96. Analytical evaluation of low-field 31P NMR spectroscopy for lipid analysis

Boris Gouilleux, Nichlas Vous Christensen, Kirsten Gade Malmos, and Thomas Vosegaard, Analytical Chemistry, (2019) DOI: 10.1021/acs.analchem.8b05416

We investigate the potential of 31P NMR with simple, maintenance-free benchtop spectrometers to probe phospholipids in complex mixtures. 31P NMR-based lipidomics has become an important topic in a wide range of applications in food- and health-sciences, and the continuous improvements of compact, maintenance- and cryogen-free instruments opens news opportunities for NMR routine analyses. A prior milestone is the evaluation of the analytical performance provided by 31P NMR at low magnetic field. To address this, we assess the ability of state-of-the-art benchtop NMR spectrometers to detect, identify and quantify several types of phospholipids in mixtures. Relying on heteronuclear cross-polarization experiments, phospholipids can be detected in 2 h with a limit of detection of 0.5 mM at 1 T and 0.2 mM at 2 T, while the headgroups of PC, PE, PI, PS and PG can be unambiguously assigned based on 2D 1H-31P TOCSY spectra. Furthermore, two quantitative methods to obtain absolute concentrations are proposed and discussed, and the performance is evaluated regarding precision and accuracy.