Ion mobility-mass spectrometry analysis of isomeric carbohydrate precursor ions

Abstract

The rapid separation of isomeric precursor ions of oligosaccharides prior to their analysis by MSn was demonstrated using an ambient pressure ion mobility spectrometer (IMS) interfaced with a quadrupole ion trap. Separations were not limited to specific types of isomers; representative isomers differing solely in the stereochemistry of sugars, in their anomeric configurations, and in their overall branching patterns and linkage positions could be resolved in the millisecond time frame. Physical separation of precursor ions permitted independent mass spectra of individual oligosaccharide isomers to be acquired to at least MS3, the number of stages of dissociation limited only practically by the abundance of specific product ions. IMS-MSn analysis was particularly valuable in the evaluation of isomeric oligosaccharides that yielded identical sets of product ions in MS/MS experiments, revealing pairs of isomers that would otherwise not be known to be present in a mixture if evaluated solely by MS dissociation methods alone. A practical example of IMS-MSn analysis of a set of isomers included within a single HPLC fraction of oligosaccharides released from bovine submaxillary mucin is described.

Ion Mobility Mass Spectrometry for Extracting Spectra of N-Glycans Directly from Incubation Mixtures Following Glycan Release: Application to Glycans from Engineered Glycoforms of Intact, Folded HIV gp120

“…Ion mobility separation coupled with principal component analysis of N-linked glycans from serum glycoproteins has shown promise for detection of cancer biomarkers [19] and ion mobility separations have also been used to examine N-linked glycan heterogeniety from monoclonal antibodies [20,21] although, in these cases, glycopeptides rather than the released glycans were examined. Isomer separation of small carbohydrates has been demonstrated [22][23][24][25][26][27] but, with current technology, the resolution of the mobility cells is not sufficient to resolve any but the smaller N-glycans [15,28]. For a review on instrumentation see [29].…”

Blackbody Infrared Radiative Dissociation of Protonated Oligosaccharides

“…From an analysis of the resulting fragment ions the sequence of sugar residues and their linkages and stereochemistry can also be determined. Analysis of the gas phase ions using ion mobility MS has also proven effective for differentiating isomeric carbohydrate structures [24][25][26].…”

Direct Infusion Electrospray Ionization – Ion Mobility – High Resolution Mass Spectrometry (DIESI-IM-HRMS) for Rapid Characterization of Potential Bioprocess Streams

“…It is not known whether these differences in cross section result from differences in ion structure or from differences between the two approaches for measurement. Although it would not be unexpected for negative ions to adopt a substantially different structure than positive ions, the collision cross sections found in this work for negative trisaccharide ions exhibit the same trend (maltotriose9 isomaltotriose9raffinose9melezitose) as CCSs for positive ions [26,37,38].…”

“…To generate representative data, collision cross sections of carbohydrate standards and select carbohydrate ions in a corn stover hydrolysate were measured. [25,26,37,38]. Negative-ion CCSs were~2 % larger than literature values for xylose and glucose and between 7 %-16 % different for the other oligosaccharides.…”

“…A few analytes common to many biomass samples have been independently investigated with IM-MS (often using commercially available standards), including acetic acid [21] and several carbohydrates [21,[25][26][27][37][38][39], such as 5-and 6-carbon mono/oligosaccharides. However, in almost all of these studies, only positive ions have been analyzed, which is contrary to established mass spectrometry protocols for biomass analysis [5,14].…”