Flame photometry is a technique that uses the intensity of light emitted from an element in a flame to determine its concentration. Samples are nebulized and introduced into a flame where atoms are excited and emit light of characteristic wavelengths. A monochromator separates this light, which is detected and the intensity measured to quantify the elemental concentration. Sodium, potassium, lithium, and calcium are commonly analyzed using this technique in applications like serum analysis and soil testing.

1. FLAME PHOTOMETRY
BY: AMAN KAPOOR
M. PHARM (PHARMACEUTICAL ANALYSIS)
IST SEMESTER

2. CONTENTS
• INTRODUCTION
• HISTORY
• PRINCIPLE
• INSTRUMENTATION
• SAMPLE INTRODUCTION
• BURNERS AND FLAME
• MIRRORS
• MONOCHROMATORS
• DETECTORS
• APPLICATIONS
• LIMITATIONS

3. INTRODUCTION
• Flame photometry or Flame Atomic Emission spectroscopy.
• It is type of emission spectroscopy where Atomic emission is measured
using spectrophotometer.
• Flame Photometer: “An instrument used in Inorganic chemical analysis
to determine the concentration of certain metal ions among them
sodium, potassium, calcium and lithium.
• Flame Photometry is based on measurement of intensity of the light
emitted when a metal is introduced into flame
• The wavelength of color tells us what the element is (qualitative)
• The color's intensity tells us how much of the element present
(quantitative).

4. HISTORY
• In the later 1800, scientists such as Kirchhoff, Bunsen, Angstrom,
Rowland, Michelson and Balmer studied the composition of the sun
based on their emissions at different wavelengths
• In February of 23rd 1955 Murray Nelson A. filed a patent for invention
of Flame Photometry which was granted in year 1958

5. BASIC PRINCIPLE
• Liquid sample containing metal salt solution
introduced into a flame
• Solvent is vaporized , leaving particles of solid salt
• Salt is vaporized into gaseous state
• Gaseous molecule dissociate to give neutral atoms
• The resulting Neutral atoms are excited by the
thermal energy of the flame which are fairly
unstable, and hence instantly emit photons and
eventually return to the ground state
• Photomultiplier tube detectors. Ground state (E0)
Excited state (E1) electron Emission

6. EVENTS OCCUR IN FLAME
PHOTOMETRY

7. BOHR’S EQUATION
• : If we consider two quantized energy levels e.g., higher as E2
and lower as E1, the radiation given out during the transition
from E2 to E1 may be expressed by the following equation
E2 – E1 = hv …(a)
where, h = Planck’s constant,
ν = Frequency of emitted light,
now, the frequency v may be defined as follows :
ν = c/λ …(b)
where, c = Velocity of light,
λ = Wavelength of the absorbed radiation

8. • Combining equations (a) and (b) we have :
E2 – E1 = hc /λ
λ = hc /E2 – E1 …..(c)
The expression (c) is the Bohr’s equation which enables us to calculate :
• Wavelength of the emitted radiation which is characteristic of the atoms of the
particular element from which it was initially emitted,
• Wavelength of radiation given out from a flame is indicative of the element(s) that
might be present in that flame, and
• Intensity of radiation may quantify the exact amount of the elements present

9. INSTRUMENTATION
1. SAMPLE DELIEVERY SYSTEM
2. BURNER AND FLAME OR SOURCE
3. MONOCHROMATOR
4. DETECTOR

10. DIAGRAMMATIC REPRESENTATION
OF FLAME PHOTOMETRY.

11. SAMPLE DELIVERY OR NEBULIZATION
• This is the part of sample delivery system in which liquid droplets of
comparatively larger size are broken or converted to smaller size.
• The process of conversion of sample into a mist of very fine droplets
through the aid of jets of compressed gas is called nebulization
• Types of nebulizers:
1. Pneumatic nebulizers
2. Electro-thermal vaporizers
3. Ultrasound nebulizers

12. Overview of the Process

13. 1. PNEUMATIC NEBULIZERS
Concentric tube - the liquid
sample is sucked through a
capillary tube by a high pressure jet
of gas flowing around the tip of the
capillary (Bennoulli effect). This is
also referred to aspiration..
Cross-flow - the jet stream flows at
right angles to the capillary tip. The
sample is sometimes pumped
through the capillary.

14. CONT.
• Fritted disk - the sample is
pumped onto a fritled disk
through which the gas jet is
flowing. Gives a finer aerosol
than the others.
• Babington - jet is pumped
through a small orifice in a
sphere on which a thin film of
sample flows. This type is less
prone to clogging and used for
high salt content samples.

15. 2. ELECTRO-THERMAL VAPORIZERS
• An electro thermal vaporizer
contains an evaporator in a closed
chamber through which an inert
gas carries the vaporized sample
into the atomizer.

16. 3.ULTRASOUND NEBULIZERS.
• Ultrasonic Nebulizer -The sample is
pumped onto the surface of a
vibrating piezoelectric crystal.
• The resulting mist is denser and
more homogeneous than pneumatic
nebulizers

17. BURNERS
• Several kinds of burners are used to convert the fine droplets of sample
solution into neutral atom ,which further due to the high heat or
temperature of flame are excited hence emit radiation of characteristic
wavelength and color.
• Types of burner used:
1. Mekker or Mecker burner
2. Total consumption burner
3. Premix burner
4. Lundergarph’s burner
5. Shielded burner
6. Nitrous oxide – Acetylene burner 20

18. 1.MECKER OR MEKKER BURNER
• This was the primitive type of burner used
in flame photometry and was used earlier.
• It generally works with aid of natural gas
and oxygen as fuel and oxidant.
• The temperature so produced in the flame
was relatively low, resulting in low
excitation energy.
• Now a days it is not used but it was best
suited for alkali metal.

19. 2. TOTAL CONSUMPTION BURNER
• Due to the high pressure of fuel and
oxidant the sample solution is aspirated
through capillary and burnt at the tip of
burner
• Hydrogen and oxygen are generally
employed as fuel and oxidant.
• The advantage over other is the entire
consumption of sample,
• It’s disadvantage is the production of
non uniform flame and turbulent.

20. 3. PREMIX BURNER
• In this burner the sample , fuel oxidant
are thoroughly mixed before aspiration
and reaching to flame.
• The main advantage of it is the
uniformity of flame produced.
• The main disadvantage is the heavy
loss of mix up to 95%.

21. 4. LUNDENGARPH’S BURNER
• A small liquid droplets vaporized and move to base of flame in the form
of cloud
• Large droplets condensed at side and then drained off.

22. 6. NITROUS OXIDE-ACETYLENE
FLAME
• These flames were superior to other flames for
effectively producing free atoms
• E.g.-metals with very reflective oxides such as
aluminum and titanium.
The drawback of it is:
• the high temperature reduces its usefulness for
the determination of alkali metals as they are
easily ionized
• Intense background emission, which makes the
measurement of metal emission very difficult

23. `LIST OF FUELAND OXIDANT USED

24. MIRRORS
• The radiation emitted by the flame is generally
towards all the direction
• Hence a mirror is place behind the flame to
focus the radiation towards the entrance slit of
the monochromator.
• A concave mirror is used as it is front faced
reflecting type.

25. MONOCHROMATORS
• The main of the monochromator is to convert
polychromatic light into the monochromatic one
• The two types of monochromator generally used
are as under:
1. Prism : Quartz material is used for making prism,
as quartz is transparent over entire region
2. Grating : it employs a grating which is essentially
a series of parallel straight lines cut into a plane
surface

27. DETECTORS

28. PHOTOMULTIPLIER TUBE
• The intensity of the light is fairly low, so a photomultiplier tube (PMT)
is used to boost the signal intensity
• A detector (a special type of transducer) is used to generate voltage from
the impingement of electrons generated by the photomultiplier tube

29. PHOTOVOLTAIC CELL
• It has a thin metallic layer coated with
silver or gold act as electrode , also has
metal base plate which act as another
electrode.
• Two layers are separated by semiconductor
layer of selenium, when light radiation
falls on selenium layer.
• This creates potential diff. between the two
electrode and cause flow of current.

30. APPLICATIONS
QUALITATIVE ANALYSIS:
• Generally alkali and alkaline earth metal can be estimated by flame
photometry As characteristic wavelength is emitted by the element hence
detector recognizes that wavelength and atom is detected. Manual
method of detection is via flame characteristic color e.g. Na produces
yellow color.
QUANTITATIVE ANALYSIS : many alkali and alkaline metals amount
can be detected by the flame photometry by:
1. External standard
2. Method of standard addition.
3. Method of internal standard

31. OTHER APPLICATIONS
• TO ESTIMATE Na , K, Ca , Li IN SERUM, BODY FLUID, CSF AND
URINE.
• Na IN EXTRACELLULAR FLUID AND K INTERACELLULAR
FLUID.
• LITHIUM ESTIMATION IN PSYCHIATRIC THERAPY.
• IN SOIL ANALYSIS.
• IN INDUSTRIAL WASTE , GLASS,CEMENT AND PETROLUEM
PRODUCTS.

32. LIMITATIONS
• Limited number of elements that can be analyzed.
• The sample requires to be introduced as solution into fine droplets.
Many metallic salts, soil, plant and other compounds are insoluble in
common solvents. Hence, they can’t be analyzed by this method.
• Since sample is volatilized, if small amount of sample is present, it is
tough to analyze by this method. As some of it gets wasted by
vaporization.
• Further during solubilisation with solvents, other impurities might mix
up with sample and may lead to errors in the spectra observed