Oligosaccharide alditols from red seaweeds: comparison of UV-MALDI-MS analysis by using different matrices

M. K. FATEMA; ,YASUTO SATO; HIROSHI NONAMI; DIOGO R. B. DUCATTI; ALAN G. GONÇALVES; EUGÌNIA R. DUARTE; MIGUEL D. NOSEDA; MARÍA C. MATULEWICZ; ALBERTO S. CEREZO; ERRA BALSELLS, ROSA

Tsukuba, Japón.

Congreso; 56th Annual Conference on Mass Spectrometry Tsukuba, The Mass Spectrometry Society of Japan (MSSJ), May 14-17, 2008,; 2008

The Mass Spectrometry Society of Japan (MSSJ),

Oligosaccharide alditols from red seaweeds: comparison of UV-MALDI-MS analysis by using different matrices (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 Organica, Facultad de Ciencias Exactas, Universidad de Buenos Aires, Argentina) Fatema MST. Kaniz,1 Yasuto Sato,1 Hiroshi Nonami,1 Diogo R. B. Ducatti,2 Alan G. Gonçalves,2 M. Eugěnia R. Duarte,2 Miguel D. Noseda,2 María C. Matulewicz,3 Rosa Erra-Balsells3, A. S. Cerezo3 Short Abstract:   Herein we report the comparative ESI-MS and UV-MALDI-TOF-MS analysis of the following oligosaccharide alditols: G→LAOH (β-D-galactopyranose→3,6-anhydro-L-galactitol), G6M→LAOH (β-D-6-O-methylgalactopyranose→3,6-anhydro-L-galactitol), G6S→LAOH (β-D-galactopyranose 6-sulfate→3,6-anhydro-L-galactitol), G4S→DAOH and G4S→DA2S→G4S→DA2SOH. UV-MALDI-TOF-MS experiments were carried out in the linear and reflectron modes and, as routine, in both in the positive- and negative-ion mode. 2,5-Dihydroxybenzoic acid (gentisic acid; GA)), nor-harmane (nHo), GA-1-butylamine (GA-BU), ferulic acid (FA) and FA-BU were used as matrices. For the sulfated oligosaccharide alditols, signals were only observed in the negative-ion mode, while the neutral oligosaccharide alditols were detected in the positive-ion mode. In the PSD mode only very few fragmentations were detected.     In addition, UV-MALDI-TOF-MS analysis of the oligosaccharide G4S→DA→G4S→DA (kappa-carratetraose) was also carried out and no molecular ion peak was detected in the linear and reflectron negative-ion mode; the spectrum obtained using FA as matrix, showed a signal due to a glycosidic C3-cleavage: the fragmentation between the reducing-end 3,6-anhydrogalactose and the adjacent galactose 4-sulfate. This type of cleavage was previously found in the UV-MALDI-TOF mass spectra of a complex mixture of oligosaccharides obtained by autohydrolysis of a partially cyclized mu/nu-carrageenan.