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Iron gall inks have been among the most used writing materials after carbon black, thus representing an important element of the historical and artistic heritage of our society. Crucially, the preservation of manuscripts and drawings is influenced by the presence of these inks, leading to conservation issues related to paper degradation and text fading. Besides all the advances obtained in paper conservation, the study of iron gall ink’s behaviour and ageing is still an important topic, which requires investigation through an accurate molecular characterisation to produce reliable models. In the present work a micro-destructive method based on liquid chromatography techniques (HPLC-DAD and HPLC-ESI-Q-ToF) has been optimised starting from a model gallic acid-based ink. An in-depth study of the behaviour of the ink in time was performed by natural and artificial ageing tests, monitored by colorimetry, showing the autoxidation of gallic acid to ellagic acid in the prepared mock-ups. The effect of relative humidity on ageing processes was also evaluated, allowing us to determine different intermediates depending on the environmental conditions. Finally, the analytical method developed was then successfully applied for investigating 19th–20th century historical ink samples, where one of the identified ageing markers was detected, besides the expected gallic and ellagic acids.

Textile fibers have represented an important resource for mankind throughout all human history. In fact, ancient cultures employed them not just to produce clothes, but also for expressing their habits and traditions. Based on the chemical composition, textile fibers are classified as natural, artificial, and synthetic. The analysis of textile fibers can be very challenging, so it is crucial to find new analytical tools capable of identifying them and studying their behavior in the environment. The collected information can be transferred in many different fields, such as the industrial sector, forensic science, environmental science, and heritage science. In the present study, the capability of Pyrolysis coupled to Gas Chromatography and Mass Spectrometry (Py-GC/MS), and Evolved Gas Analysis coupled to Mass Spectrometry (EGA-MS) to discriminate textile fibers was tested. The first part of the study was addressed to the analysis of pure samples to build a detailed database by highlighting the main differences in the chromatographic profiles. Then, three textile blends of known composition were investigated, and the results compared with those acquired by Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR). Eventually, the information obtained from the reference materials was exploited for the study of textile samples collected from the stage costumes of the lyrical opera 'I Puritani' directed by Franco Zeffirelli in 1961. The EGA-MS and Py-GC/MS results, integrated with those obtained by optical microscopy, allowed us to deepen the characterization of the historical samples.

The study and characterization of organic dyes in textiles, wastewaters, food, cosmetics and forensic specimens is an increasingly important field of research and a challenge for analytical chemistry. Sensitive and specific methods are required to determine molecular markers at very low concentrations and to detect and identify their relative degradation products. In this field, the present paper deals with the development of an extremely sensitive analytical strategy able to identify synthetic organic dyes even after ageing, such as photo-oxidation resulting in severe fading, by identifying specific stable markers. Rhodamine B (C.I. 45,170), belonging to the class of xanthenes, was chosen as representative of fugitive dyes of high commercial and historical importance, in the frame of a research promoted by the European platform IPERION-CH. The behaviour of Rhodamine B used as a dyestuff for wool yarns, subjected to accelerated photo-ageing, was investigated by chromatographic, spectroscopic and high resolution mass spectrometric techniques. The ultra-sensitive analytical method developed, based on core shell reverse phase analytical column separation, allowed us to characterize Rhodamine B oxidation products investigating their mass fragmentation and rationalizing the resulting ageing pathway. These degradation compounds, characterized in artificially aged reference wool yarns, confirmed to be valuable markers for the identification of Rhodamine B even in a complex historical textile matrix as a red Florentine velvet cope subjected to restoration in the 20th century.

Rationale Today, β-naphthol pigments are among the largest and most widely used classes of synthetic organic pigments. Their application fields range from textiles, food and beverages, printing inks, plastics to paint formulations. Most of the research dealing with their study using mass spectrometry focuses on developing sensitive methods for their quantification or their removal from industrial wastewater. Their qualitative recognition in formulations, whose composition is undisclosed by manufacturers, has not been tackled yet. Methods The collision-induced dissociation fragmentation pathways of 10 red and orange widely used pigments of the late 19th to the early 20th centuries, belonging to the β-naphthol and Naphthol AS classes, were characterized using liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry in negative-ion mode. Results The fragmentation pathways of these pigments were determined, and the pigments are discussed in relation to their chemical structures. The results were used to determine the composition in terms of the secondary components of one of our reference commercial formulations, characterized by a complex mixture of synthesis by-products. Conclusions By coupling the high sensitivity of high-resolution mass spectrometry with an efficient chromatographic separation optimized for the analysis of β-naphthol dyes and pigments, we provided a method for the qualitative recognition of this class of molecules in unknown formulations possibly used in different kinds of industrial and synthetic products.

International audience; The huge number of complex formulations of synthetic dyes and pigments commercialized in the 19th century makes their comprehensive characterization both difficult and fundamental for their successful identifications in artworks. The description of the exact starting composition of a wide collection of reference materials is preliminary to the study of the challenging photo-degradation processes in which most of the early synthetic dyes and pigments are involved. In this paper, four eosin-based lakes, all containing eosin Y, and one also containing eosin B, but differing in the organic and inorganic materials used as fillers, were fully characterized. These formulations were reconstructed on the base of historical recipes from the extensive Wiesel's collection, dated to the 19th century and bought by Dr Kremer (Kremer Pigmente, Germany) in the 1990s. The composition of each formulation was characterized by Fourier transform infrared spectroscopy (FT-IR) and luminescence spectroscopy was used as a probe for their inert-distinction. Reference paint layers were then prepared by casting the lakes in linseed oil, and their ageing and impact on color change was monitored for one year by analyzing two sets of paint model systems by colorimetry. For each system, two sets were prepared and one was stored in the dark while the other exposed to natural light. The material distribution and homogeneity of the samples were tested by Synchrotron Radiation based micro infrared spectroscopy (SR-μ-FT-IR). Finally, an ultra-sensitive method based on Liquid Chromatography coupled with High Resolution Mass Spectrometry (LC-HRMS) allowed us to characterize eosin degradation products detected but never identified before, and to evaluate their kinetics of formation.

The paint media used by contemporary artists include a wide range of formulation of industrially produced paints based on synthetic resins and natural oils. We investigated the paint media used by the British artist Alexis Harding (born in 1973) in the painting “Quartet” (2003). The artwork exemplifies the artist's technique of mixing different paint media to obtain a sliding movement of the paint over the support, raising severe conservation issues and causing long-term instability of the paint. As a basis to develop a conservation strategy for the artwork, we investigated the composition of the paint by in situ non-invasive contactless external reflection infrared spectroscopy (ER-FTIR). The combination with laboratory analytical techniques applied on micro-samples allowed the identification of the pigments and the binders. The multi-analytical approach involved micro infrared spectroscopy (µFTIR), Raman spectroscopy, X-ray fluorescence (XRF), and mass spectrometric techniques coupled to chromatography (GC/MS and HPLC-ESI-Q-ToF) and analytical pyrolysis (Py-GC/MS and EGA-MS). The results of these micro-destructive investigations showed that the causes of the gliding of the paint are due the incompatibility between different materials superimposed by the artist: a fast drying alkyd paint and a mixture of siccative and non-siccative drying oils.

Natural tannins from various plants have been used throughout human history in textile dyeing, often as mordant dyes. The ageing behavior of these dyes is a challenge in conservation science, requiring a thorough knowledge of the textile&ndash, mordant-dye system. In this work, we analyzed reference wool yarns dyed with natural tannins from oak gallnuts, walnut (Juglans regia), and catechu (Acacia catechu), after artificial ageing. To gain insights on the composition of the dyestuffs and on how they aged, an analytical procedure based on extraction with Na2EDTA/DMF (ethylenediaminetetraacetic acid/dimethylformamide) and high-performance liquid chromatography (HPLC) analysis using high-resolution mass spectrometry detection was used. Since conventional reversed-phase (RP) columns usually show poor retention efficiency of highly polar compounds such as tannins, an RP-amide embedded polar group stationary phase was used to achieve optimal retention of the most polar compounds. Tannins from oak gallnuts showed little degradation after ageing, while a significant increase in the content of hydroxybenzoic acids was observed for tannins from walnut and catechu. Finally, the analytical procedure was applied to characterize the tannin dyes in historical tapestries from the 15th to 16th century, and the results were discussed in comparison with the reference yarns.

A mixture of sphingoid esters was isolated (1.4% w/w) from the molecular distillation of crude squid visceral oil. A preliminary investigation on the bioactivity profile and toxic potential of this residue was carried out by in vitro experiments. No cytotoxicity and a moderate lipase inhibition activity were highlighted.

This study deals with the identification of anthraquinoid molecular markers in standard dyes, reference lakes, and paint model systems using a micro-invasive and nondestructive technique such as matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-ToF-MS). Red anthraquinoid lakes, such as madder lake, carmine lake, and Indian lac, have been the most widely used for painting purposes since ancient times. From an analytical point of view, identifying lakes in paint samples is challenging and developing methods that maximize the information achievable minimizing the amount of sample needed is of paramount importance. The employed method was tested on less than 0.5 mg of reference samples and required a minimal sample preparation, entailing a hydrofluoric acid extraction. The method is fast and versatile because of the possibility to re-analyze the same sample (once it has been spotted on the steel plate), testing both positive and negative modes in a few minutes. The MALDI mass spectra collected in the two analysis modes were studied and compared with LDI and simulated mass spectra in order to highlight the peculiar behavior of the anthraquinones in the MALDI process. Both ionization modes were assessed for each species. The effect of the different paint binders on dye identification was also evaluated through the analyses of paint model systems. In the end, the method was successful in detecting madder lake in archeological samples from Greek wall paintings and on an Italian funerary clay vessel, demonstrating its capabilities to identify dyes in small amount of highly degraded samples. Graphical Abstract ᅟ.

A method based on the use of a Poroshell 120 EC-C18 column (3.0. mm. ×. 50. mm, 2.7. μm) with a high resolution electrospray ionization-quadrupole-time of flight (ESI-Q-ToF) tandem mass spectrometer as detection system was optimized for the identification of triacylglycerols (TAGs) in complex archaeological residues.The best performances in chromatographic separation and Q-ToF detection sensitivity were reached by using a mixture of iPrOH/MeOH at a 0.6. mL/min flow rate. Triolein (OOO) was eluted in 12.30. min and the chromatographic resolution against tripalmitin (PPP) was 1.4. Very good limits of detection and quantification limits were also achieved (LOD.