Identification and structural analysis of cereal arabinoxylan-derived oligosaccharides by negative ionization HILIC-MS/MS

• Published in: Food chemistry 2019-03, Vol.275, p.176-185
• Main Authors: Juvonen, Minna, Kotiranta, Markus, Jokela, Jouni, Tuomainen, Päivi, Tenkanen, Maija
• Format: Article
• Language: English
• Subjects: Arabinoxylan; Linkage analysis; Negative ionization; Oligosaccharides; Tandem mass spectrometry
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2018.09.074

•The fragmentation of chlorinated (A)XOS in negative ESI-MSn was elucidated.•The linkage positions of linear (A)XOS were determined by cross-ring fragment ions.•Branches were detected by the presence/absence of diagnostic ions in the MS3.•Negative ion HILIC-MS/MS enabled the quick identification of (A)XOS. Recent works provide evidence of the prebiotic potential of arabinoxylan-derived oligosaccharides (A)XOS. In this study, we developed a structural analysis for cereal-derived (A)XOS by negative ionization HILIC-MS/MS. Initially, we assessed twelve (A)XOS samples of known structures with different linkage positions and branching points by direct-infusion negative ESI-MSn. We subsequently developed the negative ion HILIC-MS/MS with a post-column addition of ammonium chloride. The selected (A)XOS represented both linear (arabinofuranosyl residue linked to the non-reducing end of xylooligosaccharide) and branched structures. Each (A)XOS sample produced a specific spectrum in negative ion ESI-MSn. By analyzing cross-ring fragment ions, we determined the linkage positions of linear (A)XOS. The presence or absence of diagnostic ions in the MS3 allowed us to detect different branches (O-2- or/and O-3-linked arabinofuranosyl with/or without O-4-linked xylopyranosyl at the non-reducing end). Furthermore, we could identify all analyzed samples by HILIC-MS/MS, based on the formed spectral library and chromatographic retention times.