The document discusses atomic absorption spectroscopy. It begins with an introduction describing how atomic absorption spectroscopy measures the concentration of an element by measuring the amount of light absorbed at a characteristic wavelength when it passes through atoms of that element. It then describes the principle, instrumentation, applications, and sources of interference in atomic absorption spectroscopy. The key sources of interference discussed are non-spectral interferences such as matrix, chemical, and ionization interferences and spectral interferences such as background absorption.

1. Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Interference In Atomic Absorption
Spectroscopy
A Seminar as a part of curricular requirement
for Master of Pharmacy, I Year - I semester
Presented by
SHAIK GOUSE ULAZAM
(20L81S0708)
Pharmaceutical analysis
Under the guidance of
Dr. P. Ramalingam M.Pharm, Ph.D.
Professor & Director of R& D cell

2. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 2
Contents
 Introduction
 Principle
 Instrumentation
 Applications
 Interference
 References

3. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
INTRODUCTION
 Atomic Absorption Spectroscopy is a very common technique for detecting metals
and metalloids in samples.
 It is very reliable and simple to use.
 It also measures the concentration of metals in the sample.
 Atomic Absorption Spectroscopy is an analytical technique that measures the
concentration of an element by measuring the amount of light that is absorbed at a
characteristic wavelength when it passes through cloud of atoms.
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4. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 4
Principle of Atomic Absorption Spectroscopy
 The technique uses basically the principle that free atoms generated in an
atomizer can absorb radiation at specific frequency.
 Atomic Absorption Spectroscopy quantifies the absorption of ground state
atoms in the gaseous state.
 The atoms absorb UV or Visible light & make transition to higher electronic
energy level. The analyte concentration is determined from the amount of
absorption.

5. RIPER
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Schematic diagram of Atomic Absorption Spectrophotometer
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Instrumentation

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NAAC &
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Applications of Atomic Absorption Spectroscopy
 Determination of small amount of metals (lead, mercury, calcium,
magnesium)
 AAS is widely used in metallurgy, alloys and in inorganic analysis.
 Biochemical Analysis : A number of elements present in biological
samples can be analysed by AAS. These include estimated of sodium,
calcium, potassium, zinc, iron, lead, mercury, etc.

7. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Interferences In Atomic Absorption Spectroscopy
 Interference is a phenomenon that leads to change in intensity of analyte signal
in spectroscopy.
 Interferences in AAS fall into two basic categories :
1. Non-Spectral Interference : Which affect the formation of analyte Atoms
- Matrix interference
- Chemical interference
- Ionization interference
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8. RIPER
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NAAC &
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SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 8
2. Spectral Interferences :high light absorption due to presence of absorbing
species
- Background absorption
- Continuum source Background Correction
- Others spectral interferences

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Non-spectral Interferences
Matrix interferences :
 When a sample is more viscous or has different surface tension than the
standard it result in difference in sample uptake rate due to changes in
nebulization efficiency.
 Such interferences are minimized by matching the matrix composition of
standard and sample.
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10. RIPER
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Figure : Matrix interference from viscosity effects
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11. RIPER
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
 If a sample contains a species which forms a thermally stable compound with
analyte that is not completely decomposed by the flame energy then chemical
interferences exist.
 Such interferences are minimized by using higher flame temp.
 To provide higher dissociation energy.
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Chemical Interferences:

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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 12
Figure : Interference of phosphate on calcium.

13. RIPER
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Ionization Interference
 It is more common in hot flames.
 The dissociation process doesn’t stop at formation of ground state atoms.
 Excess energy of the flame lead to excitation of ground state atoms to ionic
state by loss of electrons thereby resulting in depletion of ground state atoms.
 Ionization interference is eliminated by an excess of an element which is easily
ionized thereby creating a large number of electrons in the flame &
suppressing the ionization of the analyte.
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14. RIPER
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 14
Figure : Effect of added potassium on ionization.

15. RIPER
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SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Spectral Interferences
 Atomic Spectral interferences are caused by presence of another absorption
line or a molecular absorbance band close to the spectral line of element of
interest.
 Most of these interferences are due to molecular emission from oxides of
other element is a sample.
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16. RIPER
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SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Background Absorption:
 Background Absorption Extends over a broad wavelength band.
 It is referred to as molecular absorption or non specific absorption.
 Background absorption is caused by light absorption due to un vapourised
solvents droplets in flame.
 The absorption and scattering of radiation due to matrix interference give
rise to sample background which becomes a problem at wavelength below
350nm.
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17. RIPER
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Continuum Source Background Correction
 Continuum source background correction is a technique for automatically
measuring and compensating for any background component which might be
present in an atomic absorption measurement. This method incorporates a
continuum light source in a modified optical system.
 The broad band continuum (‘‘white’’ light) source differs from the primary
(atomic line) source in that it emits light over a broad spectrum of
wavelengths.
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18. RIPER
AUTONOMOUS
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Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Other Spectral Interferences
 If the atomic absorption profile for an element overlaps the emission line of an
other, a spectral interference is said to exist. As has already been mentioned,
this is an infrequent occurrence, because of the very wavelength-specific
nature of atomic absorption.
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19. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
References :
 Dr.A.V. Kasture, Dr. S.G. Wadodkar, Nirali prakashan , Pharmaceutical
analysis Instrumental methods Volume II, page no. 23.9 - 23.12.
 G.R. Chatwal, S.K. Anand, Instrumental methods of Chemical analysis
,Himalaya publishing house, fifth edition page no. 2.340 - 2.360.
 Richard D. Beaty and Jack D.Kerber, , Instrumentation and Techniques
in Atomic Absorption Spectroscopy.
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20. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721
Thank you
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