Search

Although multiple structural, mechanical, and molecular factors are definitely involved in osteoporosis, the assessment of subregional bone mineral density remains the most commonly used diagnostic index. In this study, we characterized bone quality in the femoral neck of one osteoporotic patients as compared to an age-matched control subject, and so used a multiscale and multimodal approach including X-ray computed microtomography at different spatial resolutions (pixel size: 51.0, 4.95 and 0.9 µm), microindentation and Fourier transform infrared spectroscopy. Our results showed abnormalities in the osteocytes lacunae volume (358.08 ± 165.00 for the osteoporotic sample vs. 287.10 ± 160.00 for the control), whereas a statistical difference was found neither for shape nor for density. The osteoporotic femoral head and great trochanter reported reduced elastic modulus (Es) and hardness (H) compared to the control reference (-48% (p < 0.0001) and -34% (p < 0.0001), respectively for Es and H in the femoral head and -29% (p < 0.01) and -22% (p < 0.05), respectively for Es and H in the great trochanter), whereas the corresponding values in the femoral neck were in the same range. The spectral analysis could distinguish neither subregional differences in the osteoporotic sample nor between the osteoporotic and healthy samples. Although, infrared spectroscopic measurements were comparable among subregions, and so regardless of the bone osteoporotic status, the trabecular mechanical properties were comparable only in the femoral neck. These results illustrate that bone remodeling in osteoporosis is a non-uniform process with different rates in different bone anatomical regions, hence showing the interest of a clear analysis of the bone microarchitecture in the case of patients' osteoporotic evaluation.

Historical colour charts provide a rich and often well-dated reference materials source for studying the chemical composition of all kinds of commercial brands of artists’ paints. This article presents the results of an extensive analytical study of more than 80 paint hues from 11 colour charts that are included in the German standard book Das Deutsche Farbenbuch by H. Trillich (1925, Part II). Our research focused on the identification of synthetic organic pigments, whose quickly increasing significance for artists’ paints in the early twentieth century is impossible to evaluate by documentary source research alone. A stepwise procedure combining different non- or minimally invasive vibrational spectroscopy techniques—Normal Raman and Surface-Enhanced Raman spectroscopy as well as Metal Underlayer Attenuated Total Reflection Fourier-transform Infrared Spectroscopy—allowed the identification of 18 different organic colourants in artists’ watercolours, tempera and oil colours from six German manufacturers. In addition, micro-X-Ray Fluorescence spectroscopy was applied to determine the elemental pattern of substrates, fillers, and admixed inorganic pigments. In addition to a few traditional natural organic colourants (dark and rose madder lake, cochineal lake), most of the identified compounds comprised synthetic organic pigments or synthetic dyes from various chemical classes (indigo, anthraquinone, monoazo, ß-naphthol, xanthene, triarylcarbonium, nitroso, and azine compounds). Some of these have not or only rarely been reported in artists’ paints so far. Since the identified organic colourants have mainly poor to fair (only sometimes good) fastness to light according to modern standards and partially also to solvents typically used in conservation treatments, it is evident that works of art from this period should be treated keeping in mind the possible presence of such colourants, when planning both interventive treatments and preventive measures.

Nel mese di settembre 2020 veniva presentato nel duomo di Tarquinia il volume avente ad oggetto gli affreschi del Pastura nella cappella Vitelleschi ora nel coro della chiesa, oggetto di un impegnativo restauro allora da poco ultimato. L'intervento era stato l'occasione per ammirare da vicino il ciclo pittorico e comprendere la tecnica e lo stile di questo artista, cosí importante per la storia dell'arte del Lazio e dell'Umbria meridionale, che lavorò a fianco di artisti celeberrimi come Perugino e Pinturicchio. Le pitture erano pervenute ai nostri giorni danneggiate dal calore prodottosi da un incendio a metà Seicento, che ne aveva sciolto le applicazioni di cera dorate. Gli spunti di interesse del cantiere erano stati tali da aver raccolto la preziosa collaborazione dell'infrastruttura IPERION_CH (Integrated Project for the European Research Infrastructure on Culture Heritage) ed il coinvolgimento del CNR, del MOLAB, del Dipartimento di Chimica e Chimica Industriale dell'Università di Pisa, del Dipartimento di Chimica dell'Università di Bologna. [...] In questo volume vengono resi noti i dati degli studi e delle indagini diagnostiche relativi a quel restauro, Per una serie di positive circostanze l'attività di tutela della Soprintendenza è riuscita in questi ultimi anni a dedicarsi a più opere del Pastura nella provincia di Viterbo. Sono stati compiuti restauri finanziati dalle Diocesi proprietarie dei beni (Civitavecchia, Civita Castellana e Viterbo) ed altri realizzati con il contributo di privati [...] Parallelamente la Soprintendenza di Roma ha avviato il cantiere di restauro della cappella Ponziani in Santa Cecilia in Trastevere, e grazie alla proficua collaborazione tra i funzionari delle due Soprintendenze, attraverso lo scambio di dati ed opinioni, anche di intervento, i risultati di quel restauro sono confluiti in questo volume.'

Bones and teeth are biological archives, but their structure and composition are subjected to alteration overtime due to biological and chemical degradation postmortem, influenced by burial environment and conditions. Nevertheless, organic fraction preservation is mandatory for several archeometric analyses and applications. The mutual protection between biomineral and organic fractions in bones and teeth may lead to a limited diagenetic alteration, promoting a better conservation of the organic fraction. However, the correlation between elemental variations and the presence of organic materials (e.g., collagen) in the same specimen is still unclear. To fill this gap, chemiluminescent (CL) immunochemical imaging analysis has been applied for the first time for collagen localization. Then, Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry (LA–ICP–MS) and CL imaging were combined to investigate the correlation between elemental (i.e., REE, U, Sr, Ba) and collagen distribution. Teeth and bones from various archeological contexts, chronological periods, and characterized by different collagen content were analyzed. Immunochemical analysis revealed a heterogeneous distribution of collagen, especially in highly degraded samples. Subsequently, LA–ICP–MS showed a correlation between the presence of uranium and rare earth elements and areas with low amount of collagen. The innovative integration between the two methods permitted to clarify the mutual relation between elemental variation and collagen preservation overtime, thus contributing to unravel the effects of diagenetic alteration in bones and teeth. Results - Bone samples. - Tooth sample. Discussion Materials and methods - Sample preparation. - Laser ablation ICP–MS analyses.

In the general global rise of attention and research to seek greener attitudes, the field of cultural heritage (CH) makes no exception. In the last decades, an increasing number of sustainable and biologically based solutions have been proposed for the protection and care of artworks. Additionally, the safety of the target artwork and the operator must be kept as core goals. Within this scenario, new products and treatments should be explored and implemented in the common conservation praxes. Therefore, this review addressing metal heritage is aimed to report biologically derived gel formulations already proposed for this specific area as reliable tools for cleaning. Promising bio-gel-based protocols, still to be implemented in metal conservation, are also presented to promote their investigation by stakeholders in metal conservation. After an opening overview on the common practices for cleaning metallic surfaces in CH, the focus will be moved onto the potentialities of gel-alternatives and in particular of ones with a biological origin. In more detail, we displayed water-gels (i.e., hydrogels) and solvent-gels (i.e., organogels) together with particular attention to bio-solvents. The discussion is closed in light of the state-of-the-art and future perspectives.

Macroscopic mapping and hyperspectral imaging in the mid-infrared region (2500-25000 nm/4000-400 cm-1) are promising technologies in the field of analysis of cultural heritage. So far they have been successfully employed to study paintings and illuminated manuscripts, gathering important information on spatial distribution of artists’ materials. The present paper reports on the application of mid-infrared macroscopic mapping and hyperspectral imaging to the study of artworks. For an exhaustive overview, instrumental details, working principles and image processing methods will be also presented and discussed.

The 28 portraits of the Uomini Illustri (Famous Men) were ordered by Federico da Montefeltro to decorate his studiolo in Urbino c.1473–1476. Initially the Famous Men were painted on seven panels, with four portraits on each. They are now separated into two groups, 14 in the Musée du Louvre, Paris and 14 in the Ducal Palace of Urbino. No testimony on the context of the creation itself was left and art historians have claimed that the paintings were created by a Flemish painter, Justus of Ghent and finished by a Spanish painter, Pedro Berruguete. This hypothesis has now been reconsidered. A reconstruction of the Urbino studiolo decoration was given by Pasquale Rotondi in 1973, based particularly on iconographical considerations and on a partial material study. New analyses were performed at the Centre de recherche et de restauration des musées de France (C2RMF) in 2008, enabling the various modifications that the portraits have undergone over the centuries to be brought to light. The results of the Italo-French collaboration presented in this paper allow hypotheses on the original decoration of the studiolo to be proposed.

The present review intends to give an overview on the type of information that is possible to gather from the application of different non-invasive and micro-destructive analytical techniques. Typically, methods that require the withdrawal of a sample, such as metallography, SEM-EDS, AAS, FTIK and Py-GC-MS are employed. Through their use, it is possible to identify the material constitution, to evaluate the degradation behaviour and the state of conservation of excavated bronze artefacts. It is also underlined how a non-invasive approach might be used whenever no sampling is allowed, though some limitation should be considered. Furthermore, analytical techniques play an important role in the characterisation and evaluation of the effectiveness of protective coatings and corrosion inhibitors before and after restoration procedures. An interesting aspect is the implication of science for the recognition of forgeries, when analytical studies provide evidences able to prove or deny objects' authenticity.

Journal of analytical atomic spectrometry 37(1), 114 - 129 (2022). doi:10.1039/D1JA00271F, Redox processes activated by environmental factors have been identified as the main cause of the chromatic alterations of a number of artists' pigments, including the yellow pigment orpiment (As$_2$S$_3$). Although a general comprehension of the mechanisms has been provided through characterization of degradation compounds of As$_2$S$_3$, experimental evidences to prove how other paint components and how different environmental agents influence the formation pathways of specific secondary compounds are still lacking. Thus, it becomes fundamental to develop a methodological strategy which enable achieving a discrimination among the causes affecting the chemical stability of more heterogenous As$_2$S$_3$-based paints and defining the mechanism through which the alteration establishes and evolves, with the ultimate goal of optimizing the preventive conservation measures of unique masterpieces. In this paper, we propose a comprehensive multi-material and multi-method approach based on the combination of synchrotron radiation X-ray micro-analytical techniques (i.e., X-ray diffraction, X-ray fluorescence and X-ray absorption near edge structure spectroscopy at S K-/Ag L$_3$-/As K-edges) and vibrational micro-spectroscopy methods to unveil the causes and mechanism of darkening of ���fake-gilded��� decorations in tempera paintings, originally consisting of an unusual mixture of A$_2$S$_3$ and metallic silver (Ag$^0$). Such degradation process is a not yet understood phenomenon threatening a series of Old Master paintings, including those by the Italian painters Cimabue and Pietro Lorenzetti. The high specificity, sensitivity and lateral resolution of the employed analytical methods allowed providing first-time evidence for the presence of black acanthite ($��$-Ag$_2$S), mimetite [Pb$_5$(AsO$_4$)$_3$Cl] and syngenite [K$_2$Ca(SO$_4$)$_2$��H$_2$O] as degradation products of the ���fake-gilded��� decorations in the Maest�� by Cimabue (Church of Santa Maria dei Servi, Bologna, Italy). Furthermore, the study of the painting combined with that of tempera paint mock-ups permitted to explore and define the environmental agents and internal factors causing the darkening, by proving that: (i) Ag$^0$ and moisture are key-factors for triggering the transformation of As$_2$S$_3$ to $��$-Ag$_2$S and As-oxides; (ii) S$^2$--ions arising from the degradation of A$_2$S$_3$ are the main responsible for the formation of $��$-Ag$_2$S; (iii) light exposure strengthens the tendency of the paint components towards alteration. Based on our findings, we finally propose a degradation mechanism of As$_2$S$_3$/Ag$^0$-based tempera paints., Published by ChemSoc, Cambridge

De-pulped multilayer packaging waste containing low-density polyethylene (LDPE) and aluminium was separated into its single components by using sustainable solvents capable of solubilizing LDPE under mild conditions. LDPE and aluminium of high purity and quality were recovered with biodiesel, 2-methyl tetrahydrofuran (2-MeTHF) and cyclopentyl methyl ether (CPME). The recovered LDPE has been characterized by thermal and mechanical analysis, confirming its similarity to the polymer before the dissolution process, while the recovered aluminium was analysed by X-Ray Photoelectron Spectroscopy (XPS) depth profiling, confirming the non-oxidative behaviour of the tested solvents. The mass balance of the recovered materials and solvents at the end of the dissolution process was close to 100%

Digital restoration is a rapidly growing methodology within the field of heritage conservation, especially for early cinematic films which have intrinsically unstable dye colourants that suffer from irreversible colour fading. Although numerous techniques to restore film digitally have emerged recently, complex degradation remains a challenging problem. This paper proposes a novel vector quantization (VQ) algorithm for restoring movie frames based on the acquisition of spectroscopic data with a custom-made push-broom VNIR hyperspectral camera (380–780 nm). The VQ algorithm utilizes what we call a multi-codebook that correlates degraded areas with corresponding non-degraded ones selected from reference frames. The spectral-codebook was compared with a professional commercially available film restoration software (DaVinci Resolve 17) tested both on RGB and on hyperspectral providing better results in terms of colour reconstruction.

Chemical analysis of ancient residues of pharmaceutical or cosmetic preparations such as balms or ointments is made problematic by the high complexity of these mixtures, composed of organic and inorganic materials. Consequently, a multi-analytical approach and special caution in the interpretation of the results are necessary. In order to contribute to the improvement of analytical strategies for the characterization of complex residues and to reconstruct ancient medical practices, a replica of a pharmaceutical formulation of the seventeenth century was prepared in the laboratory according to a historically documented recipe. In a round robin exercise, a portion of the preparation was analysed as a blind sample by 11 laboratories using various analytical techniques. These included spectroscopic, chromatographic and mass spectrometric methods. None of the laboratories was able to completely reconstruct the complex formulation, but each of them gave partial positive results. The round robin exercise has demonstrated that the application of a multi-analytical approach can permit a complete and reliable reconstruction of the composition. Finally, on the basis of the results, an analytical protocol for the study of residues of ancient medical and pharmaceutical preparations has been outlined. © 2011 Springer-Verlag.

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.

This article tests the suitability of a new method to monitor the degree of substitution of cellulose acetate films, by employing a compact and inexpensive near-infrared miniaturized spectrometer (908.1-1676.2 nm) that can be easily applied in situ. The present study compares the analytical performance of the proposed method against conventional diagnostic strategies based on benchtop micro-attenuated total reflectance Fourier transform Infrared (μATR -FTIR) measurements in the mid-infrared spectral range. The novel calibration function exploits the shifts in the first overtone of the hydroxyl stretching 2νOH band of probe materials and was created using a set of analytical standards with different degrees of substitution. The robustness of the method was assessed by application on a group of sixteen historical cinematographic films. The accurate condition assessment of these films was performed in situ, in a non-invasive manner. The proposed analytical procedure is quick and easy-to-implement, and therefore it constitutes a rapid method to guide conservation strategies regarding film storage and digitalization in cultural institutions, including museums and cinematheques. Potential applications on three-dimensional objects and industrial processes are possible.

Spatial uptake patterns of microplastics (MP) by marine species are largely unexplored under field conditions. A novel “biodeposit trap” that measure uptake and egestion of MP by suspension-feeders through the analysis of their biodeposits, was designed and used to estimate the spatial variation of these processes by mussels in field conditions. Traps containing wild or farmed mussels or control empty shells were deployed at three sites characterised by different MP concentrations and water flow conditions. A different MP dimensional composition was observed between MP pools present in biodeposit and control traps, with the latter shifted towards higher dimensional range (0.05–5 mm). Conversely, mussels accumulated small MP (0.02–0.05 mm) into their biodeposits without any significant difference between wild and farmed specimens. MP uptake rates were on average 4–5 times higher at the site where MP contamination was expected to be highest and where water flow conditions were considered moderate.

Contamination by microplastics (MP) represents a critical environmental challenge with potential consequences at ecosystem, economic and societal levels. As the marine system is the final sink for MP, there is an urgent need to develop methods for the monitoring of synthetic particles in different marine compartments and sample matrices. Extensive evaluations are hindered by time and costs associated with to conventional MP spectroscopic analyses. The potential of near infrared hyperspectral imaging (NIR-HSI) has been recently evaluated. However, NIR-HSI has been poorly studied so far, limitedly to the detection of large particles (>300 μm), and its capability for direct characterization of MP in real marine matrices has not been considered yet. In the present study, a rapid near infrared hyperspectral imaging (NIR-HSI) method, coupled with a customised normalised difference image (NDI) strategy for data processing, is presented and used to detect MP down to 50 μm in environmental matrices. The proposed method is largely automated, without the need for extensive data processing, and enabled a successful identification of different polymers, both in surface water and mussel soft tissue samples, as well as on real field samples with environmentally occurring MP. NIR-HSI is applied directly on filters, without the need for particles pre-sorting or multiple sample purifications, avoiding time consuming procedures, airborne contaminations, particle degradation and loss. Thanks to the time and cost effectiveness, a large-scale implementation of this method would enable to extensively monitor the MP presence in natural environments for assessing the ecological risk related to MP contamination.

Microplastic (MP) has become ubiquitous in the marine environment. Its threat to marine organisms has been demonstrated under laboratory conditions, yet studies on wild populations still face methodological difficulties. We reviewed the methods used to separate MP from soft animal tissues and highlighted a lack of standardised methodologies, particularly critical for synthetic microfibres. We further compared enzymatic and a potassium hydroxide (KOH)-based alkaline digestion protocols on wild crabs (Carcinus aestuarii) collected from three coastal lagoons in the north Adriatic Sea and on laboratory-prepared synthetic polyester (PES) of different colour and polypropylene (PP). We compared the cost-effectiveness of the two methods, together with the potential for adverse quantitative or qualitative effects on MP that could alter the capability of the polymers to be recognised via microscopic or spectroscopic techniques. Only 5.5% of the 180 examined crabs contained MP in their gastrointestinal tracts, with a notably high quantitative variability between individuals (from 1 to 117 particles per individual). All MP found was exclusively microfibres, mainly PES, with a mean length (±SE) of 0.5 ± 0.03 mm. The two digestion methods provided comparable estimates on wild crabs and did not cause any visible physical or chemical alterations on laboratory-prepared microfibres treated for up to 4 days. KOH solution was faster and cheaper compared to the enzymatic extraction, involving fewer procedural steps and therefore reducing the risk of airborne contamination. With digestion times longer than 4 days, KOH caused morphological alterations of some of the PES microfibres, which did not occur with the enzymatic digestion. This suggests that KOH is effective for the digestion of small marine invertebrates or biological samples for which shorter digestion time is required, while enzymatic extraction should be considered as alternative for larger organisms or sample sizes requiring longer digestion times.

Gels have been recently introduced in conservation to better control the cleaning action. The slow solvent release is of utmost importance to selectively remove varnish layers of a few microns in thickness, applied on paint layers which may have similar chemical properties. To evaluate the interactions of the underlying paint with solvents, diagnostic methods should study the physical and chemical changes that occur during and after the treatment. In this paper, we propose an innovative analytical protocol based on the combination of solid phase microextraction (SPME) and nuclear magnetic resonance (NMR) relaxometry to evaluate solvent entry and retention in the paint layer, as well as the induced microscopic and macroscopic changes to the elasticity of the binder. Moreover, FTIR and optical microscopy are used to evaluate the cleaning efficacy. The proposed analytical protocol can be used to identify solvents or gels which show minimal interaction with the paint. In particular, we have tested the protocol to evaluate the performance of non-toxic and biodegradable green gels on mock-ups and on a painting dated 19th century showing that they perform better than solvents applied with swabs. Five-minute gel treatments were found to be as effective at varnish removal as thirty-second swab treatments following traditional cleaning methods. Cleaning with gels limits the mechanical stress, solvent entry and retention in the paint layer, and reduces the embrittlement due to lower mass transfer. An unusual “sandwich” system was used to avoid the retention of gel residues on the surface with the gels contained in two sheets of Japanese papers – one on top and the other at the bottom.

This paper proposes an analytical protocol for the identification of synthetic dyes in degraded wool fibres using a multi-step micro-extraction protocol coupled with Thin Layer Chromatography (TLC)/Metal-Underlayer Attenuated Total Reflection (MU-ATR) FTIR. TLC/MU-ATR is a new enhanced FTIR method, which enables even very few nanograms of analyte to be detected. The efficacy of the method was tested on synthetic dyes (both acid and base), which were artificially aged at 20 h, 60 h, 140 h and 305 h using UV light (∼365 nm). The method was validated on real samples from a pattern book dated 1893. Coupling chromatographic separation with enhanced spectroscopic detection, the method allows substantial reduction of matrix interference by means of TLC and can identify the dyes even in degraded states.

Raman spectroscopy has grown to a frequently applied technique in the analysis of art and archaeological objects. The growth in applications is further driven by the development of new, small and compact spectrometers that are well suited for in situ analysis. Different spectral databases have been composed, to allow fast identification of the materials at hand. However, the automated identification of the highly similar spectra of contemporary synthetic organic pigments is not straightforward, as spectral libraries that contain several hundreds of spectra are typically recorded on benchtop spectrometers that have different spectral resolutions and sensitivities and often use different excitation laser wavelengths. Therefore, here a simple automated spectral searching algorithm is proposed that is based on the comparison of a series of Raman band positions, to identify the materials. Thus, many of these interferences can be avoided. In this work, the proposed algorithm is tested on spectra that were recorded by using portable Raman instruments on mock-up samples as well as during the in situ analysis of street art. Graphic abstract: [Figure not available: see fulltext.]

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.

In the present study, an innovative and highly efficient near-infrared hyperspectral imaging (NIR-HSI) method is proposed to provide spectral maps able to reveal collagen distribution in large-size bones, also offering semi-quantitative estimations. A recently introduced method for the construction of chemical maps, based on Normalized Difference Images (NDI), is declined in an innovative approach, through the exploitation of the NDI values computed for each pixel of the hyperspectral image to localize collagen and to extract information on its content by a direct comparison with known reference samples. The developed approach addresses an urgent issue of the analytical chemistry applied to bioarcheology researches, which rely on well-preserved collagen in bones to obtain key information on chronology, paleoecology and taxonomy. Indeed, the high demand for large-sample datasets and the consequent application of a wide variety of destructive analytical methods led to the considerable destruction of precious bone samples. NIR-HSI pre-screening allows researchers to properly select the sampling points for subsequent specific analyses, to minimize costs and time and to preserve integrity of archaeological bones (which are available in a very limited amount), providing further opportunities to understand our past.

The paper reports on the development of an analytical method based on the use of a new miniaturised short-wave infrared (SWIR) spectrometer for the analysis of cultural heritage samples. The spectrometer is a prototype characterised by small dimension (45.0 mm in diameter x 47.5 mm in height x 60 g weight), easily handled and transferable out of research laboratories. The prototype enables the acquisition of spectra in the SWIR range of 1200–2200 nm, which is a unique feature for miniaturised spectrometers. The exploitation of this spectral range allows the detection of a high number of combination and overtone bands, which guarantees significant diagnostic power to the instrument. The present study lays a significant foundation to the development of analytical strategies based on miniaturised NIR spectrometers working in the SWIR spectral range for the characterization of complex samples such as cultural heritage specimens. Analytical performances of the new spectrometer were assessed on archaeological bones, cinematographic films and bronze patinas. The selected cases of study present challenging conservation issues not properly addressed, and their analyses usually require to be performed on-site, in places not easily accessible by restorers, archaeologists and/or scientists. The data acquired with the prototype, combined with a multivariate data analysis approach, show the possibility to i) differentiate between the materials used as a support for cinematographic film namely cellulose nitrate (CN), cellulose acetates (CA) and polyethylene terephthalate (PET); ii) sort out archaeological bone fragments according to their collagen content as an initial screening test for bones characterization; iii) differentiate between corrosion products on outdoor bronze sculpture, which is important for assessing the state of conservation of the artwork. The prototype enabled rapid information acquisition to guide restoration strategies, which need to be supported in real time by quick and easy analytical procedures.