Graphs for Far-Infrared Ion Spectroscopy
Graphs for Far-Infrared Ion Spectroscopy

Distinguishing Oligosaccharide Isomers Using Far-Infrared Ion Spectroscopy

Isomeric sugars, also known as saccharides, are challenging to characterize using common analytical techniques, for example liquid chromatography-mass spectrometry (LC-MS). However, scientists at HFML-FELIX, the IMM and Radboudumc have been exploring a new approach called far-infrared ion spectroscopy to solve this problem. Using the low-frequency part of the infrared spectrum, they show that the properties of selected ions and can often differentiate between different types of saccharides.

The structure and bonding of saccharides make their infrared spectra (which provide information about their composition) broad and lacking specific diagnostic information. In this study, the researchers focused on recording infrared spectra of ion-complexed saccharides in a previously unexplored wavelength range (300-1000 cm-1/10-33 micron), known as the far-infrared range. They found distinct and highly informative features in the room-temperature spectra of these ion-complexed saccharides.

Graphs for Far-Infrared Ion Spectroscopy
(A): Score plot resulting from the PCA of the IR spectra | (B): Normalized surface areas enveloped by the triangles drawn in (A)

By analyzing these features, the researchers were able to differentiate between saccharides that differ in their monosaccharide composition or the way their glycosidic linkages are arranged. They successfully demonstrated this method by distinguishing between saccharides with similar structures but differing in a single glycosidic linkage.

Furthermore, by combining this spectroscopic technique with a method called hydrophilic interaction liquid chromatography, the researchers were able to identify specific saccharides in complex samples taken from patients' body fluids. This shows the potential of this approach as a sensitive and versatile method for identifying saccharides in real-world samples.


The full version of this article was published in Analytical Chemistry:

Distinguishing Oligosaccharide Isomers Using Far-Infrared Ion Spectroscopy: Identification of Biomarkers for Inborn Errors of Metabolism | Analytical Chemistry (


jonathan.martens [at] (Dr. Jonathan Martens)

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