Relationships between guluronate contents in alginates determined by H-1-NMR spectroscopy and their average molecular weights

The relationships between guluronate content (G%) in alginates determined b y H-1-nuclear magnetic resonance (H-1-NMR) spectroscopy and their weight av erage molecular weight (WAMW) were examined to evaluate the reliability of the H-1-NMR method. The partially hydrolyzed alginates with WAMW of 15k, 30 k, 45k, 60k and 100k were prepared from alginates with WAMW of 150 similar to 200k by autoclaving. The G% in the partially hydrolyzed alginates determ ined by H-1-NMR spectroscopy were independent on their WAMW, when the G% wa s less than 70%. The H-1-NMR spectroscopic method using partially hydrolyze d alginates prepared by hydrolysis in an autoclave might be a convenient an d reliable for the determination of G% in alginates.