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Osteosarcoma (OS) is the most common primary malignant bone tumor and its etiology has recently been associated with osteogenic differentiation dysfunctions. OS cells keep a capacity for uncontrolled proliferation showing a phenotype similar to undifferentiated osteoprogenitors with abnormal biomineralization. Within this context, both conventional and X-ray synchrotron-based techniques have been exploited to deeply characterize the genesis and evolution of mineral depositions in a human OS cell line (SaOS-2) exposed to an osteogenic cocktail for 4 and 10 days. A partial restoration of the physiological biomineralization, culminating with the formation of hydroxyapatite, was observed at 10 days after treatment together with a mitochondria-driven mechanism for calcium transportation within the cell. Interestingly, during differentiation, mitochondria showed a change in morphology from elongated to rounded, indicating a metabolic reprogramming of OS cells possibly linked to an increase in glycolysis contribution to energy metabolism. These findings add a dowel to the genesis of OS giving new insights on the development of therapeutic strategies able to restore the physiological mineralization in OS cells.

Historical photographic negatives and cinematographic films with cellulose nitrate (CN) supports show deterioration mechanisms related to the thermal, photocatalytic and hydrolytic loss of nitro groups from the CN chain. To prevent their disappearance, their scanning and digitalization becomes a priority. However, degradation hinders the scanning of CN films. Since motion picture films are stocked as a reel, the backside of each frame touches the front of another one. During degradation, the decrease in pH contributes to lowering the viscosity of gelatin. In this way, the emulsion gets softer and some residues may deposit on the back of the superimposed frames, and the gelatin may also spread over the film surface and come out from the edges.Traditional approaches to clean gelatin residues from the surface of CN bases and from the sides of film rolls include mechanical removal with scalpels and the use of polar solvents. However, these methods are either slow, ineffective or could potentially damage the degraded CN support and the remaining gelatin emulsion at the other side of the film. Accordingly, we have evaluated the performance of three choline chloride and betaine-based Deep Eutectic Solvent (DES) formulations. These DES are unexpensive, easy to prepare, green (non volatile, safe towards operator and the environment), non flammable and have been previously proposed for the extraction of proteinaceous material, but their use for the restoration of photographic negatives or cinematographic films has not been reported yet.Selected areas over the frames of a real deteriorated CN cinematographic film were cleaned from gelatin accretions by rubbing a cotton swab soaked in DES. Isopropyl alcohol (IPOH) was then employed to remove the remaining DES residues.To evaluate the cleaning performance, each area was characterized and documented before and after treatment using Optical Microscopy (OM), Micro-Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (µATR-FTIR), and cross-section observation.All treatments using DES proved effective for the removal of gelatin residues and harmless towards the CN film supports at the selected application times, showing superior cleaning power compared to traditional methods. Thus, the proposed cleaning methods with DES are suitable for cinematographic and photographic film restoration.

The selective removal of thin varnish layers from oil and egg tempera paintings is still an open challenge in the conservation field. In this paper, a new cleaning system was developed by using a gel composed of fully green components as deep eutectic solvents (DES) and agar. The gel, prepared admixing choline chloride -urea with an EtOH-H2O agar gel, exhibited good rheological properties in terms of gel stiffness, allowing easy handling and removal of the gel. The new developed cleaning gel was successfully tested for the removal of proteinaceous layers applied over both hydrophobic (linseed oil as binder) and hydrophilic (egg temperas as binder) surfaces. The procedure consists on two steps: first the choline chloride -urea agar gel was applied and let to act then an EtOH-H2O agar gel was applied for few seconds to allow the removal of the DES residues Moreover, an innovative non-destructive approach based on micro-Spatially Offset Raman Spectroscopy (micro-SORS) allowed to demonstrate how the gel impairs the diffusion of the cleaning agents in the paint layers, highlighting the good solvent retention ability of the gel.

10 pags., 6 figs., 1 tab., Acid Organge 20 is a synthetic monoazo dye, which molecular structure consists of a naphtol unit and a sulfonated benezene ring linked together by an azo chromophore group. As a phenylazonaphthol with the OH group inparaposition respect to the azo group, it undergoes an azo-hydrazone tautomerism. In this work, the study of the preponderance of one tautomer over the other in different pH conditions was carried out by means of UV-Vis, Raman, and surface-enhanced Raman scattering (SERS) spectroscopies. Raman spectra of powder and aqueous solutions of the dye were obtained at different excitation lines at the natural pH of the AO20 solutions. The best results were obtained at 633 nm, and the observed Raman bands suggested the presence of the hydrazone tautomer. The molecular structure and the theoretical Raman spectra of the two tautomers were calculated by density functional theory (DFT) methods. The obtained results were used for the assignment of the Acid Orange 20 vibrational modes. The SERS analysis of the dye solutions were carried out employing Ag nanostars, pH below and above 4.7, and excitation at 442, 532, and 633 nm. The hydrazone tautomer was prevalent in most conditions. The azo tautomer was only detected at pH similar to 5 under excitation with the 532 nm wavelength due to resonant Raman conditions. Finally, the effect of pH on the morphology of metal nanoparticles employed as SERS substrates was evaluated by TEM., This work was supported by Ministerio de Economía, Industria y Competitividad de España (project FIS2017-84318-R) and Comunidad de Madrid/EU (project TOP Heritage).

10 pags., 7 figs., 2 tabs., Acid Red 26 and Acid Red 18 are two early synthetic dyes belonging to the monazo dye class. The molecular structure of this class of dyes is characterized by the chromophoric azo group (N[dbnd]N) generally attached to benzene or naphthalene derivatives containing electron withdrawing and/or donating groups as substituents. As both red dyes have an OH group in ortho- position respect to the azo group, they undergo an azo-hydrazone tautomerism. In this work, UV–Vis, Raman and SERS spectroscopic analysis of the red dye solutions were carried out at different pH conditions, in order to evaluate the preponderance of one tautomer over the other as a function of the pH. Different experimental conditions were tested in order to find the best ones for the detection of both dyes. Thus, Raman spectra of the powder and aqueous solutions of AR26 and AR18 were obtained at the natural pH of the solutions, and above and below that value. The SERS analysis of the dye solutions were carried out at various pH values between 2 and 10, and with excitation at 442, 532 and 633 nm. The molecular structure and the theoretical Raman spectra of the two tautomers of both red dyes were calculated by DFT methods. The obtained results were used for the assignment of the Acid Red 26 and Acid Red 18 vibrational modes. Finally, a textile sample dyed with AR18 was analyzed by SERS., This work was supported by Ministerio de Economía, Industria y Competitividad de España (project FIS2017-84318-R) and Comunidad de Madrid/EU (project TOP Heritage).

The photoreduction of aqueous Ag+ to silver nanoparticles (AgNPs) on a substrate was studied aiming at the application of surface-enhanced Raman scattering (SERS) technique to the sensitive analysis of organic colorants directly on artworks. In particular, the presence of the synthetic dyes methyl violet (BV1) and fuchsine (BV14), in both standard and historical wool fibers, was analyzed. Scanning electron microscopy was employed to study the morphology and distribution of the NPs obtained on the fiber. We have carried out an investigation of the influence of several factors on the morphology of NPs: excitation wavelength, substrate, laser power and laser irradiation time. The resulting materials were analyzed at different laser wavelengths in order to evaluate the application range of the probe laser after the NPs formation. SERS spectra of the BV1 and BV14 dyes on the fiber were obtained and compared with those obtained in suspended conventional AgNPs, in order to deduce the possible influence of the wool substrate on the Raman spectra. SERS spectra were analyzed considering the possible resonance Raman processes. Bands attributed to the protein substrate were also identified. The main goal of this work was to assess and optimize a general method of analysis of organic dyes on natural fibers based on the direct preparation of AgNPs by laser SERS technique. Copyright © 2017 John Wiley & Sons, Ltd.

Metallographic features of ancient bronze artefacts often hide peculiar micro-chemical processes and corrosion behaviours, which are worth to be studied as they can provide conservators and archaeologists with valuable tools and information. It is widely documented that Chinese bronzes were cast and the way to adjust their properties was to change the alloy composition. In particular, addition of lead, which is insoluble in the bronze matrix, results in the formation of inclusions or globules, which undergo oxidation processes leading to their conversion into corrosion products. The mechanisms through which this occurs were still poorly investigated. The present work was conducted to further study the corrosion behaviour of high-leaded bronze, especially focusing on the behaviour of lead globules. To this aim, a collection of Chinese archaeological bronzes, showing intermediate steps of degradation, were selected and investigated. The use of combined microscopy-based, molecular and elemental, analytical techniques allowed the characterization as well as the precise location of corrosion products, thus enabling us to propose a degradation pathway basing on thermodynamic data provided by Pourbaix diagram. The achieved results will be useful for researchers involved in these kinds of studies to better interpret data obtained. Metallographic features of ancient bronze artefacts often hide peculiar micro-chemical processes and corrosion behaviours, which are worth to be studied as they can provide conservators and archaeologists with valuable tools and information. It is widely documented that Chinese bronzes were cast and the way to adjust their properties was to change the alloy composition. In particular, addition of lead, which is insoluble in the bronze matrix, results in the formation of inclusions or globules, which undergo oxidation processes leading to their conversion into corrosion products. The mechanisms through which this occurs were still poorly investigated. The present work was conducted to further study the corrosion behaviour of high-leaded bronze, especially focusing on the behaviour of lead globules. To this aim, a collection of Chinese archaeological bronzes, showing intermediate steps of degradation, were selected and investigated. The use of combined microscopy-based, molecular and elemental, analytical techniques allowed the characterization as well as the precise location of corrosion products, thus enabling us to propose a degradation pathway basing on thermodynamic data provided by Pourbaix diagram. The achieved results will be useful for researchers involved in these kinds of studies to better interpret data obtained. © 2013 Elsevier Masson SAS.

The development of user-friendly devices for on site analysis and characterization of painting materials is one of the most challenging objectives in the diagnostics for cultural heritage. Thanks to the specificity of antigen–antibody reactions, immunological methods have been already successfully applied for the detection of proteins and for their localization within painting stratigraphies. Moreover, by combining the advantages of the immunological techniques with the high detectability offered by chemiluminescence detection, it has been possible to achieve good analytical performance and very low detection limits. This work was aimed at developing a portable analytical device for the detection of chicken ovalbumin (a protein found in egg tempera and in egg-based protective varnishes) in painting samples employing ready-to-use analytical cartridges and a thermoelectrically-cooled CCD camera as a chemiluminescence detector. The protein was extracted from using a simple procedure and revealed by a non-competitive immunoassay with chemiluminescence contact imaging detection. The assay was simple, fast and suitable for the detection of ovalbumin in small samples. This analytical system provided positive identification of ovalbumin in samples obtained from both fresh or artificially aged paint reconstructions and historical paintings. It might be easily employed in different contexts (such as small museums, restoration laboratories or even on site) by restorers to obtain prompt information during restoration actions, such as cleaning operations. In perspective this device could be also employed for the detection of other proteinaceous and organic painting components.

In the recent years, an increasing interest has been devoted to the development of compact macro X-ray fluorescence (MA-XRF) systems, establishing the technique as one of the most powerful non-invasive method for the characterization of artworks. Nevertheless, important information may be lost due to the poor signal-to-noise ratio, which characterises spectra collected with a limited acquisition time. Moreover, well-known drawbacks of the XRF analysis, such as the matrix effect and the penetration depth of X-rays, have to be also considered. In the attempt to overcome such limitations, without compromising the potentialities of a MA-XRF imaging analysis in terms of dimension of investigated surface and time of analysis, a specific methodological strategy is proposed. In particular, high signal-to-noise ratio maps were acquired on regions of interest selected after preliminary fast scans on the entire painting. Subsequently, the elaboration of the dataset was supported by the use of ad hoc analytical tools, such as correlation diagrams, averaged extracted spectra and line emission maps for each element. The correct interpretation of the non-invasive results allowed to define a proper sampling strategy. The proposed experimental workflow has been applied to a masterpiece panel painting by Cimabue (1240–1302) depicting “Madonna Enthroned with the Child and Two Angels”, disclosing new knowledge on the adopted execution technique, about which little is known. Thus, for the first time a painting created by Cimabue was investigated under a material and technical point of view. Due to the relevance of the information obtained by MA-XRF analyses, micro-destructive investigations were carried out. Thus, the joint evaluation of elemental distribution and the stratigraphic composition of the selected samples allowed to obtain information about Cimabue painting technique. Particular attention was devoted to the characterization of the throne decorations, pointing out new questions on a non-conventional middle-age gilding technique that need still to be investigated.

Understanding the original techniques in the creation of an artwork is a prerequisite for the selection of the most appropriate conservation method. This is particularly essential in wall paintings where control of potential agents of deterioration and efficient monitoring are limited due to the scale of the paintings and their exposure to uncontrollable environmental fluctuations. Analytical studies are increasingly focused on the investigation and study of degradation products of organic binders originally added in the paintings on a lime-based plaster ground. In the framework of IPERION-CH (Integrated Platform for the European Research Infrastructure ON Cultural Heritage) project, a collaborative task is dedicated to obtain knowledge about original organic materials used in wall paintings by evaluating and comparing different innovative methodologies and conventional diagnostic techniques used for the investigation of markers related to alteration mechanisms and degradation products. The non-invasive and microsampling methodology is first optimized on well-defined models that have been designed to simulate different painting techniques with limewater and five organic binders in different relative proportions. Future investigations will focus on the application of the optimized methodology on archaeological samples. In the present paper, preliminary results on a selected set of models, submitted in different stages of a well-established artificial ageing protocol, demonstrate the specific complementary input of each analytical technique included in the analytical approach (colour measurements, micro FTIR-ATR analyses in cross-sections, Evolved Gas Analysis-Mass Spectrometry and Gas Chromatography-Mass Spectrometry). The comparative evaluation and interpretation of the results is a step forward in the optimization of the approach and in relating the analytical findings detected on the analysed samples to the original compounds and the possible changes for each group of binders (proteins/gums) due to degradation or interaction depending on the pigment/metal ion present.

open 17 si The composition of the ancient wax-based painting technique known as encaustic has long been the subject of debate. Ancient sources provide few details of the technology, and modern understanding of the medium is restricted to theoretical interpretation and experimental observation. In this multi-analytical collaborative study, a number of analytical approaches were used to investigate the physical and molecular properties of a range of experimentally prepared encaustic paints before and after ageing. Analysis using gas chromatography mass spectrometry, Fourier transform infrared spectroscopy (invasive and non-invasive), X-ray diffraction and thermogravimetric analysis demonstrated how differences in the technology of production alter the properties and composition of the medium and showed how these are modified by the addition of pigment and the effects of ageing. Comparison of results from the different analytical techniques highlights the benefit of an integrated analytical approach to the analysis of ancient encaustic paints and the fundamental importance of insights from invasive study to evaluating the results of non-invasive analysis. open Stacey, R.J.*; Dyer, J.; Mussell, C.; Lluveras-Tenorio, A.; Colombini, M.P.; Duce, Celia; La Nasa, Jacopo; Cantisani, Emma; Prati, S.; Sciutto, G.; Mazzeo, R.; Sotiropoulou, S.; Rosi, F.; Miliani, C.; Cartechini, L.; Mazurek, J.; Schilling, M. Stacey, R.J.*; Dyer, J.; Mussell, C.; Lluveras-Tenorio, A.; Colombini, M.P.; Duce, Celia; La Nasa, Jacopo; Cantisani, Emma; Prati, S.; Sciutto, G.; Mazzeo, R.; Sotiropoulou, S.; Rosi, F.; Miliani, C.; Cartechini, L.; Mazurek, J.; Schilling, M.

Irradiation with γ rays is widely used in the sterilization of a large variety of products and materials in the field of medical supplies, pharmaceuticals, cosmetics, food industry and cultural heritage. It is also applied on wood materials, with the purpose of improving their shelf-life, by lowering the microbial charge and hence the microbial-related deterioration rate. A fundamental issue when applying γ rays is the preservation of the chemico-physical as well as of the structural and mechanical properties of the materials irradiated, since a significant change of properties may jeopardize the use of the materials for the purpose intended. To this end, in this paper, we analyzed the chemico-physical properties of four different types of wood used for the construction of musical instruments namely fir, maple, poplar and durmast oak under increasing doses of γ rays. In detail, the effect of incremental radiation doses was evaluated by comparing the results obtained by acoustic tests with those providing information at molecular level, i.e., cyclic voltammetry, linear square voltammetry and infrared spectroscopy. Moreover, in this work, the glucose released as a result of the degradation of wood cellulose and hemicellulose, has been analyzed for the first time, with an innovative tool, based on the use of a Gellan gel. The integrated approach presented here, based on both traditional and innovative techniques has proven to be highly efficient in providing a complete picture of wood behavior following γ-ray irradiation, at both the macroscopic and the molecular level.

Off-line pyrolysis coupled with GC-MS through SPME sampling, overcomes some of the limitation of online Py-GC-MS configuration without laborious sample treatment. The introduction of on fiber silylation procedure between SPME sampling and analysis allowed to obtain a complete silylation of polar pyrolysis products with diagnostic relevance. The method was applied to the analysis of pure sugars and carbohydrates, providing a picture of the type of anhydrosugars evolved by pyrolysis of natural gums, namely cellulose and polysaccharide based gums (Arabic, Ghatti, Tragacanth, Guar, Karaya and Xanthan). Characteristic anhydrosugars produced by pyrolysis of hexoses, pentoses and deoxyhexoses were tentatively identified. Despite an unambiguous marker for uronic acids was not identified, the final method allowed to obtain, with minimal work-up, a detailed picture of polar pyrolysis products as those obtainable from carbohydrates, which can be easily used for identification purposes.

InthispapersomecoloredframescomingfromtheverypopularcinematographicfilmSardinianDrummerBoy,datingbacktothebeginning of the XX century, were analyzed. The presence in the emulsion of silver nanoparticles (AgNPs), which are formedthanks to the impression–development mechanism, confers to the cinematographic film the characteristic of being an efficientSurface Enhancement Raman Spectroscopy (SERS) substrate. This peculiarity makes it possible to investigate, in a non-invasiveway, the nature of the film components, such as the dyes used for the coloring process. In particular, Raman analyses allowedthe unambiguous identification of the dyes used in tinted frames, i.e. tartrazine and safranin, in which the colorant is absorbedby the gelatin, and intoned frames, i.e.Rhodamine B, wherethe dyeisfixed thankstothe formationofaninsolublespecies withAgIobtainedbyconversionofmetallicsilver.Thissecondcaseisofparticularinteresttoevaluatethepossibilitytoidentifythedyeeven when it is present as a silver iodide derivative. For this purpose an AgI-colorant derivative has been prepared and its SERSspectrum compared with that obtained on the film sheet. Copyright © 2015 John Wiley & Sons, Ltd.Additional supporting information may be found in the online version of this article at the publisher’s web site.Keywords: cinematographic film; tinting; toning; SERS; dyes

The present research is focused on the setting up of an advanced analytical system for the detection of synthetic dyes. The system is based on the combination of an innovative thin layer chromatography (TLC) plate coupled with enhanced infrared (MU-ATR, metal underlayer attenuated total reflection) and Surface Enhanced Raman (SERS) spectroscopy. In particular, a TLC plate made of silver iodide (AgI) applied onto a gold coated glass slide (AgI@Au) is proposed as an efficient stationary phase for the separation of dyes mixtures. The separated dyes are then identified by means of both enhanced FTIR and SERS, performed directly on the same eluted spots. The use of a mid-IR transparent inorganic salt as stationary phase coupled with the underneath gold layer avoids spectral interferences, enhancing the signal obtained from ATR analyses. At the same time, SERS spectra can be recorded as the TLC plate may act as a SERS active substrate due to the photoreduction of AgI to metallic Ag caused by the exposure to the laser during the Raman analysis. Different mixtures of synthetic dyes of known composition, widely used in dyeing processes, have been tested and the method resulted to be effective in identifying trace amounts in the order of tens nanograms. Moreover, the method has been further evaluated on a real case study represented by dyes extracted from dyed wool.

The qualitative identification of proteinaceous substances, as well as their location within a complex paint stratigraphy, is one of the most challenging issues in the characterization of painting materials. Nevertheless, information on paint components represent a crucial task for studies concerning both the ancient painting techniques adopted and the state of conservation, being fundamental investigations for the selection of appropriate conservation actions. The present research was aimed at developing a new detection approach for the immunochemical localization of ovalbumin in paint cross-sections based on the use of scanning electrochemical microscopy (SECM). The immunochemical analyses were performed using an anti-ovalbumin primary antibody and a secondary antibody labelled with horseradish peroxidase (HRP). SECM measurements were performed in feedback mode using benzoquinone (BQ)/hydroquinone (H2Q) redox couple. In presence of hydrogen peroxide (H2O2), HRP catalyzes the re-oxidation of H2Q to BQ and the increment of BQ concentration in correspondence of the target protein was detected by SECM through the electrochemical reduction of the regenerated BQ at the microelectrode. Indeed, the localization of ovalbumin was possible thanks to a clear discrimination of SECM currents, achieved by the comparison of the measurements recorded before and after H2O2 administration, based on the HRP on/off approach. The method was evaluated both on samples from standard mocks-up and on a historical sample, collected from a Renaissance wood painting. The obtained results were promising, foreseeing a wider application of SECM on cultural heritage researches.

The identification of organic dyes is a challenging task in all the fields such as the forensic and conservation sciences, especially in cases where the amount of sample is extremely small. In this paper we propose a new enhanced FTIR method (MU-ATR metal underlayer ATR spectroscopy), which we believe is the first of its kind, for the analysis of a few ng of dyes. With this method, dyed fiber micro-extracts can be analyzed using a commercial FTIR microscope with a fixed incident angle, obtaining the same separation between the different classes of dyes investigated as we obtained analyzing pure dyes in transmission mode. Moreover, the new enhancement method has been validated on a real sample dated back to the 1893, showing how it can be promising for the analysis of trace amounts of organic substances in artistic samples such as dyes in paintings or textiles, varnishes and organic residues on archaeological objects.

This study proposes FTIR spectroscopy in the far-infrared region (FarIR) as an alternative method for the characterisation of natural resins. To this purpose, standards of natural resins belonging to four different categories (sesquiterpenic, i.e. elemi, shellac; diterpenic, i.e. colophony, Venice turpentine; diterpenic with polymerised components, i.e. copal, sandarac; triterpenic, i.e. mastic and dammar) used as paint varnishes have been analysed by FarIR spectroscopy in ATR mode. Discrimination between spectral data and repeatability of measurements have been magnified and verified using principal component analysis, in order to verify the effectiveness of the method in distinguishing the four resin categories. The same samples were analysed in the MidIR range, but the spectral differences between the different categories were not evident. Moreover, the method has been tested on historical samples from the painting "La Battaglia di Cialdiran" (sixteenth century) and from a gilded leather (seventeenth century). In the first case, FarIR spectroscopy allowed confirmation of the results obtained by analytical pyrolysis. In the latter, FarIR spectroscopy proved successfully, effective in the identification of the superficial resin layer that could not be detected with the bulk chromatographic analyses.

Fourier transform infrared (FTIR) spectroscopy is one of the most widely applied techniques for the investigation of cultural heritage materials. FTIR microscopy is well established as an essential tool in the microdestructive analysis of small samples, and the recent introduction of mapping and imaging equipment allows the collection of a large number of FTIR spectra on a surface, providing a distribution map of identified compounds. In this Account, we report recent advances in FTIR spectroscopy and microscopy in our research group. Our laboratory develops, tests, and refines new and less-studied IR spectroscopy and microscopy methods, with the goal of their adoption as routine analytical techniques in conservation laboratories. We discuss (i) the analysis of inorganic materials inactive in the mid-IR region by means of far-IR spectroscopy, (ii) the development of new methods for preparing cross sections, (iii) the characterization and spatial location of thin layers and small particles, and (iv) the evaluation of protective treatments. FTIR spectroscopy and microscopy have been mostly used in the mid-IR region of 4000-600 cm(-1). Some inorganic pigments, however, are inactive in this region, so other spectroscopic techniques have been applied, such as Raman spectroscopy. We suggest an alternative: harnessing the far-IR (600-50 cm(-1)). Our initial results show that far-IR spectroscopy is exceptionally useful with mural paintings or with corrosion products from which larger sample quantities can generally be collected. Moreover, the inorganic composition of a sample can be characterized by the presence of several compounds that are inactive in the mid-IR range (such as sulfides, oxides, and so forth). Stratigraphical analyses by FTIR microscopy can be hindered by the process of cross section preparation, which often involves an embedding organic polymer penetrating the sample's porous structure. Here, the polymer bands may completely cover the bands of organic compounds in the sample. However, a correct methodological approach can prevent such limitations. For example, it is always advisable to analyze the sample surface before preparing the cross section in order to characterize the preparation layers and the varnish layers, which are generally applied to the surface of a painting both to protect it and improve the color saturation. Furthermore, the innovative use of IR-transparent salts as embedding material for cross sections can prevent contamination of the embedding resin and improve detection of organic substances. Another key point in the use of FTIR microscopy in artwork analysis is spatial resolution. The high-energy output of a new integrated FTIR microscope enhances the ability to characterize and spatially locate small particles and thin layers. Moreover, the new configuration proves extremely useful in the evaluation of protective treatments, because larger areas may be analyzed in less time in comparison to traditional systems, allowing the collection of more statistical data.

Few research studies from the early seventies reported the use of far infrared (FIR) spectroscopy and its analytical potential. Especially in the field of cultural heritage, particular attention has not been given to this technique because of its destructive character; however, this can be overcome by employing Raman microscopy. Provided that enough quantity of the sample is available, FIR spectroscopy may represent a useful analytical method in the case of inorganic compounds that are not active in the mid infrared region and, because of the fluorescent effect produced by the organic media, not detectable even by Raman spectroscopy. In this article, the application of FIR spectroscopy has been applied for the characterisation of several inorganic pigments. A preparation method based on the use of polyethylene has been developed that allows analyses with moderate quantity of sample (0.5–1.5 mg). The data obtained have been compared with Raman results with the aim to build a common database. Some applications on real case studies are presented and discussed. Copyright © 2008 John Wiley & Sons, Ltd.

In the field of analytical chemistry, many scientific efforts have been devoted to develop experimental procedures for the characterization of organic substances present in heterogeneous artwork samples, due to their challenging identification. In particular, performances of immunochemical techniques have been recently investigated, optimizing ad hoc systems for the identification of proteins. Among all the different immunochemical approaches, the use of metal nanoparticles - for surface enhanced Raman scattering (SERS) detection - remains one of the most powerful methods that has still not been explored enough for the analysis of artistic artefacts. For this reason, the present research work was aimed at proposing a new optimized and highly efficient indirect immunoassay for the detection of ovalbumin. In particular, the study proposed a new SERRS probe composed of gold nanoparticles (AuNPs) functionalised with Nile Blue A and produced with an excellent green and cheap alternative approach to the traditional chemical nanoparticles synthesis: the laser ablation synthesis in solution (LASiS). This procedure allows us to obtain stable nanoparticles which can be easily functionalized without any ligand exchange reaction or extensive purification procedures. Moreover, the present research work also focused on the development of a comprehensive analytical approach, based on the combination of potentialities of immunochemical methods and Raman analysis, for the simultaneous identification of the target protein and the different organic and inorganic substances present in the paint matrix. An advanced mapping detection system was proposed to achieve the exact spatial location of all the components through the creation of false colour chemical maps.

During one of Coronelli's terrestrial globes restoration, belonging to the Bologna University, we found some substances considered not to be original. Their presence was both on the globe surface and under one of the gores. In order to characterise the organic material (original or added in restoring procedures) we employed pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The analytical results reveal the presence of the original materials, such as natural gums and animal glues, together with industrial products, such as synthetic germicides.

The mass spectra of trimethylsilyl (TMS) derivatives of possible hydroxylated pyrolysis products of glucose and cellulose were recorded by gas chromatography/mass spectrometry (GC/MS) analyses of TMS derivatives of 2-hydroxymethylfuran, 2-hydroxy-1-methyl-1-cyclopenten-3-one, 5-(hydroxymethyl)-2-furaldehyde, 5-methyl-2-furoic acid, 4-hydroxy-6-methyl-(2H)-pyran-2-one, 2-methyl-3-hydroxy-(4H)-pyran-4-one (maltol) and 1,6-anhydro-β-D-glucopyranose (levoglucosan, LG). Also, 2-O-TMS-1,6-anhydro-β-D-glucopyranose, 4-O-TMS-1,6-anhydro-β-D-glucopyranose and 2,4-bis-O-TMS-1,6-anhydro-β-D-glucopyranose were identified from the interpretation of electron impact and chemical ionisation mass spectra of products obtained from partially silylated levoglucosan solutions, together with information from the known relative reactivities of OH groups of anhydrosugars. A peak at m/z 116 was found to be characteristic of the mass spectra of partially silylated anhydrosugars, and is absent from the mass spectra of the persilylated species. Pyrolysis/GC/MS of cellulose in the presence of hexamethyldisilazane afforded principally the 2- and 4-TMS ethers and the 2,4-bis-TMS ether of LG, whereas the 5-TMS-oxymethyl-2-furaldehyde was a prominent pyrolysis/silylation product of glucose. The mass spectra of other relevant pyrolysis/silylation products are presented. Copyright © 2002 John Wiley & Sons, Ltd.

The present research was aimed at exploiting and evaluating the potentialities of FT-NIR microscopy, as a complementary approach to analysis in the MIR region, for the chemical characterisation of paint cross sections. Even if FT-NIR technique is still underutilised in the field of cultural heritage investigations, the integrated use of information recorded in the NIR and in the MIR regions proved to be extremely useful in the molecular investigation of organic and inorganic substances. In fact, combination and overtone bands present in the NIR region, even if weaker and less selective than those in the MIR region, are not distorted by reflection phenomena. Furthermore, NIR spectra can be efficiently used as a spectral fingerprint for the stratigraphic characterisation of paint cross sections. The proposed analytical protocol was applied on two historical samples, presenting different stratigraphic structures. Suitable chemometric methods were applied for the elaboration of multivariate chemical maps recorded in the range 700–7500 cm − 1 . In particular, a comprehensive and efficient procedure based on an interactive brushing approach, which combines the structural information of the score scatter plots with the spatial information of the PC score maps, was used. Interestingly, NIR data allowed a thorough characterisation of paint structures, providing information for the identification of components and suggesting the differentiation among different types of proteins. Moreover, NIR spectra permitted to achieve an efficient distinction of different classes of natural resins, demonstrating that, even working at a microscopic level, the NIR region may support the identification of different terpenoid materials. Multivariate analysis performed on MIR data did not provide satisfactory results, probably due to the distortion of the spectra and overlapping of bands. Nevertheless, MIR outcomes were investigated to support the interpretation of NIR spectra and in attempt to define an integrated protocol for the characterisation of complex paint mixtures.

In the last decades, in situ non-invasive analytical techniques have been widely used for the analysis of paintings. These techniques are useful to extensively map the surface in a non-invasive way, in order to identify the most representative areas to be sampled. When spectroscopic investigations, such as X ray fluorescence (XRF), are conducted, they usually imply the acquisition of a huge amount of measurements. Subsequently, all these data should be processed in situ , in order to immediately support the sampling strategies. To this aim, an appropriate and fast strategy for multivariate treatment of XRF spectral and hyperspectral data sets is presented, able to account for inter-correlation among variables, which is an issue of high importance for elemental analyses. The main advantage of the approach is that XRF spectral profiles are analysed directly, without computation of derived parameters, by means of principal component analysis (PCA). This procedure allows a fast interpretation of results that can be accomplished in situ . Particular attention was paid to the selection of proper spectral pre-treatments to be applied on data together with the use of several chemometric tools (peak alignment, spectra normalisation and exploratory analysis) aimed at improving the interpretation of XRF results. In addition, the application of multivariate exploratory analysis on XRF hyperspectral maps was studied by using an interactive brushing procedure. The multivariate approach was validated on data obtained from the analysis of the famous Renaissance panel painting “The Ideal City”, exhibited in Palazzo Ducale of Urbino, Italy.

Optical microscopy, cross-section and fragment Micro-FTIR spectroscopic techniques along with microchemical tests were used for the identification of pigments in two different samples of an icon. Representing the Last Judgement, and painted by the Greek master Ioannis from the village of Kapesovo in the year 1771, the kneeling desk icon under investigation is a noteworthy contribution to the study of materials in post-Byzantine visual arts. The main components found in the ground layer of both samples were gypsum, beeswax and a proteinaceous material. Cinnabar, Prussian blue and cerussite were identified on the paint layers. The binding medium on the paint layers was weddelite. The materials used in the painting and ground layers were characterized in order to clarify the painting technique. Proteinaceous materials have been identified as binders for the pigments, indicating a tempera painting technique. (C) 2011 Elsevier Masson SAS. All rights reserved. Journal of Cultural Heritage

Macro-attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopic imaging is presented as non-destructive analytical methodology with respect to the sample for the study of paint surfaces. This paper illustrates new opportunities offered by a conventional diamond ATR accessory coupled with a focal plane array detector to obtain chemical images of multi-layered paint cross-sections. The use of a large internal reflection element permits to increase the field of view of the imaging area up to 700 μm × 500 μm and to obtain FT-IR images of the complete stratigraphy of the sample. This approach represents a versatile analytical tool to determine the composition of the inorganic and organic painting materials and to obtain information on their distribution within the different layers. In the optical arrangement used, a spatial resolution of approximately 15 μm is achieved without the use of infrared microscope. This study demonstrates the possibilities offered by macro-ATR-FT-IR imaging for a simple identification of the different compounds present in paint cross-sections before performing further molecular and elemental analyses which may be time consuming or require particular sample preparation.

The vaults of the Saint Peter basilica in Vatican (Rome) are decorated with mosaics whose realisation is dated to the end of the 16th century. The mortar layers beneath the mosaics are realised with the so-called “Roman stucco”, a kind of mastic specifically employed as a binder in the mosaic's supporting layers. Its empirical recipe was known and reported by 18th century authors, accounting for the use of lime, travertine powder added to a mixture of herbs and linseed oil. A recent restoration of the mosaics has allowed to characterise the mortars from a compositional point of view by individuating the inorganic mineralogical fraction and by chemically characterising the organic components. The study of stucco samples has been performed through polarising microscope observations, X-ray diffraction (XRD) analyses, thermal analyses (TA) (thermodifferential-DTA and termogravimetric-TGA analysis), Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy, pyrolysis-gascromatography (PY-GC)–mass spectrometry. The analyses have allowed to distinguish between original stucco, produced and utilized at the same time of the realisation of the mosaics, and other mortars, presumably employed in later times during restoration interventions. The outcomes of the mineralogical investigation and TA indicate the presence of four different types of stuccos, here considered as four characteristic groups. The mineralogical analyses indicate that all the samples are constituted of two main phases: calcite and vaterite and the TA, beyond the quantification of the calcium carbonate content, have shown the presence of organic components in the stucco. The organic fraction was characterised by PY-GC–mass spectrometry, confirming the presence of the linseed oil cited in the ancient recipes. The very interesting outcome of this study is the occurrence of the rare calcium carbonate polymorph vaterite. The ATR-FTIR spectroscopy on the stucco gives further contribution to a better understanding of the FTIR spectrum of the rare mineral and an explanation of its formation is tentatively given.

In the field of FTIR spectroscopy, the far infrared (FIR) spectral region has been so far less investigated than the mid-infrared (MIR), even though it presents great advantages in the characterization of those inorganic compounds, which are inactive in the MIR, such as some art pigments, corrosion products, etc. Furthermore, FIR spectroscopy is complementary to Raman spectroscopy if the fluorescence effects caused by the latter analytical technique are considered. In this paper, ATR in the FIR region is proposed as an alternative method to transmission for the analyses of pigments. This methodology was selected in order to reduce the sample amount needed for analysis, which is a must when examining cultural heritage materials. A selection of pigments have been analyzed in both ATR and transmission mode, and the resulting spectra were compared with each other. To better perform this comparison, an evaluation of the possible effect induced by the thermal treatment needed for the preparation of the polyethylene pellets on the transmission spectra of the samples has been carried out. Therefore, pigments have been analyzed in ATR mode before and after heating them at the same temperature employed for the polyethylene pellet preparation. The results showed that while the heating treatment causes only small changes in the intensity of some bands, the ATR spectra were characterized by differences in both intensity and band shifts towards lower frequencies if compared with those recorded in transmission mode. All pigments' transmission and ATR spectra are presented and discussed, and the ATR method was validated on a real case study.

Paint cross-sections have been analysed using the attenuated total reflection technique combined with FTIR mapping microspectroscopy in order to characterise the nature of the compounds present and map their localisation in the stratigraphy. The study reveals the possibilities offered by micro-ATR devices for obtaining informations about the organic substances employed in painting techniques and in particular their distribution in the different layers, showing a real improvement over traditional analytical investigations in use for the detection of organic substances. Limitations, such as the contamination of the embedding resin and the typical spectral resolution (20 microm) are presented and alternative methods were proposed to obtain better results. In particular, the use of an infrared transparent salt (KBr) as embedding material for the cross-sections is evaluated and seems to be very promising. Furthermore, ATR mapping represent a useful non-destructive analytical technique complementary to others molecular and elemental analyses to be performed afterwards such as SEM-EDX.

Only few published information are available in the conservation literature on materials and techniques used by ancient Chinese artists to decorate wooden architectural buildings. This paper presents the results of a joint research aimed at collecting technical information through an historical survey and studying the results of the scientific examinations carried out on the paint samples collected from the decorated surfaces of the Drum Tower in Xi’an, a Ming Dynasty monument built up in 1380 AC. Optical microscopy of the cross-sections, scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), X-ray diffraction as well as pyrolysis-gas chromatography–mass spectrometry have been used to both characterise the inorganic pigments composition and the binding media used. The analytical results showed that the materials composition and technique used to plaster the wooden surface are in good agreement with the information gathered through the historical survey. In fact, clay, lime, siccative oil, probably tung oil and fabrics’ strips are the main plaster components. At the same time the plaster represents the priming material for the painted decorations whose pigments composition, indicates that they are both original and applied on the occasion of a past restoration procedure carried out in the XVIII century even though the binding medium used follows the ancient tradition.

open 10 no In this study, portable NMR was applied to monitor and evaluate cleaning treatments on the surface of a 16th century Italian wall painting. Due to the complexity of the state of degradation of the wall painting, a campaign of measurements was carried in situ to evaluate the performance of traditional and innovative eco-friendly cleaning systems such as sulphate-reducing bacteria D. vulgaris confined in hydrogels, and to compare two different cleaning systems used to remove a degraded hydrophobic organic layer. Specifically, NMR stratigraphy allowed to determine the thickness of the organic layer covering the surface of the wall painting, its distribution in the wall painting, the presence of residues after applying the cleaning treatment, and to evaluate and compare the effectiveness of applied treatments. A new analytical parameter here named the solubilization degree of the cleaning system permitted the selection of the most performing treatment. 1H NMR depth profiles allowed to evaluate changes in the permeability of the wall painting caused by the presence of organic substances during the application of water-based cleaning systems, and to evaluate the water content and its depth of penetration in the wall painting. Changes in permeability were estimated calculating another new analytical parameter, i.e. the percentage of water saturation before and after the application of the cleaning treatment. Depth profiles also permitted the evaluation of the degree of wettability of the wall painting surface as a function of the time of application, and the obtainment of a detailed information about the interaction between water molecules, the gel network and the surface of the wall painting. Finally, to obtain the chemical characterization of the artefact surface a multi analytical approach was applied using both portable and micro-invasive analytical methodologies. embargoed_20200501 Di Tullio, Valeria; Sciutto, Giorgia; Proietti, Noemi; Prati, Silvia; Mazzeo, Rocco; Colombo, Chiara; Cantisani, Emma; Romè, Valentina; Rigaglia, Davide; Capitani, Donatella Di Tullio, Valeria; Sciutto, Giorgia; Proietti, Noemi; Prati, Silvia; Mazzeo, Rocco; Colombo, Chiara; Cantisani, Emma; Romè, Valentina; Rigaglia, Davide; Capitani, Donatella