Rapid resolution of carbohydrate isomers by electrospray ionization ambient pressure ion mobility spectrometry-time-of-flight mass spectrometry (ESI-APIMS-TOFMS)

Abstract

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.

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

“…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.…”

“…In the absence of conformational change, ion adduction generally does not significantly alter the collision cross section of ions in large molecules (e.g., peptides and proteins), especially in the case [25,34,36]. It is currently not clear whether the observed change in cross section is due to conformational change or to the relative size of the anion.…”

“…IM-MS has been applied as an effective tool for complex sample analysis in several fields, including proteomics [15][16][17], petroleomics [18][19][20], and metabolomics [21][22][23], and has the ability to separate ions based on differences in chemical class [24][25][26][27] and to distinguish between various molecular conformations and geometries [16,[18][19][20]28]. IM-MS has also been utilized in small molecule analyses, including separation of pharmaceutical drug formulations [29,30], chiral amino acid enantiomers [31], alkaloid stereoisomers [32], trace analysis of drugs [33], and screening for chemical warfare agents [34][35][36].…”

“…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].…”

Distinction of sialyl anomers on ESI- and FAB-MS/MS: Stereo-specific fragmentations

“…T he necessity for distinguishing sugar anomers has led to many new methodologies on simple sugars like mono-or disaccharides [1][2][3][4]. We report here the differences on the electrospray ionization (ESI) MS 2 and MS 3 product-ion spectra of lysoglyceroganglioside anomers and seek to elucidate the differences based on stereochemical considerations.…”