Identification of structurally closely related monosaccharide and disaccharide isomers by PMP labeling in conjunction with IM-MS/MS.

Hongmei Yang,Lei Shi,Jinying Li,Fengrui Song,Xiaoyu Zhuang,Rui Su,Debin Wan,Shuying Liu

doi:10.1038/srep28079

Abstract

It remains particularly difficult for gaining unambiguous information on anomer, linkage, and position isomers of oligosaccharides using conventional mass spectrometry (MS) methods. In our laboratory, an ion mobility (IM) shift strategy was employed to improve confidence in the identification of structurally closely related disaccharide and monosaccharide isomers using IMMS. Higher separation between structural isomers was achieved using 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization in comparison with phenylhydrazine (PHN) derivatization. Furthermore, the combination of pre-IM fragmentation of PMP derivatives provided sufficient resolution to separate the isomers not resolved in the IMMS. To chart the structural variation observed in IMMS, the collision cross sections (CCSs) for the corresponding ions were measured. We analyzed nine disaccharide and three monosaccharide isomers that differ in composition, linkages, or configuration. Our data show that coexisting carbohydrate isomers can be identified by the PMP labeling technique in conjunction with ion-mobility separation and tandem mass spectrometry. The practical application of this rapid and effective method that requires only small amounts of sample is demonstrated by the successful analysis of water-soluble ginseng extract. This demonstrated the potential of this method to measure a variety of heterogeneous sample mixtures, which may have an important impact on the field of glycomics.

Highlights

Gaseous complexes[14,15]
IMMS has been increasingly applied to the separation and analysis of small molecules and biomacromolecules in the gas phase based on measuring their arrival time distributions (ATD) and their CCSs20–23
The overall ion mobility spectra of the 10 disaccharide isomers and 4 monosaccharide isomers at a 40 V, 550–2500 m/s T-Wave are displayed in Supplementary Fig. S1

Summary

Introduction

Gaseous complexes[14,15]. IMMS is a promising approach to overcoming the above mentioned limitations, making it an ideal candidate for differentiation of isomers. Harvey et al.[34] reported the use of TWIMMS combined with negative ion fragmentation, for determining the structures of high-mannose glycans. To increase the CCSs of the oligosaccharide isomers, Fenn and McLean[37] have employed boronic acid derivatization of carbohydrates as an ion mobility shift strategy, but no arrival time distributions of the derivatized isomers were reported. Both et al.[38] reported IMMS separation of isobaric monosaccharides and differentiation of CID fragment ions from disaccharides and polysaccharides, yet not all isomers were distinguishable. Water-soluble ginseng monosaccharides (WGOS-1) and water-soluble ginseng disaccharides (WGOS-2) were used to evaluate this method, demonstrating the powerful applicability of this approach for analysis of mixtures

Methods

Results

Conclusion