Differentiating planteose and raffinose using negative ion mode mass spectrometry

Abstract

Planteose, a non-reducing trisaccharide, is present in seeds of many higher plants. It is a structural isomer of raffinose comprising α-d-galactopyranosyl linked to C (6') of fructose residue. Planteose-centric studies are at a disadvantage due to the lack of relatively more straightforward methods to identify it. In the present study, the fragmentation pattern associated with planteose was demonstrated using collision-induced dissociation in negative ion mode. MS2 of planteose revealed the presence of a unique peak at m/z 233 that is three times more intense than that at m/z 221. The m/z 221 peak is commonly seen in the MS2 of raffinose. Furthermore, we evaluated the effect of the presence of a reducing end sugar building block in a similar trisaccharide (levantriose) that was revealed to affect the generation of ion at m/z 233. Overall our analysis indicated that planteose can be clearly distinguished from raffinose based on fragment patterns in the negative ion mode.