High-resolution NMR spectra in inhomogeneous and unstable fields via the three-pulse method

Abstract

In modern solution nuclear magnetic resonance (NMR), the spectral resolution is mainly dependent on the spatial homogeneity and temporal stability of the magnetic field. The spectral linewidths are usually proportional to the overall field homogeneity and the stability experienced by the sample. Many high-resolution NMR methods have been developed, but few are applicable in inhomogeneous and unstable fields. In this paper, a high-resolution three-pulse method based on intermolecular zero-quantum coherences (iZQCs) is proposed. Since this method is insensitive to field inhomogeneity and instability, spectral information such as the chemical shift can be retained in the resulting spectra. In comparison with the CPMG-HOMOGENIZED method, the new method provides almost pure solvent–solute iZQC signals.

Keywords:

• nuclear magnetic resonance
• high resolution
• unstable field
• intermolecular zero-quantum coherence
• three-pulse sequence

Acknowledgements

This work was partially supported by the NNSF of China (grants 10774125, 10875101, and 10974164) and the Research Fund for the Doctoral Program of Higher Education of China (grant 200803840019).