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Fraser Donald G - - 2011
Recent work shows a correlation between chiral asymmetry in non-terrestrial amino acids extracted from the Murchison meteorite and the presence of hydrous mineral phases in the meteorite [D. P. Glavin and J. P. Dworkin, Proc. Natl. Acad. Sci. U. S. A., 2009, 106, 5487-5492]. This highlights the need for sensitive ...
Mohammad Ali - - 2010
A new green TLC has been used for identifying and monitoring the migration behavior of amino acids through silica and kieselguhr static flat bed in contact of n-butyl alcohol, ethyl acetate or ethylene glycol and their mixtures. From the point of view of chromatographic performance, a mixture of n-butyl alcohol-70% ...
Lu Yuanqi - - 2010
Electrokinetic supercharging (EKS), a new and powerful on-line preconcentration method for capillary electrophoresis, was utilized in non-aqueous capillary electrophoresis (NACE) to enhance the sensitivity of phenolic acids. The buffer acidity and concentration, leader and terminator length and electrokinetic injection time were optimised, with the optimum conditions being: a background electrolyte ...
Oliveira Andreia P AP REQUIMTE/Laboratory of Pharmacognosy, Faculty of Pharmacy, Porto University, Rua Aníbal Cunha 164, 4050-047 Porto, - - 2010
Latex is a sticky emulsion that exudes upon damage from specialized canals from several plants. It contains several biologically active compounds, such as phytosterols, fatty acids, and amino acids. In plants, these compounds are involved in the interaction between plants, insects, and the environment. Despite its chemical, biological, and ecological ...
Kuo Jen-Ni - - 2010
Water runoff from catch basins treated with Altosid® XR Briquets for mosquito larvae control was sampled at 10 storm drainage pump stations along the outskirts of the city of Richmond, British Columbia, Canada after rainfall events in 2006 to determine the residual concentrations of methoprene and transformation products: citronellic acid, ...
Ross David - - 2010
A new method is described for two-dimensional (2D) separations using a microfluidic chip normally employed for single dimension electrophoresis. The method employs a combination of gradient elution moving boundary electrophoresis (GEMBE) and chiral capillary zone electrophoresis (CZE). The simplicity of the first dimension GEMBE method enables its implementation in the ...
Chen Jun - - 2011
(2S,3S)-2,3-Bis(3,5-dimethylphenylcarbonyloxy)-3-(benzyloxycarbonyl)-propanoic acid and (2S,3S)-2,3-bis(1-naphthalenecarbonyloxy)-3-(benzyloxycarbonyl)-propanoic acid were synthesized from D-tartaric acid. These two compounds were chlorinated to afford two chiral selectors for chiral stationary phases (CSPs). The selectors were separately immobilized on aminated silica gel to give two single selector CSPs; and were simultaneously immobilized to obtain a mixed selector CSP. ...
Matsui Toshiro T Division of Bioresources and Biosciences, Faculty of Agriculture, Graduate School of Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, - - 2010
The candidates responsible for vasorelaxation action of rutin-free tartary buckwheat extract (TBSP) were examined in this study. As a result of reversed-phase high-performance liquid chromatography (HPLC) separations, five prominent peaks in the acidic fraction of TBSP were obtained at 260 nm. Among the five collected peaks, we successfully identified four ...
Bielawska K - - 2010
Fatty acids participate in different metabolic mechanisms, but their key role is connected with their participation in membrane phospholipid organizations. This review introduces the current knowledge of fatty acid analysis with an emphasis on the analysis of these compounds in biological samples. Therefore this manuscript is focused on various aspects ...
Han Shu-ying - - 2010
Simple acids are usually applied to suppress the ionization of weakly ionizable acidic analytes in reversed-phase liquid chromatography. The purpose of this study is to investigate the retention behavior of various weak acidic compounds (monoprotic, diprotic, triprotic, and tetraprotic acids) using acetic or perchloric acid as ion suppressor in a ...
Huang Zhibing - - 2010
A high-performance liquid chromatography (HPLC) method was developed for the separation of lovastatin (LT) and its derivatives. The conversion of LT and its derivatives in alkaline or acidic solution in different storage times was also investigated by HPLC. The results showed that LT was present in different forms: as a ...
Kacprzak Karol - - 2010
Replacement of the flexible thioether linker for the novel, rigid 1,2,3-triazole spacer group in the course of immobilization of quinine tert-butyl carbamate onto a silica surface led to a chiral stationary phase (CSP) with enhanced enantioselectivity for the resolution of mandelic acid and derivatives thereof. These new CSPs allowed efficient ...
Sun Chong - - 2011
As shown herein, a normal moving reaction boundary (MRB) formed by an alkaline buffer and a single acidic buffer had poor stacking to the new important plant growth promoter of phenazine-1-carboxylic acid (PCA) in soil due to the leak induced by its low pK (a). To stack the PCA with ...
Zinellu Angelo - - 2010
The role of neurotransmitter amino acids (NAAs) in the functioning of the nervous system has been the focus of increasingly intense research over the past several years. Among the various amino acids that have important roles as neurotransmitters, there are alanine (Ala), glutamic acid (Glu), aspartic acid (Asp), serine (Ser), ...
Tóth Gábor K - - 2011
Meso diaminopimelic acid is an important noncoded amino acid found in Gram-negative bacterial peptidoglycan. In spite of its importance, this stereoisomer is not available commercially. A simple, economical procedure was developed for the isolation of pure meso diaminopimelic acid via an high-performance liquid chromatography separation. In our new approach, the ...
Zhou Lin - - 2010
Field-amplified sample stacking using a fused silica capillary coated with gold nanoparticles (AuNPs) embedded in poly(diallyl dimethylammonium) chloride (PDDA) has been investigated for the electrophoretic separation of indoxyl sulfate, homovanillic acid (HVA), and vanillylmandelic acid (VMA). AuNPs (27 nm) exhibit ionic and hydrophobic interactions, as well as hydrogen bonding with ...
Jelly R - - 2010
In this paper, we present our preliminary studies into naphthoquinones as novel reagents for the detection of latent fingermarks on paper. Latent fingermarks deposited on paper substrates were treated with solutions of selected naphthoquinones in ethyl acetate/HFE-7100, with subsequent heating. The selected compounds were 1,4-dihydroxy-2-naphthoic acid, 1,2-naphthoquinone-4-sulfonate, 2-methoxy-1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone. ...
Zhu Haibao - - 2010
Ion chromatography has been proposed for the determination of three common inorganic anions (chloride, nitrate, and sulfate) in nine weak acids (tartaric acid, citric acid, formic acid, acetic acid, metacetonic acid, butyric acid, butanedioic acid, hexafluorophosphoric acid, and salicylic acid) using a single pump, two valves, a single eluent, and ...
Desiderio Claudia - - 2010
In this review, the recent contribution of CE-MS technology to the analysis of amino acids, as well as the advantages of the hyphenation and the technologies involved in the instrumental coupling are reported. Different sections are dedicated to the recent contributions of CE-MS to the analysis of protein amino acids ...
Tůma Petr - - 2010
CE with contactless conductivity detection has been used to separate 28 biogenic amino acids in a short capillary with an effective length of 18 cm. All the tested amino acids can be mutually separated in 0.5-10 mol/L acetic acid electrolytes. The time of analysis does not exceed 6 min and ...
Zhou Wen-Hui - - 2010
In this work, we describe a simple, inexpensive and fast method for the generation of molecularly imprinted polymer (MIP) film on quartz crystal microbalance (QCM) crystals using mussel-inspired polymer. Commonly known as a neurotransmitter, dopamine is also a small-molecule mimic of the adhesive proteins of mussels. Polymerization of dopamine in ...
Wei Xiaohan - - 2010
Gold nanoparticles (GNPs) were allowed to self-assemble onto a glassy carbon electrode (GCE) that was prior modified by L-cysteine. The modified electrode was then used as a voltammetric sensor in detecting the neurotransmitter serotonin. The electrode exhibited a linear voltammetric response for serotonin within a concentration range of 6.0 x ...
Kotthaus A F - - 2011
A new chiral derivatizing agent for α-amino acids is described which leads to diastereomers that can be separated by reverse-phase HPLC with direct detection by a diode array detector. The main advantage of the presented procedure is the fact that an excess of the derivatizing reagent can be employed as ...
Weng Yu-Hsiang - - 2010
This work studied the concentration of hydrolyzates obtained from dilute acid hydrolysis of rice straw using nanofiltration (NF). In order to minimize the Donnan exclusion effect of the membrane, the hydrolyzate solution was controlled at low pH value. Negative retentions of both furans and carboxylic acids were observed. The maximum ...
Lu Yuanqi - - 2010
A method was developed to analyze phenolic acids by nonaqueous CE after online concentration with electrokinetic supercharging. The EOF was reversed using a polyelectrolyte multilayer approach based on the successive adsorption of poly(diallyldimethylamonium chloride) and poly(styrenesulfonate) to reduce the analysis time. The results showed that the coatings were stable during ...
Kim Hyun - - 2010
During the replicate analysis of melamine and cyanuric acid by LC-ESI MS/MS for the method development, recurring cyanuric acid contamination was observed. The high concentration (6,950 mg/kg) of cyanuric acid was found in the strong alkali detergent used in a glassware washing machine. However, only small concentration of cyanuric acid ...
Bhushan Ravi - - 2011
Two new chiral monochloro-s-triazines (MCT) were synthesized [viz N-(4-chloro-6-piperidinyl-[1,3,5]-triazine-2-yl)-L-leucine amide and N-(4-chloro-6-piperidinyl-[1,3,5]-triazine-2-yl)-L-leucine) (CDR 1 and 2, respectively)] by the nucleophilic displacement of chlorine atoms in s-triazine moiety. One of the Cl atoms was replaced with piperidine, and the second Cl atom in the 6-piperidinyl derivative was replaced with amino acid ...
Lin Chun - - 2010
Two types of chiral stationary phases for HPLC based on pi-acidic or pi-basic perphenylcarbamoylated beta-CDs were synthesized. The relative structural features of the two effective chiral selectors are discussed and compared in both normal-phase and RP modes. In addition, the nature and concentration of alcoholic modifiers were varied for optimal ...
Dossou Katina S S - - 2010
The resolving power of a new commercial polysaccharide-based chiral stationary phase, Sepapak-4, with cellulose tris(4-chloro-3-methylphenylcarbamate) coated on silica microparticles as chiral selector, was evaluated toward the enantioseparation of ten basic drugs with widely different structures and hydrophobic properties, using ACN as the main component of the mobile phase. A multivariate ...
Abou Elseoud Salwa M F - - 2010
Biomphalaria alexandrina snails play an indispensable role in transmission of schistosomiasis. Infection rates in field populations of snails are routinely determined by cercarial shedding neglecting prepatent snail infections, because of lack of a suitable method for diagnosis. The present study aimed at separation and quantification of oxalic, malic, acetic, pyruvic, ...
Ye Fanggui - - 2010
A new type of chiral silica monolith was successfully developed for the enantioseparation of phenylthiocarbamyl amino acids (PTC-(D/L)-AAs) by CEC. The bare monolithic silica column was prepared by a sol-gel process and has been modified chemically with aminopropyltrimethoxysilane, followed by immobilization of a chiral selector maleopimaric acid anhydride. Eight pairs ...
Ye Fanggui - - 2010
A method based on MCE coupled with chemiluminescence (CL) detection was developed for the determination of taurine (Tau) and amino acids including alanine (Ala), glycine (Gly), tryptophan (Trp), glutamic acid (Glu) and aspartic acid (Asp) present in mice single fibrosarcoma (S180) cells. Cell injection, loading, cytolysis, electrophoretic separation and CL ...
Sun Chuanmin - - 2010
We report a "mild anodization" (MA) process using aluminum oxalate (Alox) as an additive to suppress breakdown of porous anodic alumina (PAA) in the electrolyte of phosphoric acid at high potentials and comparatively high temperatures. It is shown for the first time that continuously tunable pore intervals (D(int)) from 410 ...
Puchalska Patrycja - - 2010
A new chiral stationary phase based on continuous bed (CB) technology using L-prolinamide as a chiral selector was prepared. Its ability for enantioseparation of amino acids and alpha-hydroxy acids by ligand-exchange CEC was compared with that of a CB containing L-4-hydroxyproline as chiral selector. Preparation was done by a one-step ...
Bai Yu Jing - - 2010
Allergies are highly complex disorders with clinical manifestations ranging from mild oral, gastrointestinal, recurrent wheezing, and cutaneous symptoms to life-threatening systemic conditions. The levels of arachidonic acid, eicosanoids, histamine, organic acids and valine are considered to have a variety of physiological functions in connection with allergies. In this research, we ...
Cizm?rikov? R - - 2010
An enantioseparation study of nitro-substituted aryloxyaminopropanols was performed using HPLC on a teicoplanin chiral stationary phase and TLC impregnated with L-aspartic and L-tartaric acid as chiral selectors. The type of substituent on the nitrogen in the hydrophilic part of molecule is essential for excellent separation by HPLC. L-aspartic acid seems ...
Bao Jia - - 2010
Perfluorinated compounds (PFCs) have been determined in various matrices within China including water bodies, precipitations, biota and non-occupationally PFCs-exposed populations in recent years, yet little attention has been focused on the distributions of PFCs in urban river sediments from Chinese major metropolises such as Guangzhou and Shanghai so far. In ...
Ito Akitaka - - 2010
A novel ratiometric fluorescent sensor 1 having the 4-(N,N-dimethylamino)benzoate (DMAB) group as a twisted intramolecular charge transfer (TICT) dual fluorescence site and the guanidinium group as a binding site for an amino acid at the 12- and 3-positions of cholic acid, respectively, was designed and synthesized. The sensor 1 showed ...
Zhai Chun - - 2010
A method for fast sensitive ultraviolet detection of amino acids was developed with a disposable electrophoresis microdevice. The microdevice was conveniently constructed by fixing a fused-silica capillary with a sampling fracture to a printed circuit board. During the separation process, the on-column conjugation of amino acids with cupric cation led ...
Abdul Rahman Mohd Basyaruddin - - 2010
This paper reports the synthesis of a series of new tetraethylammonium-based amino acid chiral ionic liquids (CILs). Their physico-chemical properties, including melting point, thermal stability, viscosity and ionic conductivity, have been comprehensively studied. The obtained results indicated that the decomposition for these salts proceeds in one step and the temperature ...
Tian Shuge - - 2010
A simple, precise, rapid and accurate, binary-phase high performance liquid chromatographic method has been developed for the determination of oleanolic acid and ursolic acid contents in the Ziziphora clinopodioides Lam. with short run time. Chromatographic separation is achieved by using HPLC system consisting of a Shimadzu LC-6AD and Kromasil C(18) ...
Szabo Zoltan Z Barnett Institute, Northeastern University, Boston, MA, - - 2010
CE is a high-resolution separation technique broadly used in the biotechnology industry for carbohydrate analysis. The standard sample preparation protocol for CE analysis of glycans released from glycoproteins generally requires derivatization times of overnight at 37 degrees C, using > or =100 fold excess of fluorophore reagent, 8-aminopyrene-1,3,6-trisulfonic-acid, if the ...
Liang Guodong - - 2010
A highly sensitive method for chiral analysis of amino acids by in-line single drop microextraction (SDME) and chiral capillary electrophoresis (CE) with laser-induced fluorescence (LIF) detection was developed. In SDME, a drop of a basic aqueous acceptor phase covered with a thin organic layer was formed at the tip of ...
Castro Joaudimir - - 2010
A liquid chromatography-particle beam/mass spectrometry (LC-PB/MS) method with electron impact (EI) and glow discharge (GD) ionization sources is presented for the determination of caffeic acid derivatives in echinacea tinctures. In this work, two commercially available echinacea ethanolic extracts were used as the test samples for the separation, identification, and quantification ...
Park Yang-Ki - - 2010
Single drop microextraction (SDME) can be in-line coupled with capillary electrophoresis by attaching a drop to the tip of a capillary. With a 2-layer drop comprised of an aqueous basic acceptor phase covered with a thin organic layer, acidic analytes in an aqueous acidic donor phase can be extracted into ...
Miyata Kanjiro - - 2010
Silica-coating of positively charged polyplexes was demonstrated through silicic acid condensation to improve the polyplexes for enhanced complex stability and transfection efficiency. Silicic acid was efficiently condensed by polycations to form a silica network in the polyplex through electrostatic interaction and hydrogen bonding. The silica-coated (SC) polyplexes had an anionic ...
Szabo Zoltan - - 2010
CE is a high-resolution separation technique broadly used in the biotechnology industry for carbohydrate analysis. The standard sample preparation protocol for CE analysis of glycans released from glycoproteins generally requires derivatization times of overnight at 37 degrees C, using >/=100 fold excess of fluorophore reagent, 8-aminopyrene-1,3,6-trisulfonic-acid, if the sample is ...
Hulbert A J - - 2010
More than 100 years ago, Max Rubner combined the fact that both metabolic rate and longevity of mammals varies with body size to calculate that "life energy potential" (lifetime energy turnover per kilogram) was relatively constant. This calculation linked longevity to aerobic metabolism which in turn led to the "rate-of-living" ...
Qi Li - - 2010
A new strategy for the enantioseparation of D,L-amino acids employing the principle of ligand exchange capillary electrophoresis with Zn(II)-L-valine complex as a chiral selecting system in the presence of beta-cyclodextrin has been designed. Successful enantioseparation of label free and labeled amino acids have been achieved with a buffer of 100.0mM ...
Dell'mour Madeleine - - 2010
Analysis of underivatized amino acids is challenging regarding the separation as well as the detection of these small polar analytes. Hydrophilic interaction LC using a 2.1x150 mm ZIC (ZIC, zwitterionic)-hydrophilic interaction LC from SeQuant as stationary phase with 1% v/v formic acid in water and ACN as eluents was combined ...
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