Analytical Evaluation of Low-Field 31P NMR Spectroscopy for Lipid Analysis

Anal Chem. 2019 Feb 19;91(4):3035-3042. doi: 10.1021/acs.analchem.8b05416. Epub 2019 Feb 6.

Abstract

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 new 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 phosphatidylcholine (PC), phosphatidyl-ethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), and phosphatidyl-glycerol (PG) can be unambiguously assigned based on 2D 1H-31P total correlated spectroscopy (TOCSY) spectra. Furthermore, two quantitative methods to obtain absolute concentrations are proposed and discussed, and the performance is evaluated regarding precision and accuracy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Phospholipids / analysis*
  • Phosphorus / chemistry*

Substances

  • Phospholipids
  • Phosphorus