, GDMS) still make an enormous contribution to the characterization of semiconductors. However, TXRF is now making a significant impact in this field, as a consequence of the high sensitivity of the technique and its applicability to the non-destructive analysis of wafers and thin films. The advent of r.f. boosted GDs represents a promising development but it remains to be seen whether practical advantages over more conventional techniques such as WDXRF can be demonstrated in an industrial context.
Journal of Analytical Atomic Spectrometry 01/1989; 7(8). DOI:10.1039/JA989040251R · 3.47 Impact Factor
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