Rapid Resolution of Carbohydrate Isomers by Electrospray Ionization Ambient Pressure Ion Mobility Spectrometry-Time-of-Flight Mass Spectrometry (ESI-APIMS-TOFMS)

Department of Chemistry, Washington State University, Pullman, Washington 99164-4630, USA.
Journal of the American Society for Mass Spectrometry (Impact Factor: 2.95). 08/2007; 18(7):1163-75. DOI: 10.1016/j.jasms.2007.04.007
Source: PubMed


Carbohydrates are an extremely complex group of isomeric molecules that have been difficult to analyze in the gas phase by mass spectrometry because (1) precursor ions and product ions to successive stages of MS(n) are frequently mixtures of isomers, and (2) detailed information about the anomeric configuration and location of specific stereochemical variants of monosaccharides within larger molecules has not been possible to obtain in a general way. Herein, it is demonstrated that gas-phase analyses by direct combination of electrospray ionization, ambient pressure ion mobility spectrometry, and time-of-flight mass spectrometry (ESI-APIMS-TOFMS) provides sufficient resolution to separate different anomeric methyl glycosides and to separate different stereoisomeric methyl glycosides having the same anomeric configuration. Reducing sugars were typically resolved into more than one peak, which might represent separation of cyclic species having different anomeric configurations and/or ring forms. The extent of separation, both with methyl glycosides and reducing sugars, was significantly affected by the nature of the drift gas and by the nature of an adducting metal ion or ion complex. The study demonstrated that ESI-APIMS-TOFMS is a rapid and effective analytical technique for the separation of isomeric methyl glycosides and simple sugars, and can be used to differentiate glycosides having different anomeric configurations.

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Available from: Prabha Dwivedi, Oct 01, 2015
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    • "The second mobility peak in Fig. 2(a) could tentatively be assigned to 6–4, but in general, anomers, other conformers, and/or ions with different charge site corresponding solely to isomer 6–2 might also be separated. Such species might interconvert or might be stable in the time frame of ion mobility separation as demonstrated previously for anomers [18] [19] or aniline and porphyrins differing in charge site. [30] In each case, they caused peak broadening or even peak splitting for one analyte. "
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    ABSTRACT: Hyaluronic acid is a naturally occurring linear polysaccharide with substantial medical potential. In this work, discrimination of tyramine-based hyaluronan derivatives was accessed by ion mobility-mass spectrometry of deprotonated molecules and nuclear magnetic resonance spectroscopy. As the product ion mass spectra did not allow for direct isomer discrimination in mixture, the reductive labeling of oligosaccharides as well as stable isotope labeling was performed. The ion mobility separation of parent ions together with the characteristic fragmentation for reduced isomers providing unique product ions allowed us to identify isomers present in a mixture and determine their mutual isomeric ratio. The determination used simple recalculation of arrival time distribution areas of unique ions to areas of deprotonated molecules. Mass spectrometry data were confirmed by nuclear magnetic resonance spectroscopy. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    Journal of Mass Spectrometry 06/2015; 50(6). DOI:10.1002/jms.3596 · 2.38 Impact Factor
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    • "IMS has also been applied to glycomics studies [20] [21] [22] [23] [24] [25] offering a powerful tool to separate and characterize carbohydrates and glycosidic isomers. [26] [27] The coupling of IMS to MS allows the study of molecular structures and conformational dynamics increasing, at the same time, selectivity, speed and limits of detection. "
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    ABSTRACT: Traveling wave ion mobility mass spectrometry (TWIM-MS) is shown to be able to separate and characterize several isomeric forms of diterpene glycosides stevioside (Stv) and rebaudioside A (RebA) that are cationized by Na(+) and K(+) at different sites. Determination and characterization of these coexisting isomeric species, herein termed catiomers, arising from cationization at different and highly competitive coordinating sites, is particularly challenging for glycosides. To achieve this goal, the advantage of using CO2 as a more massive and polarizable drift gas, over N2 , was demonstrated. Post-TWIM-MS/MS experiments were used to confirm the separation. Optimization of the possible geometries and cross-sectional calculations for mobility peak assignments were also performed. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.
    Journal of Mass Spectrometry 02/2015; 50(2). DOI:10.1002/jms.3532 · 2.38 Impact Factor
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    • "This contrasts with other studies with reducing sugars, which were complicated by the presence of α and β anomers and/or pyranose, furanose and ring-opened conformations. [13] [14] [15] Such phenomena can be negated by derivatisation to either alditols or methyl glycosides, but this was unnecessary in the present study. "
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    ABSTRACT: Ion mobility mass spectrometry (IMMS) has previously been shown to resolve small isobaric oligosaccharides, but larger alpha-oligoglucans are also abundant in biology and are of industrial importance. If conformational differences between such isomers are retained in the gas phase, IMMS could be used to address questions in biology and industry. Negative mode electrospray ionization (ESI) travelling-wave IMMS was used to resolve large isobaric α-glucan ions on the basis of their different gas-phase conformations. α,ω-Dicarboxy-terminated polystyrene was used to calibrate the instrument allowing the collision cross-sections (CCSs) of ions to be determined. α-1,4-Linked maltooligosaccharides with a degree of polymerisation of up to 35 could be discriminated from α-1,6-linked dextran and α-1,4/1,6-linked pullulan using IMMS. Fragmentation spectra of ions separated by IMMS could also distinguish isomers. Two conformational isomers of maltohexaose were resolvable by IMMS, likely reflecting extended and V6 helical conformations. IMMS was also able to identify a product within a mixture of maltooligosaccharides treated with the potential anti-tuberculosis drug target Mycobacterium tuberculosis GlgB branching enzyme. Biological samples of complex isobaric oligosaccharides can be analysed using IMMS in the negative mode providing facile analyses and high sensitivity without the need for either derivatisation or chromatographic separation. © 2013 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.
    Rapid Communications in Mass Spectrometry 01/2014; 28(2):191-9. DOI:10.1002/rcm.6771 · 2.25 Impact Factor
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