Structural analysis and differentiation of reducing and nonreducing neutral model starch oligosaccharides by negative-ion electrospray ionization ion-trap mass spectrometry

Negative-ion electrospray tandem mass spectrometry with an ion-trap provided a sensitive tool for sequence determination of oligosaccharides derived from starch. Fragmentations of [M−H]− as well [M+Cl]− ions allow an unambiguous differentiation between α-(1 → 4) and α-(1 → 6) linkage based on the presence of diagnostic [M−H−90]− and [M−H−78]− ions. For nonreducing saccharides with terminal sucrose groups, the fragmentation starts with elimination of the fructose unit, followed by cross-ring cleavages of the remaining rings. The specific fragmentation features of reducing and nonreducing saccharides can be used for their differentiation.

The identification of nonreducing saccharides, as well as the differentiation between α-(1 → 4) and α-(1 → 6) linkage were obtained on the basis of presence of diagnostic ions.Figure optionsDownload high-quality image (101 K)Download as PowerPoint slide