Mark–Houwink–Sakurada coefficients determination for molar mass of silk fibroin from viscometric results. SEC-MALLS approach

RSC Advances ◽  
2016 ◽  
Vol 6 (44) ◽  
pp. 38071-38078 ◽  
Author(s):  
D. Pawcenis ◽  
M. Syrek ◽  
M. A. Aksamit-Koperska ◽  
T. Łojewski ◽  
J. Łojewska
Keyword(s):  
Bombyx Mori ◽  
Size Exclusion Chromatography ◽  
Silk Fibroin ◽  
Molar Mass ◽  
Size Exclusion ◽  
Exclusion Chromatography

The results on the changes of average molar masses inBombyx morifibroin with use of size exclusion chromatography and viscometry are presented in terms of the determination of Mark–Houwink–Sakurada coefficients, which are lacking in the literature.

scholarly journals Size-exclusion chromatography of cellulose: observations on the low-molar-mass fraction

Cellulose ◽  
2020 ◽  
Vol 27 (16) ◽  
pp. 9217-9225
Author(s):  
Leena Pitkänen ◽  
Herbert Sixta
Keyword(s):  
Mass Distribution ◽  
Size Exclusion Chromatography ◽  
Mass Fraction ◽  
Molar Mass ◽  
Accurate Determination ◽  
Size Exclusion ◽  
Molar Mass Distribution ◽  
Universal Method ◽  
Exclusion Chromatography

AbstractAccurate determination of molar mass distribution for disperse cellulose samples has proved to be a challenging task. While size-exclusion chromatography coupled to multi-angle light scattering (MALS) and differential refractive index (DRI) detectors has become the most commonly used method for molar mass determination of celluloses, this technique suffers low sensitivity at the low-molar mass range. As discussed here, the universal method for accurate molar mass distribution analysis of cellulose samples not exists and thus thorough understanding on the differences of the various methodological approaches is important. In this study, the focus is in the accurate determination of the low-molar mass fraction. The results obtained by combining the two calibration strategies, MALS/DRI for polymeric region of a cellulose sample and conventional calibration for oligomeric region, was compared to the results obtained using only MALS/DRI (with extrapolation of the curve where signal-to-noise of MALS is low). For birch pulp sample, the results from the two approaches were comparable; it should be highlighted, however, that MALS/DRI slightly overestimates the molar masses at the low-molar-mass region.

scholarly journals Determination of the absolute molar mass of acetylated eucalyptus kraft lignin by two types of size-exclusion chromatography combined with multi-angle laser light-scattering detectors

Holzforschung ◽  
2019 ◽  
Vol 73 (4) ◽  
pp. 363-369 ◽  
Author(s):  
Linping Wang ◽  
Yasumitsu Uraki ◽  
Keiichi Koda ◽  
Aori Gele ◽  
Xuesong Zhou ◽  
...  
Keyword(s):  
Light Scattering ◽  
Size Exclusion Chromatography ◽  
Molar Mass ◽  
Laser Light ◽  
Kraft Lignin ◽  
Laser Light Scattering ◽  
Size Exclusion ◽  
Compact Structure ◽  
Exclusion Chromatography

AbstractThe molar mass (MM) and polydispersity indices (PDI) of acetylated hardwood kraft lignin (Ac-HWKL) and Ac-HWKL fractions were measured by size-exclusion chromatography with multi-angle laser light scattering (SEC-MALLS). The detectors worked at LL658 nmand LL785 nm. The MM of Ac-HWKL measured at 785 nm was much smaller than that measured at 658 nm. The number-average (Mn) and weight-average (Mw) molar masses of Ac-HWKL determined at 785 nm were approximately 6.2 and 6.5 times larger, respectively, than the values estimated using a conventional calibration curve created with authentic polystyrene standards in tetrahydrofuran (THF). Based on the Mw of Ac-HWKL fractions, the Mark-Houwink-Sakurada equation for Ac-HWKL was established to be [η]/ml g−1=0.320 M0.24in THF and [η]/ml g−1=0.142 M0.26in dimethyl sulfoxide (DMSO). These results demonstrate that Ac-HWKL has a more compact structure in an organic solvent than polystyrene.

Molar mass determination of lignins by size-exclusion chromatography: towards standardisation of the method

Holzforschung ◽  
2007 ◽  
Vol 61 (4) ◽  
pp. 459-468 ◽  
Author(s):  
Stéphanie Baumberger ◽  
Alfred Abaecherli ◽  
Mario Fasching ◽  
Gäoran Gellerstedt ◽  
Richard Gosselink ◽  
...  
Keyword(s):  
Mass Distribution ◽  
Size Exclusion Chromatography ◽  
Molar Mass ◽  
Size Exclusion ◽  
Molar Mass Distribution ◽  
High Molar Mass ◽  
Wide Range ◽  
Exclusion Chromatography ◽  
Technical Lignins

Abstract The reactivity and physicochemical properties of lignins are partly governed by their molar mass distribution. The development of reliable standard methods for determination of the molar mass distribution is not only relevant for designing technical lignins for specific applications, but also for monitoring and elucidating delignification and pulping processes. Size-exclusion chromatography (SEC) offers many advantages, such as wide availability, short analysis time, low sample demand, and determination of molar mass distribution over a wide range. A collaborative study has been undertaken within the “Eurolignin” European thematic network to standardise SEC analysis of technical lignins. The high-molar-mass fraction of polydisperse lignins was shown to be the main source of intra- and interlaboratory variations, depending on the gel type, elution solvent, detection mode, and calculation strategy. The reliability of two widespread systems have been tested: one based on alkali and a hydrophilic gel (e.g., TSK Toyopearl gel) and the other based on THF as solvent and polystyrene-based gels (e.g., Styragel). A set of practical recommendations has been deduced.

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