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Mandalakis Manolis - - 2010
The analysis of amino acids by gas chromatography mass spectrometry (GC-MS) after their derivatization with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide was investigated as an alternative approach for the determination of free (FAA) and combined amino acids (CAA) in aerosols. This technique showed excellent linearity with r(2) values ranging from 0.9029 to 0.9995 and instrumental ...
Tang Xiaofeng - - 2010
A novel and simple method for the direct and quantitative determination of L-tryptophan (Trp), L-tyrosine (Tyr) and L-cysteine (Cys) was proposed in this work. Carbon nanofibers (CNFs), made by electrospinning technique, were used to modify carbon paste electrode (CPE) without any treatment to study the electrochemical behaviors of the three ...
Zhang Wang-bing - - 2010
In this study we firstly report a new electrolytic cold vapor generation system for mercury determination on Pt/Ti cathode in the presence of organic acid catholyte. Comparing with the traditional inorganic acid, formic acid increased the signal intensity of Hg vapor from electrolytic generation on Pt cathode and reduced the ...
Haque Enamul - - 2009
A facile purification method for metal-organic frameworks (MOFs), especially the ones containing insoluble 1,4-benzenedicarboxylic acid (terephthalic acid) in the pore, has been suggested. The purification method consists of the treatment of the MOF with amides such as N,N-dimethylformamide, especially under ultrasound treatment. The purification is completed within 1 h at ...
Yu Jinghua - - 2009
A novel molecular imprinting-chemiluminescence (MI-CL) method for the determination of sorbic acid (SA) was established, taking the molecularly imprinted polymer (MIP) as recognition material and a novel rhodanine derivative as chemiluminescence reagent. The MIP was prepared by a self-assembly technique with SA as template molecule, methacrylic acid (MAA) as functional ...
Garrido-Delgado Rocio - - 2009
This article reports a method for determining organic acids by CE in order to obtain a characteristic fingerprint with a view to classifying white wine samples with the aid of multivariate statistics. The proposed method was optimized for the determination of the most abundant organic acids in wine (viz. succinic, ...
Caroprese Alessandro - - 2009
BACKGROUND/PURPOSE: Foot malodor is mostly due to short-chain fatty acids produced by bacterial metabolism of eccrine sweating. We aimed to develop a protocol for an objective (instrumental) efficacy evaluation of foot deodorant formulations. METHODS: Head-space solid-phase microextractions of target fatty acids from the feet of six healthy volunteers were analyzed ...
Naseri Abdolhossein - - 2009
The net analyte preprocessing/classical least-squares (NAP/CLS) method is a simple chemometric method that has been used for the simultaneous spectrophotometric determination of benzoic acid, sorbic acid, and ascorbic acid. The obtained results indicated that the performances of the NAP/CLS and partial least-squares methods were almost identical. The net analyte signal ...
Harp Bhakti Petigara - - 2009
A reversed-phase LC method was developed to determine two manufacturing intermediates in the monosulfo monoazo color additive D&C Red No. 34 and its lakes. The analytes are 2-amino-1-naphthalenesulfonic acid (Tobias acid) and 3-hydroxy-2-naphthalenecarboxylic acid (3-hydroxy-2-naphthoic acid). This method can be used for batch certification of the color additives by the ...
Liu Shubin - - 2009
Accurate predictions of molecular acidity using ab initio and density functional approaches are still a daunting task. Using electronic and reactivity properties, one can quantitatively estimate pKa values of acids. In a recent paper [S. B. Liu and L. G. Pedersen, J. Phys. Chem. A 113, 3648 (2009)], we employed ...
Zhang Shanqing - - 2009
A photoelectrochemical probe for rapid determination of chemical oxygen demand (COD) is developed using a nanostructured mixed-phase TiO2 photoanode, namely PeCOD probe. A UV-LED light source and a USB mircroelectrochemical station are powered and controlled by a laptop computer, which makes the probe portable for onsite COD analyses. The photoelectrochemical ...
Bottein Marie-Yasmine Dechraoui - - 2010
Brevetoxins (BTXs) are a class of cyclic polyether toxins produced by the dinoflagellate Karenia brevis. These substances are subject to extensive conjugative metabolism in shellfish. BTX-B forms a conjugate with cysteine and is oxidized and reduced to yield BTX-B2, which is further modified by fatty acid addition via cysteine amide ...
Schwarz Lothar - - 2009
Analytical standards are needed in latent fingerprint detection for research and development as well as for quality control in routine work because normal fingerprints are too varied for comparison studies and tests. One way is to create latent fingerprints. For the amino acid sensitive detection method this can be achieved ...
Bazel Yaroslav - - 2009
A new sensitive and selective spectrophotometric method has been developed for the determination of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid in pharmaceuticals in the presence of nicotinic acid. The method is based on the reaction of [2-(2,6-dichloro-phenylamino)-phenyl]-acetic acid with 1,3,3-trimethyl-5-phenyl-2-[3-(1,3,3-trimethyl-1,3-dihydro-indol-2-ylidene)-propenyl]-3H-indolium chloride (PIC) followed by the extraction of the formed ion associate into toluene and ...
Zhachkina Anna - - 2009
The gas phase acidity (DeltaH(acid) and DeltaG(acid)) and proton affinity (PA, and gas phase basicity (GB)) of adenine, guanine, and O(6)-methylguanine (OMG) have been examined using both theoretical (B3LYP/6-31+G*) and experimental (bracketing, Cooks kinetic) methods. We previously measured the acidity of adenine using bracketing methods; herein we measure the acidity ...
Crich David - - 2009
A method for the synthesis of peptidyl thioacids is described on the basis of the use of the N-[9-(thiomethyl)-9H-fluoren-2-yl]succinamic acid and cross-linked aminomethyl polystyrene resin. The method employs standard Boc chemistry SPPS techniques in conjunction with 9-fluorenylmethyloxycarbonyl protection of side-chain alcohols and amines and 9-fluorenylmethyl protection of side-chain acids and ...
Underwood Robyn M - - 2009
Indoor fumigation of honey bees, Apis mellifera L., with formic acid to control varroa mites, Varroa destructor Anderson & Trueman, allows simultaneous fumigation of multiple colonies with little labor input and good efficacy. Several experiments were designed to test the efficacy of formic acid as a treatment for honey bee ...
Deng Yan - - 2009
Various alkyl-phenylboronic acids have been widely used in the fields of electronics, chemistry, medicine and biology, especially in glucose sensors and intermediates of medicines. In this paper, the syntheses of two or three different alkyl-phenylboronic acids and the improvement on synthesis processes were studied with Grignard reagent method in detail. ...
Kumari Sangeeta - - 2010
We determined the gas-phase acidities (DeltaH(acid)) of four deoxyribonucleosides, i.e., 2'-deoxyadenosine (dA), 2'-deoxyguanosine (dG), 2'-deoxycytidine (dC), and 2'-deoxythymidine (dT) by applying the extended kinetic method. The negatively charged proton-bound hetero-dimeric anions, [A - H - B](-) of the deoxyribonucleosides (A) and reference compounds (B) were generated under electrospray ionization conditions. ...
Mossoba Magdi M - - 2009
Trans fatty acids are found in a variety of foods like dairy and meat products, but the major dietary sources are products that contain commercially hydrogenated fats. There has been a renewed need for accurate analytical methods for the quantitation of total trans fat since mandatory requirements to declare the ...
Golay Pierre-Alain - - 2009
To support labeling, claims, and authenticity of food products, industry needs reliable methods for the analysis of fatty acids, including trans fatty acids (TFA). In finished products, precise quantification of TFA can be problematic due to the occurrence of various positional and geometrical isomers originating from different sources, such as ...
Kanwal Shamsa - - 2009
A highly sensitive flow-injection chemiluminescent method for the direct determination of pyrogallol compounds has been developed. Proposed method is based on the enhanced effect of pyrogallol compounds on the chemiluminescence signals of KMnO(4)-H(2)O(2) system in slightly alkaline medium. Three important pyrogallol compounds, pyrogallic acid, gallic acid and tannic acid, have ...
Nurit Eric - - 2009
Biofortification programs in maize have led to the development of quality protein maize (QPM) with increased contents of the essential amino acids lysine and tryptophan, and increased nutritional value for protein deficient populations where maize is a staple food. Because multiple genetic systems control and modify the protein quality of ...
Zhu Shuyun - - 2009
Single-walled carbon nanohorn modified glassy carbon electrode (SWCNH-modified GCE) was first employed for the simultaneous determination of uric acid (UA), dopamine (DA), and ascorbic acid (AA). The SWCNH-modified GCE displayed excellent electrochemical catalytic activities. The oxidation overpotentials of UA, DA, and AA decrease significantly and their oxidation peak currents increase ...
Lee Bokyoung - - 2009
A method has been developed for the determination of the concentration of low molecular weight monocarboxylic acid gases in the atmosphere. The method involves quantitative collection of analyte gases using a parallel plate diffusion scrubber and subsequent ion analysis by ion chromatography. Among the gases are formic acid, acetic acid, ...
Gronert Scott - - 2009
The proton affinities of the 20 common amino acids have been computed at the G3MP2 level using structures derived from broad conformational searches at a variety of levels including G3MP2. In some cases, the conformational surveys identified more stable species than had been used in previous studies of proton affinities, ...
Liu Lin - - 2010
Diosgenin is an important starting material in the steroidal hormone industry. Traditionally, diosgenin is mainly produced by acid hydrolysis of Dioscorea zingiberensis C. H. Wright (DZW) tubers. This method yields numerous byproducts that can cause serious pollution. In this study, diosgenin was obtained by biotransformation of steroidal saponins in DZW ...
Vidal A - - 2009
The effect of cooking on the concentration and burden of domoic acid in two bivalve molluscs was studied. The Manila clam (Ruditapes philippinarum) and cockle (Cerastoderma edule) were subjected to steaming and boiling, respectively. In both cases, factorial plans were used to evaluate the effects of common cooking methods and ...
Seki Koh-ichi - - 2010
BACKGROUND, AIM, AND SCOPE: We recently developed a new isolation method for diesel exhaust particles (DEP), involving successive extraction with H(2)O, sodium bicarbonate, and sodium hydroxide, in which the sodium hydroxide extract was found to consist of phenolic components. Analysis of the extract revealed that vasodilative-active nitrophenols are in DEP ...
Elliott Douglas W - - 2009
The analysis of deuterium wideline NMR spectra has been an essential step in characterizing the dynamics of molecules in the solid-state. Although clearly important, the identification of quadrupolar coupling constants (QCCs) from the powder patterns is often complicated by poor sensitivity and/or spectral overlap. Previously, others have demonstrated the utility ...
Megdal Peter Andrew - - 2009
Mislabeling of farmed and wild salmon sold in markets has been reported. Since the fatty acid content of fish may influence human health and thus consumer behavior, a simplified method to identify wild and farmed salmon is necessary. Several studies have demonstrated differences in lipid profiles between farmed and wild ...
Huang Shan - - 2009
In this contribution, a simple and sensitive method for L-cysteine detection was established based on the increment of the fluorescence intensity of mercaptoacetic acid-capped CdSe/ZnS quantum dots (QDs) in aqueous solution. Meanwhile, the fluorescence characteristics and the optimal conditions were investigated in detail. Under the optimized conditions, the linear range ...
Baer Ines - - 2009
Fatty acids are the basis of so-called stearates which are frequently used as lubricants in the production of ecstasy tablets. Being a product added at the initial tablet production step its composition does not change once the compression is performed. The analysis of fatty acids can therefore provide useful information ...
Robert-Peillard Fabien - - 2009
This paper presents a simple, rapid, and accurate method suitable for on-site measurement of short-chain volatile fatty acids (SCFA) in various environmental samples. This fluorimetric method involves a derivatization step of SCFA with N-(1-naphthyl)ethylenediamine (EDAN) and allows determination of acetic, butyric, propionic, valeric, lactic, succinic, and p-hydroxybenzoic acids in approximatively ...
Qiu Jian-Ding - - 2009
Being the largest family of cell surface receptors, G-protein-coupled receptors (GPCRs) are among the most frequent targets. The functions of many GPCRs are unknown, and it is both time-consuming and expensive to determine their ligands and signaling pathways by experimental methods. It is of great practical significance to develop an ...
Guo Sheng - - 2009
A simple and sensitive HPLC-DAD method has been developed for the first time to simultaneously determine 10 triterpenoid acids (ceanothic acid, alphitolic acid, zizyberanal acid, zizyberanalic acid, epiceanothic acid, ceanothenic acid, betulinic acid, oleanolic acid, ursonic acid and zizyberenalic acid) in the dried fruit of Ziziphus jujuba (called Dazao) which ...
Rafamantanana M H - - 2009
The simultaneous quantification of madecassoside, asiaticoside, madecassic acid and asiatic acid in Centella asiatica by HPLC-UV is proposed. Asiaticoside was used as reference for the quantification of heterosides and asiatic acid for aglycones. The evaluation of the extraction efficiency of the four molecules led to use Soxhlet extraction for 8 ...
Gómez Edison Díaz - - 2009
Enantiopure alpha-amino acids were converted to 4-substituted 2-aryl- and 2-alkyl-5(4H)-oxazolones under partial racemization. These nonracemic mixtures were dissolved in CDCl(3), an equimolar amount of the chiral dirhodium complex Rh(II)(2)[(R)-(+)-MTPA](4) (MTPA-H = Mosher's acid) was added, and the (1)H NMR spectra of the resulting samples were recorded (dirhodium method). The relative ...
Dias Jailson C - - 2009
A new chromatographic method for the sequential determination of short-chain fatty acids is described. Acetic, propionic and butyric acids were determined in dietary fiber extracts using ion-exclusion chromatography equipped with inverse chemical suppression and conductivity detection. The best optimization of the chromatographic conditions were achieved when a 100 mm x ...
Nozawa Yuriko - - 2009
In the advanced Marfey's method, the resolution between the diastereomers derivatized with 1-fluoro-2,4-dinitrophenyl-5-L-leucinamide (L-FDLA) and 1-fluoro-2,4-dinitrophenyl-5-D-leucinamide (D-FDLA) is reflected by the difference of hydrophobicity of the two functional groups at the asymmetric carbon. However, no effective method has been developed for the estimation of hydrophobicity so far. For this purpose, ...
Sibrell Philip L - - 2009
Excess phosphorus in wastewaters promotes eutrophication in receiving waterways. A cost-effective method for the removal of phosphorus from water would significantly reduce the impact of such wastewaters on the environment. Acid mine drainage sludge is a waste product produced by the neutralization of acid mine drainage, and consists mainly of ...
Tonidandel Loris - - 2009
Baltic amber contains high levels of succinic acid, most of which is part of the polymer framework, and only recently has the presence of microcrystals of free succinic acid been documented by scanning electron microscopy and X-ray diffraction analysis. The determination of succinic acid can be used for an easy ...
Fukuzawa Kenji - - 2009
The ferric-xylenol orange (FOX) method has been used for quantification of hydroperoxides by measuring the colored ferric-xylenol orange (XO/Fe3+) product with a peak absorbance at 560 nm. We recently reported a modified FOX method, the sensitivity of which was increased in the presence of membranous phosphatidylcholine (PC) by forming a ...
Mayoral Jaime G - - 2010
A novel end-point fluorimetric procedure based on the use of rhodamine-110-labeled specific substrate was developed to determine trypsin activities in biological samples. We evaluated the ability of trichloroacetic acid and acetic acid to stop the enzymatic reaction without hindering the detection of the fluorescence of rhodamine-110 released into the reaction ...
Tomàs Albert - - 2009
A rapid methodology for direct analysis of meat acylglycerides is proposed. A transesterification is carried out in a microwave reactor consisting of a monomode oven using chlorotrimethylsilane (CTMS) and methanol. High-temperature gas chromatography was used to check the absence of underivatized acylglycerides. Whereas transesterification is complete after 30s at 90 ...
Patane Jonathan - - 2009
The hydrolysis of colominic acid via microwave irradiation was studied for the production of short-chain oligomers with a degree of polymerization (DP) of 1-5. This method was compared to the traditional acid hydrolytic method for the production of preparative quantities of short colominic acid oligomers. The oligomers were purified by ...
Fukuda Shinji - - 2009
BACKGROUND: Environmental processes in ecosystems are dynamically altered by several metabolic responses in microorganisms, including intracellular sensing and pumping, battle for survival, and supply of or competition for nutrients. Notably, intestinal bacteria maintain homeostatic balance in mammals via multiple dynamic biochemical reactions to produce several metabolites from undigested food, and ...
Xu Yawei - - 2009
A novel boronic acid functionalized mesoporous silica, which holds the attractive features of high surface area and large accessible porosity, was developed to enrich glycopeptides. This is the first time that mesoporous material has been introduced into glycoproteome. In comparison to direct (traditional) analysis, this novel method enabled 2 orders ...
Strable E - - 2009
Protein capsids derived from viruses may be modified by methods, generated, isolated, and purified on large scales with relative ease. In recent years, methods for their chemical derivatization have been employed to broaden the properties and functions accessible to investigators desiring monodisperse, atomic-resolution structures on the nanometer scale. Here we ...
Yasaka Yoshiro - - 2009
A sensitive in situ NMR spectroscopic method for detecting acids contaminating ionic liquids (ILs) has been developed. The chemical shift and the spectral width of water added to ILs were used as indicators to measure the impurity acid level. Owing to the high resolution power of NMR, the detection limit ...
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