Oligosaccharides from red seaweeds: comparison between ESI-MS and UV-MALDI-MS

MST. KANIZ FATEMA; YASUTO SATO; HIROSHI NONAMI; DIOGO R. B. DUCATTII .; ALAN G. GONCALVES; M. EUGENIA R. DUARTE; MIGUEL D. NOSEDA; MARÍA C. MATULEWICZ; ROSA ERRA-BALSELLS; ALBERTO S. CEREZO

Fuchu, Tokio, Japón

Conferencia; Joint Conference on Environmental Engineering in Agriculture 2007; 2007

Oligosaccharides from red seaweeds: comparison between ESI-MS and UV-MALDI-MS Fatema MST. Kaniz,1 Yasuto Sato,1 Hiroshi Nonami,1 Diogo R. B. Ducatti,2 Alan G. Gonçalves,2 M. Eugenia R. Duarte,2 Miguel D. Noseda,2 María C. Matulewicz,3 Rosa Erra-Balsells3, Alberto S. Cerezo3 (1Plant Biophys./Biochem. Research Laboratory, College of Agriculture, Ehime University, Japan 2Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Paraná, Brazil 3CIHIDECAR-CONICET, Departamento de Quimica Orgánica, Facultad de Ciencias Exactas, Universidad de Buenos Aires, Argentina) Keywords: Oligosaccharides from red seaweeds, UV-MALDI-MS, ESI-MS.   1. Introduction   　Herein we report the comparative ESI-MS and UV-MALDI-TOF-MS analysis of the following oligosaccharides: G-LA (beta-D-galactopyranose - 3,6-anhydro-L-galactose), G4S-DA (beta-D-galactopyranose 4-sulfate - 3,6-anhydro-D-galactose), G-LA-G and G-LA-G-LA.   2. Experimental 　Experiments were carried out in the linear and reflectron modes of UV-MALDI-MS and, as routine, in both in the positive- and negative-ion-mode.  2,5-Dihydroxybenzoic acid (DHB) and nor-harmane (nHo) were used as matrices.  Also, ESI-MS was used.   3. Results and Discussion 　For the sulfated oligosaccharide signals were only observed in the negative ion-mode with both matrices. In the linear spectrum of the sulfated oligosaccharide a small signal consistent with a glycosidic C-cleavage between 3,6-anhydrogalactose and the adjacent galactose 4-sulfate unit was found. This type of cleavage was previously reported in the UV-MALDI-TOF-MS analysis of a complex mixture of oligosaccharides obtained by autohydrolysis of a partially cyclized mu/nu-carrageenan. The PSD mode afforded the expected different fragmentations of the glycosidic bonds together with some fragmentations of the sugar rings. This was confirmed with ESI-MS.   (Las fórmulas de los oligosacáridos se encuentran en el texto en formato pdf correspondiente al Libro de Resúmenes)