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Yiru Wang, Wanshuang Liu, Yiping Qiu, Yi Wei
Imidazole cured epoxy resin systems were evaluated for one-component, fast-curing resins for liquid molding of automotive composite parts according to industry requirements. It was demonstrated that an epoxy resin-1-(cyanoethyl)-2-ethyl-4-methylimidazol(EP-1C2E4MIM) system would cure in a few minutes at 120 °C, while exhibiting acceptable pot life, viscosity profiles, and low water absorption. Moreover, this system yielded high T g parts with mechanical properties similar to the amine-epoxy systems, which are the mainstream two-component epoxy resin systems for automobiles...
April 27, 2018: Materials
Tyler Cosby, Zachariah Vicars, Maximilian Heres, Joshua Sangoro
Broadband dielectric spectroscopy is employed to investigate the impact of supramolecular structure on charge transport and dynamics in hydrogen-bonded 2-ethyl-4-methylimidazole and 4-methylimidazole. Detailed analyses reveal (i) an inverse relationship between the average supramolecular chain length and proton conductivity and (ii) no direct correlation between the static dielectric permittivity and proton conductivity in imidazoles. These findings raise fundamental questions regarding the widespread notion that extended supramolecular hydrogen-bonded networks facilitate proton conduction in hydrogen bonding materials...
March 30, 2018: Physical Review Letters
Prinjiya Dhungel, Yuliya Hrynets, Mirko Betti
Sous-vide is an increasingly popular method of cooking under controlled conditions of temperature and time inside vacuumed pouches to preserve the nutritional and sensory qualities of food. Sous-vide nonenzymatic browning of glucosamine (GlcN) was investigated at 50, 60, and 70 °C for 12 h. Changes investigated were pH, color, level of browning, and the concentrations of the key Maillard and caramelization reaction products, including α-dicarbonyls and pyrazines. The concentrations of undesired 4-methylimidazole (4-MEI), 2-acetyl-4(5)-tetrahydroxybutyl imidazole (THI), and 5-hydroxymethylfurfural (5-HMF) were also determined...
May 2, 2018: Journal of Agricultural and Food Chemistry
T Fierens, M Van Holderbeke, C Cornelis, G Jacobs, I Sioen, M De Maeyer, C Vinkx, G Vanermen
In Europe, 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl)imidazole (THI) and 4-methylimidazole (4-MEI) are - to a certain level - allowed to be present in the food colours ammonia caramel (E 150c) and sulphite ammonia caramel (E 150d). Besides their presence in food colours, exposure to these contaminants may also include other dietary sources. This study describes the occurrence of THI and 4-MEI in a wide variety of food products (n = 522) purchased from the Belgian market and their dietary intake in Belgian consumers from 15 years old onwards...
July 30, 2018: Food Chemistry
G Jacobs, S Voorspoels, P Vloemans, T Fierens, M Van Holderbeke, C Cornelis, I Sioen, M De Maeyer, C Vinkx, G Vanermen
Caramel colours are used by the food industry in a wide range of foods and beverages. During their manufacturing, low molecular weight compounds such as 4-methylimidazole (4-MEI), the structural isomer of 4-MEI, 2-methylimidazole (2-MEI) and 2-acetyl-4-tetrahydroxy-butylimidazole (THI) are generated. The presence of these inevitable by-products of caramel manufacturing can be hazardous to human health. This publication describes an isotope dilution Ultra-High-performance Liquid Chromatography tandem mass spectrometric method (UHPLC-MS/MS) that was developed and validated for the simultaneous quantification of these impurities in both beverages/liquids and foods...
July 30, 2018: Food Chemistry
Esam A Orabi, Ann M English
S-aromatic motifs are important noncovalent forces for protein stability and function but remain poorly understood. Hence, we performed quantum calculations at the MP2(full)/6-311++G(d,p) level on complexes between Cys (H2 S, MeSH) and Met (Me2 S) models with models of Phe (benzene, toluene), Trp (indole, 3-methylindole), Tyr (phenol, 4-methylphenol), and His (imidazole, 4-methylimidazole). The most stable gas-phase conformers exhibit binding energies of -2 to -6 kcal/mol, and the S atom lies perpendicular to the ring plane...
April 12, 2018: Journal of Physical Chemistry. B
Yosuke Fujii, Yuqi Ding, Taichi Umezawa, Takafumi Akimoto, Jiawei Xu, Takashi Uchida, Tatsuya Fujino
Food additives generally used in carbonated drinks, such as 4-methylimidazole (4MI), caffeine (Caf?), citric acid (CA), and aspartame (Apm), were measured by matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) using nanometer-sized particles of iron oxide (Fe2 O3 NPs). The quantification of 4MI in Coca Cola (C-cola) was carried out. In order to improve the reproducibility of the peak intensities, Fe2 O3 NPs loaded on ZSM5 zeolite were used as the matrix for quantification. By using 2-ethylimidazole (2EI) as the internal standard, the amount of 4MI in C-cola was determined to range from 88 to 65 μg/355 mL...
2018: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Zufei Feng, Yan Lu, Yingjuan Zhao, Helin Ye
On the basis of magnetic molecularly imprinted polymer (MMIP) solid-phase extraction coupled with high performance liquid chromatography, we established a new method for the determination of the 4-methylimidazole (4-MEI) in soy sauce. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM) were used to characterize the synthesized MMIPs. To evaluate the polymers, batch rebinding experiments were carried out. The binding strength and capacity were determined from the derived Freundlich isotherm (FI) equation...
November 2, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Tomás F Beltrán, Guillermo Zaragoza, Lionel Delaude
The superbulky N-heterocyclic carbenes (NHCs) 2,6-bis(diphenylmethyl)-4-methylimidazol-2-ylidene (IDip*Me) and its 4-methoxy analogue (IDip*OMe) reacted instantaneously with carbon disulfide to afford the corresponding imidazolium-2-dithiocarboxylate zwitterions in high yields. These new dithiolate ligands were fully characterized and their coordination chemistry toward common Re(i) and Ru(ii) metal sources was thoroughly investigated. Neutral [ReBr(CO)3 (S2 C·NHC)] chelates featured three facially-arranged carbonyl groups on a distorted octahedron, whereas cationic [RuCl(p-cymene)(S2 C·NHC)]PF6 complexes displayed a piano-stool geometry...
July 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
M Norizadeh Tazehkand
4-MEI (4-Methylimidazole) is used as a chemical intermediate, crude material or component in the manufacture of pharmaceuticals, photographic and photothermographic chemicals, dyes and pigments and agricultural chemicals. 4-MEI is unintentionally found in our food. Caramel colour (which is the most used beverage colouring and food), dark beers and common brands of cola drinks may comprise more than 100 μg of this compound per 12-ounce serving. 4-MEI is widely used by people and colon cancer is common in our countries...
2017: Bratislavské Lekárske Listy
Manolis N Tzatzarakis, Elena Vakonaki, Sofia Moti, Athanasios Alegakis, Christina Tsitsimpikou, Ioannis Tsakiris, Marina Goumenou, Alexander E Nosyrev, Apostolos K Rizos, Aristidis M Tsatsakis
The substance 4-methylimidazole (4-MEI) has raised several concerns regarding its toxicity to humans, although no harmonized classification has yet been decided. The regulatory limits for food products set by various authorities in Europe and the USA differ considerably. The purpose of the present study is to compare two liquid chromatography techniques in order to determine the levels of 4-MEI in food products from the Greek market and roughly estimate the possible exposure and relevant health risk for the consumers...
September 2017: Food and Chemical Toxicology
M Norizadeh Tazehkand, O Hajipour, F Moridikia, A Moridikia, E Valipour, M B Yilmaz, M Topaktas
4-methylimidazole is widely used in pharmaceuticals, photographic and agricultural chemicals. The substance is extensively found in many human and animals foods. In this research, anticancer effect of the 4-MEI was studded using MTT test using MCF-7 cell line. Effect of the 4-MEI on apoptosis or necrosis was analyzed by DNA fragmentation assay using Swiss Albino rats as a model organism. Antioxidant effect of the substance was investigated by assaying protective effect of the substance on circular plasmid DNA against H2O2 as an oxidative agent...
2017: Bratislavské Lekárske Listy
Pascal Mottier, Claudia Mujahid, Adrienne Tarres, Thomas Bessaire, Richard H Stadler
The presence of 4-methylimidazole (4-MEI), 2-methylimidazole (2-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in some foods may result from the usage of caramel colorants E150c and E150d as food additives. This study demonstrates that alkylimidazoles are also byproducts formed from natural constituents in foods during thermal processes. A range of heat-processed foods that are known not to contain caramel colorants were analyzed by isotope dilution LC-MS/MS to determine the contamination levels. Highest 4-MEI concentrations (up to 466µg/kg) were observed in roasted barley, roasted malt and cocoa powders, with the concomitant presence of 2-MEI and/or THI in some cases, albeit at significantly lower levels...
August 1, 2017: Food Chemistry
Sol Ji Choi, Mun Yhung Jung
We have developed a simple and fast sample preparation technique in combination with a gas chromatography-tandem mass spectrometry (GC-MS/MS) for the quantification of 2-methylimidazole (2-MeI) and 4-methylimidazole (4-MeI) in colas and dark beers. Conventional sample preparation technique for GC-MS requires laborious and time-consuming steps consisting of sample concentration, pH adjustment, ion pair extraction, centrifugation, back-extraction, centrifugation, derivatization, and extraction. Our sample preparation technique consists of only 2 steps (in situ derivation and extraction) which requires less than 3 min...
April 2017: Journal of Food Science
Rima Celik, Mehmet Topaktas
4-Methylimidazole (4-MEI), a heterocyclic organic chemical compound, is widely found in many foods and consumed by people worldwide. In this research, we aimed to investigate the cytotoxic and genotoxic effects of 4-MEI on human lymphocytes. For this purpose, human peripheral blood lymphocytes were treated with four concentrations of 4-MEI (300, 450, 600 and 750 μg/ml) for 24 h and 48 h periods and in vitro sister chromatid exchange (SCE), chromosome aberration (CA) and micronucleus (MN) tests were used...
January 2018: Drug and Chemical Toxicology
Xian-Bing Xu, Pei Yu, Shu-Juan Yu
In this study, hydrogen-deuterium (H/D) exchange experiment was carried out to reveal the promotion effect of sulfite on the formation of deoxyosones and 4-methylimidazole (4-MeI) in the Maillard reaction. Glucose-ammonium (40mmol/L, pH 7.4 in PBS) model systems with different levels of sulfite were incubated at 110°C for 2h. Alpha-dicarbonyls were detected after derivatization by a high-performance liquid chromatography with a diode array detector (HPLC-DAD). 4-MeI in the Maillard reaction was tested using a high-performance anion exchange chromatography with an electrochemical detector (HPAEC-ED)...
May 15, 2017: Food Chemistry
Malek Boukallaba, Boutheïna Kerkeni, Christine Lepetit, Dorothée Berthomieu
A quantum chemistry study of mononuclear metal coordination with four 4-methylimidazole ligands (4-MeIm) was investigated. The four complexes [Cu(4-MeIm)4 ]2+ , [Cu(4-MeIm)4 , H2 O]2+ , [Zn(4-MeIm)4 ]2+ and [Zn(4-MeIm)4 , H2 O]2+ were studied with particular attention to the Nπ or Nτ possible coordinations of the 4-MeIm ring with the metals, using different DFT methods. The results suggest that the Nτ coordination of 4-MeIm ring to ZnII or CuII is more favorable whatever the level of calculation. In contrast, the addition of one water molecule in the first coordination sphere of the metal ions provides five-coordinated complexes showing no Nπ or Nτ preferences...
December 2016: Journal of Molecular Modeling
Takeshi Morita, Chikako Uneyama
4-Methylimidazole (4-MI) is formed as a result of the Maillard reaction process, and therefore is found in many foods and beverages. It is also found in soft drinks (i.e., cola) as a by-product in the production of some caramel colors. NTP bioassays revealed clear evidence of lung carcinogenicity of 4-MI in male and female mice, but not in rats and then IARC classified 4-MI as group 2B carcinogen. Genotoxicity studies with 4-MI were negative in the Ames tests and in the erythrocyte micronucleus tests with mice or rats...
2016: Genes and Environment: the Official Journal of the Japanese Environmental Mutagen Society
M Norizadeh Tazehkand, A Moridikia, O Hajipour, E Valipour, T Timocin, M Topaktas, M B Yilmaz
4-Methylimidazole (4-MEI) is a color widely found in cola drinks, roasted foods, grilled meats, coffee and other foods. This study was aimed to investigate the 4-MEI effects on the cell proliferation, purified circular DNA and DNA from cells of rats treated with the 4-MEI.In this study, mouse 3T3-L1 cell line was treated with 4-MEI at concentrations of 300, 450, 600 and 750 µg/mL for 24 hours and 48 hours periods, after that cytotoxic effect of the 4-MEI was studied by MTT test. Also, the effect of 4-MEI on purified circular DNA (pET22b) was investigated by treating of the DNA with 4-MEI concentrations of 300, 450, 600 and 750 µg/ml...
2016: Bratislavské Lekárske Listy
Tabea Pflaum, Thomas Hausler, Claudia Baumung, Svenja Ackermann, Thomas Kuballa, Jürgen Rehm, Dirk W Lachenmeier
The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-component mixtures may additionally contain further known or suspected human carcinogens as constituent or contaminant. This review will discuss the occurrence and toxicology of eighteen carcinogenic compounds (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, glyphosate, lead, 3-MCPD, 4-methylimidazole, N-nitrosodimethylamine, pulegone, ochratoxin A, safrole) occurring in alcoholic beverages as identified based on monograph reviews by the IARC...
October 2016: Archives of Toxicology
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