21 Facts About NMR

NMR is routinely used in advanced medical imaging techniques, such as in magnetic resonance imaging .

Key feature of NMR is that the resonant frequency of a particular sample substance is usually directly proportional to the strength of the applied magnetic field.

NMR spectroscopy is one of the principal techniques used to obtain physical, chemical, electronic and structural information about molecules due to the chemical shift of the resonance frequencies of the nuclear spins in the sample.

Since the area under an NMR peak is usually proportional to the number of spins involved, peak integrals can be used to determine composition quantitatively.

Structure and molecular dynamics can be studied by NMR of quadrupolar nuclei even in the presence of magnetic "dipole-dipole" interaction broadening, which is always much smaller than the quadrupolar interaction strength because it is a magnetic vs an electric interaction effect.

Related searches

Since the NMR signal is intrinsically weak, the observed spectrum suffers from a poor signal-to-noise ratio.

The restricted range of the NMR frequencies made it relatively easy to use short radio frequency pulses to excite the entire NMR spectrum.

Fortunately, the development of Fourier transform NMR coincided with the development of digital computers and the digital fast Fourier transform .

NMR was the first to report the introduction of the MAS technique that allowed him to achieve spectral resolution in solids sufficient to distinguish between chemical groups with either different chemical shifts or distinct Knight shifts.

Since incoming radiation is equally likely to cause stimulated emission as absorption, the NMR effect depends on an excess of nuclei in the lower states.

NMR is extensively used in medicine in the form of magnetic resonance imaging.

NMR is used in organic chemistry and industrially mainly for analysis of chemicals.

NMR spectroscopy is used to unambiguously identify known and novel compounds, and as such, is usually required by scientific journals for identity confirmation of synthesized new compounds.

NMR logging, a subcategory of electromagnetic logging, measures the induced magnet moment of hydrogen nuclei contained within the fluid-filled pore space of porous media .

NMR logs provide information about the quantities of fluids present, the properties of these fluids, and the sizes of the pores containing these fluids.

NMR has now entered the arena of real-time process control and process optimization in oil refineries and petrochemical plants.

Two different types of NMR analysis are utilized to provide real time analysis of feeds and products in order to control and optimize unit operations.

Time-domain NMR spectrometers operating at low field yield free induction decay data that can be used to determine absolute hydrogen content values, rheological information, and component composition.

Earth's field NMR is typically stimulated by applying a relatively strong dc magnetic field pulse to the sample and, after the end of the pulse, analyzing the resulting low frequency alternating magnetic field that occurs in the Earth's magnetic field due to free induction decay .

An important feature of EFNMR spectrometry compared with high-field NMR is that some aspects of molecular structure can be observed more clearly at low fields and low frequencies, whereas other aspects observable at high fields are not observable at low fields.

SNMR is used to estimate aquifer properties, including quantity of water contained in the aquifer, porosity, and hydraulic conductivity.