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Hindered phenol detection

Qifeng Ma, Zeng Fan'gang, Jie Lu
OBJECTIVE: To develop a method for determination of PG, TBHQ, NDGA, BHA, Ionox100, OG, DG and BHT in olive oil by ultra-performance liquid chromatography (UPLC), and to study the migration rule of hindered phenolic antioxidants in food simulation solvent. METHODS: The samples were extracted with acetonitrile, and C18 dispersion matrix solid-phase, the separation were performed by UPLC. The migration amount of PG, BHA, BHT from polyethylene film to different simulated solvent (olive oil, 20% ethanol, 10% ethanol, 3% acetic acid) were determined at 20, 60 and 100 degrees C...
January 2016: Wei Sheng Yan Jiu, Journal of Hygiene Research
Martin G O'Toole, Patricia A Soucy, Rajat Chauhan, Mandapati V Ramakrishnam Raju, Dhruvina N Patel, Betty M Nunn, Megan A Keynton, William D Ehringer, Michael H Nantz, Robert S Keynton, Andrea S Gobin
Curcumin is known to have immense therapeutic potential but is hindered by poor solubility and rapid degradation in solution. To overcome these shortcomings, curcumin has been conjugated to chitosan through a pendant glutaric anhydride linker using amide bond coupling chemistry. The hybrid polymer has been characterized by UV-visible, fluorescence, and infrared spectroscopies as well as zeta potential measurements and SEM imaging. The conjugation reactivity was confirmed through gel permeation chromatography and quantification of unconjugated curcumin...
April 11, 2016: Biomacromolecules
Mia Kruse Guldstrand Larsen, Malene Møller Jørgensen, Tue Bjerg Bennike, Allan Stensballe
Potato late blight is one the most important crop diseases worldwide. Even though potato has been studied for many years, the potato disease late blight still has a vast negative effect on the potato production [1], [2], [3]. Late blight is caused by the pathogen Phytophthora infestans (P. infestans), which initiates infection through leaves. However, the biological activities during different stages of infection are poorly described, and could enable novel or improved ways of defeating late blight infection [4]...
March 2016: Data in Brief
Ze Xi Liu, Zhu Lian Wu, Ming Xuan Gao, Hui Liu, Cheng Zhi Huang
Photoluminescent carbon dots (CDs), hydrothermally prepared using tannic acid (TA), show visual aggregation induced emission enhancement (AIEE) properties at 455 nm when excited at 350 nm owing to the rotational hindering of the surface groups on CDs such as aromatic rings and phenolic hydroxyl ones, causing exponential decay between the ratio of the photoluminescence intensity in organic solvents to that in water and the permittivity of the solvent, and thus dazzling emissions of the CDs in the presence of solvents with small permittivity, tetrahydrofuran (THF), for instance, could be visually observed...
February 4, 2016: Chemical Communications: Chem Comm
Enni E Väisänen, Annika I Smeds, Kurt V Fagerstedt, Teemu H Teeri, Stefan M Willför, Anna Kärkönen
Externally added coniferyl alcohol at high concentrations reduces the growth of Nicotiana cells and seedlings. Coniferyl alcohol is metabolized by BY-2 cells to several compounds. Coniferyl alcohol (CA) is a common monolignol and a building block of lignin. The toxicity of monolignol alcohols has been stated in the literature, but there are only few studies suggesting that this is true. We investigated the physiological effects of CA on living plant cells in more detail. Tobacco (Nicotiana tabacum) Bright yellow-2 cells (BY-2) and Nicotiana benthamiana seedlings both showed concentration-dependent growth retardation in response to 0...
September 2015: Planta
Shela Gorinstein, Maria Leontowicz, Hanna Leontowicz, Jacek Namiesnik, Zenon Jastrzebski, Jerzy Drzewiecki, Yong-Seo Park, Kyung-Sik Ham, Buk-Gu Heo, Simon Trakhtenberg
The influence of diets supplemented with mussels, from polluted (MPoll) and non-polluted (MNPoll) areas, on some atherosclerosis indices in rats fed cholesterol (Chol) were studied. According to the results of our investigation in vitro, mussels from polluted areas had higher contents of proteins, metals and antioxidant compounds, mostly phenolics and higher antioxidant capacities. 28 male Wistar rats were divided into 4 groups of 7 and named Control, Chol, Chol/MPoll and Chol/MNPoll. The rats of the Control group received basal diet (BD) only, and the diets of the other 3 groups were supplemented with 1% of non-oxidized cholesterol (NOC), 1% of NOC and 5...
November 15, 2008: Food Chemistry
Panpan Li, Zhaoyu Jin, Meilian Zhao, Yanxue Xu, Yong Guo, Dan Xiao
In this work, we obtain two ruthenium(ii) complexes with Schiff base cavities that exhibit significantly enhanced electrochemiluminescence (ECL) intensity and quantum efficiency due to Ru(bpy)3(2+) in aqueous solution, without the addition of tri-n-propylamine (TPrA). The great increase in ECL intensity is confirmed to be due to the electrochemical oxidation of phenolic hydroxyl groups and the resonant structure of imino radicals. Thus, the electrons are transferred intramolecularly to the Ru(iii) center, leading to efficient generation of the excited state of Ru(ii)*...
February 7, 2015: Dalton Transactions: An International Journal of Inorganic Chemistry
Alexander Kassler, Ernst Pittenauer, Nicole Doerr, Guenter Allmaier
RATIONALE: For the qualification and quantification of antioxidants (aromatic amines and sterically hindered phenols), most of them applied as lubricant additives, two ultrahigh-performance liquid chromatography (UHPLC) electrospray ionization mass spectrometric methods applying the positive and negative ion mode have been developed for lubricant design and engineering thus allowing e.g. the study of the degradation of lubricants. METHODS: Based on the different chemical properties of the two groups of antioxidants, two methods offering a fast separation (10 min) without prior derivatization were developed...
January 15, 2014: Rapid Communications in Mass Spectrometry: RCM
Lu Shu, Jinkun Zhu, Qingjiang Wang, Pingang He, Yuzhi Fang
Based on the catalytic activity of hemin, an efficient biocatalyst, an indirect capillary electrophoresis-chemiluminescence (CE-CL) detection method for phenols using a hemin-luminol-hydrogen peroxide system was developed. Through a series of static injection experiments, hemin was found to perform best in a neutral solution rather than an acidic or alkaline medium. Although halide ions such as Br(-) and F(-) could further enhance the CL signal catalyzed by hemin, it is difficult to apply these conditions to this CE-CL detection system because of the self-polymerization of hemin, as it hinders the CE process...
September 2014: Luminescence: the Journal of Biological and Chemical Luminescence
Jim Luong, Ronda Gras, Hernan J Cortes, Robert A Shellie
A multidimensional gas chromatographic approach using planar microfluidic devices for Deans switching has been developed and implemented for the characterization of sterically hindered phenolic compounds used as antioxidants in fuels. Detection and quantitation was conducted with MS in selected ion monitoring mode. A complete analysis is conducted in less than 15 min with precision greater than 5.5% at 1 and 25 ppm w/w (ppm(w)). LODs of 50 ppb w/w (ppb(w)) or better in selected ion monitoring mode and a linear range of 100 ppb(w) to 100 ppm(w) with a correlation coefficient greater than 0...
September 2013: Journal of Separation Science
Amanda J Lloyd, Manfred Beckmann, Sumanto Haldar, Chris Seal, Kirsten Brandt, John Draper
BACKGROUND: An understanding of causal relations between diet and health is hindered by the lack of robust biological markers of food exposure. OBJECTIVE: We aimed to develop a data-driven procedure to discover urine biomarkers indicative of habitual exposure to different foods. DESIGN: The habitual diet of 68 participants was assessed by using 4 food-frequency questionnaires over 3 mo, and participants were assigned to different consumption-frequency classes for 58 dietary components...
February 2013: American Journal of Clinical Nutrition
Huili Wang, Jingwen Mao, Ailian Duan, Baoguang Che, Wenwei Wang, Meiping Ma, Xuedong Wang
The interactions between room temperature ionic liquids (RTILs) and weak fluorescent chemicals still remain unclear, which hinders the complete and efficient utilization of these "green" solvents in fluorescent analyses of organic chemicals. Herein, we reported the effects of four RTILs, [C8MIM]BF4, [C14MIM]BF4, [C8MIM]PF6 and [C14MIM]PF6, on fluorescence behavior of 4-tert-octylphenol (4-t-OP). In the fortified concentration range of 0.2-1.0 mM, the quenching effects were increased with increasing concentrations of RTILs...
March 2013: Journal of Fluorescence
T Schimitberger, G R Ferreira, L C Akcelrud, M F Saraiva, R F Bianchi
In this paper, we report our experimental design in searching a smart and easy-to-read dosimeter used to detect 6 MV X-rays for improving patient safety in radiation oncology. The device was based on an organic emissive solutions of poly(2-methoxy-5(2'-ethylhexyloxy)-p-phenylenevinylene) (MEH-PPV), aluminum-tris-(8-hydroxyquinoline) (Alq₃) and additive components which were characterized by UV-Vis absorption, photoluminescence and CIE color coordinate diagram. The optical properties of MEH-PPV/Alq₃ solutions have been examined as function of radiation dose over the range of 0-100 Gy...
January 2013: Medical Engineering & Physics
Mochammad Hatta, Masahiko Makino, Ratnawati, Mashudi, Yadi, Muhammad Sabir, Nataniel Tandirogang, Luh Made Mas Rusyati, Masanori Kai, Yasuo Fukutomi, Yuji Miyamoto, Tetsu Mukai, Yumi Maeda
BACKGROUND: Sero-diagnostic methods are the easiest way of diagnosing an infectious disease in developing countries. In leprosy, phenolic glycolipid-1 (PGL-I) based methods for the detection of leprosy are currently available, but the use of these methods has been hindered due to the inherent problems of sensitivity. We previously showed that antibodies to Major Membrane Protein-II (MMP-II) derived from Mycobacterium leprae could be used to diagnose leprosy in Japan. METHODS: Sera from patients and healthy individuals were collected with informed consent and the anti-MMP-II antibody levels of the sera were measured by enzyme-linked immunosorbent assay...
December 2009: Leprosy Review
Hui-Ying An, Chensheng Ma, Wen Li, Kyle T Harris, Timothy M Dore, David Lee Phillips
To investigate the substituent effect on the distribution of the forms of the ground-state species of 8-substituted 7-hydroxyquinolines, ultraviolet-absorption and resonance Raman experiments were performed for 8-chloro-7-hydroxyquinoline (CHQ-OAc) and 8-cyano-7-hydroxyquinoline (CyHQ-OAc) in acetonitrile (MeCN), in NaOH-H(2)O/MeCN (60:40, v/v, pH 11-12), and in H(2)O/MeCN (60:40, v/v, pH 6-7) solutions, and these results were compared to those previously reported for the 8-bromo-7-hydroxyquinoline (BHQ-OAc) compound...
February 25, 2010: Journal of Physical Chemistry. A
Alexander Kassler, Ernst Pittenauer, Nicole Doerr, Guenter Allmaier
The aim of this study was to investigate the utility of ion trap mass spectrometry (ITMS) in combination with the two desorption/ionization methods, electrospray (ESI) and atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI), for the detection of antioxidants which are applied in lubricants. These experiments should form the base for future investigations of antioxidants in tribologically formed thin layers on the surface of frictional systems. Seventeen different antioxidants were selected out of the group of hindered phenolic and aromatic aminic compounds...
December 2009: Rapid Communications in Mass Spectrometry: RCM
Kunzheng Cai, Dan Gao, Jining Chen, Shiming Luo
Silicon is the second most abundant mineral element in soil, it has important role in alleviating various environmental stresses and enhancing plant resistance against pathogen, but the exact mechanism by which Si mediates pathogen resistance remains unclear. One of the resistance mechanisms is related to silicon deposition in leaf that acts as a physical barrier to hinder pathogen penetration. But more evidence show that silicon can induce defense responses that are functionally similar to systemic acquired resistance, Si-treated plants can significantly increase antioxidant enzyme activities and the production of antifungal compounds such as phenolic metabolism product, phytoalexins and pathogenesis-related proteins etc...
January 2009: Plant Signaling & Behavior
Maria Leontowicz, Hanna Leontowicz, Zenon Jastrzebski, Iwona Jesion, Ratiporn Haruenkit, Sumitra Poovarodom, Elena Katrich, Zev Tashma, Jerzy Drzewiecki, Simon Trakhtenberg, Shela Gorinstein
The aim of this investigation was to assess the nutritional and health properties of Mon Thong durian cultivar at different stages of ripening. The assessment was carried out in vitro and in vivo. The contents of dietary fibers, minerals and trace metals at different stages of ripening were comparable. Total polyphenols (mgGAE/100 g FW) and flavonoids (mg CE/100 gFW) in ripe durian (358.8 +/- 31.4 and 95.4 +/- 9.3) were significantly higher (p < 0.05) than in mature (216.1 +/- 1 and 39.9 +/- 3.8) and overripe (283...
2007: BioFactors
Ileana Dragutan, Rolf J Mehlhorn
Piperidine nitroxides like 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) are persistent free radicals in non-acidic aqueous solutions and organic solvents that may have value as therapeutic agents in medicine. In biological environments, they undergo mostly reduction to stable hydroxylamines but can also undergo oxidation to reactive oxoammonium compounds. Reactions of the oxoammonium derivatives could have adverse consequences including chemical modification of vital macromolecules and deleterious effects on cell signaling...
March 2007: Free Radical Research
S Siju, R Madhubala, A I Bhat
Isolation of intact high quality RNA suitable for RT-PCR from black pepper is greatly hindered by the presence of polyphenols and polysaccharides. These compounds adversely affect the sensitivity of virus detection by RT-PCR. The present study evaluated the effect of sodium sulphite in enhancing RNA yield and quality in a modified acid guanidium thiocyanate-phenol-chloroform (AGPC) protocol. The results were compared with the standard AGPC method and RNeasy Plant Mini Kit (Qiagen) for detection of Cucumber mosaic virus through RT-PCR...
April 2007: Journal of Virological Methods
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