Timothy J. Norwood

Zero quantum NMR imaging and spectroscopy in a low homogeneity magnetic field

Zero-quantum nuclear magnetic resonance imaging and spectroscopy in an inhomogeneous or low homogeneity magnetic field are disclosed. Specific pulse sequences have been developed which produce zero-quantum coherence resolved images and spectra. Unlike conventional NMR resolved images and spectra the zero-quantum coherence resolved images and spectra are unaffected by magnetic field inhomogeneity, thereby allowing the images and spectra of substances to be obtained where magnetic field inhomogeneity would previously have made it impossible.

Use of broadband decoupled zero-quantum coherence for NMR spectroscopy and imaging

Decouplage large bande du spectre de protons de zero quantum reduisant chaque multiplet en singulet en utilisant une sequence dimpulsions qui permet aussi dediter des coherences individuelles a partir du spectre. La methode a ete etendue pour produire des images resolues en fonction du deplacement chimique

Measurement of high resolution single-quantum J resolved proton spectra in inhomogeneous magnetic fields via zero-quantum coherences

Magnetic field inhomogeneity continues to be a major problem in NMR, particularly in the context of high magnetic field strengths (in absolute, hertz, rather than relative, ppm, terms) and in the context of NMR imaging where the sample volume is large. The only NMR coherence which is intrinsically independent of magnetic field inhomogeneity is zero-quantum coherence (I, 2). Despite the fact that these coherences result in spectra with intrinsic linewidths solely dependent on their spin-spin relaxation times (3), even in an inhomogeneous magnetic field, the utility of the method is compromised because the zero-quantum spectrum does not display the parameters conventionally used in spectral analysis (4). In this communication we demonstrate a pulse sequence whereby zeroquantum coherences can be made to display singlequantum coherence coupling constants at high resolution; this permits the conventional single-quantum coherence spectrum to be reassembled, even when the original data are acquired in an inhomogeneous magnetic field. It is well known that the resonance frequencies and scalar couplings observed in an NMR spectrum are determined by the order of coherence being observed (5) and that these are two of the most important parameters used in spectral analysis. For the chemical shift, the general expression for the precessional frequency of a P-quantum coherence of spins k is given by

Observation of a high resolution heteronuclear NMR spectrum in an inhomogeneous magnetic field

A pulse sequence is described that produces a well resolved heteronuclear spectrum of pregnenolone using an inhomogeneous magnetic field, which is easily assigned since it closely resembles the conventional 1H-decoupled 13C spectrum.

High resolution n.m.r. measurements in inhomogeneous magnetic fields: use of the SECSY pulse sequence

The high resolution proton n.m.r. spectra of a D2O solution of amino acids have been measured in an inhomogeneous B0-field via the conventional SECSY pulse sequence and also a broad band decoupled variant, the latter providing a signature for each component in the mixture; the results obtained are compared with the corresponding zero-quantum coherence spectra.

Use of zero-quantum coherences to measure high resolution n.m.r. spectra in inhomogeneous magnetic fields

The use of zero-quantum coherences to facilitate the measurements of high resolution n.m.r. spectra in an inhomogeneous B0-field is demonstrated using D2O solutions of amino acids.