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

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.

Fast and Effective Ion Mobility–Mass Spectrometry Separation of d-Amino-Acid-Containing Peptides

“…34 While some epimers were easier to distinguish as multimers, the general utility of that path remains unclear. One can sometimes enhance IMS resolution using shift reagents 35 that preferentially complex specific chemical groups, but the similarity of D- and L-aa makes that approach unlikely to succeed here. However, metal cationization could improve or worsen separation of epimers by modifying their geometries in unequal ways.…”

Recent advances in ion mobility–mass spectrometry for improved structural characterization of glycans and glycoconjugates

“…Although 1-phenyl-3-methyl-5-pyrazolone (PMP) was originally developed to enhance UV detection, a recent study showed increased separation of structural isomers after PMP derivatization [31]. Reacting with cis -diols on carbohydrates, boronic acid (BA) derivatization has also been shown to have great potential in improving isobaric carbohydrate differentiation as an ion mobility shift strategy [32].…”

“…As the detection and the characterization of glycans is often hindered by the lack of a chromophore and their poor ionization properties in either spectroscopic or mass-spectrometric detection, a wide variety of glycan labeling reagents have been developed, which provide the opportunity to manipulate the conformation of the glycans in the gas-phase. Although 1-phenyl-3-methyl-5-pyrazolone (PMP) was originally developed to enhance UV detection, a recent study showed increased separation of structural isomers after PMP derivatization [31]. Reacting with cis -diols on carbohydrates, boronic acid (BA) derivatization has also been shown to have great potential in improving isobaric carbohydrate differentiation as an ion mobility shift strategy [32].…”

Differentiation and identification of ginsenoside structural isomers by two-dimensional mass spectrometry combined with statistical analysis

“…The limitations of these methods include the need for derivatization, their limited resolution, and the time required [8]. Recently, mass spectrometry (MS) has proven to be a powerful analytical technique for the structural identification and discrimination of natural products because of its advantages in terms of sensitivity, specificity, and speed [12], [13], [14], [15], [16], [17], [18]. In past decades, MS-based methods for isomer differentiation have undergone great development and have been applied in organic chemistry [19], [20], [21], phytochemistry [22], [23], [24], and lipidomics [25], [26].…”