Chapter 9
Atomic Absorption and Atomic
Fluorescence Spectrometry
Atomic Spectroscopy
Atomization is by
far the most
critical step in
atomic
spectroscopy.
In AAS and AFS
there are two
factors
involved.
 The intensity of
light source.
 The probability
of transition.
Flame Atomization
Flame Structure
Flame Atomizer
Flame Atomizer
Electrothermal Atomizers
Graphite furnace atomic absorption spectrometry (GFAAS) is also
known by various other acronyms, including electrothermal
atomic absorption spectrometry (ETAAS).
An ideal graphite furnace should fulfill the following requirements:
 A constant temperature in time and space during the interval in
which free atoms are produced
 Quantitative atom formation regardless of the sample
composition
 Separate control of the volatilization and atomization processes
 High sensitivity and good detection limits
A minimum of spectral interferences
Specialized Atomization
Techniques
 Glow
Discharge Atomization
 Hydride Atomization
 Cold-Vapor Atomization
Flame Atomic Absorption
Spectroscopy
Radiation Sources
 Doppler
Broadening
 Pressure Broadening
 Electrodeless Discharge Lamps
 Source Modulation
 Hollow Cathode Lamps:
Spectrophotometers
In general, the instrument must contain:
 Narrow bandwidth to isolate the line chosen for measurement
 Sufficient glass filter
 Interchangeable interference filters
 Good-quality ultraviolet/visible monochromators
 Photomultiplier tubes
Spectrophotometers
 Single-Beam
 Double-Beam
Spectral Interferences
 The
Two-Line Correction Method
 The Continuum-Source Correction
Method
 Background Correction Based on the
Zeeman Effect
 Background Correction Based on the
Source Self-Reversal
Chemical Interference
The equilibria of principle interest include:
 Formation of Compounds of Low
Volatility
 Dissociation Reactions
 Ionization
Calibration Curves
 Should
follow Beer’s Law
Standard Addition Method
Instrumentation
Sources:
 Hollow Cathode Lamp- only
observed the fluorescent signal
during pulses
 Electrodeless Discharge Lampproduced intensities that
exceed those of hollow cathode
lamps
 Lasers- ideal source with high
intensities and narrow
bandwidths
Instrumentation
Dispersive Instruments- They are made up of a
modulated source, an atomizer, a monochromator or
an interference filter system, a detector, and a signal
processor and readout.
Nondispersive Instruments- They ideally are made
up of a source, an atomizer, and a detector.
Advantages:
 Simplicity and low-cost instrumentation
 Ready adaptability to multi-element analysis
 High-energy throughput and thus high sensitivity
 Simultaneous collection of energy from multiple lines,
enhancing sensitivity
References














www.anachemumu.se.htm
www.aurora-instr.com/right.htm
www.anachem.umu.se/jumpstation.htm
www.anachem.umu.se/cgi/jumpstation.exe?AtomicSpectroscopy
www.anachem.umu.se/cgi/jumpstation.exe?OpticalMolecularSpectrosc
opy
www.minyos.its.rmit.edu.au/~rcmfa/mstheory.html
http://science.widener.edu/sub/ftir/intro_it.html
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/
References













www.dq.fct.unl.pt/QOF/Chroma.html
www-ssg.chem.utas.edu.au/
www.yahoo.com/science/chemistry/chromatography/
www.onlinegc.com
http://www.scimedia.com/chem-ed/analytic/ac-meth.htm
http://www.scimedia.com/chem-ed/spec/atomic/aa.htm
http://www.scimedia.com/chem-ed/spec/atomic/afs.htm
http://www.cee.vt.edu/program_areas/environmental/teach/smprimer/aa
/aa.html#Features
http://www.anachem.umu.se/aas/gfaas.htm
http://www.agsci.ubc.ca/fnh/courses/food302/atomic/aatomic03.htm#el
ectro
http://www.scpscience.com/products/AA/hollowlamps.asp
http://las.perkinelmer.com/catalog/Product.aspx?ProductId=N3050691
http://elchem.kaist.ac.kr/vt/chem-ed/spec/atomic/aa.htm