Microporous electrospun nonwovens combined with green solvents for the selective peel-off of thin coatings from painting surfaces.

Over the last few decades, significant research efforts have been devoted to developing new cleaning systems aimed at preserving cultural heritage. One of the main objectives is to selectively remove aged or undesirable coatings from painted surfaces while preventing the cleaning solvent from permeating and engaging with the pictorial layers. In this work, we propose the use of electrospun polyamide 6,6 nonwovens in conjunction with a green solvent (dimethyl carbonate). By adjusting the electrospinning parameters, we produced three distinct nonwovens with varying average fiber diameters, ranging from 0.4 µm to 2 µm. These samples were characterized and tested for their efficacy in removing dammar varnish from painted surfaces. In particular, the cleaning process was monitored using macroscale PL (photoluminescence) imaging in real-time, while post-application examination of the mats was performed through scanning electron microscopy. The solvent evaporation rate from the different nonwovens was evaluated using gravimetric analysis and Proton Transfer Reaction- Time-of-Flight. It was observed that the application of the nonwovens with small or intermediate pore sizes for the removal of the terpenic varnish resulted in the swollen resin being absorbed into the mats, showcasing a peel-off effect. Thus, this protocol eliminates the need for further potentially detrimental removal procedures involving cotton swabs. The experimental data suggests that the peel-off effect relates to the microporosity of the mats, which enhances the capillary rise of the swollen varnish. Furthermore, the application of these systems to historical paintings underwent preliminary validation using a real painting from the 20th century.

Parietin, the Vibrant Natural Dye in Xanthoria parietina.

The use of natural dyes in several areas is regulated by current European and non-European legislation, due to various problems with synthetic dyes. The analysis revealed that the lichen studied: Xanthoria parietina has potential natural dye sources and provides bright colors for extraction solvents. Furthermore, dyed wool and toile fabric have good fastness properties in ammonia fermentation and boiling water, both with and without mordants. The sample dyes with Xanthoria parietina were characterized by several analytical techniques: high-performance liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionization with tandem mass spectrometry (HPLC-ESI-Q-ToF). As compounds from Xanthoria parietina form a complex with mordants and tissues, it is impossible to identify the molecules responsible for coloring using chromatographic techniques. However, we have evaluated the dyeing power of their major molecule, parietin. To further confirm the coloring power of the isolated parietin molecule, we performed a dye test with pure parietin. Thus, CIALAB analyses have shown parietin is the molecule responsible for the coloring obtained by Xanthoria parietina. The utilization of parietin derived from lichens facilitates the development of sustainable dyes for textile coloring, presenting an environmentally friendly alternative to synthetic dyes while simultaneously enriching lichen biodiversity.

A Thermal Analytical Study of LEGO® Bricks for Investigating Light-Stability of ABS.

Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer widely used in several everyday life applications; moreover, it is also one of the most employed plastics in contemporary artworks and design objects. In this study, the chemical and thermal properties of an ABS-based polymer and its photo-degradation process were investigated through a multi-analytical approach based on thermal, mass spectrometric and spectroscopic techniques. LEGO® building blocks were selected for studying the ABS properties. First, the composition of unaged LEGO® bricks was determined in terms of polymer composition and thermal stability; then, the bricks were subjected to UV-Vis photo-oxidative-accelerated ageing for evaluation of possible degradation processes. The modifications of the chemical and thermal properties were monitored in time by a multi-technique approach aimed at improving the current knowledge of ABS photodegradation, employing pyrolysis online with gas chromatography and evolved gas analysis, coupled with mass spectrometric detection (Py-GC-MS and EGA-MS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and corroborated by external reflection FT-IR spectroscopy. The multimodal approach provided new evidence on the two-step degradation pathway proposed for ABS, defining molecular markers for polybutadiene oxidation and styrene-acrylonitrile depolymerization. Moreover, the results highlighted the feasibility of correlating accurate compositional and thermal data acquired by bulk techniques with external reflection FT-IR spectroscopy as a non-invasive portable tool to monitor the state of conservation of plastic museum objects in-situ.

The role of early synthetic materials degradation in the downfall of the Ansaldo A.1, an Italian World War I biplane fighter.

From the Pioneer Era of the aviation to World War I the evolution of aircraft technology and chemical synthesis enabled a unique coexistence of traditional craftsmanship, artistic decoration practices, and technological advancements. The study of the materials used in these early years of aviation is still an uncharted territory: a vast portion of remaining planes has been partially or completely repaired and restored, usually by total replacement of the fabric. The Italian biplane Ansaldo A.1 (1918) is a fighter aircraft and is one of the few planes in the world that still preserves its own original materials. In the last years, the fabric sections of the airplane have started to become brittle and loose cohesion, severely compromising the integrity of the aircraft, and resulting in a general alteration of the pictorial layers of the painted sections. A chemical investigation was undertaken to unveil the materials, and to elucidate the causes of the degradation. This study presents one of the first steps into the study of early historical aircrafts, defining the background for the conservation plans to preserve these objects for future generations.

A Model Iron Gall Ink: An In-Depth Study of Ageing Processes Involving Gallic Acid.

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.

Focusing on Volatile Organic Compounds of Natural Resins by Selected-Ion Flow Tube-Mass Spectrometry.

The analysis of archeological artifacts, due to the high value of antique objects, is preferably performed by nondestructive, noninvasive, and in situ techniques. At present, the most common in situ protocols used for the analysis of organic materials are spectroscopic approaches. In this work, we tested selected-ion flow tube-mass spectrometry (SIFT-MS), a transportable mass spectrometry system for the characterization and discrimination of natural resins by the analysis of their volatile organic compounds profiles. We chose diterpenoid, triterpenoid, and aromatic resins as reference materials, focusing on the most identified in archeological artifacts. This work aims to create a SIFT-MS database of mass spectra suitable for characterizing archeological samples. The spectral data obtained by SIFT-MS were interpreted with the aid of chromatograms and mass spectra obtained by head space-gas chromatography/mass spectrometry (HS-GC/MS). Finally, principal components analysis (PCA) was used to further underline the differences among the different materials and to investigate the possibility of discriminating different classes of resins based on their SIFT spectra.

Retrieving the in vivo Scopoletin Fluorescence Excitation Band Allows the Non-invasive Investigation of the Plant-Pathogen Early Events in Tobacco Leaves.

In this study, we developed and applied a new spectroscopic fluorescence method for the in vivo detection of the early events in the interaction between tobacco (Nicotiana tabacum L.) plants and pathogenic bacteria. The leaf disks were infiltrated with a bacterial suspension in sterile physiological solution (SPS), or with SPS alone as control. The virulent Pseudomonas syringae pv. tabaci strain ATCC 11528, its non-pathogenic ΔhrpA mutant, and the avirulent P. syringae pv. tomato strain DC3000 were used. At different post-infiltration time-points, the in vivo fluorescence spectra on leaf disks were acquired by a fiber bundle-spectrofluorimeter. The excitation spectra of the leaf blue emission at 460 nm, which is mainly due to the accumulation of coumarins following a bacterial infiltration, were processed by using a two-bands Gaussian fitting that enabled us to isolate the scopoletin (SCT) contribution. The pH-dependent fluorescence of SCT and scopolin (SCL), as determined by in vitro data and their intracellular localization, as determined by confocal microscopy, suggested the use of the longer wavelength excitation band at 385 nm of 460 nm emission (F385_460) to follow the metabolic evolution of SCT during the plant-bacteria interaction. It was found to be directly correlated (R 2 = 0.84) to the leaf SCT content, but not to that of SCL, determined by HPLC analysis. The technique applied to the time-course monitoring of the bacteria-plant interaction clearly showed that the amount and the timing of SCT accumulation, estimated by F385_460, was correlated with the resistance to the pathogen. As expected, this host defense response was delayed after P. syringae pv. tabaci ATCC 11528 infiltration, in comparison to P. syringae pv. tomato DC3000. Furthermore, no significant increase of F385_460 (SCT) was observed when using the non-pathogenic ΔhrpA mutant of P. syringae pv. tabaci ATCC 11528, which lacks a functional Type Three Secretion System (TTSS). Our study showed the reliability of the developed fluorimetric method for a rapid and non-invasive monitoring of bacteria-induced first events related to the metabolite-based defense response in tobacco leaves. This technique could allow a fast selection of pathogen-resistant cultivars, as well as the on-site early diagnosis of tobacco plant diseases by using suitable fluorescence sensors.

Tethering Carbohydrates to the Vinyliminium Ligand of Antiproliferative Organometallic Diiron Complexes.

Four propargyl O-glycosides derivatized with mannose, glucose, and fructose moieties were synthesized and then incorporated within a diiron structure as part of a vinyliminium ligand. Hence, six glycoconjugated diiron complexes, [2-5]CF3SO3 (see Scheme 1) and the nonglycosylated analogues [6a-b]CF3SO3, were obtained in high yields and unambiguously characterized by elemental analysis, mass spectrometry, and IR and multinuclear NMR spectroscopies. All compounds exhibited a significant stability in DMSO-d 6/D2O solution, with 63-89% of the complexes unaltered after 72 h at 37 °C and also in the cell culture medium. The cytotoxicity of [2-6]CF3SO3, as well as that of previously reported 7 and 8, was assessed on CT26 (mouse colon carcinoma), U87 (human glioblastoma), MCF-7 (human breast adenocarcinoma), and RPE-1 (human normal retina pigmented epithelium) cell lines. In general, the IC50 values correlate with the hydrophobicity of the compounds (measured as octanol-water partition coefficients) and do not show an appreciable level of selectivity against cancer cells with respect to the nontumor ones.

Detection of plastic particles in marine sponges by a combined infrared micro-spectroscopy and pyrolysis-gas chromatography-mass spectrometry approach.

Plastic pollution threatens the marine environment, especially due to the adverse effects caused by micro and nano particles interacting with the marine biota. In order to provide reliable data regarding micro and nanoplastic contamination and the related impacts, efficient analytical solutions are needed. We developed a new analysis workflow that uses marine sponges to monitor plastic pollution by characterizing the plastic particles accumulated in their tissue. Specimens of cf. Haliclona (Haplosclerida) were sampled in the Maldivian archipelago. The aim was to optimize the method and to carry out a pilot study of the contamination of the related reef habitat. Particles were isolated, size fractioned, counted and submitted to morphological and chemical characterization. The constituting polymer was identified by infrared microspectroscopy for particles >25 µm, and by pyrolysis coupled with gas chromatography mass spectrometry for those <25 µm. Method recoveries were between 87 and 83% and limits of quantitation (LOQs) were between 6.6 and 30.2 ng/g. Analyses showed that 70% of the sponges presented plastic contamination, with an average of 1.2 particles/g tissue for the 25-150 µm size range, and a total plastic concentration of up to 4.8 µg/g in the 0.2-25 µm size range, with polyolefin being the most represented polymer in both size ranges. Overall, the study demonstrated the reliability of the proposed analytical workflow and of the use of sponges as biosamplers for plastic particles.

Hetero-Bis-Conjugation of Bioactive Molecules to Half-Sandwich Ruthenium(II) and Iridium(III) Complexes Provides Synergic Effects in Cancer Cell Cytotoxicity.

Four bipyridine-type ligands variably derivatized with two bioactive groups (taken from ethacrynic acid, flurbiprofen, biotin, and benzylpenicillin) were prepared via sequential esterification steps from commercial 2,2'-bipyridine-4,4'-dicarboxylic acid and subsequently coordinated to ruthenium(II) p-cymene and iridium(III) pentamethylcyclopentadienyl scaffolds. The resulting complexes were isolated as nitrate salts in high yields and fully characterized by analytical and spectroscopic methods. NMR and MS studies in aqueous solution and in cell culture medium highlighted a substantial stability of ligand coordination and a slow release of the bioactive fragments in the latter case. The complexes were assessed for their antiproliferative activity on four cancer cell lines, showing cytotoxicity to the low micromolar level (equipotent with cisplatin). Additional biological experiments revealed a multimodal mechanism of action of the investigated compounds, involving DNA metalation and enzyme inhibition. Synergic effects provided by specific combinations of metal and bioactive fragments were identified, pointing toward an optimal ethacrynic acid/flurbiprofen combination for both Ru(II) and Ir(III) complexes.

An integrated analytical study of crayons from the original art materials collection of the MUNCH museum in Oslo.

Among the artists' materials of the nineteenth century, pastel crayons merit scientific interest since their early commercial formulations are mostly unknown and, until now, have been considerably less studied with respect to other contemporary painting materials. In this framework, research herein reports the results of a comprehensive multi-analytical study of 44 pastel crayons of two recognized brands (LeFranc and Dr. F. Schoenfeld) from the Munch museum collection of original materials belonging to Edvard Munch. The integrated use of complementary spectroscopic and hyphenated mass-spectrometry techniques allowed the compositional profiles of the crayons to be traced providing the identification of the inorganic and organic pigments, the fillers/extenders and the binders. All crayons resulted to be oil- based and the binder was identified to be a mixture of a drying oil (safflower or linseed oil), palm oil or Japan wax and beeswax. Among others, pigments such as ultramarine, chrome yellows, Prussian blue, manganese violet, viridian and madder lake have been identified. A significant alignment in formulations of the brands was observed with the only exception of the greens which showed distinctive pigment and filler compositions. The analytical information provided for these commercial artists' materials will be of great interest for academia, museum and other institutions hosting art collections dating from the same period and it will be used by the Munch museum to draw proper conservation strategies of its own artwork collections.

New methodologies for the detection, identification, and quantification of microplastics and their environmental degradation by-products.

Sampling, separation, detection, and characterization of microplastics (MPs) dispersed in natural water bodies and ecosystems is a challenging and critical issue for a better understanding of the hazards for the environment posed by such nearly ubiquitous and still largely unknown form of pollution. There is still the need for exhaustive, reliable, accurate, reasonably fast, and cost-efficient analytical protocols allowing the quantification not only of MPs but also of nanoplastics (NPs) and of the harmful molecular pollutants that may result from degrading plastics. Here a set of newly developed analytical protocols, integrated with specialized techniques such as pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS), for the accurate and selective determination of the polymers most commonly found as MPs polluting marine and freshwater sediments are presented. In addition, the results of an investigation on the low molecular weight volatile organic compounds (VOCs) released upon photo-oxidative degradation of microplastics highlight the important role of photoinduced fragmentation at a molecular level both as a potential source of hazardous chemicals and as accelerators of the overall degradation of floating or stranded plastic debris.

Liquid chromatography and mass spectrometry for the analysis of acylglycerols in art and archeology.

Lipid characterization in art and archeology, together with the study of lipid degradation processes, is an important research area in heritage science. Lipid-based materials have been used as food since ancient times, but also employed as illuminants and as ingredients in cosmetic, ritual, and pharmaceutical preparations. Both animal and plant lipids have also been processed to produce materials used in art and crafts, such as paint binders, varnishes, waterproofing agents, and coatings. Identifying the origin of the lipid materials is challenging when they are found in association with artistic historical objects. This is due to the inherent complex composition of lipids, their widespread occurrence, and the chemical alterations induced by ageing. The most common approach for lipid characterization in heritage objects entails profiling fatty acids by gas chromatography/mass spectrometry after saponification or transesterification. New developments in high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) for the characterization of acylglycerols, together with more efficient sample treatments, have fostered the introduction of liquid chromatography for characterizing the lipid profile in heritage objects. This review reports the latest developments and applications of HPLC-MS for the characterization of lipid materials in the field of heritage science. We describe the various approaches for sample pretreatment and highlight the advantages and limitations of HPLC-MS in the analysis of paint and archeological samples. © 2020 John Wiley & Sons Ltd.

Plastic breeze: Volatile organic compounds (VOCs) emitted by degrading macro- and microplastics analyzed by selected ion flow-tube mass spectrometry.

Pollution from microplastics (MPs) has become one of the most relevant topics in environmental chemistry. The risks related to MPs include their capability to adsorb toxic and harmful molecular species, and to release additives and degradation products into ecosystems. Their role as a primary source of a broad range of harmful volatile organic compounds (VOCs) has also been recently reported. In this work, we applied a non-destructive approach based on selected-ion flow tube mass spectrometry (SIFT-MS) for the characterization of VOCs released from a set of plastic debris collected from a sandy beach in northern Tuscany. The interpretation of the individual SIFT-MS spectra, aided by principal component data analysis, allowed us to relate the aged polymeric materials that make up the plastic debris (polyethylene, polypropylene, and polyethylene terephthalate) to their VOC emission profile, degradation level, and sampling site. The study proves the potential of SIFT-MS application in the field, as a major advance to obtain fast and reliable information on the VOCs emitted from microplastics. The possibility to obtain qualitative and quantitative data on plastic debris in less than 2 min also makes SIFT-MS a useful and innovative tool for future monitoring campaigns involving statistically significant sets of environmental samples.

Electrochemistry Investigation of Drugs Encapsulated in Cyclodextrins.

The biological electron transfer reactions play an important role in the bioactivity of drugs; thus, the knowledge of their electrochemical behavior is crucial. The formation of radicals during oxidation or reduction, the presence of short-living intermediates, the determination of reaction mechanisms involving electron and proton transfers, all contribute to the comprehension of drug activities and the determination of their mode of action and their metabolites. In addition, if a drug is encapsulated in the cyclodextrin cavity, its electrochemical properties can change compared to a free drug molecule. Here we describe the combination of cyclic voltammetry, UV-Vis spectroelectrochemistry, GC-MS, HPLC-DAD, and HPLC-MS/MS as techniques for evaluating the oxidation mechanism of a drug encapsulated in the cavity of a cyclodextrin. The cavity of cyclodextrin plays a significant role in increasing the stability of the encapsulated products; therefore the identification of oxidation intermediates as semiquinone and benzofuranone derivatives of quercetin is possible in these conditions. The differences in oxidation potentials of the bioactive flavonol quercetin and its cyclodextrin complex relating to its antioxidant activity and the oxidation mechanism are herein discussed.

Investigating the fragmentation pathways of ß-naphthol pigments using liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry.

RATIONALE: Today, ß-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 ß-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 ß-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.

Profiling of high molecular weight esters by flow injection analysis-high resolution mass spectrometry for the characterization of raw and archaeological beeswax and resinous substances.

This work presents a method to characterize high molecular esters in beeswax and resinous substances based on the use of microwave-assisted extraction and flow injection analysis-high resolution mass spectrometry that combines the high efficiency of the extraction procedure with the advantages of high resolution mass spectrometry. This approach allows us to identify archaeological beeswax and plant resinous substances by the characterization of the survived intact high molecular weight components. By this way, several raw materials (beeswax, pine resin and pitch, and resin extracted from Euphorbia tirucalli) were studied and used as reference substances. The procedure was then tested on an adhesive dated 44-42 ka BP recovered from Border Cave (KwaZulu-Natal, Africa), allowing us to detect the high molecular weight species even after almost 50,000 years, and then used to chemically investigate unknown archaeological adhesives from Antinoopolis (Egypt), dated to the 4th-5th century AD. The results allowed us to extend our knowledge on the long-term behavior of beeswax and resinous substances.

SIFT-ing archaeological artifacts: Selected ion flow tube-mass spectrometry as a new tool in archaeometry.

A fast non-destructive approach based on the use of portable selected ion flow tube-mass spectrometry (SIFT-MS) was used for the first time to characterize organic materials in archaeological artifacts. The high sensitivity, specificity and selectivity SIFT soft chemical ionization mass spectrometry enabled us to investigate the composition of organic residues collected from ancient Egyptian findings in order to demonstrate the robustness of the techniques with different matrices. In addition, we tested SIFT-MS directly on an archaeological Egyptian amphora to prove its suitability as a completely non-invasive technique. Parallel investigations on all the samples were performed by GC/MS analysis to correlate and confirm the data obtained by SIFT-MS. The possibility of using a portable mass spectrometer on an excavation site or in a museum would be a significant step forward in the non-invasive analysis of organic archaeological materials, enabling archeologists and conservators to obtain real-time information on the molecular composition of organic residues.

Validation Study of Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS) in Heritage Science: Characterization of Natural and Synthetic Paint Varnishes by Portable Mass Spectrometry.

The identification at molecular level of organic materials in heritage objects as paintings requires in most cases the collection of micro-samples followed by micro-destructive analysis. In this study, we explore the possibility to characterize natural and synthetic resins used as paint varnishes by mean of non-invasive analysis of released volatile organic compounds (VOCs) through selected ion flow tube-mass spectrometry (SIFT-MS). SIFT-MS is a portable direct mass spectrometric technique that achieves the analysis of VOCs at trace levels in real time, by controlled ultra-soft chemical ionization using eight different chemical ionization agents. We tested the portable instrumentation on different reference resins used as paint varnishes, both natural (mastic, dammar, and colophony) and synthetic (Paraloid B67, MS2A, Regalrez 1094, and polyvinyl acetate), to evaluate the possibility to acquire qualitative data for the identification of these materials in heritage objects avoiding any sampling. This new analytical approach was validated by comparison with the traditional approach for VOCs analysis based on solid phase micro extraction-gas chromatography/mass spectrometry (SPME-GC/MS) analysis. The results demonstrate the use of SIFT-MS as an in situ non-invasive and non-destructive mass spectrometric technique to identify organic materials, such as paint varnishes.

Analytical methods for determination of anthraquinone dyes in historical textiles: A review.

Historical and archaeological textiles are among the most crucial and vulnerable records of our social and cultural history. Analysis of organic colorants found in these materials is unquestionably one of the most powerful tools to understand historical developments, cultural exchanges, and progress in science and technology. Natural anthraquinones represent the most commonly used natural colorants for textile dyeing until the late 19th century. The identification of anthraquinones in cultural heritage objects is a challenging task due to the small size of historical samples, diversity of potential dye sources, variable extraction procedures and dyeing methods, complex chemical constitution, structurally analogous chromophores, and possible presence of degradation products and contaminants. Developments in dye analysis of historical interest have originated and expanded along with the general advances in analytical science. In the last few decades, a close cooperation between science and cultural heritage disciplines contributed enormously to this field. The topic of historical dyes and their analysis in textiles, artworks, archaeological objects and cultural heritage materials has been reviewed several times in the last fifteen years. However, no review has been published to-date exclusively on the analysis of anthraquinone colorants in historical and archaeological textiles. Overall, liquid chromatography (LC)-based techniques have been the most widely used method for anthraquinone dye analysis. Owing to increasing demand of minimally invasive/non-invasive techniques, recent developments of novel techniques have resulted in the availability of many alternative/complementary methods to LC-based analysis. This review begins with a short overview of sources, chemistry and importance of natural anthraquinone dyes found in historical textiles before turning to a detailed discussion on developments involving established and emerging analytical techniques of anthraquinone dye analysis for textile cultural heritage materials. To illustrate the state-of-the-art, representative examples of analytical techniques highlighting their advantages, limitations and applicability are also presented.