XRF
X-ray Fluorescence Spectrometry
Tom Murphy
Qualitative Screening
or
Quantitative Analysis
Major Users of XRF
Geoprospecting
Alloy identification for safety and recycling
Remediation of lead in paint, metals in soil
Waste processing such as oil industry
Forensics for legal analysis
Consumer product analysis
Art and Archeology
Industrial hygiene
More powerful units
have radioactive
source, better detection
levels, fewer
interferences, but are
not usually portable,
and if portable require
licensing
Hand-held XRF – Thermo Fisher
Loan
 -analysis in ~1 minute
 -no extraction or other preparation of
sample
 -detects ppm concentrations of many
metals
 -non destructive
 -no cross contamination or fouling of
sensor

Sample Preparation/Calibration

The sample matrix can be important

The best cases really suitable for XRF analysis is the
‘atomic mixing level’ that is found in:
-All liquids (homogenous, one physical phase!)
-Glass
-Large crystals (used for “finger printing” gem origins)
-Most alloys
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Mixing varies from impossible to easy
-results vary from qualitative to
quantitative
Oil in mineral
precipitant
“impossible” to mix
Toxic skin cream
can mix but will
separate, “Cao
Cap”
This fish needs a
better grinder but
can shoot
replicates
Interferences
A few elements interfere, arsenic and lead can effect
each other, especially in low energy XRFs
-in samples with high lead, low arsenic results will be
unreliable
The Matrix can be an issue. If there is more than 10%
water in a sample, it can either enhance or reduce the
signal. Drying of the sample is required.
Geoprospecting – Pathfinder analysis
-can’t see low concentrations of gold with XRF but can
find co-occurring elements like platinum
Jewelry
-XRF quickly detects Pb, Hg, Cd etc.
-no sample preparation
Found clasps with
>40% Pb
-ingestion has killed
child in USA
-chronic toxicity more
common
Lead Amulets/Curse Tablets oral very dangerous, dermal less dangerous but not well
documented, no sample preparation needed for XRF
Thai Charm
- Khmer Beads 45% lead
Roman
Curse
Tablet
Other Consumer Products?
-cooking ware – old ceramics, poorly made
metal ware
-Degree of extractability is important
-Cooking acidic foods is more dangerous
-1/3rd of toys here are toxic by EU regulations
-a few times toys were removed from US
Stores
Porcelain
http://www.environment.gov.au/atmosphere/airquality/publications/ceramics.html
-Lead glazes are most commonly used on earthenware, and on older bone china
and porcelain.
-If they are not properly prepared and fired, lead may leach (i.e. move from the
glaze) into food stored in or on the ceramic ware.
-Acidic foods will accelerate any leaching.
-Ceramic ware with a corroded glaze is extremely dangerous.
-Reheating coffee in an old mug in the microwave is a particularly risky thing to do.
Cooking Ware/Archeology
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Fall of Roman Empire – one theory of several
The presence of lead in the drinking water
leached in from the water pipes, glazes on
containers that came in contact with food and
beverages, and food preparation techniques
could have contributed to heavy metal
poisoning.
It was also absorbed through the pores, since
it was used in cosmetics.
Roman use of lead - as cosmetics, pipes, jewelry, curse
tablets, utensils and cooking pots, and, of course sapa
and defrutum (wine boiled down in lead pots)
Lead levels in bones from the Imperial Roman period had up
to 30 mg/kg, which is three times higher than the level the
WHO considers "very severe lead poisoning."
Paint
-lead in paint only found now in developing
countries
-essential and easy to mix can of paint
-to process dried paint on a surface requires
a more powerful XRF and results are
qualitative
Thai Paint with up to 5% lead
Problem?
Small children put pieces of
old paint in their mouths.
-price of renovation in USA
Previous Thermo Collaboration
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-processed 675 skin
creams
-33% of samples from
beauty shops exceeded
guidelines
-up to 3%Hg
Murphy, T.P., S. Lim, S.P. Huong, K. Irvine, S. Bayen, B, Kelly
and K. Wilson. 2012. Application of Handheld X-Ray
Fluorescence Analyzers to Identify Mercury in Skin Whitening
Creams in Cambodia. J Health Pollut. 3:21-31
Skin Cream Validation -1
The spiked recovery used DMSO for good mixing.
Quantitative for <2000 ppm Hg
A reduced response for >2000 Hg but still useful.
No certified reference materials available for this analysis.
XRF Validation -2
Comparison of XRF and ICP-OES is fine
Again, there were no certified reference materials for skin
creams.
There are several standard reference materials for fish etc.
When possible use certified reference materials.
Mercury in Skin Creams in Phnom Penh ppm
Product Name
Eucerin
Hua Tha Li
Chang Chun
Enjoy
Rojzy Jiali
Yimei Yellow
Guoyao
Diamond
Hua Hin
Qian Mei
FC
Malis
Lulanjena
Oreal2
Maly
Japanese
SS-II
Britney
Mlis
Apparent Source Total Mercury
USA
23200
China
19256
China
18458
USA
13800
Vietnam
12528
China
12014
China
11500
Unknown
6147
China
5454
China
5110
Cambodia
4979
Thailand
3552
China
2990
Unknown
2852
Thailand
1938
Japan
1652
Unknown
1410
Cambodia
1223
Thailand
996
Other cosmetics warrant analysis, management
-a blush containing 878 ppm of cadmium
-users all reacted to it and passed to their friends
Waste disposal
- PVC pipe has 7000 to 9000 ppm of lead
- Should not be burned without emission
treatment
- Similar concerns about future oil and gas
industry wastes
Environment
Canada
Environnement
Canada
Other Hydrocarbons, Thermal
Thermal power plants to be fired by Khmer coal
-Sulphur, Arsenic, mercury content?
-risk of acidification in soft water environment
-Mercury in natural gas?
Khmer Coal
Source
Mean Sulphur Arsenic
Mercury
Preah Vihear,
Cam.
8419
30
ND
Springfield USA1
32000
9.8
0.12
Appalachian1 USA 280002
351
0.211
Wyoming USA3
2.6
0.13
6300
Units ppm, Khmer coal formed in freshwater, low Sulphur
Concerns with Coal
The Cardamom mountains are granitic and thus they have little
buffering capacity.
Burning coal produces sulphuric acid.
Without emission treatment acid rain from burning coal in such
an environment could kill most plants and water life
At least the sulphur content is not high
Fish Anemia Study
-Some fish have more iron content than beef and
could be used to treat anemia.
-so far <30 species processed for [Fe]