Interplay of H‐Bonds with Aromatics in Isolated Complexes Identifies Isomeric Carbohydrates

Abstract

The tremendous isomeric diversity of carbohydrates enables a wide range of their biological functions but makes the identification and study of these molecules difficult. We investigated the ability of intermolecular interactions to communicate structural specificity of carbohydrates to protonated aromatic molecules in non‐covalent complexes, isolated and cooled in the gas phase. Our study revealed that small structural differences between carbohydrate isomers of any type, including enantiomers, are accurately communicated by these interactions to aromatic molecules as detectable changes in their electronic excitation spectra. The specific response of the aromatics to the isomers of carbohydrates is fine‐tuned by the interplay of the various involved non‐covalent bonds. These findings enable the gas‐phase identification and relative quantification of any isomers of oligosaccharides in their solution mixtures using the 2D UV‐MS fingerprinting technique.

Separation and Identification of Glycan Anomers Using Ultrahigh-Resolution Ion-Mobility Spectrometry and Cryogenic Ion Spectroscopy

“…Nevertheless, a vibrational spectrum will always represent a characteristic fingerprint for a given carbohydrate structure. This realization initiated a series of studies that explored the sensitivity of different spectroscopic schemes to the various forms of carbohydrate isomerism [25][26][27][28][29][30], with the idea that an unknown carbohydrate compound could be identified by comparing its fingerprint spectrum to those from a database, bringing spectroscopy closer to becoming a routine-analysis tool.…”

Lipid Analysis by Mass Spectrometry coupled with Laser Light

“…The non‐covalent intermolecular interactions induce isomer‐specific structural changes that can be detected by UVPD spectroscopy. Contrary to carbohydrates, for which all types of isomerism can be resolved by a single aromatic sensor (protonated tyrosine), [80] the structural diversity of lipids makes a one‐fits‐all approach illusory. Instead, preliminary computer simulations were performed to predict the most promising aromatic sensor for each pair of isomeric lipids.…”

Revealing the Structure of Tryptophan in Microhydrated Complexes by Cold Ion Spectroscopy

“…On the other hand, UV spectra of aromatic molecules often exhibit extremely high sensitivity to structural differences of their noncovalent complexes. 39,40 Regarding this, for the complexes with n = 4−6 produced by the two methods, we compared their respective UV spectra (Figure S2).…”

“…The spectral congestion, which increases with the size of the clusters, may hide the fine differences between the IR spectra measured for the same but differently produced complexes. On the other hand, UV spectra of aromatic molecules often exhibit extremely high sensitivity to structural differences of their noncovalent complexes. , Regarding this, for the complexes with n = 4–6 produced by the two methods, we compared their respective UV spectra (Figure S2).…”