Positive-ion ESI mass spectrometry of regioisomeric nonreducing oligosaccharide fatty acid monoesters: In-source fragmentation of sodium adducts
Structural characterization and differentiation of a novel group of regioisomeric monolaurate esters of the nonreducing trisaccharides raffinose and melezitose, and the nonreducing tetrasaccharide stachyose has been obtained using positive electrospray ionization (ESI) mass spectrometry with in-sour...
| Authors: | , , |
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| Format: | article |
| Publication Date: | 2008 |
| Country: | España |
| Institution: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repository: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/377057 |
| Online Access: | http://hdl.handle.net/10261/377057 |
| Access Level: | Open access |
| Keyword: | Oligosaccharide fatty acid monoesters Electrospray mass spectrometry In-source fragmentation Sodium adducts Nonreducing oligosaccharides |
| Summary: | Structural characterization and differentiation of a novel group of regioisomeric monolaurate esters of the nonreducing trisaccharides raffinose and melezitose, and the nonreducing tetrasaccharide stachyose has been obtained using positive electrospray ionization (ESI) mass spectrometry with in-source fragmentation. The surfactant nature and high polarity of these compounds make them appropriate analytes for being studied by conventional ESI-MS. The position of the acyl chain in each particular regioisomer has been used as a reporter group that allows unambiguous rationalization of the fragmentation routes of the corresponding natriated molecular ions [M + Na]+. In all cases, the main fragment ions were produced through cleavage of the glycosidic bond involving two anomeric carbons, the C-1′ and C-2″ of the α-D-Glcp-(1–2)-β-D-Fruf bond, and it was observed that sodium cation retention occurred on the heavier mass fragment of the two formed fragments, (e.g. di- or trisaccharide type vs monosaccharide type). Our results may help to better understand the fragmentation behavior of nonreducing oligosaccharides (as sodium adducts) in positive ESI mass spectrometry. |
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