Flame photometery DMLT 2ND

Compiled and Edited By
Prof. S. Salunke Sir
Msc, CMLT, DMLT, MLT, DLT.
2021 - 2022
DMLT 2ndYear
1
Pro S.Salunke Sir

I. Instrumental method of bio – chemical analysis
2
Flame Photometer
Pro S.Salunke Sir

II. The flame photometers from A.Krüss are used to determine the
concentration of alkali and alkaline earth elements in aqueous solutions and
are a simple and particularly cost-effective alternative to analysis techniques
such as ICP or AAS
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Flame photometer - Automatic unit with dilution
FP8700
Pro S.Salunke Sir

III. Lcd Display Microprocessor Flame Photometer, For Industrial
Use , Laboratory Use,
4
Flame photometer - Model: SSE-671
Pro S.Salunke Sir

5
Pro S.Salunke Sir
In This Slides
Principle
Mechanism
•Nebulisation
•Brief overview of process in the flame
Applications
Advantages
Disadvantages
Introduction
Atomic spectroscopy
Types of Atomic Spectroscopy
Flame Photometry
Instrumentation
Parts of flame photometer

6
INTRODUCTION
During 1980s Bowling Barnes, David Richardson,
John Berry and Robert Hood developed an instrument to measure
the low concentrations of sodium and potassium in a solution.
They named this instrument as Flame photometer.
The principle of flame photometer is based on the measurement of
the emitted light intensity when a metal is introduced into the flame.
The wavelength of the color gives information about the element
and the color of the flame gives information about the amount of the
element present in the sample.
1980 च्या दशकात बॉल िंग बार्न्स, डेव्हिड रिचडससन, जॉन बेिी आलि िॉबर्स हूड यािंनी सोल्यूशनमध्ये सोलडयम आलि
पोर्ॅलशयमची कमी प्रमाि मोजण्यासाठी एक साधन तयाि क
े े.
त्ािंनी या वाद्या ा फ्लेम फोर्ोमीर्ि असे नाव लद े. फ्लेम फोर्ोमीर्िचे लसद्ािंत मोजमापावि आधारित आहे जेिा ज्योतीत
धातूचा परिचय होतो तेिा उत्सलजसत प्रकाशाची तीव्रता. ििंगाची तििंगदैध्यस नमुना उपव्हथित घर्क त्ा घर्कालवषयी मालहती देते
आलि ज्योतचा ििंग त्ाती प्रमािािंलवषयी मालहती देतो.
Pro S.Salunke Sir

Pro S.Salunke Sir 7
Flame photometry is one of the branches of atomic absorption spectroscopy.
It is also known as flame emission spectroscopy.
Currently, it has become a necessary tool in the field of analytical chemistry.
Flame photometer can be used to determine the concentration of certain metal
ions like sodium, potassium, lithium, calcium and cesium etc.
In flame photometer spectra the metal ions are used in the form of atoms.
The International Union of Pure and Applied Chemistry (IUPAC) Committee on
Spectroscopic Nomenclature has named this technique as flame atomic emission
spectrometry (FAES).
फ्लेम फोर्ोमेर्री अिुशोषि स्पेक्ट्रोस्कोपीच्या शाखािंपैकी एक आहे.
या ा ज्योत उत्सजसन स्पेक्ट्रोस्कोपी असेही म्हितात.
सध्या हे लवश्लेषिात्मक िसायनशास्त्र क्षेत्रात आवश्यक साधन बन े आहे. सोलडयम, पोर्ॅलशयम, ल लियम, क
ॅ व्हशशयम आलि सीलियम
इत्ादी लवलशष्ट धातूिंच्या आयनची एकाग्रता लनलित किण्यासाठी ज्योत फोर्ोमीर्ि वापि ा जाऊ शकतो. ज्योत प्रकाशमापक स्पेक्ट्रामध्ये
धातूचे आयन अिूच्या रूपात वापि े जातात. इिंर्िनॅशन युलनयन ऑफ प्यूि .ण्ड अप्लाइड क
े लमस्ट्री (आयईयूपीएसी) च्या
स्पॅक्ट्रोस्कोलपक नॉमनेक्लचि या सलमतीने या तिंत्रा ा ज्योत अिु उत्सजसन स्पेक्ट्रोमेर्री (एफएईएस) असे नाव लद े आहे.

Pro S.Salunke Sir 8
In 1860 Robert Bunsen and
Gustav Kirchhoff discovered
two alkali metals, cesium and
rubidium, with the aid of the
spectroscope they had invented
the year before.
These discoveries inaugurated
a new era in the means used
to find new elements.
The potential of atomic spectroscopy in both the qualitative as well as
quantitative analysis were then well established.

Pro S.Salunke Sir 9
Atomic spectroscopy is an unavoidable tool
in the field of analytical chemistry.
It is divided into Three types which are
1 Absorption Spectroscopy
2 Emission Spectroscopy
3 Luminescence Spectroscopy
Another branch of atomic absorption spectroscopy is
❖Flame photometry or Flame Atomic Emission spectrometry
(in which the species is examined in the form of atoms)
❖Atomic Absorption Spectrophotometer (AAS)
❖Inductively coupled plasma – Atomic emission spectrometry (ICP-AES)

Pro S.Salunke Sir 10
Principle of Flame photometer
The basic principle upon which Atomic
Spectroscopy works is based on the fact that
"Matter absorbs light at the same
wavelength at which it emits light.”
When a metal salt solution is burned, the
metal provides a colored flame and each
metal ion gives a different colored flame.
Flame tests, therefore, can be used to test
for the absence or presence of a metal ion.
Atoms of
elements
Subjected to
hot flame
Specific quantum of
thermal energy
absorbed by orbital
electrons
Become
at high energy
level
Release energy as
photons of
particular
wavelength
Change back to
ground state

The potential of atomic spectroscopy in both
the qualitative as well as quantitative analysis were then well established.
Element Emitted wavelength Flame color
Sodium 589 nm Yellow
Potassium 766 nm Violet
Barium 554 nm Lime green
Calcium 622 nm Orange
Lithium 670 nm Red

instrumentation
Parts of a Flame Photometer
❖Source of Flame
A burner that provides flame and can be maintained in a constant form
and at a constant temperature.
❖Nebulizer and Mixing Chamber
Helps to transport the homogeneous solution of the substance into the flame at a steady
rate.
❖Optical System (Optical Filter)
The optical system comprises three parts: convex mirror, lens and filter.The convex mirror
helps to transmit light emitted from the atoms and focus the emissions to the lens.The convex lens help to focus
the light on a point called slit.The reflections from the mirror pass through the slit and reach the filters.This will
isolate the wavelength to be measured from that of any other extraneous emissions. Hence it acts as interference
type color filters.
❖ Photo Detector
Detect the emitted light and measure the intensity of radiation emitted by the flame.That is, the emitted
radiation is converted to an electrical signal with the help of photo detector.The produced electrical signals are
directly proportional to the intensity of light.

instrumentation
Parts of a Flame Photometer
❖Source of Flame
A burner that provides flame and can be maintained in a constant form
and at a constant temperature.
❖Nebulizer and Mixing Chamber
Helps to transport the homogeneous solution of the substance into the flame at a
steady rate.
❖Optical System (Optical Filter)
The optical system comprises three parts: convex mirror, lens and filter.The convex
mirror helps to transmit light emitted from the atoms and focus the emissions to the lens.The convex
lens help to focus the light on a point called slit.The reflections from the mirror pass through the slit and
reach the filters.This will isolate the wavelength to be measured from that of any other extraneous
emissions. Hence it acts as interference type color filters.
❖ Photo Detector
Detect the emitted light and measure the intensity of radiation emitted by the flame.That is, the emitted
radiation is converted to an electrical signal with the help of photo detector.The produced electrical
signals are directly proportional to the intensity of light.
13

Schematic diagram showing flame photometer
instrumentation

instrumentation

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Pro. S. Salunke Sir
instrumentation

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Pro. S. Salunke Sir
Nebulization
“A dispenser that turns a liquid into a fine mist called nebulizer (such as
perfume).” The solution of the substance to be analyzed is first aspirated into
the burner, which is then dispersed into the flame as fine spray particles.
A brief overview of the process
The solvent is first evaporated leaving fine divided solid particles.
This solid particles move towards the flame, where the gaseous atoms and
ions are produced.
The ions absorb the energy from the flame and excited to high energy levels.
When the atoms return to the ground state radiation of the characteristic
element is emitted.
The intensity of emitted light is related to the concentration of the element.
Mechanism

19
Pro. S. Salunke Sir
In the flame
photometry employs a variety of fuels mainly air,
oxygen or nitrous oxide (N2O) as oxidant.
The temperature of the flame depends on
fuel-oxidant ratio.
The intensity of the light emitted could be described by the
Scheibe-Lomakin Equation
𝑰 = 𝒌 × 𝒄 𝒏
Where,
𝑰 = Intensity of emitted light
𝒄 =The concentration of the element
𝒌 = Constant of proportionality
𝒏~1 (At the linear part of the calibration curve)
Then,
𝑰 = 𝒌 × 𝒄
That is the intensity of emitted light is directly related
to the concentration of the sample.
Mechanism

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Pro. S. Salunke Sir
Mechanism

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Pro. S. Salunke Sir
As seen in the figure,
the flame may be divided into following regions or zones
1. Preheating zones
2. Primary reaction zone (inner zone)
3. Internal zone- max temp, used for flame
photometry
4. Secondary reaction zone
Structure of Flame
1
2 3
4

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Pro. S. Salunke Sir
❖ a means of transporting a homogeneous solution (converting into a fine
mist) into the flame at a steady rate
❖ can be done by passing a gas of high velocity over the upper outlet of
capillary tube, the lower end of which is inserted into the sample
❖ Liquid is then drawn up into the chamber and dispersed into small droplets
The fine mist is then burnt in either laminar flow burner or total consumption
burner
❖The aerosol is desolated , vaporized and atomized in the flame of the
burner
Nebulizers or Atomizer

23
Pro. S. Salunke Sir
A number of nebulisation methods are available like;
Pneumatic nebulisation
Ultrasonic nebulisation
Electro thermal vaporization
Hydride generation(used for certain elements only).
Pneumatic Nebulizer is the most commonly used nebulizer

24
Pro. S. Salunke Sir
Burner (source):
a flame that can be maintained in a constant form and at a constant
temperature
should have ability to evaporate the liquid droplets from the sample solutions
must have capacity to excite the atoms formed and cause them to emit radiant
energy
a cylinder of compressed gas and two stage pressure regulator are required
High pressure tubing must be used to lead the gases to the flame

25
Pro. S. Salunke Sir
Pre-mixed Burner:
widely used because uniformity in flame intensity
In this energy type of burner , aspirated sample , fuel and oxidant are
thoroughly mixed before reaching the burner opening.
The fine mist or aerosol of sample solution is produced in a vaporization
chamber
Larger droplets go to waste while the fine mist enters the flame, thus
producing a less noisy single
In addition, the path length through the flame of the burner is longer than
that of the total consumption burner producing greater absorption and
increases the sensitivity of the measurement

26
Pro. S. Salunke Sir
Total consumption burner:
Made of 3 concentric tubes:
The central tube is a fine capillary tube
The sample solution is carried up by this tube directly into flame
The fuel gas, the oxidant gas and sample solution is aspirated through a
capillary by high pressure of fuel and Oxidant and burnt at the tip of burner
In this fuel and oxidant are hydrogen and oxygen gases
Entire sample is consumed.

Pro. S. Salunke Sir 27
Made of 3 concentric tubes:
The central tube is a fine capillary tube
The sample solution is carried up by this tube directly into flame
The fuel gas, the oxidant gas and sample solution is aspirated through a
capillary by high pressure of fuel and Oxidant and burnt at the tip of
burner
In this fuel and oxidant are hydrogen and oxygen gases
Entire sample is consumed.
Total consumption burner:

Slits: -
Entrance and exit slits
Entrance slit : - Cuts out most of the radiation from the surrounding –
Allows only the radiation from the flame to enter into the
monochromator
Exit slit: - Placed after the monochromator –
Allows only the selected wavelength to pass through the photo
detector

Monochromator :
❖ a means of isolating light of the wavelength to be measured from that of
extraneous emissions
❖When kept between the flame and detector, the radiation of the desired
wavelength from the flame will be entering the detector and be measured
❖ Remaining will be absorbed by the monochromator and not measured
❖ Either prisms or diffraction gratings
❖ Prism: Quartz material is used for making prism, as quartz is
transparent over entire region
❖ Grating: it employs a grating which is essentially a series of
parallel straight lines cut into a plane surface

Detectors: -
a means of measuring the intensity of radiation emitted by the flame –
Should be sensitive to radiation of all the wavelengths that has to be analyzed -The flame
instability reduces their accuracy so multichannel polychromator is used in some procedures
Photomultiplier tubes
Photo emissive cell
Photo voltaic cell
Photo emissive cells or photomultiplier tubes are commonly employed for the purpose.
Photovoltaic cell:
It has a thin metallic layer coated with silver or gold which 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.

Flame photometer has both quantitative and qualitative applications.
Flame photometer with monochromators emits radiations of characteristic
wavelengths which help to detect the presence of a particular metal in the
sample.This help to determine the availability of alkali and alkaline earth metals
which are critical for soil cultivation.
In agriculture, the fertilizer requirement of the soil is analyzed by flame test
analysis of the soil.
In clinical field, Na+ and K+ ions in body fluids, muscles and heart can be
determined by diluting the blood serum and aspiration into the flame.
Analysis of soft drinks, fruit juices and alcoholic beverages can also be
analyzed by using flame photometry.
Application

Simple quantitative analytical test based on the flame analysis.
Inexpensive.
The determination of elements such as alkali and alkaline earth metals is
performed easily with most reliable and convenient methods.
Quite, convenient, selective and sensitive to even parts per million (ppm)
to parts per billion (ppb) range.
Advantages

The concentration of the metal ion in the solution cannot be measured
accurately.
A standard solution with known molarities is required for determining the
concentration of the ions which will corresponds to the emission spectra.
It is difficult to obtain the accurate results of ions with higher
concentration.
The information about the molecular structure of the compound present in
the sample solution cannot be determined.
The elements such as carbon, hydrogen and halides cannot be detected due
to its non-radiating nature.
Disadvantages

To be continue….

1. Which of the following is the principle of Flame emission photometers?
a) Radiation is absorbed by non-excited atoms in vapor state and are excited to higher states
b) Medium absorbs radiation and transmitted radiation is measured
c) Color and wavelength of the flame is measured
d) Only wavelength of the flame is measured
MCQs

2.Which of the following is not an advantage of Laminar flow burner used in Flame
photometry?
a) Noiseless
b) Stable flame for analysis
c) Efficient atomization of sample
d) Sample containing two or more solvents can be burned efficiently

3.Which of the following is not a detector used in Flame
emission photometers?
a) Photronic cell
b) Photovoltaic cell
c) Photoemissive tube
d) Chromatogram

4. If Propane and air are used in burner how many °C temp.
is produced ?
a)1900°C
b)2200°C
c)2300°C
d)2100°C

5. If Hydrogen and air are used in burner how many °C
temp. is produced ?
a)1900°C
b)2200°C
c)2300°C
d)2100°C

6.Which is not application of flame photometry ?
a)To estimate sodium, magnesium, calcium
b) Assay of metformin.
c)Used to determine magnesium and calcium in cement.
d) To detected metalic ions in sample.

7. BOLTZMANN Equations is
a)N* / N =R Ae–∆E/kT
b)N* / N = e–∆E/kT
c)N* / N = Ae–∆E/kT
d)N* / N = Ae–∆E/kc

8. Choose correct sequence of flame photometry ?
a) Sample residue → excited state atoms → Return in ground
state → Emission of radiation
b)Sample residue → ground state → excited state → Emission of radiation
c) Emission of radiation → excited state →ground state → Sample residue
d) Sample residue → ground state → excited state → Emission of radiation

9.Which equations are used to determine wavelength of radiation ?
a)λ = hc/ E2-E1
b)N* / N = e–∆E/kT
c) λ = h/E2-E1
d)N* / N = Ae–∆E/kT

10.Which is application of flame photometry ?
a)To determine functional group
b) To study of chemical structure
c) To assay of drug
d) To estimate metallic ions like sodium, potassium, etc.

ANSWER KEY :-
1. c
2.d
3.d
4.d
5.a
6.b
7.c
8.a
9.a
10.d

Flame photometery DMLT 2ND

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