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In 2020, 500th anniversary of Raffaello Sanzio death, his Deposition (1507), -the altarpiece known also as the Pala Baglioni, today located at the Borghese Gallery in Rome-has been subjected to conservative revision and preventive conservation project. This included in-depth diagnostic campaigns through most modern non-invasive techniques, together with the analysis of old cross sections from the same Pala. These latters, prepared between 1966 and 1972, preserved in ICR laboratory of chemistry and testing materials archive, have been used to deepen the knowledge of Raffaello painting techniques. The use of such cross sections was fundamental to verify the original pictorial film and restoration re-paintings before the conservation intervention in the same years.In this paper, the results of analytical insights on Raffaello pictorial palette are presented. The information is obtained by the analysis of the old ICR stratigraphic sections, through the use of Scanning Electron Microscope with Energy Dispersive X-Ray analysis (SEM-EDX) and micro-Raman (632.8 nm), while Surface Enhanced Raman Scattering (SERS) analysis through colloidal paste has been tested for the identification of organic lake-pigments present in low concentration and for the successful recognition of copper resinate, whose SERS spectrum is here reported for the first time, according to our knowledge. This combined diagnostic approach has made it possible to recognize the pigments employed in the different pictorial layers, such species in traces and those from organic materials, responding to open questions arising previous non-invasive analyses and highlighting further aspects of the illustrious master refined painting technique.

Phytosterols (PSs) are bioactive compounds in the sterol family, present in numerous complex food and plant matrices in free and conjugated forms. The interest in these compounds arises for phytotherapeutic purposes, particularly for their action on cholesterol metabolism and impact on cardiovascular diseases. There is a need to develop approaches that can selectively extract target analytes and accurately identify and quantify them with high precision. This work proposed the synthesis of molecularly imprinted polymers (MIPs) for PSs with a sonochemical approach, enabling a rapid polymerization step (5 min). This proposed MIP was able to extract 8 PSs (brassicasterol, stigmastanol, campesterol, campestanol, stigmasterol, β-sitosterol, Δ5-avenasterol, α-spinasterol) from a wide range of plant and food matrices belonging to different classes (Brassicaceae, dried fruits and Leguminosae) and was coupled to ultra-high liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS). MIP based on dispersed solid phase extraction (dSPE-MIP) and targeted analysis has proven to be particularly effective in addressing the challenges associated with the complexity of plant-derived matrices, minimising interferences. This was demonstrated by the excellent control of the matrix effect, which was within ±15 %, ensuring the robustness and reliability of the method. The identification and quantification of 8 different PSs was successfully achieved with satisfactory recovery values ranging from 65 % to 100 %. The proposed strategy offers an affordable alternative to classical methods, providing enhanced sensitivity, selectivity and overall performance.

Currently, one of the most important challenges for the conservation of stone artworks is the removal of metal corrosion products on their surfaces. Traditional cleaning methods, which typically involve the application of aqueous solutions containing chelating agents capable of complexing these metal ions, have shown some weaknesses. These weaknesses become apparent when such methods are applied to statues and other vertical surfaces or when aiming to limit the cleaning process to a specific area with controlled application times. Furthermore, the porosity of the stone surface plays a role concerning the cleaning efficiency. To address these issues, chelating agents can be incorporated into gel-like materials. This study is a proof of concept to evaluate the cleaning efficacy of various gel formulations composed of polyvinyl alcohol (PVA), borax (B), and agarose (AG), loaded with two chelators: ethylenediaminetetraacetic acid (EDTA) and potassium sodium tartrate (PST or Rochelle salt). Three types of carbonate stones (travertine, Lecce stone, and Carrara marble) characterized by different porosities were artificially stained with copper sulphates and treated with the different PVA-B-AG formulations. The effectiveness of the treatment was directly monitored on the stones using a multi-technique approach that included scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and non-invasive portable nuclear magnetic resonance (NMR). Additionally, the rheological properties of the gels were investigated, and the Fourier transform infrared attenuated total reflection spectroscopy (FTIR ATR) was used to analyse the chemical structure of the gel before and after treatment, aiming to understand the changes induced by the cleaning process.

Introduction: The analysis of organic residue in ancient vessels to investigate early-age civilization habits is an important archeological application that needs advanced analytical methods. However, these procedures should meet inherent requisites such as low sampling invasiveness and high sensitivity for trace analysis. This study deals with the development of advanced analytical methods for the detection of opium alkaloids in ceramic vessels and its first application to the study of Daunian pots dating back to the VIII–IV sec BC.Methods: All the stages of the analytical procedure, from sampling to analysis, were carefully optimized. Concerning sampling, the traditional scraping approach was compared with a swabbing strategy which permitted minimizing sample encroachment. Extraction was based on pressurized liquid extraction or ultrasound-assisted liquid extraction, followed by dispersive liquid–liquid microextraction, which allowed concentration enrichment. On the other hand, a UHPLC-MS/MS method was specifically developed and validated to obtain reliable data. Some Daunian pots, belonging to the Ceci-Macrini private archeological collection, were selected for sample withdrawal as their iconography could suggest opium usage.Results: Several of the analyzed samples resulted positive to thebaine and less frequently to morphine and codeine; furthermore, 70% of the analyzed items tested positive for at least one opium alkaloid. Positive findings were common to all the samples collected in the pots, suggesting that scraping and swabbing provided comparable results and validating this unusual sampling strategy. All samples were additionally analyzed by UHPLC-HRMS to further improve the confidence level of the identified compounds. The obtained results shed new light on the hypothesis of opium usage by the ancient Daunian civilization. Furthermore, this study provided suitable analytical tools for further investigations on the same topic, with a good level of confidence in the quality of the results.

In this study, metal disks with different chemical composition (two Ag-based alloys and three Cu-based alloys) were buried in the soil of coastal archaeological sites for a period of 15 years. The aim was to naturally induce the growth of corrosion patinas to obtain a deeper insight into the role of alloying elements in the formation of the patinas and into the degradation mechanisms occurring in the very early stages of burial. To reach the aim, the morphological, compositional and structural features of the patinas grown over 15 years were extensively characterized by optical microscopy, field emission scanning electron microscopy coupled with energy dispersive spectrometry, X-ray diffraction and micro-Raman spectroscopy. Results showed that the Cu amount in Ag-based alloys strongly affected the final appearance, as well as the composition and structure of the patinas. Corrosion mechanisms typical of archaeological finds, such as the selective dissolution of Cu, Pb and Zn and internal oxidation of Sn, occurred in the Cu-based alloys, even if areas enriched in Zn and Pb compounds were also detected and attributed to an early stage of degradation. In addition, some unusual and rare compounds were detected in the patinas developed on the Cu-based disks.

In this paper, two different objects from the ethnographic collection of the museum of the Congregation of the Sacred Hearts of Jesus and Mary (Rome), a Polynesian barkcloth (tapa) and a Polynesian headdress in feathers (pa’e ku’a), were investigated to characterize the materials, to evaluate their state of conservation and address the restoration activities. Imaging methods such as multispectral imaging, 3D ultraviolet induced fluorescence and scanning electron microscopy have been integrated with analytical techniques such as X-ray fluorescence spectroscopy, Fourier transform infrared and surface enhanced Raman spectroscopy. Imaging investigations allowed us to differentiate constitutive materials and study their distribution, such as the yellow dye in the tapa used to trace the geometrical pattern and the psittacofulvins responsible for the feathers’ colors in the headdress. The combination of molecular spectroscopy, supported by observation under a scanning electron microscope, allowed us to propose a characterization of the organic painting materials (Morinda citrifolia, Curcuma longa) used for the tapa, and of the type of feathers (from Vini kuhlii bird) and vegetal fibers (Cocos nucifera L.) used to realize the headdress, as well as enabling the identification of degradation products and microorganisms affecting the artifacts before restoration. Fourier transform infrared spectroscopy detected the organic materials used as adhesives for the tapa and headdress: a polysaccharide, probably starch, for the tapa and a natural rubber from Cerbera manghas L. for the headdress. The results of the multi-analytic diagnostic campaign enabled the choice of proper restoration materials, compatible with the original ones, and helped us develop effective protocols for the artifacts’ conservation, such as laser cleaning of the feathers.

Tholu Bommalu are typical leather puppets of the traditional Indian shadow theatre. Two of these objects are part of a collection in the International Puppets Museum “Antonio Pasqualino” (Palermo, Sicily, Italy), which can count on one hundred-seventy-three of artifacts. These Indian puppets were investigated to obtain information related to the use of dyes for their manufacturing through a multi-technical approach exploiting the combination of highly sensitive spectroscopic techniques. Wet cotton stubbons were used to entrap small particles of dyes on the fibers from the art objects for the consequent analyses. Visible Light Micro-Reflectance spectroscopy was employed for the preliminary identification of the molecular class of dyes directly on the swabs, while Surface Enhanced Raman Scattering allowed the identification of the specific dye. Several synthetic dyes belonging to different typologies of coloring compounds were identified. The study resulted in an interesting overview of dyes used in recent Tholu Bommalata manufacturing through the combination of micro-invasive techniques directly on the sampling substrate.

To date, it is still not possible to obtain exhaustive information about organic materials in cultural heritage without sampling. Nonetheless, when studying unique objects with invaluable artistic or historical significance, preserving their integrity is a priority. In particular, organic dye identification is of significant interest for history and conservation research, but it is still hindered by analytes’ low concentration and poor fastness. In this work, a minimally invasive approach for dye identification is presented. The procedure is designed to accompany noninvasive analyses of inorganic substances for comprehensive studies of complex cultural heritage matrices, in compliance with their soundness. Liquid extraction of madder, turmeric, and indigo dyes was performed directly from paint layers and textiles. The extraction was supported by hydrogels, which themselves can undergo multitechnique analyses in the place of samples. After extraction, Ag colloid pastes were applied on the gels for SERS analyses, allowing for the identification of the three dyes. For the HPLC-MS/MS analyses, re-extraction of the dyes was followed by a clean-up step that was successfully applied on madder and turmeric. The colour change perceptivity after extraction was measured with colorimetry. The results showed ΔE values mostly below the upper limit of rigorous colour change, confirming the gentleness of the procedure.

The introduction of synthetic dyes completely changed the industrial production and use of colorants for art materials. From the synthesis of the first synthetic dye, mauveine, in 1856 until today, artists have enjoyed a wider range of colors and selection of chemical properties than was ever available before. However, the introduction of synthetic dyes introduced a wider variety and increased the complexity of the chemical structures of marketed dyes. This work looks towards the analysis of synthetically dyed objects in heritage collections, applying an extraction protocol based on the use of ammonia, which is considered favorable for natural anthraquinone dyes but has never before been applied to acid synthetic dyes. This work also presents an innovative cleanup step based on the use of an ion pair dispersive liquid–liquid microextraction for the purification and preconcentration of historical synthetic dyes before analysis. This approach was adapted from food science analysis and is applied to synthetic dyes in heritage science for the first time in this paper. The results showed adequate recovery of analytes and allowed for the ammonia-based extraction method to be applied successfully to 15 samples of suspected azo dyes from the Azienda Coloranti Nazionali e Affini (ACNA) synthetic dye collection, identified through untargeted HPLC-HRMS analyses.

The identification of the dyes present on a linen fragment from the tomb of Pharaoh Tutankhamun is the objective of the present study. Fiber optic reflectance spectroscopy (FORS) was applied to the archaeological sample for preliminary identification of the dyes and to better choose the extraction methodology for different areas of the sample. The innovative gel-supported micro-extraction with agar gel and the Nanorestore Gel® High Water Retention (HWR) gel were applied to the archaeological sample after testing of the best concentration for the extraction of the agar gels substrates, performed on laboratory mock-ups by means of UV–Vis transmittance spectroscopy. Immediately after extraction, Ag colloidal pastes were applied on the gel surface and Surface Enhanced Raman Scattering (SERS) analysis was performed directly on them. The combination of information deriving from FORS and SERS spectra resulted in the successful identification of both indigo and madder and, in hypothesis, of their degradation products.

Currently, one of the most important challenges for the conservation of stone artworks is the removal of metal corrosion products on their surfaces. Traditional cleaning methods, which typically involve the application of aqueous solutions containing chelating agents capable of complexing these metal ions, have shown some weaknesses. These weaknesses become apparent when such methods are applied to statues and other vertical surfaces or when aiming to limit the cleaning process to a specific area with controlled application times. Furthermore, the porosity of the stone surface plays a role concerning the cleaning efficiency. To address these issues, chelating agents can be incorporated into gel-like materials. This study is a proof of concept to evaluate the cleaning efficacy of various gel formulations composed of polyvinyl alcohol (PVA), borax (B), and agarose (AG), loaded with two chelators: ethylenediaminetetraacetic acid (EDTA) and potassium sodium tartrate (PST or Rochelle salt). Three types of carbonate stones (travertine, Lecce stone, and Carrara marble) characterized by different porosities were artificially stained with copper sulphates and treated with the different PVA-B-AG formulations. The effectiveness of the treatment was directly monitored on the stones using a multi-technique approach that included scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and non-invasive portable nuclear magnetic resonance (NMR). Additionally, the rheological properties of the gels were investigated, and the Fourier transform infrared attenuated total reflection spectroscopy (FTIR ATR) was used to analyse the chemical structure of the gel before and after treatment, aiming to understand the changes induced by the cleaning process. [ABSTRACT FROM AUTHOR]

The aim of this research is to study and diagnose for the first time the Polaroid emulsion transfer in the contemporary artist Paolo Gioli’s artworks to provide preliminary knowledge about the materials of his artworks and the appropriate protocols which can be applied for future studies. The spectral analysis performed followed a multi-technical approach first on the mock-up samples created following Gioli’s technique and on one original artwork of Gioli, composed by: FORS (Fiber Optics Reflectance), Raman, and FTIR (Fourier-Transform InfraRed) spectroscopies. These techniques were chosen according to their completely non-invasiveness and no requirement for sample collection. The obtained spectra from FTIR were not sufficient to assign the dyes found in the transferred Polaroid emulsion. However, they provided significant information about the cellulose-based materials. The most diagnostic results were obtained from FORS for the determination of the dye developers present in the mock-up sample which was obtained from Polacolor Type 88 and from Paolo Gioli’s original artwork created with Polacolor type 89.

Characterising synthetic dyes on heritage textiles represents a relatively recent research frontier, which aims to obtain new information about the evolution of textile manufacturing and industrial chemistry. Whilst spectral enhancement or amplification methods are often considered a requirement for the Raman analysis of textile dyes, this work highlights the potential of standard Raman spectroscopy for the non-invasive analysis of synthetically dyed fibres. In this research, Raman spectroscopy was used for the chemical characterisation of early 20th century synthetic dyes, in both powder form and on dyed fibres. The dyes were produced by the Italian company Azienda Coloranti Nazionali e Affini (ACNA) and housed in the Sapienza University Museum of Chemistry. The investigation first employed literature research into the ACNA's commercial nomenclature. This information was used to hypothesise likely molecular structures of the dyes, pointing towards the azo dye class. The application of Raman spectroscopy confirmed these hypotheses and the high-quality spectra collected provided structural information about the dye molecules. Spectral features of azo-groups, aromatic moieties, and substituents were observable in spectra. Comparison with a Raman spectrum of wool allowed confident dye signal attribution, and some spectra displayed features linked to changes in the fibre during the dyeing process. Combining literature research and Raman vibrational information proved a powerful non-invasive approach for the characterisation of synthetic dyes, allowing molecular identification of some colorants and structural information for most. Standard Raman spectroscopy may provide a widely applicable, non-invasive method for acquiring information about synthetically dyed historical and artistic textiles in future research. [ABSTRACT FROM AUTHOR]

The cleaning of buildings, statues, and artworks composed of stone materials from metal corrosion is an important topic in the cultural heritage field. In this work the cleaning effectiveness of a PVA-PEO-borax hydrogel in removing metal corrosion products from different porosity stones has been assessed by using a multidisciplinary and non-destructive approach based on relaxation times measurement by single-sided portable Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy—Energy Dispersive Spectroscopy (SEM-EDS), and Raman Spectroscopy. To this end, samples of two lithotypes, Travertine and Carrara marble, have been soiled by triggering acidic corrosion of some copper coins in contact with the stone surface. Then, a PVA-PEO-borax hydrogel was used to clean the stone surface. NMR data were collected in untreated, soiled with corrosion products, and hydrogel-cleaned samples. Raman spectroscopy was performed on PVA-PEO-borax hydrogel before and after cleaning of metal corrosion. Furthermore, the characterization of the dirty gel was obtained by SEM-EDS. The combination of NMR, SEM-EDS and Raman results suggests that the mechanism behind the hydrogel cleaning action is to trap heavy metal corrosion products, such as Cu2+ between adjacent boron ions cross-linked with PVA. Moreover, the PVA-PEO-borax hydrogel cleaning effectiveness depends on the stone porosity, being better in Carrara marble compared to Travertine.

Vesuvius eruption that destroyed Pompeii in AD 79 represents one of the most important events in history. The cataclysm left behind an abundance of archeological evidence representing a fundamental source of the knowledge we have about ancient Roman material culture and technology. A great number of textiles have been preserved, rarely maintaining traces of their original color, since they are mainly in the mineralized and carbonized state. However, one outstanding textile sample displays a brilliant purple color and traces of gold strips. Since the purple was one of the most exclusive dyes in antiquity, its presence in an important commercial site like Pompeii induces us to deepen the knowledge of such artifacts and provide further information on their history. For this reason, the characterization of the purple color was the main scope of this research, and to deepen the knowledge of such artifacts, the SERS (Surface Enhanced Raman Scattering) in solution approach was applied. Then, these data were enriched by HPLC-HRMS analyses, which confirmed SERS-based hypotheses and also allowed to hypothesize the species of the origin mollusk. In this context, a step-by-step integrated approach resulted fundamental to maximize the information content and to provide new data on textile manufacturing and trade in antiquity.