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Results 101 - 150 of 1625
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Phillips Melissa M - - 2010
Nine organic acids (citric acid, galacturonic acid, glycolic acid, isocitric acid, malic acid, oxalic acid, quinic acid, shikimic acid, and tartaric acid) and two anions (phosphate and sulfate) were determined in a suite of Vaccinium berry-containing dietary supplement standard reference materials (SRMs). Following solvent extraction, three independent methods were utilized ...
Khiaosa-ard Ratchaneewan - - 2010
The effects of three emulsifying methods on ruminal fatty acid biohydrogenation (BH) in vitro were compared. Using a static in-vitro gas test system, four replicates of each treatment were incubated in buffered ruminal fluid. Hemicellulose (300 mg dry matter) was supplemented either with or without linoleic acid (9c12c-18:2, 5% in ...
Wang Yang - - 2010
A selective, sensitive, rapid and reliable method based on molecularly imprinted polymers (MIPs) with dual templates to determine total content of parabens in cosmetics was developed. With methylparaben (MP) and propylparaben (PP) as dual-templates, methacrylic acid (MAA) as a functional monomer and tripropylene glycol diacrylate (TPGDA) as a cross-linker, MIPs ...
Nakayama Shoji F - - 2010
Despite ongoing efforts to develop robust analytical methods for the determination of perfluorinated compounds (PFCs) such as perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) in surface water, comparatively little has been published on method performance, and the environmental distribution of these materials remains poorly described worldwide. In this study, an existing ...
Dubois M - - 2010
Okadaic acid, a diarrhetic shellfish poison, domoic acid, an amnesic shellfish poison, and saxitoxin, a paralytic shellfish poison, are three of the best-known marine biotoxins. The mouse bioassay is the method most widely used to detect many of these toxins in shellfish samples, but animal welfare concerns have prompted researchers ...
Liu Xin-Ru - - 2010
Early diagnosis and treatment for thermal injury with septic complications continue to be a serious clinical problem. In this study, plasma biomarkers of rats in the burn and/or septic models were investigated with a metabolomic method. Rat plasma samples were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Multivariate ...
Meng Liping - - 2010
A simple, fast and sensitive liquid chromatography-electrospray tandem mass spectrometry method was established for trace levels of nine haloacetic acids (HAAs) in drinking water. Water samples were removed of residual chlorine by adding L-ascorbic acid, and directly injected after filtered by 0.22 microm membrane. Nine HAAs were separated by liquid ...
Au Catherine - - 2011
The enhancement of marks in blood on dark surfaces poses significant challenges to the forensic scientist. Current methods of enhancement include the sequential use of acid dyes (acid yellow, acid violet and acid black). Acid yellow is used to greatest effect on lighter deposits of blood on a non-porous background, ...
Dick Graham R - - 2010
A wide range of 2-pyridyl and other difficult-to-access heterocyclic N-methyliminodiacetic acid boronates can be readily prepared from the corresponding bromides via a new method involving direct transligation of 2-heterocyclic trialkoxyborate salts with N-methyliminodiacetic acid (MIDA) at elevated temperatures.
Newton Laura A A - - 2010
Homocysteine has gathered considerable interest in recent years after being implicated in the pathogenesis of various clinical conditions. It has been an elusive target with many conflicting studies casting some confusion over its significance, and much more needs to be done to ascertain its pathophysiological role--especially with respect to regimes ...
Zhao Xuebing - - 2010
Siam weed [Chromolaena odorata (L.) King & Robinson], an invasive exotic weed in China, was proposed as a feedstock for bioethanol production. This would be a promising way of using for an invasive weed that needs management and control. It was found that the glucan content of the weed stem ...
Rizza Luisa - - 2010
The aim of the present study was to compare the effectiveness and the safety of different topical agents (glycolic acid, mandelic acid, and grape juice acid mixture) in skin exfoliation by objective instrumental methods. To evaluate the exfoliating effects of these substances, a new experimental in vivo protocol based on ...
Huang Gang L - - 2010
Extraction of mannan oligosaccharides from the yeast cell wall and methods of deproteinization were studied. We extracted crude mannan oligosaccharides by the dilute alkali-Sevage method. The percentages of deproteinization and mannan oligosaccharide loss were compared as indexes using the Sevage method, trichloroacetic acid method, and hydrochloric acid method. The results ...
Gasperotti Mattia - - 2010
Accurate quantification and structural characterization of ellagitannins and ellagic acid conjugates in food, beverages, and food supplements are essential starting points for studying their effect on human health. However, accuracy is hindered both by the lack of pure standard compounds and by methods that maintain the compounds in their native ...
Franzmann Carolin - - 2010
Ergot alkaloid and ricinoleic acid contents of 63 ergot sclerotia samples from rye throughout Germany of the harvest years 2006-2009 were determined. Alkaloid contents were analyzed by means of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) and ricinoleic acid contents by means of gas chromatography with flame ionization detection (GC-FID). ...
Salo Kent - - 2010
The enthalpy of sublimation has been determined for nine carboxylic acids, two cyclic (pinonic and pinic acid) and seven straight-chain dicarboxylic acids (C(4) to C(10)). The enthalpy of sublimation was determined from volatility measurements of nano aerosol particles using a volatility tandem differential mobility analyzer (VTDMA) set-up. Compared to the ...
Mallakpour Shadpour - - 2010
This is the first description of the application of molten tetrabutylammonium bromide (TBAB) in the presence of triphenyl phosphite (TPP) for the synthesis of novel polyamides (PAs). Monomer diacid, 5-[(9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximido)-3-methylbutanoylamino]isophthalic acid (4), having anthracenic and amino acid S-valine pendant group, was synthesized in four steps. Several novel, optically active PAs ...
Lowenthal Mark S - - 2010
An isotope-dilution liquid chromatography-tandem mass spectrometry (ID LC-MS/MS) measurement procedure was developed to accurately quantify amino acid concentrations in National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 2389a-amino acids in 0.1 mol/L hydrochloric acid. Seventeen amino acids were quantified using selected reaction monitoring on a triple quadrupole ...
Kucklick John R - - 2010
The National Institute of Standards and Technology (NIST) has a diverse collection of control materials derived from marine mammal blubber, fat, and serum. Standard Reference Material (SRM) 1945 Organics in Whale Blubber was recertified for polychlorinated biphenyl (PCB) congeners, organochlorine pesticides, and polybrominated diphenyl ether (PBDE) congeners. SRM 1945 has ...
Liu Yan - - 2010
A novel colorimetric luminescence sensor strip for the detection of indole-3-acetic acid (IAA) has been fabricated by using green emissive quantum dots of cadmium telluride (CdTe QDs) as a background layer and a red emissive europium chelate, [4'-(9-anthryl)-2,2':6',2''-terpyridine-6,6''-diyl]bis(methylenenitrilo) tetrakis(acetate)-Eu(3+) (ATTA-Eu(3+)), as a specific sensing layer coated on the surface of ...
Ben Rejeb Ines - - 2010
A new, simple, and original method is described for specific measurement of polyunsaturated fatty acid content in olive oil. This analytical system uses coupled enzymes, lipase and lipoxygenase. The system consists of lipase-catalyzed hydrolysis of triacylglycerol and subsequent lipoxygenation of liberated polyunsaturated fatty acids. The hydroperoxy-fatty acids formed were easily ...
Reenil? Ilkka - - 2010
Novel HPLC method utilizing UV-detection was developed to analyse catechol-O-methyltransferase (COMT) products, vanillic acid and isovanillic acid, S-adenosylhomocysteine (SAH) and adenosine formed from dihydroxybenzoic acid and S-adenosyl-L-methionine (SAM) by incubation of the rat tissues. Entacapone, a COMT inhibitor, prevented the formation of SAH only partially in the striatal homogenate whereas ...
Zhao Shulin - - 2010
Since the channels in micro- and nanofluidic devices are extremely small, a sensitive detection is required following microchip electrophoresis (MCE). This work describes a highly sensitive and yet universal detection scheme based on chemiluminescence resonance energy transfer (CRET) for MCE. It was found that an efficient CRET occurred between a ...
Caligiani Augusta - - 2010
1H NMR spectra were recorded of methanolic extracts of seven soybean varieties (Glycine max.), cultivated using traditional and organic farming techniques. It was possible to identify signals belonging to the groups of amino acids, carbohydrates, organic acids and aromatic substances in the spectra. In the aromatic zone, the isoflavone signals ...
Kang Gumin - - 2010
Mixed hydrofluoric and nitric acids are widely used as a good etchant for the pickling process of stainless steels. The cost reduction and the procedure optimization in the manufacturing process can be facilitated by optically detecting the concentration of the mixed acids. In this work, we developed a novel method ...
Liao Xiangjun - - 2010
An analytical method has been developed for the measurements of five urinary acids namely, quinolinic acid, picolinic acid, nicotinic acid, 2-pyridylacetic acid and 3-pyridylacetic acid. The high performance liquid chromatograph-electrospray ionization mass spectrometry was operated in positive polarity under selected ion monitoring mode, with a column flow rate of 0.2 ...
Huang Haowen - - 2010
In this paper, we have developed a simple, rapid, selective, and ultra-sensitive assay to detect cysteine by means of gold nanorods assembly. This methodology is based on the end-to-end assembly of gold nanorods and it is very sensitive due to the useful formation of the gold nanorods chain in the ...
Brand?n S A - - 2010
Theoretical calculations on the molecular geometry and the vibrational spectrum of 4-hydroxybenzoic acid were carried out by the Density Functional Theory (DFT/B3LYP) method. In addition, IR and Raman spectra of the 4-hydroxybenzoic acid in solid phase were newly recorded using them in conjunction the experimental and theoretical data (including SQM ...
Meng Qing H - - 2010
BACKGROUND: There have been an increasing number of reports on false increase of lactate in ethylene glycol poisoning. We recently encountered two cases of ethylene glycol poisoning with very high blood lactate concentrations on ABL blood gas analyzers. METHODS: Patient plasma lactate concentrations were measured on different chemistry instruments in ...
Nakano Shigenori - - 2010
A novel flow-injection spectrophotometry has been developed for the determination of molybdenum(VI) at nanograms per milliliter levels. The method is based on the catalytic effect of molybdenum(VI) on the bromate oxidative coupling of p-hydrazinobenzenesulfonic acid with N-(1-naphthyl)ethylenediamine to form an azo dye (lambda(max)=530nm). Chromotropic acid (4,5-dihydroxy-2,7-naphthalenedisulfonic acid) acted as an ...
Bednar A J - - 2010
Interest in tungsten occurrence and geochemistry is increasing due to increased use of tungsten compounds and its unknown biochemical effects. Tungsten has a complex geochemistry, existing in most environmental matrices as the soluble and mobile tungstate anion, as well as poly- and heteropolytungstates. Because the geochemistry of tungsten is substantially ...
Issa Y M - - 2010
Two simple and highly sensitive spectrophotometric methods were developed for the quantitative determination of the drug sildenafil citrate (SC), Viagra, in pure form and in pharmaceutical formulations, through ion-associate formation reactions (method A) with mono-chromotropic acid azo dyes, chromotrope 2B (I) and chromotrope 2R (II) and ion-pair reactions (method B) ...
Hama Yoichiro - - 2010
Here we report a simple method for the structural analysis of red algal galactan containing 3,6-anhydrogalactose. Structural heterogeneity in the galactan was demonstrated by this method. For selective hydrolysis of 3,6-anhydrogalactosidic linkages in the galactan, conditions for reductive mild acid hydrolysis were examined by characterizing the resulting oligosaccharide alditols by ...
Luo Liqiang - - 2010
A simple and rapid method for the determination of ferulic acid in pharmaceutical formulations by didodecyldimethylammonium bromide (DDAB)/Nafion composite film-modified carbon paste electrode is presented. The electrochemical behavior of ferulic acid at the proposed electrode was investigated by cyclic voltammetry and a well-defined oxidation peak was observed at +0.44 V ...
Petacci Fernando - - 2010
Astilbin (5,7,3',4'-tetrahydroxy-2,3-dihydroflavonol-3-ß-o-rhamnoside), a flavonoid with a large range of biological activities, was isolated from Dimorphandra mollis, a shrub common to the Brazilian Cerrado. The purpose of this study is to verify the effects of astilbin on myeloperoxidase (MPO) and horseradish peroxidase (HRP), and its antioxidant activity against hypochlorous acid (HOCl) ...
Kim Jisun - - 2010
Dopamine (DA) is one of the most important catecholamine neurotransmitter molecules in the central nervous system (CNS). An abnormal level of DA in vivo can cause CNS diseases such as Parkinsonism and Schizophrenia. Thus, it is essential to develop an accurate and easy to use method for determining the level ...
Sun L M - - 2010
AIMS: To clarify the underlying synergistic antifungal mechanisms of retigeric acid B (RAB) in combination with azoles against Candida albicans. METHODS AND RESULTS: Increased accumulation of rhodamine 123 in C. albicans was measured by both spectrophotometric method and flow cytometry. The inhibitory properties to the drug efflux of C. albicans ...
Sugimoto Naoki - - 2010
A quantitative NMR (qNMR) method was applied for the determination of carminic acid. Carminic acid is the main component in cochineal dye that is widely used as a natural food colorant. Since several manufacturers only provide reagent-grade carminic acid, there is no reference material of established purity. To improve the ...
Kinumi Tomoya - - 2010
We have developed an accurate and traceable quantitation method of proteins and peptides by isotope-dilution mass spectrometry with the precolumn derivatization for hydrolyzed amino acid. This method utilized N-butylnicotinic acid N-hydroxysuccinimide ester iodide as the derivatization reagent and C-30 reversed phase column for the separation. Quantitative results of porcine insulin ...
Xiang Zheng - - 2010
The inhibitory effect of smallanthaditerpenic acids A, B, C and D previously isolated from leaves of Smallanthus sonchifolius (yacon) on alpha-glucosidase were examined and their IC50 were determined to be 0.48 mg/mL, 0.59 mg/mL, 1.00 mg/mL, and 1.17 mg/mL respectively. In addition, a rapid, reliable RP-HPLC method for the analysis ...
Nording Malin L - - 2010
Airway inflammation characterizing asthma and other airway diseases may be monitored through biomarker analysis of exhaled breath condensate (EBC). In an attempt to discover novel EBC biomarkers, a high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method was used to analyze EBC from ten control non-asthmatics and one asthmatic ...
Komissarov Vsevolod V - - 2010
A novel one-pot method was developed for the synthesis of the title compounds starting from 4-chloro-1-aryl-1-butanones 1, phosphorus trichloride and acetic acid. The end products 2 were obtained in 20-94% yield. The cyclization step under acidic conditions probably occurs as a result of anchimeric assistance of the phosphonic acid group.
Huang Renliang - - 2010
A convenient and cost-efficient method featuring the integration of enzymatic and acid catalysis has been developed for the selective conversion of glucose into HMF, which provides a new strategy for HMF production from glucose.
Proskurnin Mikhail A - - 2010
As a primary aim, several approaches to photothermal (thermal-lens) and optoacoustic determination of exogenous pyrogens (lipopolysaccharides) based on photometric procedures for their determination at the microgram level and below are compared. The limits of detection of lipopolysaccharides by thermal-lens spectrometry and optoacoustic spectroscopy are at a level of 2-100 ng/mL, ...
Dubé Pascal - - 2009
Carbonyldiimidazole (CDI) was found to mediate the Lossen rearrangement of various hydroxamic acids to isocyanates. This process is experimentally simple and mild, with imidazole and CO(2) being the sole stoichiometric byproduct. Significant for large-scale application, the method avoids the use of hazardous reagents and thus represents a green alternative to ...
del Campo Gloria - - 2010
A quantitative method for the determination of caffeine, formic acid, trigonelline and 5-(hydroxymethyl)furfural (5-HMF) in soluble coffees by applying the proton nuclear magnetic resonance technique ((1)H NMR) is proposed. Each of these compounds records a singlet signal at the 7.6-9.5 ppm interval of the spectrum, and its area is used ...
Terasaki Masanori - - 2009
This study combined chemical analysis and bioassays of paper mill effluents and their components in order to determine their antiestrogenic activity. The bioassay comprised a yeast two-hybrid assay incorporating the estrogen receptor alpha (hERalpha) and an hERalpha competitive enzyme-linked immunosorbent assay (ELISA). Samples were fractionated by solid phase extraction (SPE) ...
Horák Tomás - - 2009
Solid-phase extraction (SPE), solid-phase microextraction (SPME) using carbowax/divinylbenzen fiber, and stir bar sorptive extraction (SBSE) followed by solvent back extraction have been used for the extraction of free fatty acids (caproic, caprylic, pelargonic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, and linolenic acids) from beer. Subsequent gas chromatographic analyses with ...
Granger Julie - - 2009
In environmental water samples that contain both nitrate (NO3-) and nitrite (NO2-), isotopic analysis of nitrate alone by all currently available methods requires pretreatment to remove nitrite. Sulfamic acid addition, used previously for this purpose (Wu JP, Calvert SE, Wong CS. Deep-Sea Research Part I - Oceanographic Research Papers 1997; ...
Alves Susana P - - 2009
The fatty acid (FA) analysis of grass and maize silages was studied by application of a direct transesterification method (DT) followed by purification by solid-phase extraction (SPE). The choice of the internal standard (IS) for quantification of FA by gas-liquid chromatography (GLC) was also studied. The acidic DT method applied ...
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