ElectrophoresisThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

This page shows you the latest items in this publication.

Pages: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

1144 records returned

On-chip coupling of free-solution transient ITP and CGE for highly efficient separation of dsDNA with variable sample loading amountsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We developed an on-chip DNA analysis method, in which free-solution transient isotachophoresis (FstITP) were coupled with CGE. Using chloride ions in the sample matrix and HEPES in the background electrolyte, respectively, as the leading and terminating ions, dsDNAs were isotachophoretically preconcentrated in free-solution and then separated in sieving polymer. The coupling of FstITP and CGE enabled higher separation efficiency due to higher preconcentration rate in free-solution. The FstITP-CGE analysis offered adjustable signal intensities by varying sample injection time. With the maximum sample loading volume, the LOD...
Source: Electrophoresis - November 18, 2009 Category: Biochemistry Authors: Dayu Liu, Bin Chen, Lihui Wang, Xiaomian Zhou Source Type: journals

Capillary electrochromatography with packed bead beds in microfluidic devicesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Microchip-based bead-packed columns for electrochromatography are described for several types of stationary phases. Chromatography columns 2 mm in length were used for the separation of proteins and peptides by size- and ion-exchange modes of separation, respectively. In size-exclusion electrochromatograpgy, FITC-IgG and FITC-insulin were baseline resolved in less than 10 s, with efficiencies of up to 139,000 plates/m for FITC-insulin. In strong cation-exchange electrochromatography, a mixture of three fluorescently labeled peptides was baseline resolved in less than 40 s, with efficiencies up to 400,000 plates/m. The RSD ...
Source: Electrophoresis - November 18, 2009 Category: Biochemistry Authors: Abebaw B. Jemere, Dolores Martinez, Michael Finot, D. Jed Harrison Source Type: journals

Continuous fractionation of a two-component mixture by zone electrophoresisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Synchronized continuous-flow zone electrophoresis is a recently demonstrated tool for performing electrophoretic fractionation of a complex sample. The method resembles free flow electrophoresis, but unlike in that technique, no mechanical fluid pumping is required. Instead, fast electrokinetic flow switching is used to produce complex stream patterns, which results in lateral separation of components in a separation chamber. Here a solution is presented which allows for simultaneous collection of two fractions in synchronized continuous-flow zone electrophoresis. The method is demonstrated on a model mixture, with subsequ...
Source: Electrophoresis - November 18, 2009 Category: Biochemistry Authors: Dawid R. Zalewski, Han J.G.E. Gardeniers Source Type: journals

Polymer microchip CE of proteins either off- or on-chip labeled with chameleon dye for simplified analysisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Microchip CE of proteins labeled either off- or on-chip with the "chameleon" CE dye 503 using poly(methyl methacrylate) microchips is presented. A simple dynamic coating using the cationic surfactant CTAB prevented nonspecific adsorption of protein and dye to the channel walls. The labeling reactions for both off- and on-chip labeling proceeded at room temperature without requiring heating steps. In off-chip labeling, a 9 ng/mL concentration detection limit for BSA, corresponding to a [sim]7 fg (100 zmol) mass detection limit, was obtained. In on-chip tagging, the free dye and protein were placed in different reservoirs of...
Source: Electrophoresis - November 18, 2009 Category: Biochemistry Authors: Ming Yu, Hsiang-Yu Wang, Adam T. Woolley Source Type: journals

Rapid magnetic microfluidic mixer utilizing AC electromagnetic fieldEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper presents a novel simple micromixer based on stable water suspensions of magnetic nanoparticles (i.e. ferrofluids). The micromixer chip is built using standard microfabrication and simple soft lithography, and the design can be incorporated as a subsystem into any chemical microreactor or a miniaturized biological sensor. An electromagnet driven by an AC power source is used to induce transient interactive flows between a ferrofluid and Rhodamine B. The alternative magnetic field causes the ferrofluid to expand significantly and uniformly toward Rhodamine B, associated with a great number of extremely fine finger...
Source: Electrophoresis - November 17, 2009 Category: Biochemistry Authors: Chih-Yung Wen, Cheng-Peng Yeh, Chien-Hsiung Tsai, Lung-Ming Fu Source Type: journals

Monolithic silica capillary columns with immobilized cellulose tris(3,5-dimethylphenylcarbamate) for enantiomer separations in CECEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Two types of monolithic silica capillary columns with an immobilized cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) selector were prepared for enantiomer separations in CEC. The monolithic columns were prepared by a sol-gel process in fused-silica capillaries. CDMPC was then either immobilized on a silica monolith through an intermolecular polycondensation of the cellulose derivative containing a triethoxysilyl group, or on a vinylized silica monolith through radical copolymerization of the cellulose derivative, which also contained a vinyl group. IR spectra confirmed the successful immobilization of CDMPC on both col...
Source: Electrophoresis - November 3, 2009 Category: Biochemistry Authors: Chiyang He, Ans Hendrickx, Debby Mangelings, Johanna Smeyers-Verbeke, Yvan Vander Heyden Source Type: journals

Filmy channel microchip with amperometric detectionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this article, a new type of microchip with filmy channels and a sample-injection fracture is introduced. Unlike commercial microchip, new microchip possessed filmy channel with width 2-3 mm. The effective cooling ability made filmy channel microchip restrain the generation of Joule heat even under electric field of 588 V/cm. Moreover, wider channel could be more easily modified to prevent the absorption of samples, load more samples and result in a higher sensitivity. Sample-injection fracture was first applied to match the filmy channel in microchip. Equipped with an amperometric detector, the characteristics of the ne...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Wei Wang, Feng F u Fu, Xueqin Xu, Jin-Ming Lin, Guonan Chen Source Type: journals

Determination of isocyanates by capillary electrophoresis with tris(2,2[prime]-bipyridine)ruthenium(II) electrochemiluminescenceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CE with tris(2,2[prime]-bipyridyl) ruthenium(II) (Ru(bpy)32+) electrochemiluminescence (ECL) detection for the quantitative determination of isocyanates was first reported. Hexamethylene diisocyanate (HDI) and hexyl isocyanate (HI) were used as the model analytes. Commercially available N,N-diethyl-N[prime]-methylethylenediamine was used as the derivatization reagent. It has both a secondary amine group and a tertiary amine group. The secondary amine group can quantitatively react with isocyanate group, and the tertiary amine group can react with Ru(bpy)32+ to produce strong ECL signal for sensitive detection. The derivati...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Haijuan Li, Lihong Shi, Xiaoqing Liu, Wenxin Niu, Guobao Xu Source Type: journals

Chirally functionalized anion-exchange type silica monolith for enantiomer separation of 2-aryloxypropionic acid herbicides by non-aqueous capillary electrochromatographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A silica based monolithic capillary column derivatized with O-9-(tert-butylcarbamoyl)quinidine was prepared for CEC enantiomer separation of chiral 2-aryloxypropionic acid herbicides including inter alia dichlorprop, mecoprop and fenoprop. The silica monolith had a relatively low surface coverage with chiral cationic selector moieties. Due to the low selector density retention factors were low as well, yet still enabling enantiomer separations of the target solutes. Both electrophoretically and chromatographically dominated migration and separation modes, respectively, could be established depending on the employed conditi...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Stefanie Buchinger, Beatrix Follrich, Michael Lämmerhofer, Dieter Lubda, Wolfgang Lindner Source Type: journals

Surfactant-bound monolithic columns for CECEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel anionic surfactant bound monolithic stationary phase based on 11-acrylaminoundecanoic acid is designed for CEC. The monolith possessing bonded undecanoyl groups (hydrophobic sites) and carboxyl groups (weak cationic ion-exchange sites) were evaluated as a mixed-mode stationary phase in CEC for the separation of neutral and polar solutes. Using a multivariate D-optimal design the composition of the polymerization mixture was modeled and optimized with five alkylbenzenes and seven alkyl phenyl ketones as test solutes. The D-optimal design indicates a strong dependence of electrochromatographic parameters on the conce...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Congying Gu, Jun He, Jinping Jia, Nenghu Fang, Shahab A. Shamsi Source Type: journals

Functionalized carbon nanotubes as the pseudostationary phase for capillary EKC separation of non-steroidal anti-inflammatory drugsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Functionalized multiwalled carbon nanotubes (f-MWCNTs) can serve as the pseudostationary phase (PSP) for the capillary EKC separation of non-steroidal anti-inflammatory drugs (NSAIDs). To increase their hydrophilicity, we treated MWCNTs, with a sonochemical process in a concentrated nitric/sulfuric acid mixture. The oxidized MWCNTs were then characterized by FT-IR, transmission electron microscopy, and X-ray photoelectron spectroscopy. We evaluated the potential of the PSP and the effects of buffer composition, pH, addition of organic modifier, and injection temperature on the NSAID separation. The PSP created a network st...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Yi-Jin Huang, Guan-Ren Wang, Kuan-Pin Huang, Yu-Fang Hsieh, Chuen-Ying Liu Source Type: journals

CE-ESI-MS analysis of singly charged inorganic and organic anions using a dicationic reagent as a complexing agentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A dicationic ion-pairing reagent, N,N[prime]-dibutyl 1,1[prime]-pentylenedipyrrolidinium, was used to form complexes with singly charged anions for their subsequent analysis by CE-ESI-MS in positive ion mode. This methodology offers the advantages of greater versatility and sensitivity relative to direct detection of the anions in negative ion mode, and it can be realized by a number of possible complexation strategies, including pre-column, on-column, and post-column modes. Four model anions, perfluorooctanoate, benzenesulfonate (BZSN), monochloroacetate (MCA), and trifluoromethanesulfonimide were amenable to complexation...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Xiuli Lin, Anthony R. Gerardi, Zachary S. Breitbach, Daniel W. Armstrong, Christa L. Colyer Source Type: journals

Analyses of sulfonamide antibiotics by CEC using poly(divinylbenzene-1-octadecene-vinylbenzyl trimethyl ammonium chloride) monolithic columnsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a series of novel polymeric monolithic columns prepared by single-step in situ copolymerization of 1-octadecene (OD), divinylbenzene (DVB) and/or styrene (S), were developed as separation columns for the sulfonamide analyses. On the CEC method, the composition of monomer mixtures (i.e. the ratio of S versus OD), content of charge-bearing monomer (vinylbenzyl trimethylammonium chloride) and volume fraction ratio of ACN in the mobile phase, was found to be the predominant influences for sulfonamide separation. Furthermore, an online sample concentration step, field-amplified sample injection, was used to enhan...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Cheng-Lan Lin, Yi-Jie Cheng, Hsi-Ya Huang, Szetsen Lee Source Type: journals

Noncovalent poly(1-vinylpyrrolidone)-based copolymer coating for the separation of basic proteins and lipoproteins by CEEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A new simple and fast noncovalent coating method based on poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) copolymer was developed for CE. Merely 2 min flushing of the capillary with the poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) copolymer was required. The copolymer is adsorbed onto the fused-silica surface by hydrogen bonding and electrostatic interactions. EOF was almost totally suppressed over a wide pH range. The coating conditions (flushing time, copolymer concentration, and the concentration and pH of background electrolyte solution) and the stability of the coating were optimized, an...
Source: Electrophoresis - November 2, 2009 Category: Biochemistry Authors: Ai-Jun Wang, Joanna Witos, Lucia D'Ulivo, Kati Vainikka, Marja-Liisa Riekkola Source Type: journals

CEC: A tool for mimicking collagen-surface interactions with apolipoprotein B-100 peptidesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, stable collagen and collagen-decorin coatings were prepared on the inner surfaces of fused silica CEC capillaries, enabling study of the interactions between collagen and selected peptide fragments of apolipoprotein B-100 (apoB-100), the main protein of low-density lipoprotein (LDL) particles. Interactions of positive, neutral, and negative peptide fragments of apoB-100 were elucidated. The selected positive peptide contains the sequence involved in the interaction of LDL with LDL receptor and proteoglycans. Retention factors of the peptides that were determined without any voltage, by exploiting pressure, g...
Source: Electrophoresis - October 29, 2009 Category: Biochemistry Authors: Lucia D'Ulivo, Joanna Witos, Katariina Öörni, Petri. T. Kovanen, Marja-Liisa Riekkola Source Type: journals

Etched succinate-functionalized silica hydride stationary phase for open-tubular CECEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An open-tubular (OT) CEC column was designed to anchor ionizable succinate-functionalized ligands onto a silica hydride-based stationary phase through surface etching, silanization, and hydrosilation reactions beginning from a bare fused-silica tube. The modified columns that were produced in each step were monitored by analysis of the effect of performance of EOF on the changes of pH values, concentrations, and the amount of ACN added in the running buffers. By tracking the EOF patterns between columns, the author determined that the surface composition of the final product column was a combination of silanols, silica hyd...
Source: Electrophoresis - October 28, 2009 Category: Biochemistry Authors: Jian-Lian Chen Source Type: journals

Cellulose dimethylphenylcarbamate-immobilized zirconia for chiral separation in reversed-phase CECEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cellulose dimethylphenylcarbamate (CDMPC)-immobilized zirconia (CDMPCZ) was used as a chiral stationary phase for enantioseparation of a set of nine racemic compounds in reversed-phase CEC. Influences of the type and composition of organic modifier and the applied voltage on enantioseparation were examined. Separation data on CDMPCZ were also compared with those on CDMPC-immobilized silica (CDMPCS). Enantiomers of the analytes investigated are well separated in ACN/phosphate buffer mobile phases. Better enantioselectivity and resolution were obtained with ACN than MeOH as the organic modifier. Retention was longer but bett...
Source: Electrophoresis - October 28, 2009 Category: Biochemistry Authors: Jurim Gwon, Juhyeon Jin, Clayton V. McNeff, Jung Hag Park Source Type: journals

Determination of related substances of levodopa including the R-enantiomer by CEEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A CE assay for the simultaneous determination of the impurities of levodopa listed in the European Pharmacopoeia including the (R)-enantiomer was developed and validated. The analysis was performed in a fused-silica capillary employing sulfated [beta]-cyclodextrin as chiral selector at an applied voltage of 20 kV and a temperature of 18°C. The optimized background electrolyte consisted of 0.1 M sodium phosphate buffer, pH 2.0, containing 6 mg/mL sulfated [beta]-cyclodextrin. L-phenylalanine was used as the internal standard. The assay was validated in the range of 0.1-1.0% for the impurities at a concentration of levodopa...
Source: Electrophoresis - October 28, 2009 Category: Biochemistry Authors: Sudaporn Wongwan, Manuela Hammitzsch-Wiedemann, Gerhard K. E. Scriba Source Type: journals

Determination of residual cell culture media components by MEKCEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article describes a single MEKC method that can simultaneously determine all the listed compounds with acceptable LOD and LOQ. All the analytes were successfully separated by MEKC using running buffer containing 40 mM SDS, 20 mM sodium phosphate, and 20 mM sodium borate at pH 9.0. The MEKC method was compared to the corresponding CZE method using the same running buffer containing no SDS. The effect of SDS concentration on separation, the pH of the running buffer, and the detection wavelength were studied and optimal MEKC conditions were established. Good linearity was obtained with correlation coefficients of more th...
Source: Electrophoresis - October 28, 2009 Category: Biochemistry Authors: Junge Zhang, Utpal Chakraborty, Joe P. Foley Source Type: journals

Enantioselective analysis of propranolol and 4-hydroxypropranolol by CE with application to biotransformation studies employing endophytic fungiEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A CE method is described for the enantioselective analysis of propranolol (Prop) and 4-hydroxypropranolol (4-OH-Prop) in liquid Czapek medium with application in the study of the enantioselective biotransformation of Prop by endophytic fungi. The electrophoretic conditions previously optimized were as follows: an uncoated fused-silica capillary, 4% w/v carboxymethyl-[beta]-CD in 25 mmol/L triethylamine/phosphoric acid (H3PO4) buffer at pH 9 as running electrolyte and 17 kV of voltage. UV detection was carried out at 208 nm. Liquid-liquid extraction using diethyl ether: ethyl acetate (1:1 v/v) as extractor solvent was emplo...
Source: Electrophoresis - October 28, 2009 Category: Biochemistry Authors: Keyller Bastos Borges, Mônica Tallarico Pupo, Pierina Sueli Bonato Source Type: journals

On-line combination of CE and microscopy: An insight into the migration of microorganismsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Identification of microbial contamination by CE has interested many researchers mainly because of the high speed of CE analysis. However, the CE separation of such big structures brings a lot of questions mainly about the behavior of microorganisms and about the mechanism of separation. In this work, we constructed a simple apparatus where a microscope was used as one detector and a UV detector was used as the second one and we made the comparison of three typical setups for CE of microorganisms. Saccharomyces cerevisiae was chosen as a model microorganism and was analyzed in bare fused-silica capillaries, covalently modif...
Source: Electrophoresis - October 28, 2009 Category: Biochemistry Authors: Jan Petr, Olga Ryparová, Joanna Znaleziona, Vít[ecaron]zslav Maier, Juraj [Scaron]ev[ccaron]ík Source Type: journals

Sterility testing by CE: A comparison of online preconcentration approaches in capillaries with greater internal diametersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Detection of microbial contamination is of critical importance in the medical and the food industry. Rapid tests for the absence or presence of viable microorganisms are in urgent demand. CE is a modern analytical technique that can be adapted for rapid screening of microbial contamination. However, the small dimensions of capillaries allow the introduction of only a small fraction of the sample, which can be problematic when examining large samples. In this article, we examine the possibilities of introducing larger sample volumes using capillaries with greater id together with different stacking techniques. The use of 0....
Source: Electrophoresis - October 20, 2009 Category: Biochemistry Authors: Jan Petr, Chunxia Jiang, Juraj Sevcik, Eva Tesarova, Daniel W. Armstrong Source Type: journals

Separation of inorganic and small organic anions by CE using phosphonium-based mono- and dicationic reagentsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, novel phosphonium-based mono- and dicationic reagents (originally synthesized as ionic liquids) were evaluated as additives to the BGE for the separation of inorganic and small organic anions. The effects of these reagents on the EOF and their interactions with anionic analytes were compared. The effects of the additive's structure and concentration as well as the separation buffer pH have been studied. Propane-1,3-bis(tripropylphosphonium) fluoride proved to be the most effective additive, as it suppressed the EOF in the system and enabled remarkable manipulation of separation selectivity. A method for fast...
Source: Electrophoresis - October 20, 2009 Category: Biochemistry Authors: Tomá[scaron] K[rcaron]í[zcaron]ek, Zachary S. Breitbach, Daniel W. Armstrong, Eva Tesa[rcaron]ová, Pavel Coufal Source Type: journals

Photo-polymerized lauryl methacrylate monolithic columns for CEC using lauroyl peroxide as initiatorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lauryl methacrylate (LMA)-ester based monolithic columns photo-polymerized using lauroyl peroxide (LPO) as initiator were prepared, and their morphological and CEC properties were studied. The composition of the polymerization mixture (i.e. ratios of monomers/porogenic solvents, 1,4-butanediol/1-propanol and LMA/crosslinker) was optimized. The morphological and chromatographic properties of LMA columns were evaluated by means of SEM pictures and van Deemter plots of PAHs, respectively. The polymerization mixture selected as optimal provided a fast separation of a mixture of PAHs with excellent efficiencies (minimum plate h...
Source: Electrophoresis - October 7, 2009 Category: Biochemistry Authors: Virginia Bernabé-Zafón, Miriam Beneito-Cambra, Ernesto F. Simó-Alfonso, Guillermo Ramis-Ramos, José Manuel Herrero-Martínez Source Type: journals

Effect of urea on analyte complexation by 2,6-dimethyl-[beta]-CD in peptide enantioseparations by CEEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The aim of the present study was the investigation of the effect of urea on analyte complexation in CD-mediated separations of peptide enantiomers by CE in the pH range of about 2-5. pH-independent complexation and mobility parameters in the absence and presence of 2 M urea were obtained by three-dimensional, non-linear curve fitting of the effective analyte mobility as a function of pH and heptakis-(2,6-di-O-methyl)-[beta]-CD concentration. Urea led to decreased binding strength of the CD towards the protonated and neutral analyte enantiomers as well as to decreased mobilities of the free analytes. In contrast, mobilities...
Source: Electrophoresis - October 7, 2009 Category: Biochemistry Authors: Manuela Hammitzsch-Wiedemann, Gerhard K. E. Scriba Source Type: journals

Structural analysis of glycosphingolipid analogues obtained by the saccharide primer method using CE-ESI-MSEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A glycosphingolipid analogue (12-azidododecyl [beta]-lactoside) as a saccharide primer has been shown to be useful for the synthesis of oligosaccharide libraries by mammalian cells. In the present study, CE-ESI-MS was employed to elucidate the structure of glycosphingolipid analogues derived from 12-azidododecyl [beta]-lactoside (Lac-C12N3) by mammalian cells. MDCK cells and COLO201 cells were cultured with Lac-C12N3, and the glycosylated products secreted into the medium were collected and separated into acidic and neutral products by column chromatography. The acidic products could be directly analyzed by CE-ESI-MS, whil...
Source: Electrophoresis - October 6, 2009 Category: Biochemistry Authors: Xingyu Zhu, Kenichi Hatanaka, Tatsuya Yamagata, Toshinori Sato Source Type: journals

Dielectrophoretic manipulation and separation of microparticles using curved microelectrodesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper presents the development and experimental analysis of a dielectrophoresis (DEP) system, which is used for the manipulation and separation of microparticles in liquid flow. The system is composed of arrays of microelectrodes integrated to a microchannel. Novel curved microelectrodes are symmetrically placed with respect to the centre of the microchannel with a minimum gap of 40 [mu]m. Computational fluid dynamics method is utilised to characterise the DEP field and predict the dynamics of particles. The performance of the system is assessed with microspheres of 1, 5 and 12 [mu]m diameters. When a high-frequency p...
Source: Electrophoresis - October 5, 2009 Category: Biochemistry Authors: Khashayar Khoshmanesh, Chen Zhang, Francisco J. Tovar-Lopez, Saeid Nahavandi, Sara Baratchi, Kourosh Kalantar-zadeh, Arnan Mitchell Source Type: journals

Use of coated capillaries for the electrophoretic separation of stereoisomers of a growth hormone secretagogueEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The diastereoisomeric separation of peptidomimetics of hexarelin, a strong growth hormone secretagogue, in CE has been studied. Highly sulfated-[gamma]-CD was found to be an appropriate selector for the separation of the stereoisomers. However, non-repeatable analyses were obtained on bare fused silica capillary due to the progressive adsorption of the analytes on the capillary wall. Two types of polyelectrolyte coating agents were tested to prevent this phenomenon. Coating with neutral polyethylene oxide was found to be efficient but resulted in a very long analysis time (about 40 min). Coating with cationic poly(diallyld...
Source: Electrophoresis - October 5, 2009 Category: Biochemistry Authors: Reine Nehmé, Catherine Perrin, Vincent Guerlavais, Jean-Alain Fehrentz, Hervé Cottet, Jean Martinez, Huguette Fabre Source Type: journals

Electrophoretic exclusion for the selective transport of small moleculesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel method capable of differentiating and concentrating small molecules in bulk solution termed "electrophoretic exclusion" is described and experimentally investigated. In this technique, the hydrodynamic flow of the system is countered by the electrophoretic velocity to prevent a species from entering into the channel. The separation can be controlled by changing the flow rate or applied electric field in order to exclude certain species selectively while allowing others to pass through the capillary. Proof of principle studies employed a flow injection regime of the method and examined the exclusion of Methyl Violet...
Source: Electrophoresis - October 5, 2009 Category: Biochemistry Authors: Michelle M. Meighan, Michael W. Keebaugh, Alicia M. Quihuis, Stacy M. Kenyon, Mark A. Hayes Source Type: journals

SNaPshot minisequencing to resolve mitochondrial macro-haplogroups found in AfricaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
African mitochondrial DNA (mtDNA) haplogroups are divided into seven macro-haplogroups (L0[prime]1[prime]2[prime]3[prime]4[prime]5[prime]6), while the rest of the world's lineages are classified as subgroups of macro-haplogroups M, N and R. The most common approach to characterizing mtDNA variation is the sequencing of hypervariable segments I and II of the non-coding control region of the molecule. Given the higher mutation rate within the control region compared with the coding regions of the molecule, recurrent mutations in the former can sometimes hide possible phylogenetic structure. The incorporation of haplogroup-de...
Source: Electrophoresis - October 5, 2009 Category: Biochemistry Authors: Carina M. Schlebusch, Thijessen Naidoo, Himla Soodyall Source Type: journals

A splicing model-based DNA-computing approach on microfluidic chipEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
DNA computing is a new computation form based on DNA biochemical reactions, which is mainly composed of sticker and splicing computation models. In this work, a microfluidic chip-based approach was established for splicing model-based DNA computing. A finite automaton with two input symbols (a, b) and three states (S0, S1, and S2) was applied in the pattern recognition for isosceles triangles. The DNA computation processes of automaton were realized through DNA digestion, ligation, DNA separation, and detection on the microfluidic chip. The established approach is efficient, controllable, and easy to integrate, which paves...
Source: Electrophoresis - September 30, 2009 Category: Biochemistry Authors: Hua Xie, Bowei Li, Jianhua Qin, Zhende Huang, Yisheng Zhu, Bingcheng Lin Source Type: journals

Analysis of PEG-fractionated high-molecular-mass proteins in human plasma by non-denaturing micro 2-DE and MALDI-MS PMFEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The process of 0-4% PEG precipitation of high-molecular-mass proteins (around and above 1×103 kDa) in human plasma was analyzed by non-denaturing micro 2-DE employing agarose IEF gels in the first dimension, and by MALDI-MS PMF. The PEG 0-2% precipitate could be mostly re-dissolved (fraction PS2%), but some part remained as precipitate (fraction PP2%). Non-denaturing 2-DE followed by MALDI-MS PMF showed that PS2% contained fibrinogen (Fb), fibronectin (FN), and their oligomers as the major components, and von Willebrand factor and coagulation factor XIII as the minor components. PP2% was directly subjected to MALDI-MS PMF...
Source: Electrophoresis - September 30, 2009 Category: Biochemistry Authors: Ya Jin, Takashi Manabe Source Type: journals

Preparation and evaluation of the highly cross-linked poly(1-hexadecane-co-trimethylolpropane trimethacrylate) monolithic column for capillary electrochromatographyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this paper, a novel highly cross-linked porous monolithic stationary phase having a long alkyl chain ligand (C16) was introduced and evaluated in CEC. The monolithic stationary phase was prepared by in situ copolymerization of 1-hexadecene, trimethylolpropane trimethacrylate, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in the presence of ternary porogenic solvent (cyclohexanol/1,4-butanediol/water). In preparing monoliths, the ternary cross-linker trimethylolpropane trimethacrylate was usually applied to preparing molecularly imprinted polymers or molecularly imprinted solid-phase extraction, instead of bina...
Source: Electrophoresis - September 30, 2009 Category: Biochemistry Authors: Minghua Lu, Qiang Feng, Qiaomei Lu, Zongwei Cai, Lan Zhang, Guonan Chen Source Type: journals

Dual-enzyme, co-immobilized capillary microreactor combined with substrate recycling for high-sensitive glutamate determination based on CEEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A new method for high-sensitive determination of glutamate was developed and evaluated based on CE by using dual-enzyme co-immobilized capillary microreactor combined with substrate recycling. The capillary microreactor was prepared by covalently co-immobilizing glutamate dehydrogenase (GDH) and glutamic pyruvic transaminase (GPT) on the inner surface of a capillary and was characterized by SEM, ultraviolet-visible spectroscopy, and fluorescence spectroscopy. The GDH-GPT co-immobilized capillary microreactor showed great stability and reproducibility. The apparent Km for glutamate with GDH-GPT coupled reaction was determin...
Source: Electrophoresis - September 30, 2009 Category: Biochemistry Authors: Li Yang, Jing Shi, Cuijie Chen, Shaoming Wang, Liande Zhu, Wenlin Xie, Liping Guo Source Type: journals

A novel approach to tag and identify geranylgeranylated proteinsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A recently developed proteomic strategy, the "GG-azide"-labeling approach, is described for the detection and proteomic analysis of geranylgeranylated proteins. This approach involves metabolic incorporation of a synthetic azido-geranylgeranyl analog and chemoselective derivatization of azido-geranylgeranyl-modified proteins by the "click" chemistry, using a tetramethylrhodamine-alkyne. The resulting conjugated proteins can be separated by 1-D or 2-D and pH fractionation, and detected by fluorescence imaging. This method is compatible with downstream LC-MS/MS analysis. Proteomic analysis of conjugated proteins by this appr...
Source: Electrophoresis - September 25, 2009 Category: Biochemistry Authors: Lai N. Chan, Courtenay Hart, Lea Guo, Tamara Nyberg, Brandon S.J. Davies, Loren G. Fong, Stephen G. Young, Brian J. Agnew, Fuyuhiko Tamanoi Source Type: journals

Phosphate-affinity electrophoresis on a microchip for determination of protein kinase activityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe microchip-based phosphate-affinity electrophoresis ([mu]PAE) for separation of peptides aimed at determination of kinase activity. The [mu]PAE exploits two recently published technologies: autonomous sample injection for PDMS microchips and a phosphate-specific affinity ligand, Phos-tag. We prepared a fluorescently labeled substrate peptide, specific to human c-Src, and its phosphorylated form. We synthesized a Phos-tag-poly(dimethylacrylamide) conjugate. The conjugate and the sample solutions were autonomously injected into a PDMS-glass hybrid microchip. The two solutions were contacted together in the microch...
Source: Electrophoresis - September 24, 2009 Category: Biochemistry Authors: Aishan Han, Kazuo Hosokawa, Mizuo Maeda Source Type: journals

Micropump based on electroosmosis of the second kindEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A microfluidic pump based on electroosmosis of the second kind was designed and fabricated. Experimental results using DC and AC voltages showed a close to second-order relationship between flow and voltage, in good agreement with theory. The experimental flow rates were considerably lower than the predicted maximum for the micropumps, which can be attributed to the hydrodynamic resistance of the channel network. This also indicates that higher flow velocities are obtainable for modified pump designs. (Source: Electrophoresis)
Source: Electrophoresis - September 24, 2009 Category: Biochemistry Authors: Nataliya A. Mishchuk, Trond Heldal, Tormod Volden, Janko Auerswald, Helmut Knapp Source Type: journals

Highly sensitive detection of ATPase activity in native gelsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Native electrophoresis is a powerful tool for the separation of intact protein complexes. By incubating such gels in a suitable reaction solution, specific enzyme activities can be screened comprehensively. The recent standard procedure for determination of ATP hydrolysis activity in blue or clear native gels is based on formation of a lead phosphate precipitate. The resulting white bands are challenging for detection and documentation of low activities. For the analysis of photosynthetic ATP synthases, the method has to be adapted to deregulate the inhibition of latent ATPase functions. Therefore, we introduced an incubat...
Source: Electrophoresis - September 24, 2009 Category: Biochemistry Authors: Tina Suhai, Nicolas G. Heidrich, Norbert A. Dencher, Holger Seelert Source Type: journals

Formation of CaSO4(aq) and CaSeO4(aq) studied as a function of ionic strength and temperature by CEEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ca2+ complexation by both sulfate and selenate ligands was studied by CE. The species were observed to give a unique retention peak as a result of a fast equilibrium between the free ions and the complexes. The change in the corresponding retention time was interpreted with respect to the equilibrium constant of the complexation reaction. The results confirmed the formation of CaSO4(aq) and CaSeO4(aq) under our experimental conditions. The formation data were derived from the series of measurements carried out at about 15, 25, 35, 45 and 55°C in 0.1 mol/L NaNO3 ionic strength solutions, and in 0.5 and 1.0 mol/L NaNO3 ioni...
Source: Electrophoresis - September 24, 2009 Category: Biochemistry Authors: Violaine Philippini, Jean Aupiais, Thomas Vercouter, Christophe Moulin Source Type: journals

Improvement of gel-separated protein identification by DMF-assisted digestion and peptide recovery after electroblottingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In-gel digestion of gel-separated proteins is a major route to assist in proteomics-based biological discovery, which, however, is often embarrassed by its inherent limitations such as the low digestion efficiency and the low recovery of proteolytic peptides. For overcoming these limitations, many efforts have been directed at developing alternative methods to avoid the in-digestion. Here, we present a new method for efficient protein digestion and tryptic peptide recovery, which involved electroblotting gel-separated proteins onto a PVDF membrane, excising the PVDF bands containing protein of interest, and dissolving the ...
Source: Electrophoresis - September 17, 2009 Category: Biochemistry Authors: Yong Lin, Yan Li, Yi Liu, Wenjun Han, Quanze He, Jianglin Li, Ping Chen, Xianchun Wang, Songping Liang Source Type: journals

Proteomic characterization of plasma-derived clotting factor VIII-von Willebrand factor concentratesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Proteomic methods were used to identify the levels of impurities in three commercial plasma-derived clotting factor VIII-von Willebrand factor (FVIII/VWF) concentrates. In all three concentrates, significant amounts of other plasma proteins were found. In Octanate and Haemoctin, two concentrates developed in the 1990s, the major impurities identified were inter-[alpha] inhibitor proteins, fibrinogen and fibronectin. These two concentrates were also found to contain additional components such as clotting factor II (prothrombin) that are known activators of FVIII. In Wilate, a recently developed FVIII/VWF concentrate, the am...
Source: Electrophoresis - September 17, 2009 Category: Biochemistry Authors: James G. Clifton, Feilei Huang, Spomenka Kovac, Xinli Yang, Douglas C. Hixson, Djuro Josic Source Type: journals

Efficient recovery of electrophoretic profiles of nucleoside metabolites from urine samples by multivariate curve resolutionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chemometric techniques usually employed in purity assessment and resolution of multicomponent peaks have been applied to analytical data from complex biological samples obtained with CE-DAD. In the assessment of the purity of the electrophoretic peaks, the orthogonal projection approach, the orthogonal projection approach with Durbin-Watson criterion, and the simple-to-use interactive self-modeling mixture analysis method have been employed. Multivariate curve resolution with alternating least squares has been successfully implemented to resolve co-migrating peaks of metabolites in CE-DAD and to recover qualitative and qua...
Source: Electrophoresis - September 17, 2009 Category: Biochemistry Authors: Ewa Szyma[nacute]ska, Micha[lstrok] J. Markuszewski, Yvan Vander Heyden, Roman Kaliszan Source Type: journals

Analyzing and monitoring of phage-bacteria interaction using CEEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The utilization of CE for monitoring bacteria-phage interaction was investigated in this study. Streptococcus thermophilus and Lactobacillus bulgaricus strains and their phages were used as model bacteria and phages for the purpose of validation in this study. CE with heterogeneous polymer polyethylene oxide was utilized for the separation of intact bacteria and investigation of phage-bacteria interaction. An intact phage detection was carried out with CZE by adding SDS in the running buffer. Calibration graphs of bacteria and phages were obtained with R2 values of 0.963 and 0.937, respectively. S. thermophilus strain was ...
Source: Electrophoresis - September 17, 2009 Category: Biochemistry Authors: Esra Acar Soykut, [Idot]smail Hakk[iota] Boyac[iota] Source Type: journals

Dynamic light-scattering measurement of sieving polymer solutions for protein separation on SDS CEEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We evaluated the mesh size and homogeneity of polymer network by dynamic light scattering and discussed the relationship between the physical properties of polymer network and the protein separation behavior by capillary polymer electrophoresis. We compared three kinds of sieving polymers in solutions with a wide range of molecular weights and concentrations: polyacrylamide and polyethylene oxide as flexible polymers, and hydroxyethyl cellulose as a semiflexible polymer. We found that the mobility of protein was dominated primarily by the mesh size [xi], irrespective of the type of sieving polymers, and the peak spacing be...
Source: Electrophoresis - September 17, 2009 Category: Biochemistry Authors: Keiko Sumitomo, Koichi Mayumi, Hideaki Yokoyama, Yasuhiro Sakai, Hiroyuki Minamikawa, Mitsutoshi Masuda, Toshimi Shimizu, Kohzo Ito, Yoshinori Yamaguchi Source Type: journals

Microchip CE analysis of amino acids on a titanium dioxide nanoparticles-coated PDMS microfluidic device with in-channel indirect amperometric detectionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this paper, titanium dioxide nanoparticles (TiO2 NPs) were employed to construct a functional film on PDMS microfluidic channel surface, which was formed by sequentially immobilizing poly(diallyldimethylammonium chloride) and TiO2 NPs on PDMS surface by layer-by-layer assembly technique. The modified PDMS microchip exhibited a decreased and stable EOF, which was favorable for the separation of biomolecules with similar migration times. Arginine, phenylalanine, serine and threonine were used as model analytes to evaluate the performance of the modified microchip. The four amino acids were efficiently separated within 100...
Source: Electrophoresis - September 14, 2009 Category: Biochemistry Authors: Jian-Ding Qiu, Li Wang, Ru-Ping Liang, Jing-Wu Wang Source Type: journals

Design and adaptation of miniaturized electrochemical devices integrating carbon nanotube-based sensors to commercial CE equipmentEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The design of new electrochemical devices integrating carbon nanotube sensors and their adaptation to commercial CE equipments are described. One of these designs was made for using commercial screen-printed electrodes, whereas the second was projected for coupling commercial glassy carbon electrodes. The electrochemical characterization of these devices revealed that their hydrodynamic behaviour is strongly influenced by the electrode modification with multi-wall carbon nanotubes that provided faster and/or more sensitive signals. The analytical applicability of these devices was illustrated for the CZE separation of chlo...
Source: Electrophoresis - September 14, 2009 Category: Biochemistry Authors: Alberto Sánchez Arribas, Mónica Moreno, Esperanza Bermejo, M. Ángeles Lorenzo, Antonio Zapardiel, Manuel Chicharro Source Type: journals

A compact and high-resolution version of a capacitively coupled contactless conductivity detectorEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An all-in-one version of a capacitively coupled contactless conductivity detector is introduced. The absence of moving parts (potentiometers and connectors) makes it compact (6.5 cm3) and robust. A local oscillator, working at 1.1 MHz, was optimized to use capillaries of id from 20 to 100 [mu]m. Low noise circuitry and a high-resolution analog-to-digital converter (ADC) (21 bits effective) grant good sensitivities for capillaries and background electrolytes currently used in capillary electrophoresis. The fixed frequency and amplitude of the signal generator is a drawback that is compensated by the steady calibration curve...
Source: Electrophoresis - September 14, 2009 Category: Biochemistry Authors: Kelliton José Mendonça Francisco, Claudimir Lucio do Lago Source Type: journals

Study of acetylcholinesterase inhibitors using CE with contactless conductivity detectionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The hydrolysis of acetylcholine and acetylthiocholine as catalyzed by the enzyme acetylcholinesterase was monitored by CE with contactless conductivity detection by determining the acetate produced in the reaction. This approach eliminates the need for a color forming derivatization procedure. The effects of the three inhibitors galanthamine, hyperzine A and paraoxon on the enzyme kinetics could also be investigated by the new procedure and the IC50 values were determined. The contactless conductivity detection was also found to be compatible with the electrophoretically mediated microanalyis approach, in which the enzymat...
Source: Electrophoresis - September 14, 2009 Category: Biochemistry Authors: Aiping Schuchert-Shi, Peter C. Hauser Source Type: journals

A determination of submicromolar concentrations of glycine in periaqueductal gray matter microdialyzates using capillary zone electrophoresis with contactless conductivity detectionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CE with contactless conductivity detection has been used to determine the glycine neurotransmitter in periaqueductal gray matter (PAG) of rats. The LOD for glycine has been decreased to a value of 0.2 [mu]M by adding 75% v/v of ACN to the samples and increasing the sample zone introduced to a value of 20% of the overall capillary length. The repeatabilities of the analyte migration times and the zone areas amount to 2.1 and 2.7%, respectively. The optimized CE/contactless conductivity detection method makes it possible to determine the micromolar concentrations of glycine in PAG microdialyzates without the necessity of sam...
Source: Electrophoresis - September 14, 2009 Category: Biochemistry Authors: Petr T[uring]ma, Marie Soukupová, Eva Samcová, Karel [Scaron]tulík Source Type: journals

Integration of serpentine channels for microchip electrophoresis with a palladium decoupler and electrochemical detectionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Although it has been shown that microchip electrophoresis (MCE) with electrochemical detection can be used to separate and detect electroactive species, there is a need to increase the separation performance of these devices so that complex mixtures can be routinely analyzed. Previous work in the MCE has demonstrated that increasing the separation channel length leads to an increase in resolution between closely eluting analytes. This paper details the use of lengthened serpentine microchannels for MCE and electrochemical detection where a palladium decoupler is used to ground the separation voltage so that the working ele...
Source: Electrophoresis - September 7, 2009 Category: Biochemistry Authors: Amanda L. Bowen, R. Scott Martin Source Type: journals