Nuclear Magnetic Resonance (NMR)

Nuclear Magnetic Resonance is an analytical technique to determine the purity of a sample and its molecular structure.  It is used to infer basic structure of unknown compounds. It helps to determine phase changes, solubility, conformational exchange and diffusion. The technique is used to observe the local magnetic fields around atomic nuclei. Biochemists use NMR technique to identify proteins and other complex molecules.

How it works?

• The sample is placed in a magnetic field and the NMR signal is produced by excitation of the nuclei sample with radio waves into nuclear magnetic resonance, which is detected with sensitive radio receivers.
• The intramolecular magnetic field around an atom in a molecule changes the resonance frequency, thus giving access to details of the electronic structure of a molecule and its individual functional groups.
• As the fields are unique or highly characteristic to individual compounds, in modern organic chemistry practice, NMR spectroscopy is the definitive method to identify monomolecular organic compounds.

Application of Nuclear Magnetic Resonance 

• It is an analytical chemistry technique used in quality control.
• It is used in research for determining the content and purity of a sample as well as its molecular structure. For example, NMR can quantitatively analyze mixtures containing known compounds.
• NMR spectroscopy is routinely used by chemists to study chemical structure using simple one-dimensional techniques. Two-dimensional techniques are used to determine the structure of more complicated molecules.
• These techniques are replacing x-ray crystallography for the determination of protein structure.
• Time domain NMR spectroscopy techniques are used to probe molecular dynamics in solution.
• Solid state NMR spectroscopy is used to determine the molecular structure of solids.
• Other scientists have developed NMR methods-of measuring diffusion coefficients.