Ion mobility mass spectrometry analysis of isomeric disaccharide precursor, product and cluster ions

Abstract

RATIONALE Carbohydrates are highly variable in structure owing to differences in their anomeric configurations, monomer stereochemistry, inter-residue linkage positions and general branching features. The separation of carbohydrate isomers poses a great challenge for current analytical techniques. METHODS The isomeric heterogeneity of disaccharide ions and monosaccharideglycolaldehyde product ions evaluated using electrospray traveling wave ion mobility mass spectrometry (Synapt G2 high definition mass spectrometer) in both positive and negative ion modes investigation. RESULTS The separation of isomeric disaccharide ions was observed but not fully achieved based on their mobility profiles. The mobilities of isomeric product ions, the monosaccharide-glycolaldehydes, derived from different disaccharide isomers were measured. Multiple mobility peaks were observed for both monosaccharide-glycolaldehyde cations and anions, indicating that there was more than one structural configuration in the gas phase as verified by NMR in solution. More importantly, the mobility patterns for isomeric monosaccharide-glycolaldehyde product ions were different, which enabled partial characterization of their respective disaccharide ions. Abundant disaccharide cluster ions were also observed. The Results showed that a majority of isomeric cluster ions had different drift times and, moreover, more than one mobility peak was detected for a number of specific cluster ions. CONCLUSIONS It is demonstrated that ion mobility mass spectrometry is an advantageous method to assess the isomeric heterogeneity of carbohydrate compounds. It is capable of differentiating different types of carbohydrate ions having identical m/z values as well as multiple structural configurations of single compounds.

Ion Mobility Mass Spectrometry for Ion Recovery and Clean-Up of MS and MS/MS Spectra Obtained from Low Abundance Viral Samples

“…That these two compounds are present is consistent with the bimodal ATD peak (Inset to Figure 4a, red trace) and their presence was confirmed by extracting the spectra from each side of the peak to give the spectra shown in Figures 4b and 4c. ATD plots of the mass-different diagnostic fragment ions [25, 27, 34, 59–62] for these two compounds (blue and green traces for selected ions from compounds 11 and 10 respectively) maximized separately under the two peaks of the total ATD profile, further confirming the presence of these two compounds. This technique can also be used to identify the presence of isomeric high-mannose isomers and will be the subject of a future communication.…”

Ion Mobility Separations of Isomers based upon Long Path Length Structures for Lossless Ion Manipulations Combined with Mass Spectrometry

“…These peaks were potentially attributed to the carbohydrates’ α, β or open-chain configurations and the various sites of charge attachment for the sodium cation. Previously, two partially resolved IMS peaks were observed for cellopentaose and only one peak for maltopentaose and branched mannopentaose in a platform with less resolving power; [22] this is the first observation of multiple ion species for all three pentasaccharides.…”

Travelling‐wave ion mobility and negative ion fragmentation of high‐mannose N‐glycans

“…Isomer separation by ion mobility has been shown for small carbohydrates (monosaccharides to octasaccharides) and several N ‐glycans, but resolution on current commercial instruments is usually only sufficient to resolve small carbohydrates. Nevertheless, Jackson et al have been able to differentiate the larger compounds, GD1a and GD1b glycosphingolipids as caesium adducts; these compounds are isomeric in that they have sialic acid attached to different portions of the hexasaccharide moiety.…”