10. Principle of F.E.S
Sample
Solution
M+ X-
Fine Mist
M+ X-
Solid
Particles
M X
Gaseous
Molecules
M X
Gaseous
Atoms
M(g)+ X(g)
Excited
Gaseous
Metal
atoms
Emission
phenomeno
n in the
path of
flame
Principle of F.E.S.
7/29/2021 10
11. Sample Solution
M+ X-
Fine Mist
M+ X-
Solid Particles
M X
Gaseous
Molecules
M X
Gaseous Atoms
M(g)+ X(g)
Excited Gaseous Metal
atoms
Ground State gaseous
atoms
7/29/2021 11
14. Total Consumption
Burner:
• The fuel gas, oxidant gas and liquid samples are drawn to the
opening of the burner through separate inlets. The fuel gas burns in
presence of oxygen to produce the flame attached to the base of
burner. Nebulizer is attached to the base of burner.
Nebulizer:
• It is a device by which sample solution is divided into very fine droplets
which are aspirated into fine spray or aerosol.) As the oxidant flows it
withdraws the sample from the capillary in very fine droplets Then mixed in
the premixing chamber with the fuel gas . The fuel-oxidant-sample aerosol
mixture passes to the burner producing the necessary heat for atomization
and excitation. All the sample irrespective of their size is evaporated hence
the name total consumption burner.
Advantage:
• Entire sample enter into flame and hence it is more
sensitive.
• The flame can be adjusted to produce high temperature.
Total Consumption Burner:
7/29/2021 14
16. • Premix or Laminar Flow Burner
• The fuel, oxidant gas and liquid
sample are thoroughly mixed before
entering the flame. In premix burner
only small droplets of the sample are
reach the flame and large droplets
are trapped by baffles and drained off
and sample is wasted.
7/29/2021 16
18. Advantages
The flame produced is
stable, no turbulent, and
noiseless.
Vaporization, atomization
and excitation of atoms
takes place efficiently.
Sensitivity and
reproducibility is good.
Disadvantages
Only small portion of small
reaches to flame.
Due to large wastage fewer
atoms are excited and
consequently the emission
intensity is weak.
This lowers the sensitivity of
the estimation.
7/29/2021 18
22. 1.
Calibration
Curve
Method
A calibration curve is used to determine the
unknown concentration of an element in a solution.
The instrument is calibrated using several solutions
of known concentrations.
The emission intensity of each known solution is
measured
The emission intensity element in sample solution
is measured
calibration curve is obtained by plotting graph of
emission intensity v/s concentration
unknown concentration of the element is then
calculated from the calibration curve
7/29/2021 22
24. 2.Standard
Addition
Method
Emission intensity of unknown (X) is first found out by
aspirating into flame
against blank.
Then a series of standards having definite amount of
unknown (X) plus varying amount of standard are
prepared and diluted to same volume in each case .
Their emission intensity is recorded by aspirating each
solution one by one
A graph of emission intensity (EI ) against
concentrations of standard (S) gives a linear curve.
The concentration of the unknown can be determined
by extrapolation of line which cuts to X axis.
7/29/2021 24
25. Sr.No. Volume of Sample
solution
Volume of Standard
solution
Emission Intensity
1 X 0
2 X S
3 X 2S
4 X 3S
5 X 4S
6 X 5S
7/29/2021 25
27. Internal
Standard
addition
Method
A series of standard solution containing the same elements as that present in
sample solution is prepared.
A fixed quantity of suitable internal standard is then added to each of
standard solutions, blank and sample solutions alike
Each of above standard solutions and sample solutions are then aspirated into
flame one by one
The emission intensity for each of above standard solution (Is) &
(Ii) and sample solution (Ix&Ii) are measured at different
wavelength one corresponds to element and other corresponds to
the internal standard.
The ratio of absorbance of the standard solutions to that of internal
standard (Is/Ii) are plotted against the concentration of standard solutions.
This gives a straight line from this curve concentration of sample solution
can be read by finding where the ratio (Ix/Ii) falls on concentration scale.
7/29/2021 27
28. 7/29/2021 28
Sr.No. Volume of Standard
Solution ( 100 PPM)
and Sample
Volume of Internal
standard
10 PPM
Emission
Intensity
𝑰𝒔
𝑰𝒊
1 Blank 5 ml
2 5 ml 5 ml
3 10 ml 5 ml
4 15 ml 5 ml
5 20 ml 5 ml
6 25 ml 5 ml
7 Sample Solution 5 ml
Is = Emission Intensity of Standard Solution
Ii = Emission Intensity of Internal Standard Solution
30. Application of
Flame Emission Spectroscopy
Soil analysis: Na,K,Ca,Mg.
Fertilizer : Na,K,Ca,Mg.
Biological Fluids : Na,K,Ca,Mg.
Petrol : Lead
Cement: Ca and Mg.
Glass Analysis: Na,Ca,Mg, K,and Li.
Organic Compounds : Boron
Physiology and Clinical Studies : Electrolyte Balance.
7/29/2021 30
31. Limitation of Flame
Photometry
The number of excited atoms in flame is very
small. Only alkaline and alkaline earth metals
that can be practically determined.
It needs perfect control of flame temperature.
Interference by other elements is not easy to be
eliminated
In Heavy and transition metals , the number of
absorption and emission lines is enormous and
the spectra are complex
7/29/2021 31
