Relationships between Guluronate Contents in Alginates Determined by ¹H-NMR Spectroscopy and Their Average Molecular Weights

Abstract

The relationships between guluronate content (G%) in alginates determined by ¹H-nuclear magnetic resonance (¹H-NMR) spectroscopy and their weight average molecular weight (WAMW) were examined to evaluate the reliability of the ¹H-NMR method. The partially hydrolyzed alginates with WAMW of 15k, 30k, 45k, 60k and 100k were prepared from alginates with WAMW of 150_??_200k by autoclaving. The G% in the partially hydrolyzed alginates determined by ¹H-NMR spectroscopy were independent on their WAMW, when the G% was less than 70%. The ¹H-NMR spectroscopic method using partially hydrolyzed alginates prepared by hydrolysis in an autoclave might be a convenient and reliable for the determination of G% in alginates.