Atomic Absorption Spectroscopy (AAS) or Absorption Flame Photometry (Light source-hallow cathode lamp,nebulizer,chopper,lens,atomizer,monochrometer,detector,amplifier.Concentration of element in a given sample solution,uses in minning,geochemist,archeology,idustry etc..

1. Atomic Absorption
Spectroscopy
PRESENTED BY:
M.BABU VIGNESH
M.SC.,GEOLOGY 5TH YEAR
(INT)
DEPT.OF EARTH SCIENCES
ANNAMALAI UNIVERSITY

2. Introduction
Principle
Instrumentation
Working
Applications

3. This method is useful for
determination of various elements, it
may be trace elements or it may be
various metallic elements.It is also
called as Absorption Flame
Photometry.

4. Sample Vapour
(Liquid) Heat
Excited Ground
State State
(Atomic Emission (Atomic Absorption
Spectroscopy) Spectroscopy)

5. “If the amount of ground state atom is
higher then absorption is higher and if
amount of ground state atom is lower
then absorption will be lower”.

6.  When a beam of electromagnetic radiation of a
particular wavelength is passed through the
vapourized atoms present in the flame,then atoms
absorb the radiation and decrease in the intensity of
the radiation will be directly proportional to the
atoms present in ground state.(No other elements
absorb this wavelength).

7. Light source:
 Generally,Hallow cathode
lamp is used.
 Cathode is coated with
Element of interest.
 Anode is made up of
tungsten filament.
 It is full with inert gas at
low pressure.
 Element of interest go
into excited state and
emit radiation.

8. Nebulizer:
 It suck up liquid samples
at controlled rate.
 It creates a fire aerosol
spray for introduction
into flame.
 It mixes the aerosol and
fuel and oxidant
thoroughly for
introduction into flame.

9. Atomizer:
 Elements to be analyzed
needs to be in atomic
state.
 Atomization is separation
of particles into individual
molecules and breaking
molecules into
atoms.This is done by
exposing the analyte to
high temperatures in a
flame or graphite
furnance.

10. Monochrometer:
 Prism is present and move
to slit.(moving slit)
 By using slit it moves in a
specified wavelength.
 It is used to select the
specific wavelength of light
which is absorbed by the
sample and to exclude
other wavelengths.
 And it points to detector.

11. Detector:
 In detector photon
multiplier tube is present.
 It converts photons into
electrons further goes
into dynodes.
 Dynodes is using for the
multiplication of
electrons.
 Finally it goes to
amplifier,it amplifies
signal and goes to
recorder and displays.

12.  When we provide 500/1000V of current to hollow cathode tube the inert gas is
present,it begins ionisation and this ionised gas hit the cathode.When it hit the
cathode the element present in the cathode,it starts exciting and when they come
back to the ground state from the exciting state,they release energy/emit
energy.The process of emitting the energy is known as sputtering.
 After sputtering,atoms get excited and radiates the electromagnetic
radiation.And it forward towards the lens it emit the radiation in focused
manner.After it forward towards the flame.In burner,the sample is injected and it is
burnt.The sample taken here is known as analyst,which may be liquid or solid is
taken,we must convert it into liquid.When this liquid reaches the burner then it
burns liquid and analyte gets atomised.Some radiation get absorb and rest are
transmitted.

13.  The transmitted electromagnetic radiation then reaches
monochrometer,where the specific wavelength of light is
absorbed by the sample and exclude the other
wavelengths.The scattered electromagnetic radiation is then
passes through the lens which converges the radiation to the
photomultiplier.In photomultiplier the photons are multiplied
to the radiation then it is transmitted to amplifier and reading
displayed on the screen.

15.  Mining:
By using AAS the amount of metals such as gold in
rocks can be determined to see whether it is worth mining the
rocks to extract the gold.
 Industry:
Many raw materials are examined and AAS is widely
used to check that the major elements are present and that
impurities are lower than specified – eg in concrete, where
calcium is a major constituent, the lead level should be low
because it is toxic.

16.  Environmental Analysis:
Monitoring our environment – eg finding out
the levels of various elements in rivers, seawater, drinking water,
air, petrol and drinks such as wine, beer and fruit drinks.
 Archeology:
Atomic Absorption Spectrophotometry (AAS)
analysis has proven to be a useful archaeological tool
for characterizing the elemental composition of pottery clays.

17.  Geological Analysis:
When studying rocks, preparation can include acid
digestions or leaching. If the sample needs to have silicon
content analyzed, acid digestion is not a suitable preparation
method.

18. Bibliography:
 Instrumental Methoda of Chemical Analysis,B.K.Sharma.
 https://lab-training.com/aas/
 http://www.liskeard.cornwall.sch.uk/images/Liskeard-Sixth-Form/Atomic-
Absorption-Spectrometry.pdf
 https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Physical_Me
thods_in_Chemistry_and_Nano_Science_(Barron)/01%3A_Elemental_Analy
sis/1.04%3A_Introduction_to_Atomic_Absorption_Spectroscopy
 https://www.youtube.com/watch?v=HBegTB_WDxQ
 https://www.youtube.com/watch?v=qGei9mAP81w
 https://www.youtube.com/watch?v=v-gEjs6VHDs
 https://www.youtube.com/watch?v=QRKc1IzB5vQ