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Prepared by Lawrence Kok

Video Tutorial on Atomic Absorption /Emission Spectroscopy, Nuclear Magnetic Resonance Spectroscopy.

Clear explanation on how AAS works Short demo on flame chamber

Video on Atomic Absorption Spectroscopy

Detail explanation on how AAS works

Video on how MRI body imaging works

Video on MRI in detail Video on MRI simplified

Video tutorial on chemical shift Spin spin coupling for HNMR

Video on flame test Video on emission spectrum explained

How Atomic Emission spectroscopy works

Atomic Emission Spectroscopy vs Atomic Absorption Spectroscopy

Ground state

Excited state

Atomic Absorption Spectroscopy

Uses of AAS

Samples metals ions found

Uses of AAS and Part of AAS

Parts of Atomic Absorption Spectroscopy1

Parts of Atomic Absorption Spectroscopy• Light Source• Fuel Atomiser• Monochromator• Detector

Parts of Atomic Absorption Spectroscopy1

2

Parts of Atomic Absorption Spectroscopy• Light Source• Fuel Atomiser• Monochromator• Detector

Parts of Atomic Absorption Spectroscopy

Parts of AAS

1

2

3

Parts of Atomic Absorption Spectroscopy• Light Source• Fuel Atomiser• Monochromator• Detector

Atoms of a particular element (Pb) absorb light exactly the same frequency emitted by the lamp

How Atomic Absorption Spectroscopy Works ?

How to determine Pb2+ ion in a sample ?

Atoms of a particular element (Pb) absorb light exactly the same frequency emitted by the lamp

How Atomic Absorption Spectroscopy Works ?

Pb determination in a sample

How to determine Pb2+ ion in a sample ?1

2

100dm3 of contaminated water was reduced by boiling to 7.50dm3. The reduced volume was tested, it had absorbance of 0.55. Calculate the conc Pb2+ ions (mg/dm3) in original sample.

Ans: Conc of Pb2+ from graph (interpolation) – 1.15mgdm3

100dm3

7.50dm3

Volume reduced by

Vol = 100dm3M = ?

Vol = 7.50dm3M = 1.15mgdm3

Amt moles before = Amt moles after M x V = M X V M x 100 = 1.15 x 7.50 M = (1.15 x 7.50)/ 100 = 8.63 x 10-2 mgdm3

3

Question

Answer

Clear explanation on how AAS works Short demo on flame chamber

Video on Atomic Absorption Spectroscopy

Detail explanation on how AAS works

Nuclear Magnetic Resonance Spectroscopy

In the absence of External Magnetic Field (EMF)

Nuclear Magnetic Resonance Spectroscopy1

2

Nuclear Magnetic Resonance Spectroscopy

3In the presence of External Magnetic Field (EMF)

Split into TWO different level

Nuclear Magnetic Resonance Spectroscopy

3In the presence of External Magnetic Field (EMF)

Split into TWO different level

4Absorb radiofrequency to move to higher energy state

Nuclear Magnetic Resonance Spectroscopy

How to interpret NMR spectra ?

Nuclear Magnetic Resonance Spectroscopy

Chemical shift for CH3CH2OH 1

Nuclear Magnetic Resonance Spectroscopy

Chemical shift for CH3CH2OH and TMS (STD) 1

2 TMS as internal reference/STD

Hydrogen is deshielded as electronsare withdrawn away from H by CO group

Hydrogen is shielded by electrons donated to H by CH2 group

Chemical Shift (Shielding and Deshielding Effect)1

2

3

Hydrogen deshielded Hydrogen shielded

Placed in external magnetic field Placed in external magnetic field

4

Absorb higher radiofrequency – appears downfield Absorb lower radiofrequency – appears upfield

Chemical shift of various electron withdrawing groups

Video on how MRI body imaging works

Video on MRI in detail Video on MRI simplified

Video tutorial on chemical shift Spin spin coupling for HNMR

Click here to NMR spectra library for various organic compounds

Uses of HNMR1. Structural Determination of Organic compound

2. Medical uses in body scanner using Magnetic Resonance Imaging• Body placed inside a magnetic field (MRI) and 3D image of various organs produced• Protons found inside our body tissues – water, lipids, proteins, carbohydrates

different water/lipid ratios in different tissues

absorb harmless radiofrequency

different NMR signals due to different proton environment

different image will be produced

Acknowledgements

Thanks to source of pictures and video used in this presentation

Thanks to Creative Commons for excellent contribution on licenseshttp://creativecommons.org/licenses/

Prepared by Lawrence Kok

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