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Gel-permeation Chromatography (gel-permeation + chromatography)

Distribution by Scientific Domains
Chemistry87%
Distribution within Chemistry
General & Introductory Chemistry28%

Selected Abstracts

Structure of a 2-aminoethyl phosphate-containing O-specific polysaccharide of Proteus penneri 63 from a new serogroup O68

FEBS JOURNAL, Issue 2 2000
Aleksander S. Shashkov
Lipopolysaccharide of Proteus penneri strain 63 was degraded by mild acid to give a high molecular mass O-specific polysaccharide that was isolated by gel-permeation chromatography. Sugar and methylation analyses and NMR spectroscopic studies, including two-dimensional 1H,1H COSY, TOCSY rotating-frame NOE spectroscopy, H-detected 1H,13C and 1H,31P heteronuclear multiple-quantum coherence (HMQC), and 1H,13C HMQC-TOCSY experiments, demonstrated the following structure of the polysaccharide: where FucNAc is 2-acetamido-2,6-dideoxygalactose and PEtn is 2-aminoethyl phosphate. The polysaccharide studied shares some structural features, such as the presence of d -GlcNAc6PEtn and an ,- L -FucNAc-(1,3)- d -GlcNAc disaccharide, with other Proteus O-specific polysaccharides. A marked cross-reactivity of P. penneri 63 O-antiserum with P. vulgaris O12 was observed and substantiated by a structural similarity of the O-specific polysaccharides of the two strains. In spite of this, the polysaccharide of P. penneri 63 has the unique structure among Proteus O-antigens, and therefore a new, separate serogroup, O68, is proposed for this strain. [source]

Laser desorption/ionization techniques in the characterization of high molecular weight oil fractions.

JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2006
Part 1: asphaltenes
Abstract The molecular weight distribution of the asphaltene fractions of two types of crude oils from two different Italian fields (samples 1 and 2) was investigated. The analytical tools used to perform these analyses were matrix assisted laser desorption ionization (MALDI) and laser desorption ionization (LDI) mass spectrometry. After observing that the use of the matrix (as well as the addition of Ag+) did not improve the quality of the data compared to that obtained in LDI conditions, all further measurements were performed with the latter technique. Operating under usual conditions of laser power and delay time, a very low resolution was observed, showing only macroscopic differences between the two samples in the molecular weight distribution of the different components. An accurate study on the possible reasons of this undesirable behavior indicates that it can originate from space charge phenomena occurring either in the ion source region or during the flight. A valid parameterization of the delay time and the laser power allowed higher quality spectra to be obtained. Surface-enhanced laser desorption ionization (SELDI) measurements were also performed using normal phase (silica) as the sample holder surface. Under these conditions, better results are obtained, proving that the sample,surface interaction is important to achieve, by means of laser irradiation, a homogeneous set of product ions. Both asphaltene samples were fractionated in five subfractions by gel-permeation chromatography (GPC) to obtain a better separation of the molecular weight distributions; the related spectra confirmed these findings. By using different approaches, relevant and reproducible differences between the asphaltene fractions of the two oil samples were observed. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Rubber plasticizers from degraded/devulcanized scrap rubber: A method of recycling waste rubber,

POLYMER ENGINEERING & SCIENCE, Issue 7 2004
Amiya R. Tripathy
Seeking a solution to the problem of disposing scrap tires, we attempted to depolymerize or degrade vulcanized rubber scrap such that the resulting pseudo-liquid material could be used as an extender/plasticizer in virgin rubber compounds. As degraded natural rubber (DNR) and degraded styrene-butadiene rubber (DSBR) are polymeric in nature (confirmed from gel-permeation chromatography (GPC) and differential scanning calorimetry (DSC) results), they can be unique substitutes for typical rubber plasticizers (oil). DNR-loaded samples have shown better mechanical property retention after aging and a lower extractable content in acetone than the respective oil-plasticized samples. Solvent swelling in toluene and 100% modulus values indicate that DNR-added rubber vulcanizates undergo a phase adhesion between the rubber matrix and the degraded polymer, as well as incurring extra reinforcement due to particulate carbon black present in the degraded rubber. Polym. Eng. Sci. 44:1338,1350, 2004. © 2004 Society of Plastics Engineers. [source]

Characterization of a [(O3/2SiMe)x(OSi(OH)Me)y(OSiMe2)z] silsesquioxane copolymer resin by mass spectrometry

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 22 2001
Ron E. Tecklenburg
Electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were applied to a complex silsesquioxane-siloxane copolymer resin. The wide-polydispersity starting material was fractionated into 21 separate fractions in order to facilitate the analysis by mass spectrometry. ESI-FTICR exact mass measurements were able to identify the specific oligomers present in the lowest mass fractions and showed that very few unreacted silanol groups remained, that is, topologically closed structures predominated. MALDI-TOFMS was able to show that gel-permeation chromatography substantially underestimated the molecular masses of the higher mass fractions. Mass autocorrelation was able to show that the silsesquioxane monomer appeared only in even numbers in any given oligomer. This is a natural consequence of the highly condensed nature of the resin. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of the collagen-binding region of RspB from Erysipelothrix rhusiopathiae

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010
Aribam Swarmistha Devi
RspB is a surface adhesin of Erysipelothrix rhusiopathiae. A recombinant form of the collagen-binding region of this protein, RspB(31,348), has been overexpressed in Escherichia coli in native and selenomethionine-derivative forms and purified using affinity and gel-permeation chromatography. Thin plate-like crystals were obtained by the hanging-drop vapour-diffusion method using the same condition for both forms. The native crystals diffracted to a resolution of 2.5,Å using an in-house X-ray source, while the selenomethionine-derivative crystals diffracted to a resolution of 2.2,Å using synchrotron radiation. The crystals belonged to the monoclinic space group P21, with unit-cell parameters a = 46.19, b = 66.65, c = 101.72,Å, , = 94.11°. [source]

Rapid analysis of N -linked oligosaccharides in glycoproteins (ovalbumin, ribonuclease B and fetuin) by reversed-phase ultra-performance liquid chromatography with fluorescence detection and electrospray ionization time-of-flight mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 5 2009
Takamasa Kurihara
Abstract Rapid, selective and sensitive determination of N -linked oligosaccharides in glycoproteins (ovalbumin, ribonuclease B and fetuin) was performed by ultra-performance liquid chromatography (UPLC) with fluorescence (FL) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). The asparaginyl-oligosaccharide moiety was first liberated from each glycoprotein by pronase E (a proteolitic enzyme). The oligosaccharide fractions separated by gel-permeation chromatography were labeled with 1-pyrenesulfonyl chloride (PSC, a fluorescence reagent), separated by UPLC in a short run time, and then detected by FL and TOF-MS. The PSC-labeled oligosaccharides were selectively identified from the FL detection and then sensitively determined by ESI-TOF-MS. As the results, 15, eight and four kinds of N -linked oligosaccharides were detected from ovalbumin, ribonuclease B and fetuin, respectively. Because the present method is rapid (within 9 min), selective and sensitive (approximate 60 fmol, S/N = 5), the determination of N -linked oligosaccharides in various glycoproteins seems to be possible. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Synthesis and Optical Properties of Europium-Complex-Doped Inorganic/Organic Hybrid Materials Built from Oxo,Hydroxo Organotin Nano Building Blocks

CHEMISTRY - A EUROPEAN JOURNAL, Issue 6 2010
Wei-Qiang Fan Dr.
Abstract Hybrid materials doped with novel europium complexes were synthesized using PMMA- co -Sn12Clusters (copolymers from oxohydroxo-organotin dimethacrylate and methylmethacrylate) as the matrix material. Two types of hybrid materials were obtained: the physically doped product, PMMA- co -Sn12Cluster/Eu(TTA)3phen, and the grafted product, PMMA- co -Sn12Cluster- co -[EuAA(TTA)2phen] (TTA=2-thenoyltrifluoroacetone, phen=phenanthroline and AA=acrylic acid). The hybrid materials exhibited characteristic luminescence of the Eu3+ ions, and also showed relative especial optical properties compared with samples just using PMMA as the matrix material. The PMMA- co -Sn12Cluster matrix exhibited a high physical doping quantity of [Eu(TTA)3phen], which can be attributed to the special structure of this kind of hybrid material. GPC (gel-permeation chromatography), TGA (thermogravimetric analysis), SEM, 1H,NMR, ICP (inductively coupled plasma), 119Sn,NMR, FTIR, and diffuse reflectance techniques were employed to characterize the structures and properties of these hybrid materials. [source]

Studies on the Physicochemical Properties, Structure and Antitumor Activity of Polysaccharide YhPS-1 from the Root of Cordalis yanhusuo Wang

CHINESE JOURNAL OF CHEMISTRY, Issue 2 2006
Yi-Wen Tao
Abstract A polysaccharide named YhPS-1 was isolated from the root of Cordalis yanhusuo Wang and purified by means of gel-permeation chromatography and ionexchange chromatography. Its physicochemical properties, including monosaccharide composition, carbohydrate content, molecular weight and elemental composition, were determined. The structure of YhPS-1 was elucidated by chemical methods along with 1H and 13C NMR spectroscopy ways, such as including two-dimensional HMQC and HMBC experiments. These results show that YhPS-1 possesses a backbone consisting of terminal , -Glcp -(1,, , -Glcp -(1,6), , -Glcp -(1,4) and , -Glcp -(1,4,6). The bioactive assay showed that it could inhibit the growth of Sarcoma 180 and Lewis pulmonary carcinoma implanted in mice. [source]