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Molecular weight of chitosan: From structural complexity to analytical reliability
Anastasia А Zubareva1, Ekaterina R Gasilova1, Daria N Poshina1
1Branch of Petersburg Nuclear Physics Institute named by B.P. Konstantinov of the National Research Centre "Kurchatov Institute" - Institute of Macromolecular Compounds, Bolshoi VO 31, St. Petersburg, 199004, Russia.
Carbohydrate Polymers
|May 22, 2026
Summary
Determining chitosan's molecular weight (MW) is challenging due to various factors. Size-exclusion chromatography with multi-angle laser light scattering is the gold standard for accurate MW determination.
Area of Science:
- Polymer Chemistry
- Analytical Chemistry
- Biomaterials Science
Background:
- Chitosan's functional properties are critically dependent on its molecular weight (MW).
- Accurate MW determination of chitosan presents significant analytical challenges.
- Polydispersity, aggregation, and polyelectrolyte effects complicate MW characterization.
Purpose of the Study:
- To critically review and compare methods for characterizing chitosan MW.
- To address discrepancies in reported MW data arising from methodological limitations.
- To highlight the need for standardized protocols and interlaboratory validation.
Main Methods:
- Evaluation of techniques including size-exclusion chromatography (SEC), light scattering, viscometry, and analytical ultracentrifugation.
- Analysis of the impact of structural heterogeneity (degree of deacetylation, acetylation patterns) on MW measurements.
- Discussion of recent methodological advances for improved precision.
Main Results:
- Widespread inconsistencies in reported chitosan MW data exist due to a lack of standardized protocols for routine methods.
- SEC coupled with multi-angle laser light scattering (SEC-MALS) is identified as the gold standard for absolute MW determination (ASTM F2602-18).
- Current methods often yield unreliable relative MW due to issues like polydispersity and aggregation.
Conclusions:
- Standardized protocols and interlaboratory validation are urgently needed for reliable chitosan MW characterization.
- Robust MW determination is essential for advancing chitosan applications in biomedicine and other fields.
- SEC-MALS offers a precise and absolute method for determining chitosan MW, crucial for commercial applications.
Keywords:
Analytical ultracentrifugation and sedimentationCapillary viscometryChitosanLight scatteringMolecular weightSize exclusion chromatographyMore Related Videos
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