High-Resolution NMR Spectroscopy with a Portable Single-Sided Sensor

Abstract

We report construction of a portable nuclear magnetic resonance sensor with a single-sided open probe design. The resulting magnetic field inhomogeneity is compensated by a pulse sequence that takes advantage of parallel inhomogeneity in the applied radio frequency field. We can thereby acquire fluorine-19 spectra of liquid fluorocarbons with 8 parts per million resolution, surmounting the long-standing obstacle of obtaining chemical shift information with open probe instruments.

Multinuclear nanoliter one-dimensional and two-dimensional NMR spectroscopy with a single non-resonant microcoil

“…Another immediate, noteworthy consequence of the non-resonant concept of the BBC system is that the NMR probe as such is magnetic fieldindependent, and one and the same probe can be utilized on different (field) NMR systems. Moreover, the small detection volume alleviates the problems related to field homogeneity over large sample volumes and, consequently, BBC probes are likely to play a major role in portable or table-top NMR systems with inhomogeneous magnetic fields or built around compact permanent or cryogen-free superconducting magnets 39 . Besides the direct applications in medical diagnostics, drug or catalyst screening, there are many emerging aspects of this new technology, for dynamic nuclear polarization schemes or for time-saving 'multinuclear multitasking' strategies in which acquisition scans are alternated between two kinds of nuclides in a way that while one nuclide is scanned, the other is relaxing.…”

Compact magnets for magnetic resonance

“…The gradient along y is brought from 0.1 to 0.04 T/m by shimming. A MR spectrum was then achieved with the open magnet, using ex situ methodologies (25). Such methodologies have been shown to cancel the effects of field imperfections by the application of space-dependent phase corrections via the use of special pulse sequences, custom rf field profiles, and imaging gradients.…”

A Spectral-Scanning Nuclear Magnetic Resonance Imaging (MRI) Transceiver

“…This means that by implementing scaled-down coils which are in intimate proximity of a scaled-down sample and without changing the magnetization strength we increase the by while decreasing by due to volume reduction. This fundamental scaling law is very well understood in small volume NMR [3], [6]- [8] and high-resolution MRI systems [5], [9], [10].…”

“…In Fig. 2, we show as an example the envelope decay of H in water at room temperature as a function of magnetic field gradient, [8]. In this system, the zero-gradient relaxation time-constant is approximately 50 ms, which is a typical value for H in aqueous biological environments with 1 T. The additional envelope decay factor , which is due to , is computed using the Torrey-Bloch formulations and is described by the following: (2) where m , s is the diffusion coefficient of water molecules (and H) and rad T s is the gyromagnetic ratio of H in the water molecules [15].…”