An investigation into the stereochemistry of the boronate di-esters of some monosaccharides using tandem mass spectrometry

The aim of this work was to probe the stereochemistry of a series of monosaccharides. Firstly, the underivatized sugars were investigated using linked‐scans and tandem mass spectrometry on a ‘hybrid’ instrument (hybrid MS/MS) and secondly, a comparison of linked‐scan and hybrid MS/MS was carried out on the butyl and phenyl boronate di‐esters. In situ derivatization of the sugar to the boronate di‐ester allows a negative‐ion fast‐atom bombardment (FAB) investigation with greater sensitivity than for the underivatized sugar. The linked‐scan data allow a great deal of information on the structure and chemistry of the sugars to be obtained, but the sensitivity at lower mass is limited. The hybrid MS/MS data give similar fragmentation information, plus improved sensitivity at lower molecular weight.