EarlyView Articles

Application of hollow‐fiber‐assisted liquid‐phase microextraction to identify avermectins in stream water using MS/MS

Published: Jul 29, 2013

Author(s): Jong‐Hyouk Park, A. M. Abd El‐Aty, Md. Musfiqur Rahman, Jeong‐Heui Choi, Jae‐Han Shim

Journal: Journal of Separation Science

In this study, a hollow‐fiber‐assisted liquid‐phase microextraction (HF‐LPME) technique coupled with LC–MS/MS is described to detect avermectins (abamectin, ivermectin, moxidectin, and doramectin) in stream water. An Accurel polypropylene membrane was used as the hollow fiber, and dihexyl ether was used as the extraction solvent. The optimal extraction conditions for HF‐LPME were 4 cm fiber length, 45 min extraction time, 200rpm, and 1...

High‐performance liquid chromatographic enantioseparation of naphthol‐substituted tetrahydroisoquinolines on polysaccharide‐based chiral stationary phases

Published: Jul 29, 2013

Author(s): István Ilisz, Zsanett Gecse, István Szatmári, Ferenc Fülöp, Antal Péter

Journal: Biomedical Chromatography

ABSTRACT The stereoisomers of 15 naphthol‐substituted tetrahydroisoquinoline analogs were separated on chiral stationary phases containing the chiral selectors cellulose tris‐(3,5‐dimethylphenyl carbamate) (Cellulose 1), cellulose tris‐(3‐chloro‐4‐methylphenyl carbamate) (Cellulose 2), cellulose tris‐(4‐methylbenzoate) (Cellulose 3) and cellulose tris‐(4‐chloro‐3‐methylphenyl carbamate) (Cellulose 4). Experiments were performed in normal‐phase mode with...

Determination of phenylethanoid glycosides and iridoid glycosides from therapeutically used Plantago species by CE‐MEKC

Published: Jul 29, 2013

Author(s): Sándor Gonda, Nhat Minh Nguyen, Gyula Batta, Gyöngyi Gyémánt, Csaba Máthé, Gábor Vasas

Journal: ELECTROPHORESIS

CE methods are valuable tools for medicinal plant quality management, screening, and analysis. Therefore, the aim of the current study was to optimize and validate a CE‐MEKC method for simultaneous quantification of four chief bioactive metabolites from Plantago species. The two most important secondary metabolite groups were aimed to be separated. Different electrolyte and surfactant types were tested. Surfactant concentration, BGE pH,...

New pressure‐assisted sweeping on‐line preconcentration for polar environmentally relevant nitrosamines: P art 1. Sweeping for polar compounds and application of auxiliary pressure

Published: Jul 29, 2013

Author(s): Ali Modir‐Rousta, Christina S. Bottaro

Journal: ELECTROPHORESIS

Typically sweeping reversed migration EKC (RM‐EKC) is used for online enrichment and separation of neutral compounds in CE, however sweeping is not usually suitable for highly polar neutral compounds due to the lack of strong interaction with micellar phase. Since acidic BGE or coated capillaries (BGE pH 2–8) are used to virtually eliminate the EOF, migration of neutral analytes is only through association with the micelles with...

In vivo GABA T ₂ determination with J ‐refocused echo time extension at 7 T

Published: Jul 26, 2013

Author(s): A. Andreychenko, D. W. J. Klomp, R. A. Graaf, P. R. Luijten, V. O. Boer

Journal: NMR in Biomedicine

A method to measure the T2 relaxation time of GABA with spectral editing techniques is proposed. Spectral editing techniques can be used to unambiguously extract signals of low concentration J‐coupled spins such as γ‐aminobutyric acid (GABA) from overlapping resonances such as creatine and macromolecules. These sequences, however, generally have fixed and relatively long echo times. Therefore, for the absolute quantification of the edited spectrum, ...

Discrimination of glycoproteins via two‐color laser‐induced fluorescence detection coupled with postcolumn derivatization in capillary electrophoresis

Published: Jul 26, 2013

Author(s): Ayumi Tabara, Takashi Kaneta

Journal: ELECTROPHORESIS

Here, we report a novel method consisting of capillary electrophoretic separation followed by two‐color LIF detection with postcolumn derivatization. The method can be used to discriminate glycoproteins in a protein mixture containing both glycosylated and unglycosylated proteins. The detector permitted simultaneous measurements of two electropherograms obtained by 450 nm (diode laser) and 532 nm (Nd:YAG laser) lasers excited native...

Enhanced glycan nanoprofiling by weak anion exchange preparative chromatography, mild acid desialylation, and nanoliquid chromatography‐mass spectrometry with nanofluorescence detection

Published: Jul 26, 2013

Author(s): Hakan Kalay, Martino Ambrosini, Fabrizio Chiodo, Yvette Kooyk, Juan J. García‐Vallejo

Journal: ELECTROPHORESIS

The structural characterization and quantification of the glycome of cells and glycoproteins is necessary for the understanding of glycan functions in Biology, the development of diagnostics tests, and the monitoring of glycoprotein pharmaceuticals. Classical N‐glycan characterization methods involve enzymatic release followed by derivatization with a fluorochrome and separation by normal‐phase HPLC. We have recently developed glycan...

Sheathless capillary electrophoresis electrospray ionization‐mass spectrometry interface based on poly(dimethylsiloxane) membrane emitter and thin conducting liquid film

Published: Jul 26, 2013

Author(s): Che‐Wei Wang, Guor‐Rong Her

Journal: ELECTROPHORESIS

This study develops a sheathless CE‐MS interface using a robust PDMS membrane emitter and liquid‐film electric conduction. A 3D mold was constructed for casting the device by using a one‐step casting procedure. The interface consisted of a 125 μm‐thick triangular emitter with a 50 μm‐diameter microchannel, a conducting reservoir, and a 375 μm‐diameter channel for assembling the separation capillary. The separation capillary was inserted...

Serum protein fractionation using supported molecular matrix electrophoresis

Published: Jul 26, 2013

Author(s): Weijie Dong, Yu‐ki Matsuno, Akihiko Kameyama

Journal: ELECTROPHORESIS

Supported molecular matrix electrophoresis (SMME), in which a hydrophilic polymer such as PVA serves as a support within a porous PVDF membrane, was recently developed. This method is similar to cellulose acetate membrane electrophoresis but differs in the compatibility to glycan analysis of the separated bands. In this report, we describe the first instance of the application of SMME to human serum fractionation, and demonstrate the...

Neoglycoproteins as carbohydrate antigens: Synthesis, analysis, and polyclonal antibody response

Published: Jul 26, 2013

Author(s): Márta Kerékgyártó, Anikó Fekete, Zoltán Szurmai, János Kerékgyártó, László Takács, István Kurucz, András Guttman

Journal: ELECTROPHORESIS

The analysis and polyclonal antibody response for newly synthesized maltose–BSA conjugate neoglycoproteins is described. In this first proof of concept study, a simple carbohydrate antigen, maltose, was linked to BSA by reductive amination. An aglycone spacer was utilized to conserve the intact annular maltose structure and to promote the accessibility of the carbohydrate immunogen hapten during immunization. The neoglycoproteins were...

Development of a high‐throughput glycoanalysis method for the characterization of oligosaccharides in human milk utilizing multiplexed capillary gel electrophoresis with laser‐induced fluorescence detection

Published: Jul 26, 2013

Author(s): Robert Kottler, Marko Mank, René Hennig, Beate Müller‐Werner, Bernd Stahl, Udo Reichl, Erdmann Rapp

Journal: ELECTROPHORESIS

During the last decade, enormous progress regarding knowledge about composition and properties of human milk (HM) has been made. Besides nutrition, the three macro‐nutrients: proteins, lipids, and carbohydrates combine a large variety of properties and functions. Especially, complex oligosaccharides emerge as important dietary factors during early life with multiple functions. The characterization of these HM oligosaccharides (HMOS)...

Surface characterization of TEMPO‐oxidized bacterial cellulose

Published: Jul 26, 2013

Author(s): Chen Lai, Liyuan Sheng, Shibo Liao, Tingfei Xi, Zhixiong Zhang

Journal: Surface and Interface Analysis

Abstract In this study, we focused on the surface character of bacterial cellulose (BC) before and after oxidation mediated by 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO).Solid‐state 13C NMR, XPS, SEM, contact angle and surface free energy analyses were performed to investigate the effects of various parameters (reaction time and oxidant and catalyst concentrations) on the surface composition, morphology and polarity of the BC. The ...

The VI Edition of the International Aluminium Surface Science and Technology Symposium

Published: Jul 26, 2013

Author(s):

Journal: Surface and Interface Analysis

Comparative core fucosylation analysis of some major therapeutic antibody N ‐glycans by direct infusion ESI‐MS and CE–LIF detection

Published: Jul 26, 2013

Author(s): Yueju Wang, Marcia Santos, András Guttman

Journal: Journal of Separation Science

The analysis of carbohydrate moieties of glycoprotein biopharmaceuticals is of high importance, especially because glycosylation changes can impact the biological effect of the drugs. In the case of monoclonal antibody therapeutics, the degree of core fucosylation significantly influences its effector function, thus should be closely monitored during the clone selection, development and manufacturing processes. MS analysis of labile sugar...

Rapid separations by LC using ion‐exchange media based on spongy monoliths

Published: Jul 26, 2013

Author(s): Takuya Kubo, Tetsuya Tanigawa, Yuichi Tominaga, Ken Hosoya, Koji Otsuka

Journal: Journal of Separation Science

Novel sponge‐based monoliths containing ionic functional groups were developed for rapid separation and/or concentration of ionic solutes. The cationic and anionic spongy monoliths were prepared by chemical modifications of the pore surface on an original spongy monolith consisting of poly(ethylene‐co‐vinyl acetate). After hydrolysis of the spongy monolith, an anionic or a cationic moiety was introduced with succinyl chloride or acryloyl...

Multidimensional GC using planar microfluidic devices for the characterization of phenolic antioxidants in fuels

Published: Jul 26, 2013

Author(s): Jim Luong, Ronda Gras, Hernan J. Cortes, Robert A. Shellie

Journal: Journal of Separation Science

A multidimensional gas chromatographic approach using planar microfluidic devices for Deans switching has been developed and implemented for the characterization of sterically hindered phenolic compounds used as antioxidants in fuels. Detection and quantitation was conducted with MS in selected ion monitoring mode. A complete analysis is conducted in less than 15 min with precision greater than 5.5% at 1 and 25 ppm w/w (ppmw). LODs of...

Polymer monoliths as efficient solid phases for enzymatic polynucleotide degradation followed by fast HPLC analysis

Published: Jul 26, 2013

Author(s): M. V. Volokitina, E. G. Vlakh, G. A. Platonova, D. O. Vinokhodov, T. B. Tennikova

Journal: Journal of Separation Science

Two ribonuclease A bioreactors based on lab‐made macroporous monolithic columns and intended for polynucleotide degradation were prepared using in situ free‐radical polymerization. Different methods of enzyme immobilization were applied. In the first case, the biocatalyst molecule was attached to the solid surface via direct covalent binding, while in the second bioreactor the flexible‐chain synthetic polymer was used as an intermediate ...

Change in I g G ₁ F c N ‐linked glycosylation in human lung cancer: Age‐ and sex‐related diagnostic potential

Published: Jul 26, 2013

Author(s): Guoqiang Chen, Yanmin Wang, Xuzhen Qin, Hexiang Li, Yumei Guo, Yanying Wang, Hui Liu, Xiaodong Wang, Gaoguang Song, Fang Li, Fenjie Li, Shuai Guo, Ling Qiu, Zhili Li

Journal: ELECTROPHORESIS

The interactions of IgG Fc region with Fc receptors are optimized by the tailoring of a single‐conserved N‐linked glycosylation site at Asn‐297. Our previous study has demonstrated that the age‐related Fc‐glycosylation change is featured by sex specificity and that the Fc‐glycosylation has the potential for disease discrimination. Here, we conducted a Fourier transform ion cyclotron resonance MS‐based profiling study involving 410 control individuals...

Nonmonotonous variation of DNA angular separation during asymmetric pulsed field electrophoresis

Published: Jul 26, 2013

Author(s): Neda Nazemifard, Subir Bhattacharjee, Jacob H. Masliyah, D. Jed Harrison

Journal: ELECTROPHORESIS

Asymmetric pulsed field electrophoresis within crystalline arrays is used to generate angular separation of DNA molecules. Four regimes of the frequency response are observed, a low frequency rise in angular separation, a plateau, a subsequent decline, and a second plateau at higher frequencies. It is shown that the frequency response for different sized DNA is governed by the relation between pulse time and the reorientation time of DNA...

N ‐linked glycoproteome profiling of human serum using tandem enrichment and multiple fraction concatenation

Published: Jul 26, 2013

Author(s): Cheng Ma, Xinyuan Zhao, Huanhuan Han, Wei Tong, Qi Zhang, Peibin Qin, Cheng Chang, Bo Peng, Wantao Ying, Xiaohong Qian

Journal: ELECTROPHORESIS

N‐linked glycosylation is an important protein posttranslational modification that is involved in numerous biological processes. Different methods, including chemical reaction and affinity interaction, have been developed to enrich glycosylated peptides or proteins from biological systems. However, due to the common occurrence of low glycosites occupancy in proteins and the low efficiency of enrichment approaches, only a small fraction of...