Nd:YAG laser systems (1064 nm) have been widely applied in the removal of protective layers from stones, and many studies have been conducted both on laboratory model sample and real cases, investigating different laser parameters, among them the pulse duration length. The Er:YAG laser (2940 nm) effectiveness of cleaning of stones has been mainly investigated on model samples and for the removal of natural varnishes [1]. This study aims to make a comparison of the ablation rate, effectiveness and safeness of the laser assisted removal of synthetic protectives and consolidants from stones, by using Q Switched Nd:YAG laser with different pulse duration and Er:YAG laser (250 ?s). Different limestone and sandstone model samples have been chosen as representative of the most common stone artifacts which have been subjected to conservative interventions in the past, The selected products (Pulvistop and Idroblock by Geal S.r.l., Hydrophase Acqua by Phase Italia) were aqueous emulsions of silanes/siloxanes having low and medium molecular weight, with water repellent and consolidant (Pulvistop only) properties for stone materials, and Paraloid B72 as consolidant. The products were applied by absorption until refusal on the 5x5 cm and 10x10 cm l model samples. Two set of laboratory models have then been submitted to different artificial aging procedures: i) in Solar Box (CO.FO.ME.GRA 3000e, equipped with Xenon lamp, ?>295 nm) for 400 h at 500 W/m2 and ii) in climate chamber for the (Challenge 500, by Angelantoni) with -20/+70°C temperature cycles. To evaluate the performances of the materials, the evolution of ageing tests and the removal of products a multi-analytical approach was chosen: as: -preliminary characterisation of the materials and investigation of the physical properties of the model samples; a Pyroprobe EGA/PY-3030D (Frontier Lab) coupled with a Gas Chromatograph/Mass Spectrometer (PY-GC-MS, Agilent technology) and a portable Fourier Transform Infrared Spectroscopy (FT-IR ALPHA, Bruker) have been used for the characterisation of the not aged products. The water repellence imparted to the laboratory models has been tested by means of capillary absorption measurements following the UNI EN 15801:2010 standard. Colorimetry data (using a ChromaMeter CM-700d by MINOLTA) have been obtained on different spots of the model samples following the UNI EN 15886:2010 standard; - all the preliminary tests have been performed before and after artificial aging; - the investigation of the residue of protective/consolidant after laser removal has been performed by means of capillary absorption measurements and FTIR analysis. The degradation phenomena has been investigated by means of PY-GC-MS, both on the removed material (after Er:YAG laser application) and on the residue of material, collected by scalpel on a few selected area. Finally Environmental Scanning Electron Microscopy (ESEM) has been used in order to follow the laser removal in a some test areas. This paper shows how the optimization of the different laser parameters can lead to a safe removal of those materials used for conservation purposes, which over time have led to yellowing or darkening phenomena on a stone artifacts.

ICVBCmobile è il laboratorio mobile dell'Istituto per la Conservazione e la Valorizzazione dei Beni Culturali (ICVBC), mediante il quale l'Istituto può intervenire a supporto di progetti che riguardano i Beni Culturali seguendo diversi percorsi. Diagnostica. La strumentazione portatile in dotazione permette di eseguire campagne diagnostiche in situ combinando tecniche di imaging con quelle single spot. L'attività può essere integrata con l'esecuzione di analisi di laboratorio mediante il prelievo di micro-campioni. Monitoraggio. Il monitoraggio dello stato di conservazione e delle prestazioni dei trattamenti applicati è propedeutico alla manutenzione programmata. Rilievo 3D. Il rilievo 3D è alla base per una corretta interpretazione dei risultati della diagnostica e del monitoraggio finalizzato all'intervento e per fini documentativi finalizzati anche alla valorizzazione stessa del bene.

This paper explores the added value of micro-chemical and microscopic approaches to gather scientific evidence that can technically explain the pictorial quality of an egg-tempera painting, and underpin assessments that otherwise would be based on naked eye observations only. Demonstration is here provided via the interdisciplinary investigation of the original technique used by Giovanni del Biondo in the polyptych Annunciation and Saints (1385 ca), Galleria dell'Accademia, Florence, Italy. The exquisite surface appearance makes this panel painting remarkable compared to artworks by coeval artists. Imaging techniques (UV, IR and IR false color), non-invasive single spot techniques (XRF and FORS spectrometry) and analytical investigations on eight selected microsamples (ATR-FTIR, GC/MS and Py/GC-MS, ESEM-EDS) were combined to retrieve the palette and identify organic binding media and superficial coating layer. Stratigraphic and micro-chemical data confirmed the use of a relatively simple egg-tempera technique applied on a ground made of gypsum mixed with animal glue, without complex stratigraphic superimposition of preparation and pictorial layers. Various pigments were identified, among which the precious lapis lazuli. While Py/GC-MS highlight that the coating is made of dammar resin and honey mixed with animal glue, the results allow us to state that the painting was not intentionally varnished by Giovanni del Biondo. These outcomes shed a new light on the technical knowledge of this polyptych, and prove how challenging is the attempt to categorize egg-tempera recipes used by ancient painters at the turn of the 14th century

In the occasion of the celebrations for the 150th anniversary of the founding of Italy (1861-2011), it was decided to analyse the artwork "The Italian Flag" (La Bandiera Italiana) created by the artist Fernando Melani (Pistoia, 1907-1985), one of the precursors of the Poor Art artistic movement in Italy. This project is a follow-up to a previous study which was mainly focused on the pigments and dyes found in his home-studio.

A multi-analytical approach was used to study the constituent materials, manufacturing technique, and state of conservation of a contemporary sculpture. This sculpture, entitled Nuredduna, was created by Aligi Sassu in 1995 and is located in the "Bellariva garden" in Florence (Italy). Fourier transform infrared spectroscopy (FT-IR), optical and electronic microscopy (OM and SEM-EDS), X-ray diffraction (XRD), and portable X-ray fluorescence (XRF) highlighted the multi-layered structure of the statue: fiberglass and an overlay of different layers (gel coat) applied with an unsaturated polyester resin added with aggregate materials and bromine compounds. A top-coat in acrylic black varnish, used as a finish, was also found. The combination of these materials with their different compositions, environmental impact, and even vandalism have negatively affected the state of conservation of Nuredduna, causing the loss of strata in its lower parts (legs and feet).

Alum-treated archaeological woods from the Oseberg collection, excavated and treated in the early 1900s demonstrate an extreme deterioration, only discovered in the past decade. This research was aimed at understanding the characteristics of the naturally aged material through chemical analyses of both organic and inorganic components, in order to provide information for the preservation/conservation of these precious objects. Analytical pyrolysis-gas chromatography/mass spectrometry with in situ silylation using hexamethyldisilazane (Py(HMDS)-GC/MS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) were used to investigate a set of samples of alum-treated archaeological wood and untreated archaeological wood. Sound woods of the same species were also analysed in order to compare the results. Results from Py(HMDS)-GC/MS analyses of alum-treated woods from Oseberg showed an extreme depletion of carbohydrates and a highly deteriorated lignin network. The majority of the lignin had undergone oxidation reactions, illustrated by high relative amounts of acidic pyrolysis products. In particular, p-hydroxy-benzoic acid was detected for the first time as a degradation product of archaeological wood. Results from ICP-AES showed variable concentrations of aluminium and potassium from the alum treatment, as well as iron, copper, zinc and calcium. The extent of oxidation observed by Py(HMDS)-GC/MS appeared to correlate with relative amounts of iron and calcium in the samples, which may suggest that degradation promoted by iron compounds is inhibited in the presence of calcium compounds. The results obtained for a sample of archaeological wood treated with alum salts five years ago showed that chemical deterioration of lignin had already begun, mainly involving depolymerisation reactions, though only a slight increase in oxidation was evident. In addition to increased insight into potential deterioration reactions, occurring in a complex material such as alum-treated archaeological wood, it was possible to relate the degree of chemical degradation of the Oseberg woods to their visual condition (observed with the naked eye).

In order to identify the best practices and guidelines for the conservation of contemporary artworks, innovative approaches are needed, based on a monitoring campaign to assess the rate of alteration/decay of the objects placed outdoors. In this project, which is still in its first stage, the evolution in time of characteristic parameters is being used to establish thresholds for maintenance or restoration of three installations in the monumental garden of the "Fattoria di Celle", located in Santomato (Pistoia, Italy). This garden hosts the Gori collection of 43 site-specific artworks created by contemporary artists. The three installations selected have different material compositions: bronze, stone and mortar painted with acrylic colors and glass. Each installation had its own conservation problems related to the constituent materials, together with the important impact of outdoor exposure and location. After a preliminary investigation, the major issues and risks for each artwork were identified and the monitoring campaign was started. Portable diagnostic tools and micro-sampling were used to monitor the parameters chosen. One year into the campaign, the preliminary diagnostic documentation has been realized, mainly for the bronze artistic object. Furthermore, the initial guidelines for monitoring campaigns have been defined.

This work proposes a multi-analytical approach to determine the additives in historical mortars, the use of which is widely described in bibliographical sources, but has rarely been reported in the literature. A protocol to thoroughly analyse mortars was created (optical microscopy, X-ray diffraction, infrared spectroscopy, thermal analyses and gas chromatography - mass spectrometry). These techniques, which had already been carried out on samples from various sites from the Roman to the modern era, determined that additives had only been used in the mortars from the internal masonry at our sampling site: the medieval military shipyard of Amalfi (Italy). The investigations yielded information on the production technology, and FT-IR and GC-MS revealed a saccharide material-based additive in the mortars, of plant origin. The FT-IR spectra suggested the presence of a natural gum, which has been used since ancient times to strengthen the cohesion properties of mortars and their resistance to tensile stress.

In this contribution the authors describe the project on monitoring of conservation issues on some artefacts of environmental art in the Fattoria di Celle, reporting some preliminary results. The project aims at evaluating the conservation status of some artefacts, identifying their conservation issues and, through monitoring, evaluating the risk for their conservation. The results of these three activities are essential for scheduling the maintenance of the artefacts. The importance of this project lies both in analyzing the selected artefacts using the best analytical techniques available at the state of art, and in the definition of protocols, standards, and good practice norms aimed at planning Abstract of maintenance for environmental art. Artefacts made by different materials and with different manufacturing techniques are selected for the project: Labyrinth by R. Morris, 1982, in Trani stone, serpentinite and cement; Open Field Vertical Elevations by R. Serra, 1982, in sandstone; Servi muti by R. Barni, 1988, bronze; La cabane éclatée aux 4 salles by D. Buren, 2005, concrete, mirrors, marble and acrylic colors; Cette obscure clarté qui tombe des étoilesby A. Kiefer, 2009, mixed media on canvas and lead/terracotta, lead/charcoal on wall. The obtained results on the selected artefacts can be generalized to other artefacts stored outdoors

Eight samples of ca. 3000 year old oak wood from the Biskupin site and a piece of sound oak (Quercus sp.) wood were analysed. The degradation state of archaeological oak wood was investigated using two analytical approaches: classical wet chemical analysis and analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS) with in situ silylation. The results were compared with those obtained for sound oak wood. Chemical analysis provided information on the amount of wood components. Their alteration at a molecular level was investigated by Py-GC/MS, highlighting how degradation can affect the formation of primary and secondary wood pyrolysis products. The results showed that the chemical changes in the wood material in the eight samples examined had different entities and extents with comparison to sound oak wood. Samples taken from the external parts of the fragments had undergone a significant loss in polysaccharide components, whereas the internal parts were in a relatively good state of preservation. Evaluation of the relative amounts of pyrolysis products deriving from holocellulose and lignin highlighted that specific categories of compounds, such as lignin monomers and anhydrosugars, can be taken as an index for good preservation of wood components. These results will be used to evaluate the effectiveness of the in situ conservation strategy by repeating the analyses on these samples after some years and comparing the results.

The chemical characterization of the bark from eight broad-leaved trees (Betula pendula, Quercus suber, Quercus ilex, Castanea sativa, Quercus robur, Carpinus betulus, Fagus sylvatica and Populus nigra) was carried out using evolved gas analysis-mass spectrometry (EGA-MS) and gas chromatography/mass spectrometry (GC/MS) following alkaline hydrolysis, solvent extraction and derivatisation with a sylilating agent. Not only does bark account for a high percentage of residues from forestry and the wood industry, but it is also rich in suberin, a biopolyester, whose sub-monomeric units can be converted into value added chemicals, as well as being used as starting blocks for the production of new materials. EGA-MS along with principal component analysis (PCA) of the mass spectral data were used to obtain information on the thermal complexity of the barks and on the thermal degradation areas of all their main chemical constituents: suberin, polysaccharides, lignin, tannins and extractives. GC/MS analysis was used for the depolymerisation of suberin, and to examine its monomeric composition. This enabled us to determine aliphatic and mid-chain substituted long-chain ?,?-diacids and ?-hydroxyacids (all with mainly 16, 18, and 22 carbon atoms) along with aliphatic long-chain alkanoic acids and alkanols. Our results may be useful for the exploiting the investigated barks - but not just for energy recovery. In fact, as their suberin shows a high abundance of mid-chain substituted monomers, alternative uses are possible such as the synthesis of polymeric materials by condensation and cross-linking reactions.

Analytical pyrolysis coupled with gas chromatography and mass spectrometry is a very powerful tool to analyze polymers and macromolecules. In this paper this technique was applied to the characterization of the urushi oriental lacquer (qi-lacquer in Chinese) with the aim to set up an alternative analytical method to identify the lacquer. Urushi is mostly rich in alcoholic polar moieties, thus, a derivatization step is required, which is crucial for the detection and MS identification of all the compounds deriving from the thermal degradation. In this work hexamethyldisilazane (HMDS) was used for the first time as a derivatizing agent, thus, proving to be a valid alternative to more common methylating agents. Adopting this in situ Py/silylation-GC-MS procedure, we were able to characterize urushi lacquer and identify characteristic pyrolytic profiles of silylated alkylcatechols, silylated alkylphenols, aliphatic hydrocarbons, alkylbenzenes as well as characteristic molecular biomarkers. The method was thus used to analyze six archaeological samples from Sichuan (China) dating back from the 2nd century BC to the 12th century AD, in which the presence of urushi was suspected, and the lacquer was identified in all of them through the identification of all the characteristic pyrolytic profiles and molecular biomarkers. The method set up is also promising to be used for the characterization of the other oriental lacquers, such as laccol and thitsi.

Introduction: Since ancient times, the unique properties of birch barks (Betula genus) have made them a material of choice for producing both everyday-life and artistic objects. Yet archaeological birch bark artefacts are rare, and little is known about the chemical transformations undergone by bark (chemically composed mainly of suberin and triterpenes) in archaeological contexts. Understanding the chemical modifications induced by ageing is essential for selecting suitable preservation and conservation approaches. Thus, the main aim of this research is to assess the preservation and state of degradation of archaeological findings made of birch bark: a Neolithic bow case recovered from a melting ice patch in the Bernese Alps (Switzerland) and a waterlogged birch bark vessel discovered at Moossee Lake (Canton of Bern, Switzerland). Scanning electron microscopy (SEM) and gas chromatography/mass spectrometry (GC/MS) were used to obtain information at micro-morphological and molecular levels on the state of degradation of the birch bark findings. GC/MS analysis followed two different sample preparations, alkaline hydrolysis and solvent extraction, in order to investigate respectively the hydrolysable and soluble constituents, and to test whether part of the suberin structure was depolymerised by the long period of burial. Results and conclusions: SEM investigations on archaeological birch bark samples have shown that the extent of degradation of the microstructure is much higher in waterlogged birch bark than in birch bark preserved in ice. GC/MS analysis revealed that at a molecular level, the birch bark was quite well preserved. In both the archaeological environments, ice patch and lake water, various reactions had taken place leading to the depletion of reactive and sensitive compounds such as unsaturated acids and epoxy-compounds. In addition, archaeological birch bark had undergone depolymerization and oxidation reactions leading to the appearance of free suberin monomers and of oxidised triterpenes (betulone and lupenone). GC/MS data also seems to suggest that the birch bark preserved in the waterlogged site had a more pronounced degradation both in terms of oxidation and depolymerisation.

Historically, a very large variety of everyday artifacts were made of wood, which makes them representative of their historical period or social context and valuable for archaeologists and historians. In order to preserve degraded wood and to develop and apply suitable conservation treatments, chemical and physical characterization of archaeological wood is needed. This review provides the reader with a survey on state-of-the-art of instrumental analytical tools available to understand the morphology and the chemical composition of archaeological wood. The focus is on microscopic and spectroscopic techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman, nuclear magnetic resonance (NMR) and analytical techniques based on pyrolysis, such as direct exposure-mass spectrometry (DE-MS), pyrolysis-mass spectrometry (Py-MS), pyrolysis-gas chromtography-mass spectrometry (Py-GC/MS), with emphasis on their respective potentialities and limitations. The advantages of techniques based on synchrotron radiation are also discussed. In addition, the applicability of each examined technique is illustrated and discussed through specific examples from the literature.

The painting Ri de Pomme (1988) by American artist Julian Schnabel was recently subjected to an extensive and disputed restoration with polyvinyl acetate (PVAc) paints. To characterize and locate on the painting the materials used in the original and in the repainted areas, we employed several spectroscopic and chromatographic techniques. Fibre Optics Reflectance Spectroscopy (FORS), Micro-Raman, Pyrolysis-Gas Chromatography/Mass Spectrometry (Py- GC/MS) and Gas Chromatography/Mass Spectrometry (GC/MS) were used. The original and restoration paint layers were differentiated by a preliminary FORS survey. The pigments were studied with Micro-Raman and the oil binder was characterized by GC/MS. Moreover, the support of the painting, a weathered tarpaulin, was characterized by Py-GC/MS.

The paint materials in three different Keith Haring outdoor murals, Tuttomondo in Pisa (1989), the Necker Hospital mural in Paris (1987), and the Melbourne mural (1984), were investigated using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS).The aim of the study was to characterize the chemical composition of the paint materials used by the artist in the three mural paintings and to correlate their chemical composition to their state of conservation. The analyses were performed using a PY-3030D pyrolyzer (Frontier Lab, Japan).The analyses of the paint samples from Tuttomondo showed the presence of a styrene/. n-butylacrylate copolymer, which had been used as a paint binder. The results were then compared with those obtained with a Pyroprobe 5000 pyrolyzer (CDS Analytical, U.S.A.).The pyrolysis profiles of the paint samples of the Paris mural were characterized by the presence of benzene and acetic acid, together with small amounts of toluene, styrene, indene, and different aromatic compounds, which indicated the presence of a vinyl resin. The various isomers of the vinyl ester of versatic acid were attributed to VeoVa^TM, present in the vinyl polymer as an internal plasticizer.In the Melbourne mural, there was a high heterogeneity of paint materials, both original and deriving from a restoration intervention. The Py-GC/MS analyses revealed the presence of alkyd, vinyl, and acrylic resins.The samples were collected within the framework of conservation campaigns carried out on the three artworks. The results enabled the materials used by the artist to be identified, and highlighted the conservation state of the murals. They also provided conservators and restorers with helpful information for the choice of cleaning and protection procedures. Having access to three different examples of Haring's street art enabled us to compare the paint techniques and to relate them to the state of conservation.

Two oriental lacquers from Rhus Succedanea and Melanorrhoea Usitata were characterised by Py-GC-MS with in situ silylation using HMDS. Pyrolytic markers, which were helpful in differentiating between the lacquers, were identified in their silylated forms, and the mass spectra are presented and discussed. Aliphatic and aromatic hydrocarbons were formed as well as TMS derivatives of alkylcatechols and alkylphenols, and relative characteristic pyrolytic profiles were compared for the two lacquers. The method, here applied for the first time to the characterisation of the Vietnamese and Burmese lacquers, proved successful not only in distinguishing between the two lacquers, but also in highlighting the polymerisation processes undergone by the saps in the formation of the lacquer layers.The results obtained demonstrated that in situ Py/silylation-GC-MS with using HMDS is a suitable tool for the analysis of all oriental lacquers with possible application to diagnose their presence in samples of unknown composition.

Archaeological excavations carried out in the ancient settlement of Sumhuram (3rd century BC-5th century AD) in the area of Khor Rori (Dhofar Governorate, southern Oman), brought to light pottery showing a pink-violet substance. In order to reveal the nature of this pink-violet colour, the substance was chemically examined by laser desorption-ionization mass spectrometry (LDI-MS) and high performance liquid chromatography-diode array detection (HPLC-DAD). The analytical investigations provided a detailed molecular composition of the organic fraction of the pink-violet material, highlighting the presence of 6,6'-dibromoindigo, 6-monobromoindigo, 6,6'-dibromoindirubin, 6- and 6'-monobromoindirubin, indigo and indirubin. The results revealed that shellfish purple was the source. In addition, in some of the pottery fragments, alizarin and purpurin, which are the molecular markers of madder type dyestuffs, were also ascertained by LDI-MS. The analytical results enabled us to draw hypotheses not only on the possible function of such vessels as dye baths, but also that, since Sumhuram was one of the most important harbours in southern Arabia during the pre-Islamic time, it was also possibly a centre for the production and trade of purple pigments.

Evolved gas analysis-mass spectrometry (EGA-MS) was used for the first time to study archaeological wood, in order to investigate its chemical degradation. The archaeological wood was from an oak pile from a stilt house found in the Neolithic 'La Marmotta' village (Lake Bracciano, Rome, Italy). The sampling was performed from the external to the internal part of the pile, following the annual growth rings in groups of five. In addition, sound oak wood and isolated wood components (holocellulose and cellulose) were also analyzed, and the results were used to highlight differences because of degradation. Our study demonstrated that EGA-MS provides information on the thermo-chemistry of archaeological wood along with in-depth compositional data thanks to the use of MS. Our investigations not only highlighted wood degradation in terms of differences between carbohydrates and lignin content, but also showed that lignin oxidation and depolymerization took place in the archaeological wood. Mass spectral data revealed differences among the archaeological samples from the internal to the external part of the pile. An increase in the formation of wood pyrolysis products bearing a carbonyl group at the benzylic position and a decrease in the amount of lignin dimers were observed. These were related to oxidation and depolymerization reactions, respectively.

The beiwusheng huiguan ('Meeting hall of the Five Northern Dynasties') is a building complex from the Qing dynasty (1636-1912 ad) located in Wafangdian, near Ziyang, in the south of the Chinese Province of Shaanxi. Two of the preserved halls are richly decorated with wall paintings dated probably in 1848 ad and representing scenes of the 'Romance of the Three Kingdoms' and Confucian moral tales. They are a rare example of well-preserved mural paintings of high artistic value inside civil buildings. The aims of this paper are the chemical characterization and localization of organic materials used as binders and colorants in the wall paintings. A multi-analytical approach, consisting in the combined use of gas chromatographic-mass spectrometric techniques (GC/MS and Py-GC/MS) and high-pressure liquid chromatography with diode array detector (HPLC-DAD), was chosen for these purposes. Proteinaceous materials (animal glue and egg), saccharide material (fruit tree gum) and a siccative oil were identified in different paint layers supplying invaluable information about the painting technique used. Moreover, the analyses of organic dyes allowed identifying indigo and gallic acid in more than one sample adding fundamental information about Chinese artists' techniques in mural paintings, missing from the previous studies. To shed light on the gilding technique, the distribution of the painting materials was achieved by means of synchrotron radiation Fourier transform infrared spectroscopy (SR micro-FTIR) and X-ray fluorescence (SR micro-XRF). The results obtained from the multi-analytical approach enabled us to determine the organic materials both binders and organic colorants used by Chinese artisans, highlighting the high technical level achieved in nineteenth century. The binding media and the organic colorants identified, as well as their distribution, allowed the discussion on the painting technique used by the artists of the Qing dynasty giving information for the first time about the decoration of Chinese civil buildings.