Nuclear magnetic resonance (NMR) spectroscopy is an analytical technique that exploits the magnetic properties of atomic nuclei to determine the structure and purity of molecules. NMR works by placing a sample in a strong magnetic field, which causes the magnetic nuclei in the sample to absorb and emit radio frequency radiation. The signal produced provides information about the molecular structure based on factors like chemical shifts and spin-spin splitting. NMR has applications in chemistry, medicine, and other fields such as determining molecular structures, imaging tissues for medical diagnosis via MRI, and assessing purity in quality control.

1. NUCLEAR MAGNETIC
RESONANCE (NMR)
PRESENTED TO: DR KASHIF-UR-REHMAN
PRESENTED BY: SAKINA ZAHOOR

2. CONTENTS
• Introduction
• Principle
• Theory of NMR
•
• Types of Samples
• Proton NMR
•
• Applications
• Advantages and Disadvantages

3. INTRODUCTION
• Nuclear Magnetic Resonance NMR spectroscopy is an analytical technique
used in quality control and research for determining the content and purity
of sample as well as it's molecular structure.
• This technique exploits the magnetic properties of nuceli.

4. PRINCIPLE
• Radiations in the radio frequency region are used to excite atoms, like
protons or C-13 atoms, so that their spins switch from being with to - being
alligned against an applied magnetic field.
• The range of the frequencies required for excitation and the complex
splitting patterns produced are special characteristic features of the
chemical structure of the molecule.

5. SCHEMATIC DIAGRAM FOR NMR SETUP

6. THEORY OF NMR
• When a charged particle such as proton , spin around its’ axis and creates a
magnetic field.Thus nucleus can be considered to be a “tiny bar magnet”.
• Normally these tiny bars are randomly oriented in space.However, in the
presence of magnetic field (B°) they are oriented with or against this field.
• In a magnetic field there are two energy states for a proton: a low energy
state in which Nucelus aligned in the same direction as the magnetic field
and a high energy state in which Nucelus aligned against the magnetic field.

7. • Two Variables characterize NMR:
1. Applied magnetic field (strength of which measured in Tesla-T)
2. Frequency of radiations used for Resonance (measured in Hertz or Megahertz- Hz/MHz)

8. RELATIONSHIP BETWEEN MAGNETIC FIELD AND
FREQUENCY

9. TYPES OF SAMPLES

10. TYPES OF NMR

11. INTERPRETATION

12. NUCLEAR RESONANCE

13. CHEMICAL SHIFT

15. SHIELDING & DESHIELDING

16. FACTORS AFFECTING CHEMICAL SHIFT
1. Electronegative group
2. Electronegative group attached to C-H system decreases the electron density
around the proton as a result there will be less shielding & thus chemical shift
will increase.
3. Magnetic anisotropy
4. Hydrogen bonding

17. APPLICATIONS
1. Chemistry
• By studying the NMR spectra , Chemists can determine the structure of many
compounds.
• It can be a very selective technique, distinguishing among many atoms within a
molecule or collection of molecules of same type.
• The detailed investigation include:
Identification of structural isomers
Ddetection of Hydrogen bonding

Detection of Electronegative atom or group

18. 2.Purity Determination(w/w NMR)
• NMR is primarily used for sructure determination , however it can also be used for
purity determination provided that structure and molecular weight of the
compound are known.This technique requires an internal standard of known purity.
3.Medicine
Useful for determining lead compounds and conformation of compounds bound to
receptors,enzymes and other Proteins etc.
• Best known application of NMR to general public is Magnetic Resonance Imaging
(MRI) for medical diagnosis.

19. MRI SCANNERS
• MRI scanners use strong magnetic fields, electric field gradients and radio waves
to generate the images of organs in the body.
• In most medical applications, protons (hydrogen atom) in tissues containing water
molecules create a signal that is processed to form an image of the body.
• Each subatomic particle , such as proton, has a certain level of spin.
• By adjusting plethora (produced by applying external magnetic field) of these
subatomic particles an image of tissue can be developed giving researchers a
picture of subject’s particular area.

20. MRI LABS IN PAKISTAN

21. OTHERS
• NMR is used to study molecular structure and interactions and for determining
3D structure of proteins and other macromolecules.Morever , also used in
cosmetics, polymers production and food manufacturing.

22. PROS AND CONS OF NMR

23. AVAILABILITY OF NMR IN PAKISTAN
1. International Center for Chemical and Biological Sciences , University of Karachi.

25. 2. QUAID E AZAM UNIVERSITY, ISLAMABAD
• List of instruments in QAU, Islamabad

26. 3. LUMS-SBASSE, LAHORE
• The Department of Chemistry and Chemical Engineering SBASSE-LUMS

27. NMR COST

29. REFERENCES
• Pharmaceutical Analysis by David G.Watson (3rd Edition)
• Nuclear Magnetic Resonance-Central labs. (centrallab.lums.edu.pk)
• chem.qau.edu.pk
• www.elsevier.com/locate/pnmrs
• https://www.aiinmr.com

30. ANY QUESTION?
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Jazak Allah for your time and patience!!! :)