The RRUFF Project and Homeland Security
Dr Robert T Downs
Department of Geosciences
University of Arizona
Tucson AZ
The RRUFF Project and Homeland Security
• Homeland Security Depends on Reliable
Identification of Suspect Materials.
• This Can Be Accomplished With Raman
Spectroscopy
Richard Reid, the
Shoe bomber
Raman Spectra of TATP
Explosive In Shoe Is
Unique Fingerprint
RRUFF Project Goals
• Complete Measurement of Known Minerals Via Raman
Spectroscopy
• Improve Accuracy and Predictability of Raman Search/match
Software
• Collaborate With Hardware Manufacturers to Integrate
RRUFF Database With Handheld Raman Instruments
• Characterize Specialized Substances for Inclusion in Database
(Drugs, Explosives, Etc.)
• Explore Applicability of Raman Spectra to Develop
Geographic Markers for Suspect Materials
Why Raman Spectroscopy?
RRUFF Project Database
• Quick Acquisition of Spectra
• Little to No Sample Preparation
• Useful on Solids, Liquids and Organics (Leaves,
Seeds, Etc.)
• Portable Units, Soon to Be Handheld Sized
• Can Be Deployed on Robots
• Database Critical to Reliable and Accurate Identification of
Suspect Materials
• Completion of Database Critical to Error Free Identification
of Suspect Materials
• RRUFF Team in Place And Proven
• 50% Complete (2000 of 4300 Known Species
Characterized)
• Remaining Species Are More Complex – Require More
Time to Characterize
• Funding Required to Complete Raman Materials
Characterization for Database - $1M Per Year for 5 Years
Restrictions
• Must Be in Close Proximity to Suspect Material
• Fluorescence May Interfere
• Will Not Work on Everything – Metals
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The RRUFF Project and Homeland Security
The Raman spectrum of a substance is a fingerprint that can
be used to uniquely identify it.
Richard Reid, the Shoe bomber
Dec 22, 2001
The technique would be used to
unambiguously identify targeted
compounds of interest.
Raman spectrum of TATP explosive that was
found in his shoe.
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The RRUFF Project and Homeland Security
The RRUFF Project
• The RRUFF Project at the University of Arizona is creating a Raman
database of carefully characterized minerals. This means that chemical
composition and X-ray diffraction are performed on each sample in
order to properly identify them. Then the Raman spectrum is used to
match a recorded signal to the sample.
• Minerals represent the naturally occurring inorganic compounds. There
are about 4300 known phases, 2000 have already been characterized by
the RRUFF project.
• Almost all known substances, including man-made synthetics,
originated from minerals as their raw material.
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The RRUFF Project and Homeland Security
RRUFF Project Goals
• Complete the measurement and characterization of the known minerals
• Continue the development of the search/match software to improve its
accuracy and predictability.
• Identify and collaborate with hardware manufacturers to integrate the
data and software with handheld instruments.
• Characterize other specialized substances for inclusion in the databases,
for instance, drugs and explosives. Data already exist for some of these
materials, but we have developed the expertise to effectively measure any
substance.
• Further investigate the capability of the Raman instrument to record
spectral artifacts that can be used to determine the geographical origin of
a sample with certainty.
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The RRUFF Project and Homeland Security
This is not a startup operation; the
RRUFF project has been running
successfully for four years with a
team of well-trained undergraduate
and graduate students, postdocs
and research scientists
• Procedures are developed
• Validation and verification
schemes are in place
• Equipment already exists
The RRUFF project has been funded by the National Science Foundation,
NASA, and the generosity of Michael Scott, founding president of the
Apple Computer Corporation.
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The RRUFF Project and Homeland Security
Raman Spectroscopy
• Raman spectroscopy offers a means to identify
compounds with no sample preparation.
• Recent technology is creating inexpensive and
compact instruments, suitable for handheld field
equipment.
• Databases are required to make identification.
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The RRUFF Project and Homeland Security
A Raman signal can be created by the interaction of a laser with
a substance, using specialized spectrometers.
The signal is a series of
Raman peaks whose
positions are determined
by the masses of the
constituent atoms and
the strength of their
chemical bonds.
The spectral lines
produce a unique
chemical and structural
fingerprint of a
substance.
Raman spectrum of aegirine, NaFeSi2O6
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The RRUFF Project and Homeland Security
Raman Instrumentation
NASA spearheaded the development of
miniaturized Raman spectrometers for planetary
exploration*. The technical advances are rapidly
being transferred to handheld instruments, mainly in
response to homeland security concerns. Here are
examples of four generations of instrumentation.
Typical bench top unit, circa 2000
Mars rover, conceptual
design, 2003
Ahura FirstDefender, 2005
Delta Nu Reporter, 2007
*A high performance Raman spectroscopy system for Mars surface studies. (2003-2005) Co-PI: B. McIntosh (Hamilton
Sundstrand Sensor Systems), M.B. Denton & R.T. Downs (U of Arizona), and W. Doyle (Axiom Analytical, Inc.) NASA
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The RRUFF Project and Homeland Security
Pros and Cons of Raman Spectroscopy for Identification
Purposes
Pros:
• Signal can be recorded in seconds
• Very little, if any, sample preparation is required
• Useful on solids, liquids, even for identifying organics like leaves and seeds, representing
99% of the compounds of interest.
• Portable units will soon be hand size
• Can be deployed by robots
Cons:
• Needs a database
• Instrument sensor must be near the suspect material
• Fluorescence may swamp signal
• Will not work for everything, metallic compounds generally do not give good spectra.
Failure on about 1% of the compounds of interest.
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The RRUFF Project and Homeland Security
Example: Raman spectrum of Excedrin tablet, through the bottle
With a red laser, a signal can be recorded through
the white bottle, with no sample preparation. The
three components of Excedrin are correctly
identified.
Raman Intensity
Ranked list of search/match results
1
2
3
Acetylsalicylic acid
4-Acetamidophenol
Caffeine
These are the components of Excedrin.
300
800
1300
1800
Raman Shift (cm -1)
Raman spectrum of Excedrin tablet, through the bottle
Materials in certain closed containers
can be identified.
Another example, anthrax in an
envelope.
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The RRUFF Project and Homeland Security
The Database
• To effectively use Raman spectroscopy to identify unknown
materials, a database is required.
• Natural materials are ubiquitous. They are found entrained or attached
to clothing, shoes, luggage, or computers. For example, anthrax in the
US mail system was carried on a mineral binder. These natural materials
represent compounds from the mineral kingdom. The project is
completing the database on all the known minerals. The completion of
the database will provide the proper identification of these materials in
homeland security environments.
• The samples are correctly identified and characterized by X-ray
diffraction and chemical composition, and then their Raman spectra are
collected. The result is a database of Raman spectra that can be used to
correctly identify minerals.
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The RRUFF Project and Homeland Security
Database website
http://rruff.info
This is the front
end of our project
database website.
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The RRUFF Project and Homeland Security
Database contains a collection of mineral sample pages:
• Photo of sample, its source and locality where sample was found
• Microprobe analyses that contains detailed chemical composition
A microprobe is a $1M laboratory instrument that requires several days work to produce a
well-characterized chemical composition by a PhD level analyst. The technique is
destructive.
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The RRUFF Project and Homeland Security
Database contains:
• Oriented and unoriented Raman spectra
Raman spectra of solids show intensity variation that is dependent upon the orientation
of the sample and its crystallographic symmetry. The RRUFF project collects Raman
spectra that are shot from all the symmetrically distinct orientations, so unknown
materials can be identified regardless of how they are presented to the spectrometer.
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The RRUFF Project and Homeland Security
Database contains:
• Broad ranged scan of the unoriented sample using several wavelengths of
lasers
One of the results of the project has been the observation that the spectrum contains more signal
than just Raman. For instance, peaks are observed that are not Raman in origin. We are still
learning what these other artifacts represent, though it is clear that fluorescence peaks are
recorded. These are the results of minor or trace element contamination, and can be used, in
some cases, to constrain the geographical origin of the sample.
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The RRUFF Project and Homeland Security
Database contains:
• Infrared spectrum
Another spectroscopic method for identification of unknown samples is infrared
spectroscopy. This is a technique that is not uncommon to many forensic laboratories.
The instruments are not miniaturized and they require sample preparation. But the
method is well-established. We are including these spectra in our database.
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The RRUFF Project and Homeland Security
Database contains:
• X-ray diffraction profile and refined crystallographic parameters
The standard way to identify an unknown crystalline substance is to apply X-ray
diffraction techniques. This is a destructive technique that requires a laboratory
instrument and takes many hours to days to analyze. Every mineral that we examine is
analyzed by X-ray diffraction in order to assure that it is correctly identified.
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The RRUFF Project and Homeland Security
Database contains:
• Selection of the important scientific literature for additional information
on the minerals
In collaboration with the major professional mineralogical associations, the important
papers have been collected and are made available when permission from the editors
has been granted.
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The RRUFF Project and Homeland Security
The project has also developed search/match software for the unoriented
Raman and X-ray diffraction measurements
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