High-Resolution,>1GHzNMR in Unstable Magnetic Fields

Abstract

Resistive or hybrid magnets can achieve substantially higher fields than those available in superconducting magnets, but their spatial homogeneity and temporal stability are unacceptable for high-resolution NMR. We show that modern stabilization and shimming technology, combined with detection of intermolecular zero-quantum coherences (iZQCs), can remove almost all of the effects of inhomogeneity and drifts, while retaining chemical shift differences and J couplings. In a 25-T electromagnet (1 kHz/s drift, 3 kHz linewidth over 1 cm(3)), iZQC detection removes >99% of the remaining inhomogeneity, to generate the first high-resolution liquid-state NMR spectra acquired at >1 GHz.

In vivo NMR detection of diet-induced changes in adipose tissue composition

“…This approach is based on the detection of the nonlinear signal from intermolecular zero quantum coherences (iZQC), which is well known to be insensitive to magnetic fi eld inhomogeneities and which has previously been used to enhance spectral resolution in a deshimmed sample ( 22 ), for a strongly drifting magnet ( 23 ), and in vivo (24)(25)(26). The iZQC signal is sensitive to simultaneous opposing transitions of two or more spins on different molecules.…”

Localized intermolecular zero‐quantum coherence spectroscopy in vivo

“…Further modifications of HOMOGENIZED to select distinct coherence pathways more efficiently have been proposed in the literature (15)(16)(17)(18)(19)(20)(21)(22)(23). iZQC methods were successfully applied to achieve line-narrowing in spectra acquired in a strongly drifting magnet (24), and for in vivo MRS on earthworms (20), on the rodent brain (22,25), on the rat spinal cord, and on xenograft tumors grown on mice (22).…”

A primer for nuclear magnetic relaxation in liquids

“…Its ability to yield such information in the liquid state is so remarkable that its development has been tremendous (16). The quest for understanding the structure and dynamics of large molecules (Ͻ100 kDa) is pushing the technique to very high fields (17)(18)(19). Aside from the benefits in terms of sensitivity and spectral spread, the advantages stemming from relaxation effects at high fields can aid in the study of large molecules.…”