Characterising polar compounds using supercritical fluid chromatography-nuclear magnetic resonance spectroscopy (SFC-NMR)

• Published in: Faraday discussions 2019-08, Vol.218, p.219-232
• Main Authors: van Zelst, F. H. M, van Meerten, S. G. J, Kentgens, A. P. M
• Format: Article
• Language: English
• Subjects: Chromatography; Chromatography, Supercritical Fluid - instrumentation; Glucosamine - analogs & derivatives; Glucosamine - analysis; Hexosamines - analysis; Magnetic Resonance Spectroscopy - instrumentation; Molecular Conformation; NMR; Nuclear magnetic resonance; Spectrum analysis; Supercritical fluids
• ISSN: 1359-6640; 1364-5498
• DOI: 10.1039/c8fd00237a

To detect and characterise compounds in complex matrices, it is often necessary to separate the compound of interest from the matrix before analysis. In our previous work, we have developed the coupling of supercritical fluid chromatography (SFC) with nuclear magnetic resonance (NMR) spectroscopy for the analysis of nonpolar samples [Van Zelst et al. , Anal. Chem. , 2018, 90 , 10457]. In this work, the SFC-NMR setup was successfully adapted to analyse polar samples in complex matrices. In-line SFC-NMR analysis of two N -acetylhexosamine stereoisomers was demonstrated, namely N -acetyl-mannosamine (ManNAc) and N -acetyl-glucosamine (GlcNAc). ManNAc is a metabolite that is present at elevated concentrations in patients suffering from NANS-mediated disease. With our SFC-NMR setup it was possible to distinguish between the polar stereoisomers. Until now, this was not possible with the standard mass-based analysis techniques. The concentrations that are needed in the SFC-NMR setup are currently too high to be able to detect ManNAc in patient samples (1.7 mM vs. 0.7 mM). However, several adaptations to the current setup will make this possible in the future. In this work, a novel SFC-NMR setup was successfully adapted to separate and characterize polar compounds in complex matrices.