High-resolution Molecular Fingerprinting of Algal Polysaccharides Extracted at Alkaline Hydrothermal Conditions

High Resolution Image Download MS PowerPoint Slide Alkaline hydrothermal water extraction was applied to macroalgae Ascophyllum nodosum ( A. nodosum ) and microalgae Arthrospira platensis ( A. platensis ) to separate alginate-like polysaccharides and evaluate their structural integrity. A multidimensional analytical workflow combining solution-state 1 H NMR, solid-state 13 C CP/MAS NMR, and ultrahigh-resolution FT-ICR-MS (ESI and GALDI) was established to bridge polymer backbone analysis with molecular-level fingerprinting. NMR analyses indicated the retention of characteristic glycosidic and carboxyl-associated functionalities in A. nodosum, whereas corresponding signals were absent in A. platensis, indicating fundamental compositional differences. FT-ICR-MS resolved up to 1591 molecular formulas, revealing high extract complexity dominated by lipid-like and hydrocarbon species, while carbohydrate-assigned formulas were comparatively underrepresented due to limited ionization efficiency. Nonetheless, the presence of oxygen-rich compounds in the macroalgal residue sample supported the presence of alginate-related molecules. The combined approach demonstrates the complementary strengths of NMR and FT-ICR-MS for process monitoring, structural verification, and molecular fingerprinting of complex algal extracts, advancing analytical strategies for sustainable polysaccharide valorization.