Iron gall inks have been among the most used writing materials after carbon black, thus representing an important element of the historical and artistic heritage of our society. Crucially, the ...preservation of manuscripts and drawings is influenced by the presence of these inks, leading to conservation issues related to paper degradation and text fading. Besides all the advances obtained in paper conservation, the study of iron gall ink's behaviour and ageing is still an important topic, which requires investigation through an accurate molecular characterisation to produce reliable models. In the present work a micro-destructive method based on liquid chromatography techniques (HPLC-DAD and HPLC-ESI-Q-ToF) has been optimised starting from a model gallic acid-based ink. An in-depth study of the behaviour of the ink in time was performed by natural and artificial ageing tests, monitored by colorimetry, showing the autoxidation of gallic acid to ellagic acid in the prepared mock-ups. The effect of relative humidity on ageing processes was also evaluated, allowing us to determine different intermediates depending on the environmental conditions. Finally, the analytical method developed was then successfully applied for investigating 19th-20th century historical ink samples, where one of the identified ageing markers was detected, besides the expected gallic and ellagic acids.
Natural tannins from various plants have been used throughout human history in textile dyeing, often as mordant dyes. The ageing behavior of these dyes is a challenge in conservation science, ...requiring a thorough knowledge of the textile-mordant-dye system. In this work, we analyzed reference wool yarns dyed with natural tannins from oak gallnuts, walnut (
), and catechu (
), after artificial ageing. To gain insights on the composition of the dyestuffs and on how they aged, an analytical procedure based on extraction with Na
EDTA/DMF (ethylenediaminetetraacetic acid/dimethylformamide) and high-performance liquid chromatography (HPLC) analysis using high-resolution mass spectrometry detection was used. Since conventional reversed-phase (RP) columns usually show poor retention efficiency of highly polar compounds such as tannins, an RP-amide embedded polar group stationary phase was used to achieve optimal retention of the most polar compounds. Tannins from oak gallnuts showed little degradation after ageing, while a significant increase in the content of hydroxybenzoic acids was observed for tannins from walnut and catechu. Finally, the analytical procedure was applied to characterize the tannin dyes in historical tapestries from the 15
to 16
century, and the results were discussed in comparison with the reference yarns.
•Development of the first detailed pyrolysis database for sheep and camel wool.•Interpretation of the pyrolysis profiles of the keratin proteins in wool.•Characterization of wool samples and ...historical threads by Double Shot Py-GC/MS and EGA/MS.•Evaluation of the relevant parameters affecting wool degradation.
Wool has been the most widely used textile fiber in Europe since the Iron Age. It was largely employed to weave fabrics and clothes, and also for artistic purposes such as producing tapestries. This kind of artworks is among the most fragile of our heritage and is often in bad preservation conditions. Thus, the knowledge on the degradation processes of wool fibers is crucial for conservation issues.
In the present study, we tested the potentialities of Pyrolysis coupled with Gas Chromatography and Mass Spectrometry (Py-GC/MS) and Evolved Gas Analysis coupled to Mass Spectrometry (EGA/MS) for the characterization of woolen reference samples, also subjected to artificial ageing, and of historical and archeological samples. The reference sheep wool yarns were prepared with different mordants and dyes, and have been analyzed both after storage in the dark for three years after preparation, and artificially aged for different time intervals and at different relative humidity values. We created a detailed pyrolysis database, evidencing the phenomena occurring with ageing and including camel wool for comparison. The ageing process undergone by the proteinaceous fraction of wool has also been investigated through monitoring specific fragment ions in the EGA profiles. The relevant parameters affecting the degradation process identified in this study match those assessed in previous investigations by different and complementary techniques, thus validating our approach. We proved that the novel approach based on EGA/MS is suitable for quickly assessing the conservation conditions of the woolen yarns and represents an advantage with respect to more time-consuming and complex methods, such as GC/MS or High Performance Liquid Chromatography (HPLC).
Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer widely used in several everyday life applications; moreover, it is also one of the most employed plastics in contemporary artworks and ...design objects. In this study, the chemical and thermal properties of an ABS-based polymer and its photo-degradation process were investigated through a multi-analytical approach based on thermal, mass spectrometric and spectroscopic techniques. LEGO
building blocks were selected for studying the ABS properties. First, the composition of unaged LEGO
bricks was determined in terms of polymer composition and thermal stability; then, the bricks were subjected to UV-Vis photo-oxidative-accelerated ageing for evaluation of possible degradation processes. The modifications of the chemical and thermal properties were monitored in time by a multi-technique approach aimed at improving the current knowledge of ABS photodegradation, employing pyrolysis online with gas chromatography and evolved gas analysis, coupled with mass spectrometric detection (Py-GC-MS and EGA-MS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and corroborated by external reflection FT-IR spectroscopy. The multimodal approach provided new evidence on the two-step degradation pathway proposed for ABS, defining molecular markers for polybutadiene oxidation and styrene-acrylonitrile depolymerization. Moreover, the results highlighted the feasibility of correlating accurate compositional and thermal data acquired by bulk techniques with external reflection FT-IR spectroscopy as a non-invasive portable tool to monitor the state of conservation of plastic museum objects in-situ.
The aim of this paper is to analyse, through the toolbox of gender geography, the methodology of positionality and situated knowledge. The article examines some spatial practices of the transfeminist ...movement Non Una di Meno that involve us both as researchers and activists. The different forms of territorialisation and ways of “doing with” the space of the movement, are here presented through the specific cases of the demonstrations organised during the Covid-19 pandemic on the 25th of November 2020 and 8th March 2021. This enables us to present the methodology of positionality, and to analyse how feminist spatial practices can be the object of research and vice versa.
Among the artists' materials of the nineteenth century, pastel crayons merit scientific interest since their early commercial formulations are mostly unknown and, until now, have been considerably ...less studied with respect to other contemporary painting materials. In this framework, research herein reports the results of a comprehensive multi-analytical study of 44 pastel crayons of two recognized brands (LeFranc and Dr. F. Schoenfeld) from the Munch museum collection of original materials belonging to Edvard Munch. The integrated use of complementary spectroscopic and hyphenated mass-spectrometry techniques allowed the compositional profiles of the crayons to be traced providing the identification of the inorganic and organic pigments, the fillers/extenders and the binders. All crayons resulted to be oil- based and the binder was identified to be a mixture of a drying oil (safflower or linseed oil), palm oil or Japan wax and beeswax. Among others, pigments such as ultramarine, chrome yellows, Prussian blue, manganese violet, viridian and madder lake have been identified. A significant alignment in formulations of the brands was observed with the only exception of the greens which showed distinctive pigment and filler compositions. The analytical information provided for these commercial artists' materials will be of great interest for academia, museum and other institutions hosting art collections dating from the same period and it will be used by the Munch museum to draw proper conservation strategies of its own artwork collections.
Modern art materials introduced since the end of XIX century include a large number of formulations of synthetic polymers and pigments, whose degradation processes and best preservation conditions ...are a major issue in heritage science. Analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS) is widely used for the characterisation of polymeric materials and organic pigments, however the interpretation of the pyrograms obtained from samples containing different analytes is not straightforward. To improve our understanding on how these materials behave in complex matrices, we used evolved gas analysis coupled with mass spectrometry (EGA-MS) and multi shot Py-GC/MS to highlight and analyse the different fractions in a sample from a pop-art made of painted polyurethane (PU) foam. The study represents a proof of concept to evaluate EGA-MS potential in studying composite modern art materials in combination with multi-shot pyrolysis. The aim of the investigation was establishing the composition of the PU formulation, the paint binder and the pigments, thereby contributing to planning the stabilisation and conservation of the object. The polymers and the class of synthetic organic pigments present in the paint were assessed by determining their specific pyrolysis products and through comparisons with data in the literature. EGA-MS analysis provided both thermal and chemical information in one analytical run, so that we could select four temperatures for use in multi-shot Py-GC/MS analysis and thus to selectively study the different fractions evolved at different temperatures. Information on the various components of the mixture was obtained, including additives and organic pigments, separating them on the basis of their different thermal degradation temperatures. The multianalytical approach included also non-destructive ATR-FTIR and enabled us to characterize in detail different synthetic materials: polyether-based polyurethane produced by the polyaddition of 2,6-diisocyanate toluene, hexamethylene diisocyanate and polypropylene glycol, vinyl paint, and a mixture of β-naphthol and mono-azo as pigments. HPLC–DAD and HPLC–ESI–MS analyses confirmed the pigments, and provided a positive identification of two β-naphthols (PO5 and PR1) and two monoazo pigments (PY1 and PY3).
The identification of natural dyes in ancient textiles is a longstanding challenge for scientists; yet, the effort honours the skill and knowledge of master dyers by retracing traditional dyeing ...methods and assisting in conserving historical treasures for future generations. Here, the main constituents of selected native Japanese extracts from the roots of Lithospermum erythrorhizon and Scutellaria baicalensis, the barks of Phellodendron amurense and Morella rubra, the dried flower bud of Syzygium aromataticum, and the fruit of Terminalia chebula are determined by surface‐enhanced Raman spectroscopy following traditional Japanese extraction methods. The analytical amalgamation of data from SERS examinations on crude extracts and on subsequently refiltered and diluted extracts provides further effective and sensitive results for the combined identification of napthoquinones (shikonin and alkanin), alkaloid (berberine), polyhydroxyflavonoids (baicalin/baicalein, myricetin/myricitrin), diarylheptanoids, allylbenzene (eugenol), and tannins (gallic/ellagic acid). The comparison of results from this analytical protocol with those achieved by the more traditional chromatographic and mass spectrometric method provides and questions data regarding generally accepted marker components and enantioselective discriminations that serve to enrich the database of biological sources of colouring materials to be used in determining historically important Japanese colorants and dyestuffs.
In this work, the high sensitivity and selectivity of colloidal SERS has been applied to investigate six natural Japanese plant sources on aqueous extraction by traditional recipes. The collection of reference spectra by SERS methods on both the crude extracts and following a further sample dilution provides a simple yet effective SERS protocol leading to a more thorough interpretation of data.
The determination of carbohydrate composition is extremely important for quality control in food and beverages, in material science, in pharmaceutics, and in the field of cultural heritage. ...Considering the complexity and the heterogeneity of the matrices, the optimization of extraction and purification steps aiming at maximizing the saccharide recovery from the matrix and effectively removing interferences is mandatory. The presence of inorganic components, besides being detrimental to the analytical instrumentation, can catalyze the isomerization of some sugars causing an alteration to their quantitative and qualitative profiles. In the present paper, protocols for suppressing the interference of inorganic ions in the quantification of monosaccharides and uronic acids by Gas Chromatography–Mass Spectrometry (GC-MS) are proposed. Two clean-up methods based on ion exchange resins (Amberlite MB-6113 and Amberlite IRN-150) and one making use of solid-phase extraction with a polypropylene Solid-Phase Extraction (SPE) column were tested on a standard carbohydrate solution, and the elution conditions optimized. The best purification conditions, in terms of higher recovery yield values for seven monosaccharides and two uronic acids, were obtained using SPE. Furthermore, the optimized SPE method was validated on a sample of mural painting rich in saccharides and inorganic material.
This article reviews the research recently undertaken to characterise and identify early synthetic dyes (ESDs) and synthetic organic pigments (SOPs) as well as study their degradation pathways with a ...focus on cultural heritage applications. Since the invention of the first fully synthetic dye in 1856, these materials have been used in a variety of historic objects and artworks, such as textiles, furniture, prints, paintings, drawings, etc. The synthesis of new dyes and their implementation into pigment formulations were rapid phenomena, so that by the beginning of the 20th century, thousands of new molecules were patented and commercialised. This review will focus on these early formulations synthesised up to approximately 1914 and the outbreak of World War I. ESDs and SOPs represent a challenge from an analytical point of view. Molecular databases are fundamental for the unequivocal identification of these compounds, but reference materials are not always readily available. A combination of analytical techniques is often needed for characterisation, especially in the case of SOPs, which have both organic and inorganic components. Furthermore, the degradation of these molecules can jeopardise their detection in historic objects that have been exposed to light, humidity and temperature fluctuations. Nevertheless, ESDs and SOPs are important research tools. As the dates of their first synthesis are often known with precision, based on patent information, their detection can be used to refine the production date of objects. Additionally, their trade from Europe to the world and their adoption in artistic practices around the globe is an active area of research.
PDF
