The sodium alginate was prepared from brown seaweeds in Thua-Thien-Hue coastal area. The obtained alginate was characterized by 1 H-NMR, 1 H-1 H TOCSY and COSY spectra. The assignment of alginate peaks in 1 H-NMR spectrum is , , , , ppm in correspondence to H1, H2, H3, H4, H5 of D-mannuronic acid and , , , , ppm in correspondence to H1, H2, H3, H4, H5 of L-guluronic acid, respectively. The present results are essential for the investigating guidance of alginate and its derivatives. | Journal of Chemistry, Vol. 45 (6), P. 772 - 775, 2007 INTERPRETATION OF 1H-NMR SPECTRUM OF ALGINATE BY 1 H-1H TOCSY AND COSY SPECTRUM Received 16 January 2007 Chu Dinh Kinh1, Tran Vinh Thien2, Tran Thai Hoa3, and Dinh Quang Khieu3 1 Institute of Chemistry, Vietnamese Academy of Science of Technology 2 Department of Chemistry and Biology, Phu Yen College of Pedagogy 3 Department of Chemistry, College of Sciences, Hue University SUMMARY The sodium alginate was prepared from brown seaweeds in Thua-Thien-Hue coastal area. The obtained alginate was characterized by 1H-NMR, 1H-1H TOCSY and COSY spectra. The assignment of alginate peaks in 1H-NMR spectrum is , , , , ppm in correspondence to H1, H2, H3, H4, H5 of D-mannuronic acid and , , , , ppm in correspondence to H1, H2, H3, H4, H5 of L-guluronic acid, respectively. The present results are essential for the investigating guidance of alginate and its derivatives. I - INTRODUCTION Alginates are quite abundant in nature since they occur both as a structural component in marine brown algae, comprising up to 40% of dry matter. All commercial alginates are at present still extracted from algal sources [1]. Alginate, a family of unbranched binary copolymers of 1-4 glycosidically linked -Dmannuronic acid (M) and -L-guluronic acid (G) residues can be considered as patterns of homo-polymeric blocks of G and M, respectively, and blocks with an alternating sequence, all in co-existence [2]. Alginate has widespread applications in foods and drinks, pharmaceutical and bioengineering industries [3, 4]. The industrial utilization of any particular alginate will depend on its properties and therefore on its uronic acid composition, so it has become important to investigate relative proportions of the uronic acids. 772 The composition and sequential structure of alginate can be determined by 1H-NMR and 13CNMR [4] in which the 1H-NMR spectrum is very useful to quantitative analysis
