Atomic Emission Spectros

Atomic Emission
Spectroscopy.
Name: Hamza Ali, Ayesha Naveed, Nimra Batool

Roll: BSEN01191016
Submitted to: Prof. Sabiha Khurram
Course: Analytical Techniques
The University Of Lahore.

Introduction
 Atomic absorption is the absorption of light
by free atoms.
 An atomic absorption spectrophotometer is
an instrument that uses this principle to
analyze the concentration of metals in
solution.
 The substances in a solution are suctioned
into an excited phase where they undergo
vaporization, and are broken down into
small fragmented atoms by discharge, flame
or plasma.
2
Atomic Emission
Spectroscopy
 By exposing these atoms to such
temperatures they are able to “jump”
to high energy levels and in return,
emit light.
 The versatility of atomic absorption an
analytical technique (Instrumental
technique) has led to the development
of commercial instruments. In all, a
total of 68 metals can be analyzed.
3
Advantages of AA
 Determination of 68 metals
 Ability to make ppb determinations on
major components of a sample
 Precision of measurements by flame are
better. There are few other instrumental
methods that offer this precision so easily.
 Sample preparation is simple (often
involving only dissolution in an acid).
 Instrument easy to tune and operate.
4
Flame Emission and Atomic
Absorption Spectroscopy
(3 main types)
 Atomic Emission (with thermal excitation), AES
 Atomic Absorption, (with optical photon unit) AAS
 Atomic Florescence, AFS
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AES experiment set-up
6
Three types of high-temperature
plasmas
 The inductively coupled plasma (ICP).
 The direct current plasma (DCP).
 The microwave induced plasma (MIP).
 The most important of these plasmas

is the inductively coupled plasma
(ICP).
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The Direct Current Plasma
Technique
 The direct current plasma is created by the
electronic release of the two electrodes. The
samples are placed on an electrode. In the
technique solid samples are placed near the
discharge to encourage the emission of the
sample by the converted gas atoms.
8
Picture of an inductively-coupled plasma
atomic emission spectrometer
9
Atomic Emission
Spectroscopy
 Qualitative analysis is done using AES in the same manner
in which it is done using FES.
 The spectrum of the analyte is obtained and compared
with the atomic and ionic spectra of possible elements in
the analyte.
 Generally an element is considered to be in the analyte if
at least three intense lines can b matched with those
from the spectrum of a known element.
 Quantitative analysis with a plasma can be done using

either an atomic or an ionic line. Ionic lines are chosen
for most analyses because they are usually more intense
at the temperatures of plasmas than are the atomic lines.
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AES WITH ELECTRICAL
DISCHARGES
 An electrical discharge between two electrodes can be used to
atomize or ionize a sample and to excite the resulting atoms or
ions.
 The sample can be contained in or coated on one or both of the
electrodes or the electrode(s) can be made from the analyte. The
second electrode which does not contain the analyte is the counter
electrode.
 Electrical discharges can be used to assay nearly all metals and
metalloids.
 Approximately 72 elements can be determined using electrical
discharges.
 For analyses of solutions and gases the use of plasmas is generally
preferred although electrical discharge can be used. Solid samples
are usually assayed with the aid of electrical discharges.
 Typically it is possible to assay about 30 elements in a single
sample in less than half an hour using electrical discharges.
 To record the spectrum of a sample normally requires less than a
minute.
11
ELECTRODES FOR AES
 The electrodes that are used for the various forms of AES
are usually constructed from graphite.
 Graphite is a good choice for an electrode material
because it is conductive and does not spectrally
interfere with the assay of most metals and metalloids.
 In special cases metallic electrodes (often copper) or
electrodes that are fabricated from the analyte are
used.
 Regardless of the type of electrodes that are used, a
portion of each of the electrodes is consumed during the
electrical discharge.
 The electrode material should be chosen so as not to
spectrally interference during the analysis.
12
WAVELENGTH SELECTION
AND DETECTION FOR AES
 Arc and spark instruments normally contain
non scanning monochromators. Either a
series of slits is cut in the focal plane of the
and a photomultiplier tube is placed behind
each slit that corresponds to the wavelength
of a line that is to be measured, or one or
more photographic plates or pieces of film
are placed on the focal of the
monochromators.
13
QUALITATIVE ANALYSIS WITH
ARC AND SPARK AES
 Qualitative analysis is performed by

comparing the wavelengths of the
intense lines from the sample with
those for known elements.
 It is generally agreed that at least three
intense lines of a sample must be
matched within a known element in
order to conclude that the sample
contains the element
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QUANTITATIVE ANALYSIS
WITH ARC AND SPARK AES.
 Regardless of the type of detection used for
the assay, the precision of the results can be
improved by matrix-matching the standards
with the sample. Use of the internal-standard
method also improves precision.
 Usually a working curve is prepared by
plotting the ratio or logarithm of the ratio of
intensity of the standard's line to the internal
standard's line as a function of the logarithm
of the concentration of the standard.
 The corresponding ratio for the analyte is
obtained and the concentration determined
from the working curve.
15
References
 www.anachem.umu.se/jumpstation.htm
 http://www.s-a-s.org/
 http://www.chemsw.com
 http://www.scimedia.com/chem-ed/spec/atomic/aa.htm
 http://nercdg.org
 http://www.analyticon.com
 www.lcgmag.com/
 www.lcms.com/
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Atomic Emission

Name: Hamza Ali, Ayesha Naveed, Nimra Batool

The University Of Lahore.

 Atomic Emission (with thermal excitation), AES

 Atomic Absorption, (with optical photon unit) AAS

 Atomic Florescence, AFS

 The inductively coupled plasma (ICP).

 The direct current plasma (DCP).

 The microwave induced plasma (MIP).

 The most important of these plasmas

 Quantitative analysis with a plasma can be done using

 Qualitative analysis is performed by

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