The 1955 AAS paper
A. Walsh, "The application of atomic absorption spectra to
chemical analysis", Spectrochimica Acta, 1955, 7, 108-117.
Reprinted from Spectrochimica Acta, Vol 7, A. Walsh, The application of atomic absorption
spectra to chemical analysis, Pages 108-117, © (1955), with permission from Elsevier.
Constructivism: effective learning
Engagement and understanding
Link VCE physics (science) to topical events
 2005 = 50th anniversary of paper of Victorian invention
Multiple teachers running in the same
direction
Integrated curriculum
 Themes crossing curriculum boundaries
 Each discipline offers different insights
Electromagnetic spectrum
Electromagnetic spectrum: Figure 6.4, Brown, Lemay, Bursten, Burdge, Chemistry the Central Science (9e),
Prentice-Hall, 2003.
Electromagnetic spectrum: Figure 6.4, Brown, Lemay, Bursten, Burdge,
Chemistry the Central Science (9e), Prentice-Hall, 2003.
Light passing through a prism
Light passing through a prism: Figure 6.10, Brown, Lemay, Bursten, Burdge, Chemistry the
Central Science (9e), Prentice-Hall, 2003.
Light passing through a prism: Figure 6.10, Brown, Lemay, Bursten,
Burdge, Chemistry the Central Science (9e), Prentice-Hall, 2003.
Intensity, I
Sodium atomic emission spectrum
Wavelength, 
Solar spectrum: 400 to 700 nm
Solar spectrum: N.A.Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF
<http://www.noao.edu/image_gallery/images/d5/suna.jpg>
Absorption spectroscopy
Iinit , Iout  light intensity
Light source
Iinit
Iout
Sample
I init
Absorbance  log10
I out
Solar flare image: NSO/AURA/NSF
<http://www.noao.edu/image_gallery/images/d1/02245b.jpg>
Detector
Solar spectrum
http://www.shef.ac.uk/physics/teaching/phy103/solspec72.gif
Solar spectrum: N.A.Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF
<http://www.noao.edu/image_gallery/images/d5/suna.jpg>
Atomic spectroscopy
Atomic spectroscopy
Atomic spectroscopy
Energy
~0% population
Emission
Absorption
~100% population
Boltzmann distribution
Atomic energy
Molecular energy
E j 
E j 
population( j) N j

 exp   exp  
population(0) N 0
 kT 
RT 
Atom
Wavelength
Nj /N0 at 3000 K
Cs
852.1 nm
7.24  10-3
Na
589.0 nm
5.88  10-4
Ca
422.7 nm
3.69  10-5
Zn
213.9 nm
5.58  10-10
Light sources
Wide spectrum (thermal) light sources
Narrow spectrum light sources
Solar spectrum: N.A.Sharp, NOAO/NSO/Kitt Peak FTS/AURA/NSF
<http://www.noao.edu/image_gallery/images/d5/suna.jpg>
Atomic spectroscopy
Atomic emission
 Zero background (noise)
Atomic absorption
 Bright background (noise)
 Measure intensity change
 More signal than emission
 Trace detection
The 1955 AAS paper
A. Walsh, "The application of atomic absorption spectra to
chemical analysis", Spectrochimica Acta, 1955, 7, 108-117.
Reprinted from Spectrochimica Acta, Vol 7, A. Walsh, The application of atomic absorption
spectra to chemical analysis, Pages 108-117, © (1955), with permission from Elsevier.
The 1955 AAS paper
A. Walsh, "The application of atomic absorption spectra to
chemical analysis", Spectrochimica Acta, 1955, 7, 108-117.
 Remove bright background
> Hollow cathode lamp
 Measure intensity change
> Light chopper
 Atomic spectra
> Flame atomisation
Photo of Sir Alan Walsh. © Australian Academy of Science.
Reproduced from Historical Records of Australian Science vol. 13 (P. Hannaford,
2000) by permission of CSIRO Publishing and Australian Academy of Science.
Hollow cathode lamp
low-pressure inert gas
Electron and ionic impact on cathode
M(s)  M(g)
M(g)    M*(g)
M*(g)  M(g) + hn
The black "getter" spot
Thin lay of cathode material
Pictures of hollow cathode lamp, © Varian inc.
Reproduced with permission from Varian Australia.
Flame burner
Mn+(aq) + anion(aq)  salt(s)
salt(s)  salt(g)
salt(g)  atoms (g)
M*(g)  M(g) + hn
Flame burner: D. C. Harris, Quantitative Chemical Analysis,
6th Edn., W.H. Freeman and Company, New York, 2002, from
Figure 21-2.
Flame burner: D. C. Harris, Quantitative Chemical Analysis, 6th Edn.,
W.H. Freeman and Company, New York, 2002, from Figure 21-2.
Light chopper
Emission
only
Light chopper
Emission
and
transmitted light
The original 1954 AAS instrument
Reprinted from Spectrochimica Acta Part B, Vol 54, A. Walsh, The development of the atomic
absorption spectrophotometer, Pages 1943-1952, © (1999), with permission from Elsevier.
The first commercial prototype
Reprinted from Spectrochimica Acta Part B, Vol 54, A. Walsh, The development of the atomic
absorption spectrophotometer, Pages 1943-1952, © (1999), with permission from Elsevier.
Modern commercial AAS instrument
Hollow cathode lamps
Flame atomiser
Pictures of Varian AA280 flame instrument, © Varian inc.
Reproduced with permission from Varian Australia.
Sample inlet
Detection limits (ppm = ng mL-1)
Element
Ag
Ca
Cd
Fe
K
Mg
Mn
Na
Ni
Pb
Zn
Flame AAS
3
1
1
6
2
0.2
2
0.2
3
5
1
Flame AES
20
0.1
2000
50
3
5
15
0.1
600
200
200
Data compiled by D. A. Skoog, D. M. West, F. J. Holler and S. R. Crouch,
Fundamentals of Analytical Chemistry, 8th Edn., Brooks/Cole, Belmont (CA), 2004.
Student determination of Fe
1.00 mL pipette
1 mL
2 mL 3 mL
4 mL
Fe:
0.05
mg mL-1
50.00 mL volumetric flasks
First-year chemistry exercise at Deakin University.
5 mL
Student determination of Fe
Calibration curve for absorbance of Fe
Absorbance
1.5
1
y = 0.2093x + 0.001
0.5
0
0
1
2
3
4
Fe concentration / ppm
Actual student data from first-year chemistry exercise at Deakin University.
5
6
Classroom use of atomic absorption
VCE topic
VCE topic
AAS idea 3
reviews
AAS idea 4
VCE topic
previews
AAS idea 5
VCE Physics Unit 1 (Light and waves)
Key knowledge and skills
 describe mathematically connections between wavelength,
frequency, period and speed of travel of waves;
 identify visible light as a particular region of a spectrum of
transverse electromagnetic radiation;
 describe the colour components of white light …;
 describe colour dispersion in prisms and lenses
VCE Physics Unit 2 (Astrophysics)
Light is the basic tool of astrophysicists and … the nature of the
nuclear atom is the same throughout the Universe.
Key knowledge and skills
 describe characteristics of the Sun as a typical star,
including size, mass, energy output, colour and information
obtained from the Sun’s radiation spectrum;
VCE Physics Unit 4 (… light and matter)
Outcome 1
 On completion of this unit the student should be able to
use wave and photon models to explain interactions of light
and matter and the quantised energy levels of atoms.
Key knowledge and skills
 interpret atomic absorption and emission spectra in terms
of a quantised energy level model of the atom, including
calculations of the energy of photons … DE = hf
VCE Physics Unit 4 (3.2: Photonics)
Key knowledge and skills
 explain the production of light by incoherent light sources,
in terms of
> thermal motion of charged particles in materials for
wide spectrum light sources, including the Sun…
> transitions between quantised energy states of atoms
for narrow spectrum light sources, including metal
vapour lamps
VCE Chemistry Unit 3 (Analytical chem.)
Key knowledge:
 … analytical procedures … including … flame tests and …
atomic absorption spectroscopy
Determination of Hg in fish
Observations on metal concentrations in tilapia (Oreochromis
mossambicus) in reservoirs of south Sri Lanka
Locations of the reservoirs from which tilapia samples were obtained.
Cities: Cl, Colombo; G, Galle. Reservoirs: C, Chandrikewewa; R,
Ridiyagama; M, Meegahanjandura; B, Badagiriya; K, Kirribanwewa.
Reprinted from Ecotoxicology and Environmental Safety, Vol. 50, G. Allinson, et al.,
Observations on metal concentrations in tilapia (Oreochromis mossambicus) in reservoirs of
south Sri Lanka, Pages 197-202 , © ( 2002), with permission from Elsevier.
Selected elements (mg) in 60 g tilapia
Observations on metal concentrations in tilapia (Oreochromis
mossambicus) in reservoirs of south Sri Lanka
c
UN FAO PWTDI (Provisional Tolerable Weekly Intake).
d
UN FAO PMTDI (Provisional Maximum Tolerable Daily Intake). All calculations assume an
average male adult body weight of 70 kg.
Reprinted from Ecotoxicology and Environmental Safety, Vol. 50, G. Allinson, et al.,
Observations on metal concentrations in tilapia (Oreochromis mossambicus) in reservoirs of
south Sri Lanka, Pages 197-202 , © ( 2002), with permission from Elsevier.
Metal intake in Sri Lankan fish diet
Observations on metal concentrations in tilapia (Oreochromis
mossambicus) in reservoirs of south Sri Lanka
 Average diet: 60 g tilapia day-1
 Provisional tolerable weekly intake (PTWI)
Hg ~15% of PTWI
As ~6% of PTWI
Cd < 0.1% of PWTI
 Provisional maximum tolerable daily intake (PMTDI)
Cu and Zn < 1% of PMTDI
 ~ 15% of the required daily intake of Fe
G. Allinson, M. Nishikawa, S. S. De Silva, L. J. B. Laurenson, and K. De Silva.
Ecotoxicology and Environmental Safety, Vol. 50, pp. 197-202 (2002).
VCE Math Methods Units 3, 4
This area of study will include:
 Coordinate geometry
> graphs of inverse functions derived from graphs of
original functions;
 Algebra
> one-to-one and many-to-one functions, conditions for
existence of inverse functions;
Calibration curves
A
Absorbance,
Calibration curves
 Often curved
 Linear if concentration range is carefully chosen
Concentration, c
VCE Chemistry Unit 1 (Corrosion)
This area of study will include:
 reactions of metals in the atmosphere; corrosion of metals;
 corrosion minimisation, including passive, sacrificial and
cathodic measures.
Hollow cathode lamp
Black "getter" spot
 Material from anode
 Reductant scavenges oxygen from lamp gas
The black "getter" spot
Thin lay of cathode material
Pictures of hollow cathode lamp, © Varian inc.
Reproduced with permission from Varian Australia.
Constructivism: effective learning
Engagement and understanding
Link VCE physics (science) to topical events
 2005 = 50th anniversary of paper of Victorian invention
Multiple teachers running in the same
direction
Integrated curriculum
 Themes crossing curriculum boundaries
 Each discipline offers different insights
Constructivism: effective learning
Extends VCE Physics study design
 Related to topics in VCE Physics SD
 Extension topics
> Critically evaluate knowledge
> apply knowledge
 Connections to other study designs
> Reinforce/review learning
> Deeper understanding
Acknowledgements
Support, time release etc:
 Deakin University
 Loyola College, Watsonia
Permission to use material
Thank you to:
Dr Graeme Allinson (Deakin University)
Australian Academy of Science
CSIRO Publishing
Elsevier
National Optical Astronomy Observatory /
Association of Universities for Research in Astronomy /
National Science Foundation (USA)
 Varian Australia / Varian Inc.





Reading list
A. Walsh, "The application of atomic absorption spectra to
chemical analysis", Spectrochimica Acta, 1955, 7, 108-117.
A. Walsh, "The development of atomic absorption methods of
elemental analysis 1952-1962", Analytical Chemistry, 1991,
63, 933A-941A.
A. Walsh, "The development of the atomic absorption
spectrophotometer", Spectrochimica Acta Part B, 1999, 54,
1943-1952.
P. Hannaford, "Alan Walsh 1916-1998", Historical Records of
Australian Science, 2000, 13, 45-72
<http://www.science.org.au/academy/memoirs/walsh2.htm>.
Reading list
G. Allinson, M. Nishikawa, S.S. De Silva, L.J.B. Laurenson and
K. De Silva, "Observations on metal concentrations in tilapia
(Oreochromis mossambicus) in reservoirs of south Sri Lanka",
Ecotoxicology and Environmental Safety, 2002, 51, 197-202.
D. A. Skoog, D. M. West, F. J. Holler and S. R. Crouch,
Fundamentals of Analytical Chemistry, 8th Edn., Brooks/Cole,
Belmont (CA), 2004.
D. C. Harris, Quantitative Chemical Analysis, 6th Edn.,
W.H. Freeman and Company, New York, 2002.
Reading list
More information about Australian science and scientists can be
found at
 Australian Academy of Science
<http://www.science.org.au/academy/>
 Historical Records of Australian Science
http://www.publish.csiro.au/journals/hras