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A 900 MHz NMR instrument with a 21.1 T magnet at HWB-NMR, Birmingham, UK. Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic field.
Nuclear magnetic resonance (NMR) spectroscopy uses the intrinsic magnetic moment that arises from the spin angular momentum of a spin-active nucleus. [1] If the element of interest has a nuclear spin that is not 0, [1] the nucleus may exist in different spin angular momentum states, where the energy of these states can be affected by an external magnetic field.
In conventional NMR spectroscopy, T 1 limits the pulse repetition rate and affects the overall time an NMR spectrum can be acquired. Values of T 1 range from milliseconds to several seconds, depending on the size of the molecule, the viscosity of the solution, the temperature of the sample, and the possible presence of paramagnetic species (e.g ...
In NMR relaxometry (NMRR) only one specific NMRR parameter is measured, not the whole spectrum (which is not always needed). This helps to save time and resources and makes it possible to use an NMR relaxometer as a portable express analyzer in different branches of industry, science and technology, environmental protection, etc. [4] [5]
Solid-state 900 MHz (21.1 T [1]) NMR spectrometer at the Canadian National Ultrahigh-field NMR Facility for Solids. Solid-state nuclear magnetic resonance (ssNMR) is a spectroscopy technique used to characterize atomic-level structure and dynamics in solid materials. ssNMR spectra are broader due to nuclear spin interactions which can be categorized as dipolar coupling, chemical shielding ...
However, using an off-resonance saturation pulse to irradiate protons in the bound (hydration) population can have a detectable effect on the NMR signal of the mobile (free) proton pool. When a population of spins is saturated, such that the magnitude of the macroscopic magnetization vector approaches zero, there is no remaining spin ...
Triple resonance experiments can also be used in sequence-specific backbone resonance assignment of magic angle spinning NMR spectra in solid-state NMR. [4] [8] A large number triple-resonance NMR experiments have been created, and the experiments listed below is not meant to be exhaustive.
In solid-state NMR spectroscopy, magic-angle spinning (MAS) is a technique routinely used to produce better resolution NMR spectra. MAS NMR consists in spinning the sample (usually at a frequency of 1 to 130 kHz ) at the magic angle θ m (ca. 54.74°, where cos 2 θ m =1/3) with respect to the direction of the magnetic field .