4-o-methyl-d-glucurono-d-xylan degradation by γ-irradiation. Part 1 — Dose effects on the macromolecular properties

Ebringerová, Anna; Eremeeva, T.; Khinoverova, O.E.; Ершов, Б. Г.

doi:10.1016/0144-8617(91)90040-j

Cited by 7 publications

(3 citation statements)

References 3 publications

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“…26 However, the values determined here do agree very well with more recent values obtained for birch xylans utilizing SEC and viscometry measurements. 38,39,81 It is not unlikely that the strong tendency for hardwood glucuronoxylans to form larger aggregates, even in aqueous alkaline solutions (as discussed in connection with Figure 5), may have caused earlier osmometric or sedimentation studies to somewhat overestimate the molar mass…”

Section: Resultsmentioning

confidence: 99%

Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Jacobs¹,

Dahlman²

2001

Biomacromolecules

107

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The molar mass parameters for arabino-4-O-methylglucuronoxylans, arabinohexenuronoxylans, 4-O-methylglucuronoxylans, hexenuronoxylans, and galactoglucomannans extracted from wood and pulps have been determined. To characterize different types of hemicelluloses, delignified wood (spruce, pine, larch, aspen, and birch) and chemical pulps (unbleached and totally chlorine-free bleached) were extracted with dimethyl sulfoxide (DMSO) or alkaline aqueous solutions. Size exclusion chromatography (SEC) with off-line matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-MS) were employed to characterize the molar masses. The hemicellulose extracts were separated by SEC into fractions each containing components with a narrow range of molar masses and the average molar mass of each fraction subsequently determined by MALDI-MS. The molar mass parameters for the hemicelluloses were then calculated on the basis of the SEC distribution curves and MALDI-MS spectra. As expected, in most cases the hemicelluloses extracted from wood (holocellulose) exhibited higher molar masses than did the corresponding hemicelluloses from chemical pulps. The molar mass parameters for hemicelluloses isolated from pulps derived from cooking samples of the same batch of softwood chips decreased in the following order: ASAM pulp > MSSAQ pulp > kraft pulp. The lowest molar masses were demonstrated by the glucuronoxylans extracted from pulps obtained by cooking with acidic sulfite. The xylans from bleached kraft pulp were characterized by molar masses that were only slightly lower than those of the corresponding xylans from unbleached pulp. The xylans extracted into DMSO exhibited somewhat lower molar masses than did the corresponding xylans extracted into alkaline aqueous solutions. In all cases the range of molar masses demonstrated by the hemicelluloses investigated was found to be rather narrow, i.e., the polydispersity index Mw/Mn was found to be approximately 1.1-1.4.

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Section: Resultsmentioning

confidence: 99%

Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Jacobs¹,

Dahlman²

2001

Biomacromolecules

107

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“…The irradiation of xylan is accompanied by its intense degradation. 122,123 Figure 9 shows the gel-filtration curves of xylans girradiated to different doses (the molecular-mass characteristics were monitored with a refractometer). It is seen that the peak height decreases, while the distribution curve broadens.…”

Section: Radiation-chemical Transformations Of Xylansmentioning

confidence: 99%

“…It was also found that xylan, like cellulose, produces hydrogen and carbon dioxide, whose radiation-chemical yields are 2.8 and 4.4. 122,123 The presence of carbon dioxide indicates that the formation of radicals actually does not occur directly upon cleavage of the glycosidic bond but involves rupture of the…”

Section: Radiation-chemical Transformations Of Xylansmentioning

confidence: 99%

Radiation-chemical degradation of cellulose and other polysaccharides

Ершов

1998

Russ. Chem. Rev.

151

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The state-selective dissociation dynamics for anionic and excited neutral fragments of gaseous SiCl 4 following Cl 2p and Si 2p core-level excitations were characterized by combining measurements of the photoninduced anionic dissociation, x-ray absorption and UV/visible dispersed fluorescence. The transitions of core electrons to high Rydberg states/doubly excited states in the vicinity of both Si 2p and Cl 2p ionization thresholds of gaseous SiCl 4 lead to a remarkably enhanced production of anionic, Si − and Cl − , fragments and excited neutral atomic, Si * , fragments. This enhancement via core-level excitation near the ionization threshold of gaseous SiCl 4 is explained in terms of the contributions from the Auger decay of doubly excited states, shake-modified resonant Auger decay, or/and post-collision interaction. These complementary results provide insight into the state-selective anionic and excited neutral fragmentation of gaseous molecules via core-level excitation.

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High-performance size-exclusion chromatography of wood hemicelluloses on a poly(2-hydroxyethyl methacrylate—co-ethylene dimethacrylate) column with sodium hydroxide solution as eluent

Eremeeva

Bykova

1993

Journal of Chromatography A

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4-o-methyl-d-glucurono-d-xylan degradation by γ-irradiation. Part 1 — Dose effects on the macromolecular properties

Cited by 7 publications

References 3 publications

Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Characterization of the Molar Masses of Hemicelluloses from Wood and Pulps Employing Size Exclusion Chromatography and Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry

Radiation-chemical degradation of cellulose and other polysaccharides

High-performance size-exclusion chromatography of wood hemicelluloses on a poly(2-hydroxyethyl methacrylate—co-ethylene dimethacrylate) column with sodium hydroxide solution as eluent

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