Articles de revues : « Coloranti organici »

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Nascimento, Matheus Vinícios Leal do, Patrick Luan Ferreira dos Santos, João Victor Costa, Juliana Trindade Martins, Roberto Lyra Villas Bôas et Leandro José Grava de Godoy. « Durability and concentration of organic colorant in the visual quality of Discovery TM bermudagrass ». Ornamental Horticulture 26, n^o 4 (décembre 2020) : 621–32. http://dx.doi.org/10.1590/2447-536x.v26i4.2211.

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Abstract The painting of sports turfs with colorants is a common practice, with the main objective to maintain grass appearance for maximum aesthetic quality. Colorants are used to provide green color to grasses during periods of stress and dormancy and are considered an alternative for warm weather grasses during the winter months. Recent increases in the use of colorants is due to water conservation efforts as well as lower operating costs compared to winter overseeding. The objective of this study was to evaluate durability and doses of organic colorant in terms of visual quality of DiscoveryTM bermudagrass. The experiment was installed in the field, subdivided into plots of DiscoveryTM bermudagrass treated with lawn-specific commercial, organic colorant as follows 0 ml L-1 (Control); 33 ml L-1; 50 ml L-1; 66.6 ml L-1 (manufacturer’s recommendation); 83 ml L-1; 100 ml L-1. At 10 day intervals the green color index, reflectance, normalized difference vegetation index (NDVI), and digital images were measured and assessed. The results indicate that, given the durability of the product, doses between 66.6 and 83.3 ml L-1 are recommended.

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Mortensen, Alan. « Carotenoids and other pigments as natural colorants ». Pure and Applied Chemistry 78, n^o 8 (1 janvier 2006) : 1477–91. http://dx.doi.org/10.1351/pac200678081477.

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Food colorants may be classified into synthetic, nature-identical, inorganic, and natural colorants. Natural colorants for food are made from renewable sources. Most often, the colorants are extracted from plant material, but other sources such as insects, algae, cyanobacteria, and fungi are used as well. Natural colorants are usually extracted and concentrated using either water or lower alcohols for water-soluble pigments and organic solvents for lipophilic pigments. Legislation restricts which colorants are allowed, what sources may be used for that particular colorant, what solvents may be used to extract it, and the purity of the pigment. Colorants are formulated to make them more suitable for a variety of foods and drinks (e.g., lipophilic pigments for use in beverages) and to increase their stability. The natural colorants allowed in the EU and the USA are presented. Many of these colorants are also allowed in most parts of the world. A few colorants that are not allowed in the EU and the USA, but are important food colorants in other parts of the world, are also presented.

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Marzec, Anna, Bolesław Szadkowski, Jacek Rogowski, Waldemar Maniukiewicz, Dariusz Moszyński, Przemysław Rybiński et Marian Zaborski. « Carminic Acid Stabilized with Aluminum-Magnesium Hydroxycarbonate as New Colorant Reducing Flammability of Polymer Composites ». Molecules 24, n^o 3 (3 février 2019) : 560. http://dx.doi.org/10.3390/molecules24030560.

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In this study, hybrid pigments based on carminic acid (CA) were synthesized and applied in polymer materials. Modification of aluminum-magnesium hydroxycarbonate (LH) with CA transformed the soluble chromophore into an organic-inorganic hybrid colorant. Secondary ion mass spectroscopy (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and UV-Vis spectroscopy were used to study the structure, composition, and morphology of the insoluble LH/CA colorant. Successful modification of the LH was confirmed by the presence of interactions between the LH matrix and molecules of CA. XPS analysis corroborated the presence of CA complexes with Mg2+ ions in the LH host. The batochromic shift in UV-Vis spectra of the organic-inorganic hybrid colorant was attributed to metal-dye interactions in the organic-inorganic hybrid colorants. Strong metal-dye interactions may also be responsible for the improved solvent resistance and chromostability of the modified LH. In comparison to uncolored ethylene-norbornene copolymer (EN), a modified EN sample containing LH/CA pigment showed lower heat release rate (HRR) and reduced total heat release (THR), providing the material with enhanced flame retardancy.

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Viera, Isabel, Antonio Pérez-Gálvez et María Roca. « Green Natural Colorants ». Molecules 24, n^o 1 (2 janvier 2019) : 154. http://dx.doi.org/10.3390/molecules24010154.

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Although there is no legal and clear definition of the term “natural food colorant”, the market trends, and consequently industrial and commercial interest, have turned to foods with added natural pigments. This progressive substitution of artificial colorants has faced chemical complications with some colors, with a lack of stable green hues being one of them. Several strategies have been applied for green color stabilization in processed foods, from the formation of metallochlorophylls to the microencapsulation of green pigments. However, at present, the utilization of green coloring foodstuffs, which are considered an ingredient in the EU, seems to be the more successful solution for the market. Besides those topics, the present review aims to clarify the current confusion between the different chlorophyll compounds that form part of the authorized green food colorants. In this sense, legislations from different countries are compared. Finally, and in line with current concerns, the knowledge gathered so far in relation to the absorption, distribution, metabolism and excretion of all green natural food colorants is reviewed.

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Kiseleva, Daria, Evgeny Shagalov, Elizaveta Pankrushina, Vladimir Shirokov, Arina Khorkova et Danil Danilov. « Microanalytical Investigation of Prehistoric Colorants from Uralian Rock Art (Ignatievskaya Cave and Idrisovskaya II and Zmiev Kamen’ Pictographs) ». Heritage 6, n^o 1 (21 décembre 2022) : 67–89. http://dx.doi.org/10.3390/heritage6010004.

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Uralian parietal and rock art (cave paintings and pictographs, or “pisanitsy”) represents a unique archaeological and cultural phenomenon, comprising 90 sites stretching for more than 800 km from north to south, which date from the Paleolithic era extending into the present Holocene epoch. The identification of the nature of prehistoric colorants provides an insight into their provenance, manufacture and utilization, as well as contributing to the conservation and restoration of drawings. The studies of mineral, elemental and organic phase composition of the colorant micro-samples from the drawings of Ignatievskaya cave and Idrisovskaya II and Zmiev Kamen’ pictographs (Southern and Middle Urals, Russia) discussed in the present work were carried out using a special set of microspectroscopic methods (SEM-EDS and Raman spectroscopy) offering high spatial resolution. The fatty acid composition of the organic phase was analyzed by GC–MS. The technology of colorant manufacture could have included thorough grinding and mixing of unheated hematite with an organic binder made from animal fat and a clayey extender in order to achieve the desired hue and intensity of the color. It is possible that the colorant was applied in layers (Idrisovskaya II and Zmiev Kamen’ pictographs). The development of authigenic phosphate and sulfate (gypsum) mineralization, which is observed in all studied sites, as well as oxalate encrustation on the Idrisovskaya II pictograph, indicates the conditions and processes of secondary mineral formation.

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Hashimoto, R. Y., E. S. K. Menon et J. Fiorillo. « Analysis of Metallic Pigments Used in 19th Century Japanese Prints ». Microscopy and Microanalysis 5, S2 (août 1999) : 594–95. http://dx.doi.org/10.1017/s1431927600016299.

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Japanese color woodblock prints ("ukiyo-e") from the Edo (1615-1868) and Meiji periods (1868- 1912) are among the most celebrated examples of color printmaking in the world. Full-color prints became technically and commercially viable around 1765. Traditional ukiyo-e colorants were watersoluble, uniform, translucent, organic (vegetal) and inorganic pigments of very small particle size. (Synthetic colorants were also introduced from the West in the 19th C, probably beginning with "Prussian blue" in the 1820s.) A pigment was applied with a brush to a color block, and then rice flour paste was mixed with the pigment to thicken it, facilitate control and rubbing into the paper, improve the uniformity of the colorant, and avoid a dry or granular texture. The dampened paper, sized with cooked bovine skins and alum, was then placed on the block (aligning with registration marks cut into the blocks). The colorants were then pressed into the paper by rubbing a bamboo pad against the back of the paper so that the colors were absorbed on the front surface.

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Kumar, Pankaj, Prashant K. Sarswat et Michael L. Free. « Growth and Capacitive Performance of Metals Engineered Tungsten Oxide Structures and Application in Colorant Sensors ». MRS Advances 3, n^o 13 (2018) : 691–96. http://dx.doi.org/10.1557/adv.2018.279.

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ABSTRACTTungsten oxide based micro and nanostructures as well as their 2-D integrated counterparts with appropriate surface modifications such as sensitization, coating of other semiconductors or growth of functional groups have been examined to enhance supercapacitance and sensing capabilities. With the goal of investigation of these changes, the electrochemical capacitance behavior of newly prepared nano and micro-structured tungsten oxide coated substrates were examined. The utilization of WO3 based sensors to differentiate edible colorant and toxic pigments, was also explored. The systematic electrochemical analysis and comparative study of selected colorants was done in order to establish a roadmap to detect model organic compounds for better preventive action.

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Marzec, Anna, Bolesław Szadkowski, Jacek Rogowski, Waldemar Maniukiewicz, Przemysław Rybiński et Mirosława Prochoń. « New Organic/Inorganic Pigments Based on Azo Dye and Aluminum-Magnesium Hydroxycarbonates with Various Mg/Al Ratios ». Materials 12, n^o 8 (25 avril 2019) : 1349. http://dx.doi.org/10.3390/ma12081349.

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This study set out to investigate the impact of aluminum-magnesium hydroxycarbonates (LHs) with various Mg/Al ratios on the formation of hybrid pigments. The colorants were also evaluated for their flame-retardant properties. In the first part of the study, the hybrid pigments were submitted to comprehensive characterization using time-of-flight secondary ion mass spectrometry (TOF-SIMS), 27Al solid-state nuclear magnetic resonance (NMR) spectroscopy, powder X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), and N2 adsorption as well as scanning and transmission electron microscopy (SEM/STEM). The relationship between the Mg/Al ratios of the LH carriers and the formation of lake pigments was explored. The TOF-SIMS spectrum of LH modified with azo chromophore (AC) showed an intense peak for the C19H15O5N2Mg+ ion, confirming metal-dye interactions. Incorporation of the organic colorant into the LH host enhanced its resistance to dissolution in organic solvent (butyl acetate), as well as improving its color stability under elevated temperatures. The second part of the study evaluated the flammability of ethylene-norbornene (EN) composites, in which the pigments had been applied as colorants. Cone calorimetry revealed that addition of the organic-inorganic pigments resulted in a substantial improvement of the flame retardancy, reflected by the decreased values of the heat release rate (HRRMAX) and total heat release parameter (THR) of the EN composites in comparison to a neat sample (unfilled EN).

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Hiawi, Furat A., et Inaam H. Ali. « Study the Interaction Adsorptive Behavior of Sunset Yellow Dye and Loratadine Drug : Kinetics and Thermodynamics Study ». Ibn AL-Haitham Journal For Pure and Applied Sciences 36, n^o 1 (20 janvier 2023) : 186–96. http://dx.doi.org/10.30526/36.1.2974.

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The performance of drug treatment and assessments of different drugs' side effects both can be affected by the interaction between food additives and drugs. Organic compounds such as food colorants dyes are utilized as additives in a wide range of foods. In this study, the adsorption interaction behavior between the colorant food dye sunset yellow (SY) and the drug loratadine was examined. The adsorption procedure is conducted at different drug dosages, various SY dye concentrations, and different temperature (288-318K). The equilibrium data were explained by using Freundlich and Langmuir adsorption isotherms, but Langmuir offering the best fit model. Kinetics adsorptive behavior of sunset yellow on loratadine matched pseudo-second order kinetics. Thermodynamics study show that the process is exothermic, spontaneous and the disorder at the solid-solution interface was proven from the negative entropy (-140.556 J/ K.mol) of adsorption process.

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Palanisamy, Satish Kumar, Arun Kumar Udayakumar, Azher M. Abed, Parthasarathy Panchatcharam, Suvitha Athisaya Rajah, Bradha Madhavan et Ananth Steephen. « Computational, Investigational Explorations on Structural, Electro-Optic Behavior of Pelargonidin Organic Colorant for TiO2 Based DSSCs ». Symmetry 15, n^o 1 (22 décembre 2022) : 22. http://dx.doi.org/10.3390/sym15010022.

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In an expedition for green-energy generation and to lower the cost per watt of solar energy, environmentally friendly biotic colorants were separated from Tectona grandis seeds. The prime colorant in the extract is pelargonidin which sensitizes titanium dioxide (TiO2)-based photo anodes. The pelargonidin-sensitized TiO2 nanomaterials endured structural, photosensitive, spectral and current-voltage interpretations. Frontier molecular orbital analysis, physicochemical and electronic parameter computation, UV–visible and DOS spectral analysis, van der Waals prediction and molecular electrostatic potential map were performed theoretically with Gaussian tools, and IR symmetry response was computed using the crystal maker software package. The pelargonidin-sensitized TiO2-created dye-sensitized solar cells which exhibited capable solar light energy to photon conversion proficiency. For comparative purposes, the commercial P25 Degussa TiO2-based DSSC was also fabricated and its proficiency was analyzed. The commercial TiO2 exhibited 57 % higher proficiency in comparison to the sol-gel-derived TiO2-based DSSC.

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Lombardelli, Claudio, Ilaria Benucci, Caterina Mazzocchi et Marco Esti. « A Novel Process for the Recovery of Betalains from Unsold Red Beets by Low-Temperature Enzyme-Assisted Extraction ». Foods 10, n^o 2 (24 janvier 2021) : 236. http://dx.doi.org/10.3390/foods10020236.

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Food waste management plays a central role in the circular economy. To our knowledge, only a few studies have investigated the use of unsold fruit and vegetables from supermarkets as a substitute source for the extraction of natural colorants. Thus, the aim of this paper was to suggest a green, tailored protocol that avoids the use of organic solvents for the recovery of betalains from unsold red beets for use as a food colorant. The recovery of such pigments was carried out by a tailored enzymatic mix, blended considering the polysaccharide composition of the beetroot cell wall; thus, it consisted of: cellulase (37%), xylanase (35%), and pectinase (28%). The enzyme-assisted extraction protocol was optimized, and the most suitable conditions (in terms of pigment yield and color attributes) for the recovery of betalains from unsold beets appeared to be: 25 U/g total dose of enzymatic mix, temperature 25 °C, and processing time 240 min.

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Akkapinyo, Chutimon, Kittitat Subannajui, Yingyot Poo-arporn et Rungtiva P. Poo-arporn. « Disposable Electrochemical Sensor for Food Colorants Detection by Reduced Graphene Oxide and Methionine Film Modified Screen Printed Carbon Electrode ». Molecules 26, n^o 8 (16 avril 2021) : 2312. http://dx.doi.org/10.3390/molecules26082312.

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A facile synthesis of reduced graphene oxide (rGO) and methionine film modified screen printed carbon electrode (rGO-methionine/SPCE) was proposed as a disposable sensor for determination of food colorants including amaranth, tartrazine, sunset yellow, and carminic acid. The fabrication process can be achieved in only 2 steps including drop-casting of rGO and electropolymerization of poly(L-methionine) film on SPCE. Surface morphology of modified electrode was studied by scanning electron microscopy (SEM). This work showed a successfully developed novel disposable sensor for detection of all 4 dyes as food colorants. The electrochemical behavior of all 4 food colorants were investigated on modified electrodes. The rGO-methionine/SPCE significantly enhanced catalytic activity of all 4 dyes. The pH value and accumulation time were optimized to obtain optimal condition of each colorant. Differential pulse voltammetry (DPV) was used for determination, and two linear detection ranges were observed for each dye. Linear detection ranges were found from 1 to 10 and 10 to 100 µM for amaranth, 1 to 10 and 10 to 85 µM for tartrazine, 1 to 10 and 10 to 50 µM for sunset yellow, and 1 to 20 and 20 to 60 µM for carminic acid. The limit of detection (LOD) was calculated at 57, 41, 48, and 36 nM for amaranth, tartrazine, sunset yellow, and carminic acid, respectively. In addition, the modified sensor also demonstrated high tolerance to interference substances, good repeatability, and high performance for real sample analysis.

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Molino, Ralph John Emerson J., Klidel Fae B. Rellin, Ricky B. Nellas et Hiyas A. Junio. « Sustainable Hues : Exploring the Molecular Palette of Biowaste Dyes through LC-MS Metabolomics ». Molecules 26, n^o 21 (2 novembre 2021) : 6645. http://dx.doi.org/10.3390/molecules26216645.

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Underutilized biowaste materials are investigated for their potential as sustainable textile colorants through an approach based on mass spectrometry, bioinformatics, and chemometrics. In this study, colorful decoctions were prepared from the outer bark of Eucalyptus deglupta and fruit peels of Syzygium samarangense, Syzygium malaccense, Diospyros discolor, and Dillenia philippinensis. Textile dyeing was performed along with liquid chromatography–mass spectrometry (LC–MS)-based untargeted metabolomics to determine the small molecules responsible for the observed colors. Global Natural Products Social Molecular Networking (GNPS) guided the annotation of black-producing proanthocyanidins in D. philippinensis and E. deglupta through complexation with FeSO4 mordant. Flavonoids from the yellow-colored D. philippinensis extracts were found to be similar to those in Terminalia catappa, a known traditional dye source. A higher intensity of epicatechin in E. deglupta produced a red-brown color in the presence of Cu2+. Furthermore, Syzygium fruit peels have poor wash-fastness in cotton fibers, but bioactive chalcone unique to S. samarangense samples may be a potential nutritional food colorant. Unsupervised PCA and supervised OPLS-DA chemometrics distinguished chemical features that affect dyeing properties beyond the observed color. These findings, along with growing data on natural dyes, could guide future research on sustainable colorants.

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Rizkiyah, Dwila Nur, Nicky Rahmana Putra, Mohd Azizi Che Yunus, Ibham Veza, Irianto Irianto, Ahmad Hazim Abdul Aziz, Sri Rahayuningsih, Erny Yuniarti et Ikhwani Ikhwani. « Insight into Green Extraction for Roselle as a Source of Natural Red Pigments : A Review ». Molecules 28, n^o 3 (31 janvier 2023) : 1336. http://dx.doi.org/10.3390/molecules28031336.

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Roselle (Hibiscus sabdariffa L.) is a source of anthocyanins as red pigments that is extensively farmed in tropical and subtropical regions, including Indonesia, Malaysia, China, Thailand, Egypt, Mexico, and West India. The roselle plant contains a variety of nutrients, including anthocyanins, organic acids, pectin, etc. Due to the toxicity and combustibility of the solvents, traditional extraction methods for these compounds are restricted. Obtaining pure extracts is typically a lengthy procedure requiring many processes. Supercritical carbon dioxide (ScCO2) extraction as a green technology is rapidly improving and extending its application domains. The advantages of this method are zero waste production, quicker extraction times, and reduced solvent consumption. The ScCO2 extraction of natural pigments has great promise in food, pharmaceuticals, cosmetics, and textiles, among other uses. The ScCO2 technique for natural pigments may also be advantageous in a variety of other contexts. Due to their minimal environmental risk, the high-quality red pigments of roselle rich in anthocyanins extracted using ScCO2 extraction have a high sustainability potential. Therefore, the objective of this review is to increase knowledge related to the natural colorant of roselle as a substitute for chemically manufactured colorants using ScCO2 as a green method. This article covers ScCO2 extraction, particularly as it relates to the optimization of pigments that promote health. This article focuses on the high extraction efficiency of ScCO2 extraction. Natural colorants extracted via ScCO2 are regarded as safe compounds, especially for human consumption, such as novel functional food additives and textile and pharmaceutical colors.

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Shkolnikova, Marina, Olga Chugunova et Svetlana Ivanova. « Secondary raw materials of agricultural processing companies as a source of anthocyanin colorants ». E3S Web of Conferences 176 (2020) : 03019. http://dx.doi.org/10.1051/e3sconf/202017603019.

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Many recent researches in vitro and in vivo proved the large therapeutic potency of non-toxic anthocyans in anti-inflammatory, anti-infective, anti-oxidative actions. Anthocyanin is a natural phenolic colorant approved in many countries. A reason why the world market of natural food colorants is reduced is because fruit and berry raw materials are expensive. Yet the fruit and berry raw materials are extracted with significant losses and by-products. This constitutes around 23-45% of the whole amount of berries processes in the Russian Federation. Thus, a priority direction of the food industry is a development of technologies allowing to use precious berry pomace with high bioactive compounds, i.e. anthocyans, organic acids, pectin. The aim of the research is to extract food colorant from the pomace of Vaccínium myrtíllus and Vaccínium vítis-idaéa to identify individual anthocyanin pigments. The food safety and composition of the pomace of Vaccinium myrtillus and Vaccinium vitis-idaea as raw material for food colorant extraction were found. Individual anthocyanin pigments of anthocyanin extracts were identified through the method of high-performance liquid chromatography. Cyanidin-3-galactoside was found in the extracts of berries (85,6 %) and pomaces (81,2%) of Vaccinium vitis-idaea. Fifteen compounds were identified in the extracts of Vaccinium myrtillus. The major ones were delphinidin-3-glucoside (13,4 %), delphinidin-3-galactoside (12,4 %), and cyanidin-3-glucoside for the fresh berries. As for the pigments of its pomaces, they were delphinidin-3-glucoside (15,3 %), delphinidin-3-galactoside (14,7 %), and delphinidin-3-arabinoside (10,5 %). Hence, there are more anthocyanin pigments in the extracts of pomaces, than in those of the fresh berries with identical compounds – 24,7 % more for Vaccinium myrtillus and 11,1 % more for Vaccinium myrtillus. The possibility to extract anthocyanin pigments from by-products of the local fruit and berry raw materials – i.e. of Vaccinium myrtillus and Vaccinium vitis-idae ones – and identify them is discussed.

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Sugaya, Naeko, Mitsuko Takahashi, Katsumi Sakurai, Nobuko Tanaka, Ichiro Okubo et Tsuyoshi Kawakami. « Mass Spectrometric Analysis of Synthetic Organic Pigments ». Journal of AOAC INTERNATIONAL 101, n^o 5 (1 septembre 2018) : 1328–40. http://dx.doi.org/10.5740/jaoacint.18-0049.

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Abstract Though synthetic organic colorants are used in various applications nowadays, there is the concern that impurities by-produced during the manufacturing and degradation products in some of these colorants are persistent organic pollutants and carcinogens. Thus, it is important to identify the synthetic organic colorants in various products, such as commercial paints, ink, cosmetics, food, textile, and plastics. Dyes, which are soluble in water and other solvents, could be analyzed by chromatographic methods. In contrast, it is difficult to analyze synthetic organic pigments by these methods because of their insolubility. This review is an overview of mass spectrometric analysis of synthetic organic pigments by various ionization methods. We highlight a recent study of textile samples by atmospheric pressure solid analysis probe MS. Furthermore, the mass spectral features of synthetic organic pigments and their separation from other components such as paint media and plasticizers are discussed.

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Ferreira, Ana M., Isa Sucena, Vanessa Otero, Eva Mariasole Angelin, Maria João Melo et João A. P. Coutinho. « Pretreatment of Plastic Waste : Removal of Colorants from HDPE Using Biosolvents ». Molecules 27, n^o 1 (24 décembre 2021) : 98. http://dx.doi.org/10.3390/molecules27010098.

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Plastics recycling remains a challenge due to the relatively low quality of the recycled material, since most of the developed recycling processes cannot deal with the additives present in the plastic matrix, so the recycled products end up in lower-grade applications. The application of volatile organic solvents for additives removal is the preferred choice. In this study, pretreatment of plastic packaging waste to remove additives using biosolvents was investigated. The plastic waste used was high-density polyethylene (HDPE) with blue and orange colorants (pigment and/or dye). The first step was to identify the type of colorants present in the HDPE, and we found that both plastics presented only one colorant that was actually a pigment. Then, limonene, a renewable solvent, was used to solubilize HDPE. After HDPE dissolution, a wide range of alcohols (mono-, di-, and tri-alcohols) was evaluated as antisolvents in order to selectively precipitate the polymer and maximize its purity. The use of limonene as solvent for plastic dissolution, in combination with poly-alcohols with an intermediate alkyl chain length and a large number of hydroxyl (OH) groups, was found to work best as an antisolvent (1,2,3-propanetriol and 1,2,4-butanetriol), leading to a removal of up to 94% and 100% of the blue and orange pigments, respectively. Finally, three cycles of extraction were carried out, proving the capability of the solvent and antisolvent to be recovered and reused, ensuring the economic viability and sustainability of the process. This pretreatment provides a secondary source of raw materials and revenue for the recycling process, which may lead to an increase in the quality of recycled polymers, contributing to the development of an economical and sustainable recycling process.

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Castro, Tiago Alves, Bruna Santos Leite, Larissa Santos Assunção, Tayane de Jesus Freitas, Nelson Barros Colauto, Giani Andrea Linde, Deborah Murowaniecki Otero, Bruna Aparecida Souza Machado et Camila Duarte Ferreira Ribeiro. « Red Tomato Products as an Alternative to Reduce Synthetic Dyes in the Food Industry : A Review ». Molecules 26, n^o 23 (25 novembre 2021) : 7125. http://dx.doi.org/10.3390/molecules26237125.

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Most dyes used in the food industry are synthetic and can be a health hazard. Red tomato may serve as a natural alternative dye to replace synthetic colorants. This study aimed to review the literature on the addition of red tomato products (powder tomato, paste, freeze-dried, tomato peel powder, tomato pomace) to reduce the usage of synthetic dyes in the food industry. Red tomato products have been used as coloring in pasta, bologna, sausages, cookies, crackers, macaroons, hamburgers, breads, muffins, cheeses, and nuggets. The trans-cis isomerization of lycopene by oxidative processes directly affects the color of the pigment. The lycopene contained in tomato has antioxidant activity and could reduce or eliminate other oxidants and/or synthetic preservatives in food. Moreover, tomatoes in foods have high sensory scores, nutritional appeal, and marketing potential. However, its use as a food colorant has been not extensively explored. Therefore, further studies are still required, especially on the stability of carotenoids in tomatoes used in processed foods.

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Cui, Hongyan, Wenjing Xie, Zhongjie Hua, Lihua Cao, Ziyi Xiong, Ying Tang et Zhiqin Yuan. « Recent Advancements in Natural Plant Colorants Used for Hair Dye Applications : A Review ». Molecules 27, n^o 22 (20 novembre 2022) : 8062. http://dx.doi.org/10.3390/molecules27228062.

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There is an on-going demand in recent years for safer and “greener” hair coloring agents with the global consumer awareness of the adverse effects of synthetic hair dyes. The belief in sustainability and health benefits has focused the attention of the scientific community towards natural colorants that serve to replace their synthetic toxic counterparts. This review article encompasses the historical applications of a vast array of natural plant hair dyes and summarizes the possible coloration mechanisms (direct dyeing and mordant dyeing). Current information on phytochemicals (quinones, tannins, flavonoids, indigo, curcuminoids and carotenoids) used for hair dyeing are summarized, including their botanical sources, color chemistry and biological/toxicological activities. A particular focus is given on research into new natural hair dye sources along with eco-friendly, robust and cost-effective technologies for their processing and applications, such as the synthetic biology approach for colorant production, encapsulation techniques for stabilization and the development of inorganic nanocarriers. In addition, innovative in vitro approaches for the toxicological assessments of natural hair dye cosmetics are highlighted.

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MAEZAWA, Daisuke. « The Use of Organic Colorants in Cosmetics ». Journal of the Japan Society of Colour Material 85, n^o 1 (2012) : 19–26. http://dx.doi.org/10.4011/shikizai.85.19.

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Wu, Qiang, Xueying Fu, Zhuo Chen, Huafeng Wang, Jian Wang, Zhixin Zhu et Guopeng Zhu. « Composition, Color Stability and Antioxidant Properties of Betalain-Based Extracts from Bracts of Bougainvillea ». Molecules 27, n^o 16 (11 août 2022) : 5120. http://dx.doi.org/10.3390/molecules27165120.

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Betalains in bracts of Bougainvillea are of great application potential as natural food colorants and antioxidants. This study explored the color, spectra, composition, storage stability, and antioxidant properties of betalain-based Bougainvillea bracts extracts (BBEs) to verify their application value. The results showed that Bougainvillea bract color variance is due to varied contents and proportions of betacyanins (Bc) and betaxanthins (Bx). Bc or Bx alone determined hues of purple or yellow, respectively; the co-existence of Bc and Bx would produce varied hues of red. BBEs showed bright color and good antioxidant properties under a wide pH range. The pH range of 5–6 was optimal for the highest color stability, and pHs 3–8 were optimal for stronger antioxidants. Bc mainly underwent color fading during storage, while Bx easily produced dark precipitates or melanism under strong acidic (pH < 4) or alkaline conditions (pH > 8). However, Bougainvillea Bx showed 3–4 times higher antioxidant ability than Bc. Different considerations for Bc and Bx are needed for varied application purposes. The purple bracts containing only Bc would be more suitable as colorant sources, while additional Bx can bring enhancement of antioxidant ability and richness of Bougainvillea extract color.

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Chen, Jun-hua, Guang-ming Zhou, Hong-ying Qin, Yi Gao et Gui-long Peng. « Organic solvent-free matrix solid phase dispersion (MSPD) for determination of synthetic colorants in chilli powder by high-performance liquid chromatography (HPLC-UV) ». Analytical Methods 7, n^o 16 (2015) : 6537–44. http://dx.doi.org/10.1039/c5ay01105a.

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A green and simple organic solvent-free matrix solid phase dispersion (MSPD) was developed and applied to the extraction of four synthetic colorants (amaranth, sunset yellow, allura red and erythrosine) in chilli samples.

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Anliker, Rudolf, et Eric A. Clarke. « International Regulation of Chemicals - Implications for Organic Colorants ». Journal of the Society of Dyers and Colourists 98, n^o 2 (22 octobre 2008) : 42–55. http://dx.doi.org/10.1111/j.1478-4408.1982.tb03618.x.

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Nakazumi, Hiroyuki. « Organic colorants for laser disc optical data storage ». Journal of the Society of Dyers and Colourists 104, n^o 3 (22 octobre 2008) : 121–25. http://dx.doi.org/10.1111/j.1478-4408.1988.tb01153.x.

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Clarke, E. A., et D. Steinle. « Health and environmental safety aspects of organic colorants ». Review of Progress in Coloration and Related Topics 25, n^o 1 (23 octobre 2008) : 1–5. http://dx.doi.org/10.1111/j.1478-4408.1995.tb00098.x.

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Peters, A. T. « Colorants and auxiliaries : organic chemistry and application properties ». Dyes and Pigments 19, n^o 2 (janvier 1992) : 157–58. http://dx.doi.org/10.1016/0143-7208(92)87020-2.

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Vega, Erika N., Adriana K. Molina, Carla Pereira, Maria Inês Dias, Sandrina A. Heleno, Paula Rodrigues, Isabel P. Fernandes et al. « Anthocyanins from Rubus fruticosus L. and Morus nigra L. Applied as Food Colorants : A Natural Alternative ». Plants 10, n^o 6 (10 juin 2021) : 1181. http://dx.doi.org/10.3390/plants10061181.

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Given the importance of colour in the general acceptance or rejection of a product, the use of colorants is a widespread practice, particularly in the food industry. At the same time, with the increasing consumers’ awareness of the health effects that some artificial colorants can exert, there is a growing tendency to prioritize foodstuffs containing natural additives. In this work, Morus nigra L. and Rubus fruticosus L. fruit juices were characterized in terms of anthocyanins, organic acids, free sugars, and tocopherols, as also regarding their bioactive properties. Given their richness in anthocyanins, this study also aimed to prepare different solid colouring formulations by the spray-drying technique, using as stabilizers maltodextrin and arabic gum. Six free sugars and two organic acids were detected in the fruit juices, as well as the four tocopherol isoforms. Two cyanidin derivatives were found in M. nigra (cyanidin-3-O-glucoside and cyanidin-O-rhamnoside) and other four in R. fruticosus (cyanidin-O-hexoside, cyanidin-3-O-glucoside, cyanidin-O-pentoside, and cyanidin-3-O-dioxaloilglucoside). The developed colouring formulations revealed a good stability over time, in terms of anthocyanin concentration and colour parameters, and revealed to be safe for consumption, either concerning their low microbial load and lack of cytotoxicity. Thus, they represent a promising natural alternative to the massively used artificial colorants.

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Prado, Juliana M., Priscilla C. Veggi, Grazielle Náthia-Neves et M. Angela A. Meireles. « Extraction Methods for Obtaining Natural Blue Colorants ». Current Analytical Chemistry 16, n^o 5 (8 juillet 2020) : 504–32. http://dx.doi.org/10.2174/1573411014666181115125740.

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Background: Blue is a color not often present in food. Even so, it is especially attractive to children. Today, most blue coloring agents used by the food industry are synthetic. With increasing health issues concern by the scientific community and the general population, there is a trend to look for natural alternatives to most synthetic products. There only exist few natural blue colorants, which are presented in a literature survey, along with the methods currently used for their recovery from natural sources. The best extraction methods and process parameters for the extraction of blue anthocyanins, iridoids and phycocyanin are discussed. Methods: A literature survey was conducted to detect the main sources of blue colorants found in nature. The focus was on the extraction methods used to recover such molecules, with the objective of finding efficient and environmentally safe techniques for application at industrial level, and, thus, allowing the production of natural blue colorants at scale high enough for food industry consumption. Results: The main natural blue colorants found in literature are anthocyanins, phycocyanin, and genipin. While anthocyanins can be recovered from a variety of plants, the source of phycocyanin are algae, and genipin can be obtained specifically from Gardenia jasminoides Ellis and Genipa americana L. Several extraction techniques have been applied to recover blue colorants from such sources, from classical methods using organic solvents, to more sophisticated technologies as ultrasoundassisted extraction, supercritical fluid extraction, pressurized liquid extraction, high-pressure extraction, and enzyme-assisted extraction. Conclusion: There is great potential for anthocyanins, phycocyanin and genipin use as natural food additives with health benefits, besides imparting color. However, the technologies for the colorants recovery and application are not mature enough. Therefore, this area is still developing, and it is necessary to evaluate the economic feasibility of the proposed extraction processes, along with the safety and acceptance of colored food using these additives.

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Wright, Krista, Ina Vanden Berghe, Jenni Sahramaa et Jenni A. Suomela. « Colorants Detected by HPLC-PDA in Textiles from 13th Century Lieto Ristinpelto, Finland ». Heritage 6, n^o 2 (27 janvier 2023) : 1209–26. http://dx.doi.org/10.3390/heritage6020067.

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Organic colorants of textiles found in the female burial of Lieto Ristinpelto, SW Finland, were analyzed by HPLC-PDA. The textiles’ visible colors varied from different brownish shades to blueish, greenish, and reddish hues. The aim of the chromatographic analysis was to deepen the current understandings of the dyes used in Finland at the transition between the 12th and 13th centuries AD, i.e., at the beginning of the local Medieval period, and to contribute important new information about dyes and clothing from this less-known period of textile history of Finland. The textile finds consisted of a bronze spiral ornamented shawl, an apron tied at the waist, two tablet-woven bands, and a diagonally plaited band with plaited tassels. A unique find was a textile possibly made using the sprang technique. Other textile finds were an orange wool tabby and twill fragments. Analysis of thirty samples from fourteen different textiles indicated that woad colorants were present in most samples, accompanied with lichen compounds, and dyer’s madder was in two visually orange fragments. The visually reddish samples contained luteolin, but no red colorants.

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Harpreet, Kaur, Kaur Harpreet, Vandana Kamboj et Vandana Kamboj. « Bioremediation of organic dyes using combination of plants ash ». Foods and Raw Materials 7, n^o 2 (28 octobre 2019) : 240–46. http://dx.doi.org/10.21603/2308-4057-2019-1-240-246.

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Water is the most crucial thing to mankind and so its contamination by various agencies is posing a threat to the natural balance. So, in the present work, the efficiency of various adsorbents derived from plant waste, to remove different dyes from aqueous solution was evaluated. Parameters for study were contact time, concentration and pH. Various combinations of plant ashes were used for the study. It was found that adsorbent prepared from the combination of orange peels, pomegranate and banana peels ashes, exhibited good adsorption capacity for methylene blue, congo red and crystal violet. All these dyes were completely removed from the aqueous solution while methyl orange was not removed. Congo red was removed completely within 40 min of contact with the adsorbent while methyl orange took 3 hrs to be removed to the extent of 48% only. The adsorption coefficient of congo red was found to be 2.33 while value for methylene blue and crystal violet was 1 and 1.66 respectively. The characterization of adsorbent was done by Scanning Electron Microscopy and IR spectroscopy. SEM image revealed the surface of adsorbent to be made of differential pores. From the results it became evident that the low-cost adsorbent could be used as a replacement for costly traditional methods of removing colorants from water.

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Kronenberg, Nils M., Manuela Deppisch, Frank Würthner, Hans W. A. Lademann, Kaja Deing et Klaus Meerholz. « Bulk heterojunction organic solar cells based on merocyanine colorants ». Chemical Communications, n^o 48 (2008) : 6489. http://dx.doi.org/10.1039/b813341g.

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Gheorghe, Viorel, Catalina Gabriela Gheorghe, Andreea Bondarev, Vasile Matei et Mihaela Bombos. « The Malachite Green Biodegradation in Bioreactors on Various pH Domains ». Revista de Chimie 70, n^o 8 (15 septembre 2019) : 2996–99. http://dx.doi.org/10.37358/rc.19.8.7472.

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In the experimental study was studied the malachite green colorant biodegradation in biological sludge with biological activity. The biodegradability tests were carried out in laboratory bioreactors, on aqueous solutions of green malachite contacted with microorganisms in which the dominant species is Paramecium caudatum, in a pH range between 8 and 12, temperatures in the ranges 25-350C, using pH neutralizing substances and biomass growth promoters. The colorant initial concentrations and those obtained after biological degradation depending on the contact time, at certain pH values, were established through UV-Vis spectrometry. The studies have shown the measure of possible biological degradation of some organic substances with extended uses, with largely aromatic structure, resistance to biodegradation of microorganisms, commonly used in wastewater treatment plants.

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García, O., A. Costela, I. García-Moreno, C. Gómez et R. Sastre. « Obtención de nuevos materiales híbridos orgánico-inorgánicos fotosensibles utilizables como láseres de colorante en estado sólido ». Boletín de la Sociedad Española de Cerámica y Vidrio 43, n^o 2 (30 avril 2004) : 331–36. http://dx.doi.org/10.3989/cyv.2004.v43.i2.533.

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Whitmore, Paul M., Glen R. Cass et James R. Druzik. « The Ozone Fading of Traditional Natural Organic Colorants on Paper ». Journal of the American Institute for Conservation 26, n^o 1 (1987) : 45. http://dx.doi.org/10.2307/3179660.

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Whitmore, Paul M., Glen R. Cass et James R. Druzik. « The Ozone Fading of Traditional Natural Organic Colorants on Paper ». Journal of the American Institute for Conservation 26, n^o 1 (janvier 1987) : 45–57. http://dx.doi.org/10.1179/019713687806027906.

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Langhals, Heinz. « The rapid identification of organic colorants by UV/vis spectroscopy ». Analytical and Bioanalytical Chemistry 374, n^o 3 (1 octobre 2002) : 573–78. http://dx.doi.org/10.1007/s00216-002-1473-x.

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Clarke, E. A., et R. Anliker. « Safety in Use of Organic Colorants : Health and Safety Aspects ». Review of Progress in Coloration and Related Topics 14, n^o 1 (23 octobre 2008) : 84–89. http://dx.doi.org/10.1111/j.1478-4408.1984.tb00048.x.

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Basu, S. « The charging mechanism of organic colorants in metal soap solutions ». Colloid & ; Polymer Science 276, n^o 5 (19 juin 1998) : 420–26. http://dx.doi.org/10.1007/s003960050261.

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HUNGER, K., et R. JUNG. « ChemInform Abstract : On the Toxicology and Ecology of Organic Colorants ». ChemInform 23, n^o 3 (22 août 2010) : no. http://dx.doi.org/10.1002/chin.199203316.

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Chernyshev, V. M., et N. P. Shabelskaya. « Comparative Analysis of Catalytic Activity in Complex NiO-CuO-Fe₂O₃-Cr₂O₃ Oxide System of Different Production Technologies ». Materials Science Forum 870 (septembre 2016) : 118–22. http://dx.doi.org/10.4028/www.scientific.net/msf.870.118.

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The paper presents the comparative analysis of phase formation in NiO-CuO-Fe2O3-Cr2O3 system at salt decomposition reactions. Spinel phase formation is proven for each material. Synthesized materials are examined with X-ray phase analysis, low temperature nitrogen absorption, electronic microscope scanning. Highly dispersed spinel samples are proven to be obtained through synthesis at organic precursor presence. High catalytic activity of synthesized materials in the process of methyl orange oxidative destruction at hydrogen peroxide presence is determined. The fact is extremely useful for industrial sewage water treatment materials development for enterprises that employ organic pigments or colorants at their production process.

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Rodrigues, Santos, Melo, Otero et Vilarigues. « Magic Lantern Glass Slides Materials and Techniques : the First Multi-Analytical Study ». Heritage 2, n^o 3 (29 août 2019) : 2513–30. http://dx.doi.org/10.3390/heritage2030154.

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This paper presents the first systematic investigation of hand-painted magic lantern glass slides using multi-analytical techniques combined with a critical analysis of historical written sources of the painting materials and techniques used to produce them. The magic lantern was an optical instrument used from the seventeenth to the twentieth century that attained great success and impact on the entertainment industry, science, religion, and advertisement industry. The glass, colorants, and organic media of five magic lantern slides from the Museum of Natural History and Science of the University of Lisbon were studied. By means of energy-dispersive X-ray fluorescence spectrometry, the glass was characterized and the oxide quantification unveiled that the glass substrate was possibly produced between 1870 and 1930. Ultraviolet-Visible, Raman and Fourier transform infrared spectroscopies allowed the characterization of the colorants: Prussian blue, an anthraquinone red lake pigment of animal origin (such as cochineal), an unidentified organic yellow, and carbon black. The remaining colors were achieved through mixtures of the pure pigments. Infrared analysis detected a complex fingerprint in all colors, nevertheless, a terpenoid resin such as shellac was identified. Metal carboxylates were also detected, contributing to the assessment of the state of conservation of the paints.

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Kawakami, Tsuyoshi, Tomoko Obama, Maiko Tahara et Yoshiaki Ikarashi. « Determination of carcinogenic primary aromatic amines contained as impurities in synthetic organic colorants ». Journal of AOAC INTERNATIONAL, 5 août 2022. http://dx.doi.org/10.1093/jaoacint/qsac095.

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Abstract Background Several primary aromatic amines (PAAs) have been designated carcinogenic or suspected of carcinogenicity. Several kinds of PAAs may occur either via the reduction of azo compounds or as impurities in azo colorants or other agents. Objective Analytical method was developed and applied to determine whether certain PAAs are present as impurities in synthetic organic colorants. Methods Target chemicals were analyzed by the ultrasound extraction of the synthetic organic colorant with a hydrochloric acid solution containing 20% methanol, followed by conversion from an acidic to alkaline solution, and then extraction using a diatomaceous earth column. Results We analyzed certain PAAs in 38 synthetic organic colorants, resulting in the detection of 2,4-dimethylaniline in 4 samples at 1.2 to 19 μg/g, o-toluidine in 3 samples at 1.0 to 3.4 μg/g, p-phenylazoaniline in 2 samples at 74 to 305 μg/g, and, in one sample each, 2,4,5-trimethylaniline (13 μg/g), 5-nitro-o-toluidine (12 μg/g), and 2-methyl-4–(2-tolylazo)aniline (13 μg/g). Nearly all PAAs were determined to be starting materials for colorant synthesis, although p-phenylazoaniline in Yellow No. 407 was apparently a byproduct formed during synthesis. For Red No. 225, in which high concentrations of p-phenylazoaniline were detected, additional samples were purchased from five companies, and p-phenylazoaniline was detected at concentrations of 88 to 370 μg/g in all samples. Conclusion A method to analyze certain PAAs contained as impurities in synthetic organic colorants was developed, and the actual status of them in colorants was clarified. Highlights The analytical method developed in this study for the determination of certain PAAs contained as impurities in synthetic organic colorants may be used to improve the safety of colorants.

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Hansen, Eric F., Arie Wallert et Michele Derrick. « An Organic Colorant used in Painted Ancient Maya Architectural Sculpture at Nakbe, Peten, Guatemala ». MRS Proceedings 462 (1996). http://dx.doi.org/10.1557/proc-462-287.

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ABSTRACTThe ancient Lowland Maya are generally considered to have used a limited number of inorganic colorants in their polychrome reliefs due to the lack or inaccessibility of mineral resources, especially during the Late Preclassic period (300 B.C. – 300 A.D.). A notable exception is the manufacture of a blue pigment from indigo and specific types of clay, known as Maya blue, from the Classic Period (300 – 900 A.D.) through Colonial times. Another exception is a recently analyzed cream (or reddish-yellow) colored paint found on exceptionally large architectural polychrome stuccoed sculpture dating to the early Late Preclassic at the site of Nakbe, Petén, Guatemala. The cream paint layer exhibits a dramatic peach-colored fluorescence upon exposure to ultraviolet light. An organic material, extracted with organic solvents from the acid hydrolyzed lime-based plaster surface, was characterized by means of visible light microspectroscopy, FT-IR microspectroscopy and three-dimensional fluorescence spectroscopy. Analysis of the spectra obtained from the cream colorant and comparison with spectra of reference organic materials suggests that anthraquinone derivatives may be responsible for the color, and that these compounds are similar to some of those present in organic red dyes. The cream paint was applied as a single layer with good hiding power overlying the stucco ground. The cream paint is of the same thickness (averaging 15 microns) as the only other paint present on the sculpture, a red paint pigmented with red iron oxide. The presence of organic colorants on exposed architectural features raises particular preservation problems in relation to the increased possibility and rate of deterioration due to environmental exposure of this type of organic colorant in comparison with most inorganic colorants.

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« Japan : Yamamoto – organic colorants ». Focus on Pigments 2006, n^o 6 (juin 2006) : 5. http://dx.doi.org/10.1016/s0969-6210(06)71022-0.

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« Ciba organic colorants expansion ». Additives for Polymers 1995, n^o 6 (juin 1995) : 10. http://dx.doi.org/10.1016/0306-3747(95)90803-x.

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« European organic colorant markets ». Additives for Polymers 1994, n^o 10 (octobre 1994) : 5. http://dx.doi.org/10.1016/0306-3747(94)90382-4.

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Sfez, Ruthy, Sophie De-Botton, David Avnir et Racheli Wakshlak. « Sol–gel glazes - a safe glass and ceramics coloring approach ». Journal of Sol-Gel Science and Technology, 24 janvier 2022. http://dx.doi.org/10.1007/s10971-021-05699-4.

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AbstractMajor attention has been given to safety, environmental, and health hazard issues which arise from using toxic inorganic colorants and pigments in ceramic and glass technologies. A safe alternative is presented, wherein organic colorants approved for human use are entrapped within sol–gel aluminosilicate hybrid matrices and used for glazing porcelain ceramic and glass substrates. Among the colorants used are brilliant blue FCF replacing the toxic cobalt blue, curcumin replacing the toxic cadmium sulfide yellow, and a mixture of carmine and allura-red replacing the toxic cadmium selenide red. Additional advantages of the proposed approach are lowering of energy consumption, offering convenient and efficient recyclability of the colored glasses (thus also solving the current requirements for color-classified recycling), offering a huge library of thousands of organic colorants, opening for the artist and product designer a wide range of visual effects, and opening new artistic coloration methods to be explored. Full characterization was carried out including UV-vis spectroscopy, photoluminescence, topographic thickness analysis, wettability, SEM and XRD analyses, and FIB elemental analyses. The glazes are bright, of the order of 250 microns thick, crack free, chemically stable, with good adherence to both ceramic and glassy surfaces, and recyclable to the pure colorless ceramics or glass by heating. The potential for artistic applications, is demonstrated.

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« Colorants ». Additives for Polymers 1992, n^o 11 (novembre 1992) : 11. http://dx.doi.org/10.1016/s0306-3747(05)80019-3.

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« Colorants ». Additives for Polymers 1992, n^o 9 (septembre 1992) : 8. http://dx.doi.org/10.1016/0306-3747(92)90254-w.

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« Colorants ». Additives for Polymers 1993, n^o 4 (avril 1993) : 3. http://dx.doi.org/10.1016/0306-3747(93)90003-v.

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