NMR Spectroscopy: Definition, Principle, Steps, Parts, And Its Uses

What is NMR?

NMR Spectroscopy (Nuclear magnetic resonance spectroscopy) is a spectroscopic technique for studying the localised magnetic fields surrounding atomic nuclei. It is also known as magnetic resonance spectroscopy (MRS) or nuclear magnetic resonance (NMR) spectroscopy.

It is a method of spectroscopy that relies on the nuclei of atoms to absorb electromagnetic radiation between four and nine hundred megahertz.

In the last 50 years, NMR has emerged as the technique of choice for determining the structure of organic compounds.

This is the unique spectroscopic method for which a comprehensive analysis and explanation of the whole spectrum is often requested.

The Principle of Nuclear Magnetic Resonance (NMR) Spectroscopy

  1. According to the NMR fundamental concept, many nuclei generate rotation as well as every nucleus have electrically charged. If an external magnetic field is present, energy may increase from its lowest level to a higher one (generally a single energy gap).
  2. Only when rotation restores to its initial position, power is released at the similar frequency as the energy transfer, which corresponds to radio frequencies.
  3. An NMR spectrum for the relevant nucleus is produced by various measurements and signal processing which correlate to this transmission.

The Working of Nuclear Magnetic Resonance (NMR) Spectroscopy

  • A sample is placed under a magnetic field, and the nuclear magnetic resonance (NMR) signal is formed by radio wave stimulation of the sample’s nuclei, which is monitored using sensitive radio receivers.
  • The intramolecular magnetic field of an atom inside a molecule may affect the resonance frequency, revealing its electronic structure and active groups.
  • NMR spectroscopy provides the sole reliable method for identifying monomolecular organic compounds due to the unique or extremely specific magnetic fields associated with each material.
  • In addition to molecular identification, NMR spectroscopy provides extensive information on the structure, dynamics, reaction state, as well as chemical environment of molecules.
  • Proton and carbon-13 NMR spectroscopy are the two most used forms of NMR, but it may be used with any material that has nuclei with spin.

Instrumentation for Nuclear Magnetic Resonance (NMR) Spectroscopy

  1. The Sample container 

glass tube, 0.3 cm in diameter, 8.5 cm in length.

  1. Permanent magnet

It offers a uniform magnetic field between 60 and 100 MHZ.

  1. Magnetic coils

A magnetic field is created by these coils when electricity passes through them.

  1. Sweep generator

Pass the sample through the magnetic field to create an equivalent quantity of it.

  1. A radio frequency transmitter

a radio transmitter coil that emits a brief yet strong radio wave pulse

  1. Radio frequency receiver

a radio receiver coil that listens for radio frequencies released as nuclei drop their energy

  1. Read out systems

a device that captures and analyses the data.

Applications of Nuclear Magnetic Resonance (NMR) Spectroscopy

The study of how electromagnetic radiation interacts with matter is known as spectroscopy. The study of matter’s physical, chemical, and biological characteristics is done using NMR spectroscopy.

  • It is a quality control method in analytical chemistry.
  • It is used in research to ascertain a sample’s molecular composition, purity, and content. NMR may be used to analyse mixtures containing known chemicals quantitatively, for example.
  • Chemists often employ NMR spectroscopy to investigate chemical structures using straightforward one-dimensional methods. The structure of increasingly complex molecules is determined using two-dimensional methods.
  • These methods are taking the place of x-ray crystallography in the analysis of protein structures.
  • Molecular dynamics in solution are investigated using time-domain NMR spectroscopy methods.
  • A solid state In order to ascertain the molecular makeup of solids, NMR spectroscopy is used.
  • Other researchers have created NMR techniques for calculating diffusion coefficients.


  1. http://chem.ch.huji.ac.il/nmr/whatisnmr/whatisnmr.html
  2. https://www.slideshare.net/solairajananant/nmr-spectroscopy-13887430
  3. https://www.ias.ac.in/article/fulltext/reso/009/01/0034-0049
  4. https://www2.chemistry.msu.edu/faculty/reusch/virttxtjml/spectrpy/nmr/nmr1.htm
  5. https://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_spectroscopy
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