Molar mass distribution measurements are performed by SEC-MALLS-RI, i.e. size-exclusion chromatography (SEC) with multi-angle laser light scattering (MALLS) / refractive index (RI) detection, in the solvent system N,N-dimethylacetamide (DMAc)/LiCl.

The samples are directly dissolved after activation and solvent exchange (Potthast et al. 2015). No derivatization step is necessary, which means that the molar mass remains unaltered by substituents. In addition, the solvent system has become the standard solvent for SEC of celluloses as it has been proven to completely retain cellulose integrity. Most pulps (kraft, sulfite pulp, organosolv), cotton, as well as cellulose II substrates (viscose fibers, lyocell fibers and others) are soluble in the DMAc/LiCl solvent system. In addition, there is ample experience in dissolution of different historic papers, bacterial celluloses, Asian papers, such as Washi and Hanji papers, cotton, or papyrus.  Also many – although not all – nano- and microstructured celluloses (nanofibrillated, microfibrillated, nanocrystalline, microcrystalline celluloses) can be analyzed by this approach.

Different alternative approaches (DMSO activation, derivatization, holocellulose isolation etc.) can be performed upon request or if the substrate requires to do so for proper analysis.

For cotton matrices, man-made fibers and all hemicellulose-free pulp variants we provide a specific DMSO activation protocol (Siller et al. 2014, Silbermann et al. 2017) that makes the substrate accessible for SEC analysis.

Two MALLS systems with 488 nm and 660 nm lasers are available. For very low molar mass celluloses combined approaches or single calibration with cellulose model compounds can be performed to increase accuracy of the number average molar mass (Mn) (Oberlerchner et al. 2016).

Sample amount required for approaches with pulp, fibers and micro-/nanostructured celluloses: 50- 100 mg of cellulose, preferably in the “natural” state, i.e., not specially dried or treated. Analysis of smaller amounts, e.g. in case of valuable historic materials, is possible upon request.


Oberlerchner, J. T.; Vejdovszky, P.; Zweckmair, T.; Kindler, A.; Koch, S.; Rosenau, T.; Potthast, A.
Filling the gap: Calibration of the low molar-mass range of cellulose in size exclusion chromatography with cello-oligomers.
J. Chromatogr. A 2016, 1471, 87-93.

Potthast, A.; Radosta, S.; Saake, B.; Lebioda, S.; Heinze, T.; Henniges, U.; Isogai, A.; Koschella, A.; Kosma, P.; Rosenau, T.; Schiehser, S.; Sixta, H.; Strlic, M.; Strobin, G.; Vorwerg, W.; Wetzel, H.,
Comparison testing of methods for gel permeation chromatography of cellulose: coming closer to a standard protocol.
Cellulose 2015, 22 (3), 1591-1613.

Silbermann, S., Weilach, C., Kliba, G., Fackler, K., Potthast, A.
Improving molar mass analysis of cellulose samples with limited solubility.
Carbohydrate Polymers, 2017, 178, 302-310.

Siller, M.; Ahn, K.; Pircher, N.; Rosenau, T.; Potthast, A.,
Dissolution of rayon fibers for size exclusion chromatography: a challenge.
Cellulose (Dordrecht, Neth.) 2014, 21 (5), 3291-3301.