Żółte barwniki organiczne w XIX-wiecznych farbach Jana Matejki – identyfikacja substancji barwiących, nośników oraz wypełniaczy

Natural organic dyes can be found in many objects of cultural heritage. Identification of coloring substances present in historical paints provides relevant information for a wide range of specialists involved in art science. Determination of the composition of paints allows application of appropriate procedures for restoration and conservation of historical works of art. This information enables treatment in accordance with the ideological and esthetic decisions of the authors. The complexity of the chemical composition of art paints, which, apart from organic dyes can also include inorganic pigments, binders and other additives, hinders isolation and identification of its individual components. Nowadays, there are several analytical techniques and methods for extraction and identification of organic dyes, each of them has its limitations, however. For that reason, the development of the universal methodology for the analysis of colorant composition in art paints remains a challenge for chemists. In present work, an analytical protocol for identification of yellow dyes using reversed phase liquid chromatographymass spectrometry with atmospheric pressure electrospray ionization (LC-ESI/ /MS) is presented. The developed method was successfully applied to identification of the main components of Indian Yellow, weld (Reseda luteola L.), buckthorn berries (Rhamnus) and madder lake (madder plant’s root) extracts, in the historical oil paints from tubes of Richard Ainès company, formerly Mulard, owned before him by recognizable French art materials supplier Eduard. The recognition of paints composition was broadened by identification of non organic compounds – carriers of the dye: aluminum hydroxide, tin chloride, chalk, as well as filler like silica and or lead white. Researched samples of painting materials belonged to 19th century famous Polish painter Jan Matejko (1839–1893) and will be very helpful in understanding paintings of him and of his contemporaries

The Mechanism of a Retro-Diels–Alder Fragmentation of Luteolin: Theoretical Studies Supported by Electrospray Ionization Tandem Mass Spectrometry Results

The mechanisms of retro-Diels–Alder fragmentation of luteolin are studied theoretically using the Density Functional Theory method (B3LYP hybrid functional) together with the 6-311++G(d,p) basis set and supported by electrospray ionization tandem mass spectrometry (ESI-MS) results. The reaction paths leading to the formation of 1,3A− and 1,3B− fragment ions observed as the main spectral features in the ESI-MS spectrum are described and discussed, including the structures of the transition states and intermediate products. The heights of the activation energy barriers which have to be overcome along the reaction paths corresponding to 1,3-retrocyclization cleavage of the ionized luteolin are predicted to span the 69–94 kcal/mol range (depending on the initial isomeric structure) for the concerted retrocyclization mechanism and the 60–89 kcal/mol (first barrier) and 24–52 kcal/mol (second barrier) barriers for the stepwise mechanism (also depending on the initial isomeric structure). It is also demonstrated that the final fragmentation products (1,3A− and 1,3B−) are in fact represented by various isomeric systems which are not experimentally distinguishable. In addition, the absence of the spectral feature corresponding to the [M-B]− fragment ion formed by the rupture of the C-C bond connecting luteolin’s B and C rings (which does not occur during the ESI-MS experiment) is explained by much larger energy barriers predicted for such a process

The Mechanism of a Retro-Diels–Alder Fragmentation of Luteolin: Theoretical Studies Supported by Electrospray Ionization Tandem Mass Spectrometry Results

The mechanisms of retro-Diels–Alder fragmentation of luteolin are studied theoretically using the Density Functional Theory method (B3LYP hybrid functional) together with the 6-311++G(d,p) basis set and supported by electrospray ionization tandem mass spectrometry (ESI-MS) results. The reaction paths leading to the formation of 1,3A− and 1,3B− fragment ions observed as the main spectral features in the ESI-MS spectrum are described and discussed, including the structures of the transition states and intermediate products. The heights of the activation energy barriers which have to be overcome along the reaction paths corresponding to 1,3-retrocyclization cleavage of the ionized luteolin are predicted to span the 69–94 kcal/mol range (depending on the initial isomeric structure) for the concerted retrocyclization mechanism and the 60–89 kcal/mol (first barrier) and 24–52 kcal/mol (second barrier) barriers for the stepwise mechanism (also depending on the initial isomeric structure). It is also demonstrated that the final fragmentation products (1,3A− and 1,3B−) are in fact represented by various isomeric systems which are not experimentally distinguishable. In addition, the absence of the spectral feature corresponding to the [M-B]− fragment ion formed by the rupture of the C-C bond connecting luteolin’s B and C rings (which does not occur during the ESI-MS experiment) is explained by much larger energy barriers predicted for such a process

Structure and Stability Characterization of Natural Lake Pigments Made from Plant Extracts and Their Potential Application in Polymer Composites for Packaging Materials

Natural dyes were extracted from various plant sources and converted into lake pigments based on aluminum and tin. Three different plants (weld, Persian berries, and Brazilwood) were chosen as representative sources of natural dyes. High-performance liquid chromatography (HPLC) and triple-quadrupole mass spectrometry (QqQ MS) were used to identify dyestuffs in the raw extracts. The natural dyes and lake pigments were further characterized by optical and scanning electron microscopy (SEM), UV-Vis spectrophotometry, and thermogravimetric analysis (TGA). The stabilization of the studied plant extracts onto aluminum and tin salts led to the formation of natural lake pigments characterized by different color shades. The natural lake pigments showed improved thermal and chemical stability, which was confirmed by their higher degradation temperatures and lower solubility in chemical agents compared to natural dyes extracted from plants. This improvement can be attributed to electrostatic attraction due to the process of chelation. Ethylene-norbornene (EN) composites colored with the lake pigments exhibited uniform color and improved resistance to long-term UV exposure aging. After 300 h of UV exposure, the aging factor of the neat EN copolymer reduced to 0.3, indicating an advanced aging process of polymer compared to colored samples. Prolonged UV exposure deteriorated the mechanical properties of EN by approximately 57%, compared to about 43% with the application of BW/Al lake pigment. Natural lake pigments could be used as effective substitutes for commercial colorants in plastics for packaging applications

Chromatographic and Spectroscopic Identification and Recognition of Natural Dyes, Uncommon Dyestuff Components, and Mordants: Case Study of a 16th Century Carpet with Chintamani Motifs

A multi-tool analytical practice was used for the characterisation of a 16th century carpet manufactured in Cairo. A mild extraction method with hydrofluoric acid has been evaluated in order to isolate intact flavonoids and their glycosides, anthraquinones, tannins, and indigoids from fibre samples. High-performance liquid chromatography coupled to spectroscopic and mass spectrometric detectors was used for the identification of possible marker compounds with special attention paid to natural dyes present in the historical samples. Weld, young fustic, and soluble redwood dye were identified as the dye sources in yellow thread samples. Based on the developed method, it was possible to establish that red fibres were coloured with lac dye, whereas green fibre shades were obtained with indigo and weld. Tannin-containing plant material in combination with indigo and weld were used to obtain the brown hue of the thread. Hyphenation of high-performance liquid chromatography (HPLC) with quadrupole time-of-flight mass spectrometry (QTOF MS) and triple-quadrupole mass spectrometry (QqQ MS) enabled us to recognise four uncommon and thus-far unknown dye components that were also found in the historical samples. These compounds probably represent a unique fingerprint of dyed threads manufactured in a Turkish workshop. Scanning electron microscopy with energy-dispersive X-ray detector (SEM-EDS) and Fourier transform infrared spectroscopy (FT-IR) were used for the identification and characterisation of substrates and mordants present in the historical carpet. Carbon and oxygen were detected in large quantities as a part of the wool protein. The presence of aluminium, iron, and calcium indicated their usage as mordants. Trace amounts of copper, silica, and magnesium might originate from the contaminants. FT-IR analysis showed bands characteristic for woollen fibres and SEM micrographs defined the structure of the wool

Investigation into the Effect of Spinel Pigments on the Photostability and Combustion Properties of Ethylene-Norbornene Copolymer

Multicolor ethylene-norbornene (EN) composites filled with three different spinel pigments (Cobalt Green-PG50, Zinc Iron Yellow-PY 119, Praseodym Yellow-PY159) were prepared by melt mixing and characterized in terms of their stability under destructive environmental conditions. The EN films were subjected to accelerated aging by ultraviolet (UV) photooxidation for 300 h, 600 h, or 900 h. The mechanical performance of the EN composites was investigated in static and dynamic mechanical tests. The morphologies of the EN samples and their color changes during the aging process were evaluated by scanning electron microscopy (SEM) and spectrophotometric measurements. Fourier transform infrared (FTIR) spectroscopy was applied to determine the amount of carbonyl groups resulting from surface oxidation at different aging times. The effects of the spinel pigments on the thermal stability and combustion properties of the multicolor polymer composites were also assessed, and compared with a sample containing the organic Pigment Yellow 139 (PY139). The results show that the color changes (ΔE) in the spinel pigments were minor in comparison to those in the organic pigment (PY139) and the reference film. The Zinc Yellow (PY119) pigment was the most effective stabilizer of EN copolymer. Moreover, the spinel pigments had a positive effect on the flame retardancy of the EN composites. Microcombustion tests (MCC) showed that the incorporation of both the spinels and the organic pigment PY139 into the EN matrix reduced the heat release rate (HRR) and total heat release (THR) parameters

Influence of Thermal Decomposition of Wood and Wood-Based Materials on the State of the Atmospheric Air. Emissions of Toxic Compounds and Greenhouse Gases

This paper presents the energy characteristics of wood and wood-based materials in the form of commercially available pellets, furniture board (MDF) and OSB. Toxicometric indices were determined for gaseous destructs arising from thermal decomposition and combustion of the materials studied. The paper proves that combustion conditions are crucial in terms of toxic destructive emissions. It has been shown that the combustion of wood-based materials under controlled conditions can lead to equally low emissions of toxic wastes as the combustion of traditional wood materials. The paper also presents the index of greenhouse gas emission, the so-called CO2 equivalent, for the examined wood and wood-based materials

The Effect of Posaconazole, Itraconazole and Voriconazole in the Culture Medium on Aspergillus fumigatus Triazole Resistance

Triazoles are the only compounds used as antibiotics in both medicine and agriculture. The presence of triazoles in the environment can contribute to the acquisition of azole resistance among isolates of Aspergillus fumigatus. The objective of this study was to investigate the effect of A. fumigatus exposure to triazoles on susceptibility to these compounds. Seventeen triazole-resistant and 21 triazole-sensitive A. fumigatus isolates were examined. The isolates were transferred 20 times on the Sabouraud medium supplemented with posaconazole, itraconazole or voriconazole, followed by five times on the medium not supplemented. The minimum inhibitory concentrations of antimycotics were examined according to the EUCAST broth microdilution method after the 20th transfer and also the 25th transfer. In addition, the expression levels of genes mdr1, mdr2, mdr3, atrF, cyp51A and cyp51B were determined. Cultivation of A. fumigatus on media supplemented with posaconazole, itraconazole and voriconazole resulted in the acquisition of resistance to the tested triazoles of all examined isolates. After recultivation on Sabouraud without azoles, most of the isolates lost their acquired resistance. The long-term use of triazole compounds in agriculture may result in the occurrence of triazole resistant A. fumigatus isolates in the environment, not only by induction or selection of mutations in the cyp51A gene, but also by contribution to changes in the gene expression

Various physical-chemical properties of AML and its photodegradation products, and their estimated removal with sewage sludge based on QSAR (EPI Suite).

a<p>Octanol-water partition coefficient (criteria: log K_ow <1 highly soluble in water (hydrophilic);>4 not very soluble in water (hydrophobic)).</p>b<p>Soil organic carbon-water partitioning coefficient (criteria: log K_oc <1.5 negligible sorption to sludge, rapid migration to ground water; 1.5–2.4 low sorption to sludge, moderate migration to ground water; 2.5–3.4 moderate sorption to sludge, slow migration to ground water; 3.5–4.4 strong sorption to sludge, negligible to slow migration to ground water).</p><p>Various physical-chemical properties of AML and its photodegradation products, and their estimated removal with sewage sludge based on QSAR (EPI Suite).</p

Phototransformation of Amlodipine: Degradation Kinetics and Identification of Its Photoproducts

<div><p>Nowadays, monitoring focuses on the primary compounds and does not include degradation products formed during various biological and chemical processes. Transformation products may have the same effects to human health and the environment or sometimes they can be more toxic than the parent compound. Unfortunately, knowledge about the formation of degradation products is still limited, however, can be very important for the environmental risk assessment. Firstly, the photodegradation kinetic of amlodipine was investigated in two experimental conditions: during the exposure to solar radiation and during the exposure to the light emitted by the xenon lamp. In all cases degradation of amlodipine followed a pseudo-first-order kinetics. In the next step, identification of transformation products of amlodipine formed during the exposure to xenon lamp irradiation was performed using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). As a result sixteen photoproducts were identified, their structures were elucidated and ultimately the transformation pathway was proposed. Fifteen compounds (out of 16 photoproducts) were newly identified and reported here for the first time; some of those compounds were formed from the first photoproduct, amlodipine pyridine derivative. Several analytes were formed only in acidic or basic conditions. Furthermore, the occurrence of amlodipine and its identified degradation products was investigated in environmental waters. Only one out of 16 compounds was found in wastewater effluent. The possibility of the sorption of examined analytes to sewage sludge particles was discussed based on QSAR.</p></div