Flame Atomic Absorption Spectroscopy

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INSTRUMENTALANALYSIS
LAB.
Mr Haydar A.M.S
BSc, MSc
Faculty of Science
Chemistry Department
Email: Haydar.kovly@gmail.com

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Flame Atomic Absorption
Spectroscopy
Lab 9

3. Aim of the experiment
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 To be familiar with using flame atomic absorption spectroscopy.
 Determination of calcium (Ca) in bottled water.

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Atomic Absorption Spectroscopy
Atomic absorption spectrometry (AAS) is an analytical technique that
measures the concentrations of elements.
• Used for qualitative and quantitative detection.
• It’s used for the determination of the presence and concentrations of
metals in liquid samples.
• Metals that can be detected include Fe, Cu, Al, Pb, Ca, Zn, Cd and many
more.
• Concentrations range is in the low mg/L (ppm) range.

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The AAS instrument
Atomic Absorption Spectroscopy

6. Flame Atomic Absorption Spectroscopy:
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The technique requires a liquid sample to be aspirated, aerosolized, and mixed with
combustible gases, such as acetylene and air or acetylene and nitrous oxide.
The mixture is ignited in a flame whose temperature ranges from 2100 to 2800 ºC.
Atomic Absorption Spectroscopy

7. Flame Atomic Absorption Spectroscopy:
•When metals are exposed to heat, they absorb light
that emit from the source.
•Each metal absorbs light at a characteristic frequency.
For example:
Metal Zn Fe Cu Ca Na
λ (nm) 214 248 325 423 589
Atomic Absorption Spectroscopy

8. 1. We set the instrument
at certain wavelength
suitable for a certain
element 2. The element in the
sample will be atomized by
heat
4. The monochromator
isolates the line of
interest
3. The element in the sample
will absorb some of the light,
thus reducing its intensity
5. The detector
measures the change in
intensity
6. A computer data system
converts the change in
intensity into an absorbance
The simple diagram for the AAS
Atomic Absorption Spectroscopy

9. Light absorption
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unexcited ground state atoms, which absorb light at characteristic wavelengths,
as shown in the figure.
Atomic Absorption Spectroscopy

10. Lamp (Hollow Cathode Lamp)
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Consists of a cathode and an anode. The
cathode is made of the element of interest.
The Anode consists of tungsten
1. A large voltage across the anode and cathode will
cause the inert gas to ionize.
2. The inert gas ions will then be accelerated into
the cathode, sputtering off atoms from the
cathode.
3. Both the inert gas and the sputtered cathode
atoms will in turn be excited by collisions with
each other.
Atomic Absorption Spectroscopy

11. Lamp (Hollow Cathode Lamp)
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4- When these excited atoms decay to lower energy
levels they emit a few spectral lines characteristic of
the element of interest.
5- The light is emitted directionally through the lamp's
window, a window made of a glass transparent in the
UV and visible wavelengths.
6- The light can then be detected and a spectrum can
be determined.
Atomic Absorption Spectroscopy

12. Lamp (Hollow Cathode Lamp)
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Atomic Absorption Spectroscopy

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Fuel and oxidant
flame
b Air – acetylene
Air- propane
Air- hydrogen
b Nitrous oxide – acetylene
Auxiliary
oxidant
Fuel
Atomic Absorption Spectroscopy

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Common fuels and oxidants used in flame spectroscopy
Atomic Absorption Spectroscopy

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The Flame
Calcium Flame Copper Flame Potassium Flame Manganese Flame
Atomic Absorption Spectroscopy

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Atomic Absorption Spectroscopy
PerkinElmer Analyst 200

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Atomic Absorption Spectroscopy
Lamp installation

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Atomic Absorption Spectroscopy
Nebulizer
To convert the test solution to
gaseous atoms (produce a mist or
aerosol)

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Atomic Absorption Spectroscopy
Safety Consideration

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Atomic Absorption Spectroscopy
Safety Consideration

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Atomic Absorption Spectroscopy
Safety Consideration
Dealing carefully with gas cylinder
and air compressor.