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https://www.readbyqxmd.com/read/30317076/determination-of-caffeoylquinic-acid-derivatives-in-azolla-imbricata-by-chitosan-based-matrix-solid-phase-dispersion-coupled-with-hplc-pda
#1
Weilin Wu, Wenqi Qian, Haitian Hao, Yun Kang, Yaqin Wang, Yuanrong Deng, Chengjie Ni, Jianming Huang, Weiyu Weng
Five main components of Azolla imbricata were isolated and identified as caffeoylquinic acid derivatives, four of which were isolated from this species for the first time. The five compounds exhibited strong antioxidant activities and were used as chemical markers for quantitative analysis. A chitosan-based matrix solid-phase dispersion (MSPD) extraction coupled with high-performance liquid chromatography (HPLC) was developed for the determination of the five analytes in A. imbricata. The optimal conditions for the chitosan-based MSPD extraction were as follows: low viscosity chitosan HL-1 as the dispersant, sample-to-dispersant mass ratio of 1:1, 10 mL of a methanol-sulfuric acid aqueous solution (0...
October 4, 2018: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/30314364/quantitative-evaluation-of-twelve-major-components-of-sulfur-fumigated-astragali-radix-with-different-durations-by-uplc-ms
#2
Xiaoyan Xing, Zhonghao Sun, Meihua Yang, Nailiang Zhu, Junshan Yang, Guoxu Ma, Xudong Xu
In this study, an improved UPLC-MS (Ultra-high performance liquid chromatography-tandem mass spectrometry) method for simultaneously quantifying twelve major components belonging to two chemical types was developed and validated, and was applied to quantitatively compare the quality of sulfur-fumigated Astragali Radix of different durations and of the fresh reference sample. The results showed that the contents of triterpenes astragaloside III and astragaloside IV decreased moderately, while the flavonoids calycosin, formononetin, and 7,2'-dihydroxy-3',4'-dimethoxyisoflavane decreased significantly...
October 11, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/30310867/upgrading-traditional-liquid-electrolyte-via-in-situ-gelation-for-future-lithium-metal-batteries
#3
Feng-Quan Liu, Wen-Peng Wang, Ya-Xia Yin, Shuai-Feng Zhang, Ji-Lei Shi, Lu Wang, Xu-Dong Zhang, Yue Zheng, Jian-Jun Zhou, Lin Li, Yu-Guo Guo
High-energy lithium metal batteries (LMBs) are expected to play important roles in the next-generation energy storage systems. However, the uncontrolled Li dendrite growth in liquid electrolytes still impedes LMBs from authentic commercialization. Upgrading the traditional electrolyte system from liquid to solid and quasi-solid has therefore become a key issue for prospective LMBs. From this premise, it is particularly urgent to exploit facile strategies to accomplish this goal. We report that commercialized liquid electrolyte can be easily converted into a novel quasi-solid gel polymer electrolyte (GPE) via a simple and efficient in situ gelation strategy, which, in essence, is to use LiPF6 to induce the cationic polymerization of the ether-based 1,3-dioxolane and 1,2-dimethoxyethane liquid electrolyte under ambient temperature...
October 2018: Science Advances
https://www.readbyqxmd.com/read/30307226/experimental-validation-of-calculated-atomic-charges-in-ionic-liquids
#4
Richard M Fogarty, Richard P Matthews, Claire R Ashworth, Agnieszka Brandt-Talbot, Robert G Palgrave, Richard A Bourne, Tom Vander Hoogerstraete, Patricia A Hunt, Kevin R J Lovelock
A combination of X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure spectroscopy has been used to provide an experimental measure of nitrogen atomic charges in nine ionic liquids (ILs). These experimental results are used to validate charges calculated with three computational methods: charges from electrostatic potentials using a grid-based method (ChelpG), natural bond orbital population analysis, and the atoms in molecules approach. By combining these results with those from a previous study on sulfur, we find that ChelpG charges provide the best description of the charge distribution in ILs...
May 21, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/30301507/characterization-of-antioxidant-activity-of-sulfur-compounds-in-black-garlic
#5
Wei-Dong Wang, Yue-E Sun, Hong-Wei Chen
Different types of sulfur compounds, namely S-allyl-L-cysteine (SAC), S-allyl-L-cysteine sulfoxide (ACSO) and a synthetic γ-L-glutamyl-S-allyl-L-cysteine (GSAC) were extracted from black garlic and their inhibition to the advanced glycation end-products (AGEs) were investigated. Upon addition of inhibitor, the amount of produced fructosamine was determined by UV visible spectroscopy. The change of pentosidine and fluorescent AGEs during reaction was detected by fluorescence method and the change of carboxymethyl lysine (CML) was detected by high performance liquid chromatography...
September 30, 2018: Cellular and Molecular Biology
https://www.readbyqxmd.com/read/30296106/poor-man-s-atomic-layer-deposition-of-lif-for-additive-free-growth-of-lithium-columns
#6
Wesley Chang, Jeung Hun Park, Daniel A Steingart
Lithium metal is an ideal material for high-energy, cost-effective rechargeable energy storage systems. The thermodynamically unfavorable solid-liquid interface between the lithium metal and organic electrolyte necessitates the formation of an interlayer (SEI) which is known to have significant impact on lithium morphologies. Less well understood is the impact of the current collector substrate on the morphology of electrodeposited lithium. Here we report on the morphology of electrodeposited lithium as a function of the chemical pretreatments of the working electrode...
October 8, 2018: Nano Letters
https://www.readbyqxmd.com/read/30287813/sustainable-scalable-synthesis-of-sulfide-nanocrystals-at-low-cost-with-an-ionic-liquid-sulfur-precursor
#7
Bin Yuan, Timothy Karl Egner, Vincenzo Venditti, Ludovico Cademartiri
Increasing the sustainability of nanocrystals is crucial to their application and the protection of the environment. Sulfur precursors for their synthesis are commonly obtained through multiple steps from H2 S, only to be converted back to H2 S during the synthesis of the nanocrystals. This convoluted process requires energy, reduces yields, increases waste and auxiliaries, and complicates recycling. Using H2 S directly could drastically improve sustainability, but is prevented by toxicity and handling. We here show that H2 S is stabilized by reaction with oleylamine (the most common and versatile ligand in nanoparticle synthesis) to form an ionic liquid precursor that addresses all major principles of green chemistry: it is made in one exothermic step, it leaves the reaction yielding a safer product and allowing the separate recycling of the precursors, and it produces high quality nanocrystals with high yields (sulfur yield > 70%) and concentrations (90 g L-1 ) in ambient conditions...
October 4, 2018: Nature Communications
https://www.readbyqxmd.com/read/30286706/identification-of-an-aldehyde-oxidase-involved-in-indole-3-acetic-acid-synthesis-in-bombyx-mori-silk-gland
#8
Mami Takei, Syota Kogure, Chiaki Yokoyama, Yoshiaki Kouzuma, Yoshihito Suzuki
Auxin is thought to be an important factor in the induction of galls by galling insects. We have previously shown that both galling and nongalling insects synthesize indole-3-acetic acid (IAA) from tryptophan (Trp) via two intermediates, indole-3-acetaldoxime (IAOx) and indole-3-acetaldehyde (IAAld). In this study, we isolated an enzyme that catalyzes the last step "IAAld → IAA" from a silk-gland extract of Bombyx mori. The enzyme, designated "BmIAO1", contains two 2Fe-2S iron-sulfur-cluster-binding domains, an FAD-binding domain, and a molybdopterin-binding domain, which are conserved in aldehyde oxidases...
October 5, 2018: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/30252003/the-impact-of-sulfur-functionalisation-on-nitrogen-based-ionic-liquid-cations
#9
Ana R Santos, Magnus W D Hanson-Heine, Nicholas A Besley, Peter Licence
It has been demonstrated that bonding and interactions within ionic liquids (ILs) can be elegantly tuned by manipulation of structure and the introduction of functional groups. Here we use XPS to investigate the impact of sulfur containing substituents on the electronic structure of a series of N-based cations, all with a common anion, [NTf2]-. The experiments reveal complexity and perturbation of delocalised systems which cannot be easily interpreted by NMR and XPS alone, DFT provides critical insight into bonding and underpins the assignment of spectra and development of deconstruction models for each system studied...
October 9, 2018: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/30248775/-detecting-the-concentrations-of-diphenylamine-in-air-of-workplace-with-hplc
#10
T T Yu, Q T Tan, Y Wang
Objective: To establish the method of detecting the concentrations of diphenylamine in air of workplace with high performance liquid chromatographic (HPLC) . Methods: According to standards of methods for determining the chemical substances in workplace air, diphenylamine in the air was collected by glass fiber filter treated with sulfuric acid, then dissolved by methanol and determined by high performance liquid chromatography with UV-detector. Results: There was a linear relationship within the range of 0-30...
July 20, 2018: Chinese Journal of Industrial Hygiene and Occupational Diseases
https://www.readbyqxmd.com/read/30244748/evaluation-of-sulfur-trioxide-detection-with-online-isopropanol-absorption-method
#11
Jin Xiong, Yuran Li, Jian Wang, Yang Yang, Tingyu Zhu
Measurement of the SO3 concentration in flue gas is important to estimate the acid dew point and to control corrosion of downstream equipment. SO3 measurement is a difficult question since SO3 is a highly reactive gas, and its concentration is generally two orders of magnitude lower than the SO2 concentration. The SO3 concentration can be measured online by the isopropanol absorption method; however, the reliability of the test results is relatively low. This work aims to find the error sources and to evaluate the extent of influence of each factor on the measurement results...
October 2018: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/30226639/investigation-of-low-molecular-weight-peptides-1kda-in-chicken-meat-and-their-contribution-to-meat-flavor-formation
#12
Ruiyin Zhou, Jennifer Grant, Erin M Goldberg, Donna Ryland, Michel Aliani
BACKGROUND: Low molecular weight peptides (LMWPs) (<1kDa) generated in meat during chilled conditioning can act as flavor precursors in the Maillard reaction with a potential contribution to key volatile organic compound (VOC) formation upon heating. Liquid-chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) successfully detected 44 LMWPs in chicken breast and thigh muscles stored at 4°C for up to 6 days. Carnosine (350mg/100g); glutathione (20mg/100g) (concentrations based on reported values in the literature) and Cysteine Glycine (5mg/100g) (concentration based on results from LC-QTOF-MS) were used in model systems containing ribose (25mg/100g)...
September 18, 2018: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/30223532/gastric-emptying-and-dynamic-in-vitro-digestion-of-drinkable-yogurts-effect-of-viscosity-and-composition
#13
Olivia Ménard, Marie-Hélène Famelart, Amélie Deglaire, Yann Le Gouar, Sylvie Guérin, Charles-Henri Malbert, Didier Dupont
Gastric emptying of food is mainly driven by the caloric concentration, the rheological properties of the chyme, and the physical state (liquid/solid) of food once in the stomach. The present work investigated: (1) The effect of the composition and the viscosity of drinkable yogurts on gastric emptying in pigs, and (2) the behavior of yogurts during dynamic in vitro digestion. Three isocaloric liquid yogurts were manufactured: Two enriched in protein and fiber showing either a low (LV) or high (HV) viscosity, one control enriched in sugar and starch (CT)...
September 14, 2018: Nutrients
https://www.readbyqxmd.com/read/30223166/adsorptive-mercaptan-removal-of-liquid-phase-using-nanoporous-graphene-equilibrium-kinetic-study-and-dft-calculations
#14
Seyyed Salar Meshkat, Omid Tavakoli, Alimorad Rashidi, Mehdi D Esrafili
This research investigated the adsorption of tertiary butyl mercaptan (TBM) from liquid phases by using nanoporous graphene. Nanoporous graphene synthesized through chemical vapor deposition method was characterized using Brunauer-Emmett-Teller method, transmission electron microscopy, field-emission scanning microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy techniques. The TBM adsorption equilibrium was investigated by using Langmuir, Freundlich, and Tempkin models. The obtained results were in good agreement with the Freundlich isotherm...
September 14, 2018: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/30222335/in-situ-electrochemical-afm-imaging-of-a-pt-electrode-in-sulfuric-acid-under-potential-cycling-conditions
#15
Xin Deng, Federica Galli, Marc T M Koper
Understanding the electrochemical behavior of Pt at the solid/liquid interface is of significant importance for the development of efficient electrochemical devices, such as fuel cells and water electrolyzers. In this work, the evolution of the surface morphology of a polycrystalline platinum under potential cycling conditions was investigated by in situ electrochemical atomic force microscopy (EC-AFM). After 50 cycles between 0.05 and 1.8 V in 0.1 M H2 SO4 , the Pt surface is coarsened and nanoparticles of several nanometers appear on the surface...
October 3, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/30211149/nhc-in-imidazolium-acetate-ionic-liquids-actual-or-potential-presence
#16
REVIEW
Isabella Chiarotto, Leonardo Mattiello, Fabiana Pandolfi, Daniele Rocco, Marta Feroci
Ionic liquids (ILs) are considered in the majority of cases green solvents, due to their virtually null vapor pressure and to the easiness in recycling them. In particular, imidazolium ILs are widely used in many fields of Chemistry, as solvents or precursors of N-heterocyclic carbenes (NHCs). The latter are easily obtained by deprotonation of the C2-H, usually using strong bases or cathodic reduction. Nevertheless, it is known that weaker bases (e.g., triethylamine) are able to promote C2-H/D exchange. From this perspective, the possibility of deprotonating C2-H group of an imidazolium cation by means of a basic counter-ion was seriously considered and led to the synthesis of imidazolium ILs spontaneously containing NHCs...
2018: Frontiers in Chemistry
https://www.readbyqxmd.com/read/30199132/sulfur-polymers-meet-poly-ionic-liquid-s-bringing-new-properties-to-both-polymer-families
#17
Iñaki Gomez, Asier Fdz De Anastro, Olatz Leonet, Jose Alberto Blazquez, Hans-Jürgen Grande, Jeffrey Pyun, David Mecerreyes
Sulfur-containing polymers and poly(ionic liquid)s are emerging macromolecules with unique properties and applications. This article shows the first integration of these two polymer families, leading to materials with a unique combination of properties. The synthetic strategy toward sulfur-containing poly(ionic liquid)s involves first the copolymerization of elemental sulfur with 4-vinylbenzyl chloride and subsequent quaternization of the alkyl chloride group using N-methyl imidazole. The synthetic pathway is completed by the anion exchange reaction of the poly(sulfur-co-4-vinylbenzyl imidazolium chloride) by a sulphonamide anion...
September 10, 2018: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/30186365/hydrogenation-of-co-2-at-ambient-pressure-catalyzed-by-a-highly-active-thermostable-biocatalyst
#18
Fabian M Schwarz, Kai Schuchmann, Volker Müller
Background: Replacing fossil fuels as energy carrier requires alternatives that combine sustainable production, high volumetric energy density, easy and fast refueling for mobile applications, and preferably low risk of hazard. Molecular hydrogen (H2 ) has been considered as promising alternative; however, practical application is struggling because of the low volumetric energy density and the explosion hazard when stored in large amounts. One way to overcome these limitations is the transient conversion of H2 into other chemicals with increased volumetric energy density and lower risk hazard, for example so-called liquid organic hydrogen carriers such as formic acid/formate that is obtained by hydrogenation of CO2 ...
2018: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/30153631/performance-of-geopolymers-for-direct-immobilization-of-solvent-extraction-liquids-metakaolin-lix-84-formulations
#19
Mohamed R El-Naggar, Eman A El-Sherief, Hamida S Mekhemar
Direct immobilization of organic wastes, such as solvent extraction liquids, is an imperative demand in the nuclear sector. This demand has been met in the present study through the development of typical metakaolin-based geopolymeric formulations containing 8% LIX-84 (8LIXGP45) which were pre-saturated with Cu2+ . They were completely homogeneous at very young ages and had 28-day compressive strength values of twice the waste acceptance criteria. Effect of 0.1 M of nitric, hydrochloric or sulfuric acids on the leaching of Cu2+ were studied in comparison to de-mineralized water...
October 15, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/30153011/-cocktail-of-xenobiotics-at-human-relevant-levels-reshapes-the-gut-bacterial-metabolome-in-a-species-specific-manner
#20
Yingdan Zhang, Tharushi Prabha Keerthisinghe, Yuan Han, Min Liu, Elvy Riani Wanjaya, Mingliang Fang
The human gut microbiome experiences long-term exposure to numerous organic contaminants (e.g., xenobiotics) in the digestive tract, and the possible consequences have rarely been characterized. To date, very few studies have investigated the metabolic variation from different species of gut bacteria in response to xenobiotic mixtures. In this study, we applied liquid chromatography mass spectrometry-based global metabolomics, coupled with targeted metabolomics, to characterize the model gut bacterial responses toward the xenobiotic mixture, covering diverse classes of compounds at human relevant concentrations...
October 2, 2018: Environmental Science & Technology
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