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You searched for: Subject term acetic acid Remove constraint Subject term: acetic acid Subject term ethyl ether Remove constraint Subject term: ethyl ether
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1. Stereoselective Determination of Ornidazole Enantiomers in Human Plasma and Urine Samples by Chiral LC: Application to Pharmacokinetic Study

Author:
Wang, Huan; Chen, Yan; Zhou, Jia; Ma, Chen; Chen, Yuancheng; Liu, Xiaoquan
Source:
Chromatographia 2008 v.67 no.11-12 pp. 875-881
ISSN:
0009-5893
Subject:
acetic acid; enantiomers; ethyl ether; humans; liquid chromatography; pharmacokinetics; urine
Abstract:
... A stereoselective liquid chromatographic method to determine the enantiomers of ornidazole in human plasma and urine has been developed and validated. After addition of the internal standard (naproxen), samples were acidified and extracted with diethyl ether. The separation was performed on a Chiralcel OB-H column, using hexane-ethanol- glacial acetic acid (94:6:0.08, v/v) as the mobile phase. The ...
DOI:
10.1365/s10337-008-0625-3

2. Ciprofibrate quantification in human plasma by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry for pharmacokinetic studies

Author:
Fabiana D. Mendes; Lu Shi Chen; André Borges; Tainah Babadópulos; Jaime O. Ilha; Khalid M. Alkharfy; Gustavo D. Mendes; Gilberto De Nucci
Source:
Journal of chromatography 2011 v.879 no.24 pp. 2361-2368
ISSN:
1570-0232
Subject:
Food and Drug Administration; absorption; acetic acid; acetonitrile; confidence interval; energy; ethyl ether; formic acid; high performance liquid chromatography; humans; liquid-liquid extraction; methylene chloride; pharmacokinetics; solvents; tandem mass spectrometry; volunteers; United States
Abstract:
... A rapid, sensitive and specific method for quantifying ciprofibrate in human plasma using bezafibrate as the internal standard (IS) is described. The sample was acidified prior extraction with formic acid (88%). The analyte and the IS were extracted from plasma by liquid–liquid extraction using an organic solvent (diethyl ether/dichloromethane 70/30 (v/v)). The extracts were analyzed by high perfo ...
DOI:
10.1016/j.jchromb.2011.05.055

3. Identification of the active species in oxidation reactions on mixed oxide catalysts: Supra-surface or bulk surface species

Author:
B. Mehlomakulu; T.T.N. Nguyen; P. Delichère; E. van Steen; J.M.M. Millet
Source:
Journal of catalysis 2012 v.289 no. pp. 1-10
ISSN:
0021-9517
Subject:
acetaldehyde; acetic acid; active sites; catalysts; cations; ethanol; ethyl acetate; ethyl ether; oxidation; oxides; temperature; vanadium
Abstract:
... Mixed metal oxides have been used as catalysts for the partial oxidation of ethanol to acetaldehyde. The solids were shown to be active and selective for the reaction at relatively low temperature. Various physical techniques have been used to establish the active sites for this reaction and understand the role of the different elements. The results obtained showed that Brønsted acidic sites were ...
DOI:
10.1016/j.jcat.2012.01.001

4. Solid-Phase Extraction for Photometric Determination of Rosmarinic Acid in Lemon Balm (Melissa Officinalis) Extracts

Author:
Miroslav Ondrejovič; Tibor Maliar; Hana Benkovičová; Jana Kubincová
Source:
Nova biotechnologica et chimica 2012 v.11 no.1 pp. 62-72
ISSN:
1338-6905
Subject:
Melissa officinalis; acetic acid; adsorption; ethyl ether; high performance liquid chromatography; ions; iron; rosmarinic acid; silica gel; solid phase extraction
Abstract:
... The aim of this study was evaluation of the solid-phase extraction for elimination of interference compounds from lemon balm extracts aimed for photometric determination of rosmarinic acid. In experiments, evaluated conditions were as follows: composition and volume of mobile phase, ratio between volume of sample and mass of stationary phase and flow rate of mobile phase during separation. The res ...
DOI:
10.2478/v10296-012-0007-y

5. Integrally skinned PSf-based SRNF‐membranes prepared via phase inversion—Part B: Influence of low molecular weight additives

Author:
Agnieszka K. Hołda; Ivo F.J. Vankelecom
Source:
Journal of membrane science 2014 v.450 pp. 499-511
ISSN:
0376-7388
Subject:
acetic acid; acetone; additives; artificial membranes; butanol; diethylene glycol; dimethyl phthalate; dimethyl sulfoxide; dioxane; ethyl ether; glycerol; hydrophobicity; isopropyl alcohol; nanofiltration; polyethylene glycol; scanning electron microscopy; solvents; viscosity
Abstract:
... This paper is Part B of a two-paper series aiming at a better understanding of membrane formation via phase inversion process by means of immersion precipitation for hydrophobic, integrally skinned membranes. Four different polysulfone (PSf)/solvent systems, namely PSf/N-methyl-2-pyrrolidone (NMP), PSf/N,N-dimethylacetamide (DMAc), PSf/methyl sulfoxide (DMSO) and PSf/N,N-dimethylformamide (DMF), w ...
DOI:
10.1016/j.memsci.2013.08.051

6. The curing reaction of epoxidized methyl esters of corn oil with Diels–Alder adducts of resin acids. The kinetic study and thermal characterization of crosslinked products

Author:
Fanica Mustata; Tudorachi Nita; Ioan Bicu
Source:
Journal of analytical and applied pyrolysis 2014 v.108 pp. 254-264
ISSN:
0165-2370
Subject:
Fourier transform infrared spectroscopy; acetic acid; barium; catalysts; chemical bonding; computer software; corn oil; crosslinking; cycloaddition reactions; cyclohexanes; differential scanning calorimetry; epoxidation reactions; epoxides; esters; ethyl ether; gases; hydrogen peroxide; kinetics; pyrolysis; resin acids; solvents; thermal properties; thermogravimetry; transesterification
Abstract:
... The methyl esters of corn oil (COE) obtained by the optimized transesterification reaction using Ba(OH)2 as catalyst, in presence of diethyl ether as solvent were converted in monomer by in situ epoxidation using peracid method (H2O2/acetic acid solutions). The epoxidation was carried out in presence of Amberlite IR 120H as catalyst and cyclohexane as solvent, at molar ratio 0.5/1.5/1 (acetic acid ...
DOI:
10.1016/j.jaap.2014.04.007

7. Liquid–Liquid Extraction of Phenolic Compounds from Spent Sulphite Liquor

Author:
T. Llano; M. Alexandri; A. Koutinas; Chr. Gardeli; H. Papapostolou; A. Coz; N. Quijorna; A. Andres; M. Komaitis
Source:
Waste and biomass valorization 2015 v.6 no.6 pp. 1149-1159
ISSN:
1877-2641
Subject:
2,2-diphenyl-1-picrylhydrazyl; acetic acid; ambient temperature; antioxidant activity; cellulose; depolymerization; ethyl ether; furfural; gallic acid; hemicellulose; high performance liquid chromatography; hydrolysis; hydroxymethylfurfural; lignin; liquid-liquid extraction; moieties; pH; pulping; solvents; sugars; sulfites; wood
Abstract:
... The sulphite pulping process for cellulose extraction consists of lignin depolymerisation of wood by sulphonation and hydrolysis leading to the production of spent sulphite liquor (SSL) as waste stream enriched in hemicellulose sugars and lignin derivatives. In this work, liquid–liquid extraction was used in order to separate phenolics from the sugar-rich SSL fraction. The effects of type of solve ...
DOI:
10.1007/s12649-015-9425-9

8. Mass spectrometric monitoring of oxidation of aliphatic C6–C8 hydrocarbons and ethanol in low pressure oxygen and air plasmas

Author:
Dilshadbek T. Usmanov; Lee Chuin Chen; Kenzo Hiraoka; Hiroshi Wada; Hiroshi Nonami; Shinichi Yamabe
Source:
Journal of mass spectrometry 2016 v.51 no.12 pp. 1187-1195
ISSN:
1076-5174
Subject:
Lewis bases; acetic acid; air; alkenes; cathodes; cyclohexanes; ethanol; ethyl acetate; ethyl ether; formates; heptane; hexane; ions; iso-octanes; monitoring; octane; oxidation; oxygen; ozone; tandem mass spectrometry
Abstract:
... Experimental and theoretical studies on the oxidation of saturated hydrocarbons (n‐hexane, cyclohexane, n‐heptane, n‐octane and isooctane) and ethanol in 28 Torr O₂ or air plasma generated by a hollow cathode discharge ion source were made. Ions corresponding to [M + 15]⁺ and [M + 13]⁺ in addition to [M − H]⁺ and [M − 3H]⁺ were detected as major ions where M is the sample molecule. The ions [M + 1 ...
DOI:
10.1002/jms.3890

9. Preparation of reminiscent aroma mixture of Japanese soy sauce

Author:
Kaori Bonkohara; Maiko Fuji; Akito Nakao; Noriyuki Igura; Mitsuya Shimoda
Source:
Bioscience, biotechnology, and biochemistry 2016 v.80 no.3 pp. 533-539
ISSN:
1347-6947
Subject:
acetic acid; biochemistry; biotechnology; ethyl ether; flavor; isoamyl alcohol; odor compounds; odors; polyethylene; soy sauce
Abstract:
... To prepare an aroma mixture of Japanese soy sauce by fewest components, the aroma concentrate of good sensory attributes was prepared by polyethylene membrane extraction, which could extract only the volatiles with diethyl ether. GC-MS-Olfactometry was done with the aroma concentrate, and 28 odor-active compounds were detected. Application of aroma extract dilution analysis to the separated fracti ...
DOI:
10.1080/09168451.2015.1101336

10. An alternative method based on enzymatic fat hydrolysis to quantify volatile compounds in wheat bread crumb

Author:
Joana Pico; María Jesús Nozal; Manuel Gómez; José Luis Bernal
Source:
Food chemistry 2016 v.206 pp. 110-118
ISSN:
0308-8146
Subject:
acetic acid; acetoin; carboxylic ester hydrolases; ethyl ether; free fatty acids; gas chromatography-mass spectrometry; glycerol; hydrolysis; methylene chloride; phenylethyl alcohol; solid phase extraction; volatile compounds; wheat
Abstract:
... An alternative method to quantify 40 volatile compounds in wheat bread crumb is proposed. It consists of a Soxhlet extraction with a mixture of dichloromethane and diethyl ether containing lipases and a subsequent concentration with Vigreux column. It is the first time that lipases are added to transform the fat into free fatty acids and glycerol, which elute at the end of the chromatogram after t ...
DOI:
10.1016/j.foodchem.2016.03.054

11. An improved LC–MS/MS method for the simultaneous determination of pyrazinamide, pyrazinoic acid and 5-hydroxy pyrazinoic acid in human plasma for a pharmacokinetic study

Author:
Priyanka A. Shah; Primal Sharma; Jaivik V. Shah; Mallika Sanyal; Pranav S. Shrivastav
Source:
Journal of chromatography 2016 v.1017-1018 pp. 52-61
ISSN:
1570-0232
Subject:
acetic acid; bioavailability; chromatography; ethyl ether; humans; ionization; liquid-liquid extraction; metabolites; methanol; monitoring; pharmacokinetics; spectrometers; storage conditions
Abstract:
... In the present work the plasma levels of PZA and its two active metabolites, pyrazinoic acid (PA) and 5-hydroxy pyrazinoic acid (5-OH PA) were determined by a sensitive and rapid LC–MS/MS method. The analytes and their labeled internal standards were extracted from 200μL plasma samples by liquid-liquid extraction with methyl tert-butyl ether: diethyl ether (90:10, v/v) under acidic conditions. The ...
DOI:
10.1016/j.jchromb.2016.02.036

12. Development of a fast and cost-effective gas chromatography–mass spectrometry method for the quantification of short-chain and medium-chain fatty acids in human biofluids

Author:
Cesare Lotti; Josep Rubert; Francesca Fava; Kieran Tuohy; Fulvio Mattivi; Urska Vrhovsek
Source:
Analytical and bioanalytical chemistry 2017 v.409 no.23 pp. 5555-5567
ISSN:
1618-2642
Subject:
acetic acid; colon; colorectal neoplasms; cost effectiveness; ethyl acetate; ethyl ether; feces; fermentation; gas chromatography-mass spectrometry; humans; intestinal microorganisms; medium chain fatty acids; methylene chloride; monitoring; solvents
Abstract:
... The quantification of short-chain and medium-chain fatty acids is becoming more and more relevant in fecal and plasma samples due to their biological impact, which has been associated with colon rectal cancer and fiber consumption. For these reasons, a fast, cost-effective, and reproducible analytical method is highly required. In this research, a gas chromatography–mass spectrometry method based ...
DOI:
10.1007/s00216-017-0493-5

13. Vacuum-Ultraviolet-Excited and CH2Cl2/H2O-Amplified Ionization-Coupled Mass Spectrometry for Oxygenated Organics Analysis

Author:
Bo Yang; Haixu Zhang; Jinian Shu; Pengkun Ma; Peng Zhang; Jingyun Huang; Zhen Li; Ce Xu
Source:
Analytical chemistry 2018 v.90 no.2 pp. 1301-1308
ISSN:
1520-6882
Subject:
acetic acid; acetone; energy; ethanol; ethyl ether; formaldehyde; hydrochloric acid; ionization; ions; isotope labeling; mass spectrometry; nitrogen; photons; volatile organic compounds
Abstract:
... The mass spectrometry analysis of oxygenated volatile organic compounds (OVOCs) remains challenging due to their limited ionization efficiencies. In this study, we surprisingly found that, under vacuum-UV (VUV) excitation, a gaseous mixture of CH₂Cl₂/H₂O/analyte (OVOCs) in N₂ buffer generated large amounts of H₃O⁺ and protonated analyte even when the photon energy was lower than the ionization ene ...
DOI:
10.1021/acs.analchem.7b04122

14. Development and validation of a GC-FID method for the analysis of short chain fatty acids in rat and human faeces and in fermentation fluids

Author:
Serena Scortichini; Maria Chiara Boarelli; Stefania Silvi; Dennis Fiorini
Source:
Journal of chromatography 2020 v.1143 pp. 121972
ISSN:
1570-0232
Subject:
acetic acid; acidification; chemical species; derivatization; ethyl ether; feces; fermentation; flame ionization; hexanoic acid; humans; intestinal microorganisms; metabolites; mice; polyethylene glycol; propionic acid; quantitative analysis; rats
Abstract:
... Short-chain fatty acids (SCFAs) are gut microbiota metabolites recognized for their beneficial effects on the host organism. In this study, a simple and rapid sample preparation method combined to SCFAs analysis by direct injection and gas chromatography coupled with flame ionization detection (GC-FID), for the determination and quantification of eight SCFAs (acetic, propionic, i-butyric, butyric, ...
DOI:
10.1016/j.jchromb.2020.121972

15. Effect of Sorbus domestica and its active constituents in an experimental model of colitis rats induced by acetic acid

Author:
Esra Küpeli Akkol; Fatma Tuğçe Gürağaç Dereli; Hakkı Taştan; Eduardo Sobarzo-Sánchez; Haroon Khan
Source:
Journal of ethnopharmacology 2020 v.251 pp. 112521
ISSN:
0378-8741
Subject:
Sorbus domestica; acetic acid; anhydrite; antioxidant activity; blood; butanol; caspase-3; catalase; chromatography; colon; ethyl acetate; ethyl ether; fractionation; fruits; glutathione; histopathology; interleukin-6; isolation techniques; leaves; lipid peroxidation; malondialdehyde; methylene chloride; models; myeloperoxidase; nitrites; rats; superoxide dismutase; traditional medicine; tumor necrosis factor-alpha; ulcerative colitis; vanillic acid
Abstract:
... In Turkish folk medicine, leaves of Sorbus domestica are used for the treatment of burns, cough, stomachache, bradyuria, kidney stone. The fruits of this plant are used for diarrhoea.This study was carried out to investigate the effect of S. domestica on ulcerative colitis induced by acetic acid in rats.The crude methanolic extract of fruits was sequentially fractionated into five subextracts; dic ...
DOI:
10.1016/j.jep.2019.112521

16. HPTLC fingerprint profile analysis of coffee polyphenols during different roast trials

Author:
Vasilisa Pedan; Elisa Stamm; Tiên Do; Mirjam Holinger; Eike Reich
Source:
Journal of food composition and analysis 2020 v.94 pp. 103610
ISSN:
0889-1575
Subject:
acetic acid; acetophenones; ethyl ether; evolution; food composition; formic acid; heptane; phytochemicals; polyphenols; principal component analysis; quantitative analysis; silica gel; solvents
Abstract:
... Coffee beans are a rich source of bioactive phytochemicals such as chlorogenic acids (CGA). During the roasting process, the CGA content changes dramatically. An effective HPTLC method was developed which allows a fast characterization of the eight main CGA present in green and roasted coffee beans and their distribution during roasting trials. The method was optimized with regard to three caffeoy ...
DOI:
10.1016/j.jfca.2020.103610

17. Analysis of balms taken from Egyptian human mummies using solid‐phase extraction and gas chromatography–mass spectrometry

Author:
Elodie Mezzatesta; Annie Perraud; Cathy Vieillescazes; Carole Mathe
Source:
Journal of separation science 2021 v.44 no.4 pp. 850-859
ISSN:
1615-9306
Subject:
acetic acid; archaeology; beeswax; bitumen; ethanol; ethyl ether; gas chromatography-mass spectrometry; hexane; humans; museums; saponification; separation; solid phase extraction; France
Abstract:
... The aim of this paper is to establish a protocol by solid‐phase extraction–gas chromatography–mass spectrometry leading to a wide and fine qualitative chemical characterization of the several natural substances present in human mummies’ balms, using a minimal quantity of samples. In this study, nine samples were analyzed from mummies dating back from the Third Intermediate Period to the Roman Peri ...
DOI:
10.1002/jssc.202000746

18. Non-Boltzmann Effects in Chain Branching and Pathway Branching for Diethyl Ether Oxidation

Author:
Clayton R. Mulvihill; Aaron D. Danilack; C. Franklin Goldsmith; Maria Demireva; Leonid Sheps; Yuri Georgievskii; Sarah N. Elliott; Stephen J. Klippenstein
Source:
Energy & fuels 2021 v.35 no.21 pp. 17890-17908
ISSN:
1520-5029
Subject:
acetic acid; biofuels; energy; ethyl ether; isomers; mass spectrometry; oxidation; photolysis
Abstract:
... Low-temperature (LT) engine applications have several potential benefits, including reduced emissions and increased efficiency. Attaining these benefits requires accurate kinetic modeling of LT chain branching, which depends heavily on ketohydroperoxide (KHP) decomposition. For diethyl ether (DEE), a promising biofuel, current estimates of the KHP decomposition rate constant are largely based on e ...
DOI:
10.1021/acs.energyfuels.1c02196

19. Effect of Temperature on Ethanol Reaction Pathways during the (Ethanol + NH₃)-SCR Process over Cu-SSZ-13 Catalyst: a Photoionization Mass Spectrometry Study

Author:
Hanyu Chen; Sirui Sun; Wei Lou; Xi Wang
Source:
Energy & fuels 2022 v.36 no.7 pp. 3835-3847
ISSN:
1520-5029
Subject:
X-ray diffraction; X-ray photoelectron spectroscopy; acetic acid; aqueous solutions; catalysts; energy; ethanol; ethyl ether; ethylene; ion exchange; mass spectrometry; oxidation; temperature
Abstract:
... The selective catalytic reduction (SCR) of NOₓ with ethanol and NH₃ over Cu-SSZ-13 catalyst was studied by using the synchrotron vacuum ultraviolet photoionization mass spectrometry technique. The Cu-SSZ-13 catalyst was synthesized by an aqueous solution ion-exchange method and characterized using X-ray powder diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy techniqu ...
DOI:
10.1021/acs.energyfuels.1c04387