Welcome to PicarroFood Analysis by Cavity Ring-Down Spectroscopy
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Molecules Are In Constant Motion
Symmetricalstretching
Antisymmetricalstretching
Scissoring
Rocking Wagging Twisting
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It’s All Springs and Mirrors
O
H
H
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Very High Sensitivity and Precision
• Small, 35 cc sample cavity
• Laser intensity builds up…
• …Laser is shut off
• Removes laser fluctuations
• Up to 20 km pathlength
• Light reflects around the cavity
• Cavity loss mechanisms decrease intensity each pass
• Measurement is decay rate not absolute absorbance
Time-basis and long pathlength provide high sensitivity & precision
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Time Based Measurement
Laser
Photo Detector
Pho
to D
etec
tor
Time (s)
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Increase Concentration, Faster Ring-Down
Absorbing species in the cavity follow Beer-Lambert Law
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From Wavelength to Ringdown
Time (micro-seconds)
Det
ecto
r S
igna
l Measure Ring-down
Select Wavelength
Wavelength (nm)
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From Ring-Down to Concentration
Time (micro-seconds)
Det
ecto
r S
igna
l Ringdowns
t
tItI ocirccirc exp)()(
1549.6 1549.8 1550.0 1550.2 1550.4
0.0
1.0x10-6
2.0x10-6
3.0x10-6
4.0x10-6
5.0x10-6
Ab
so
rba
nce
(1
/cm
)
Wavelength (nm)
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Combustion Module
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Extending the Reach of CRDS
iCO2
iH2O
DIC/DOC
DIC
DIC
Automate FX
OI Analytical 1030W
Thermo GasBench II
Costech
EA
Liaison
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Benefits of Cavity Ringdown
• Low capital cost - $50K to $120K.• Low cost of ownership- $100 to $1000/year.• Small Size – as small as 17” x 8” x 23”.• Low power consumption – 100W to 400W• No high vacuum pumps.• Very rugged.• Easy to Use.
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Food Authenticity
• Fraud is a $50 Billion/yr problem– Wine– Coffee– Olive oil– Milk
• Using costly equipment and scantily adopted methods– IRMS ($350,000)– NMR ($300,000)
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Consumer Rights, Tariffs and Duties
• OJ – where is it from, Florida or Brazil?
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Consumer Safety
• Has cane sugar been added to this honey?• Is this “pure” sesame oil diluted with corn oil?
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Sustainable Plastic Packaging
• $50 Billion/yr by 2014– Adding annually
renewable resources
• Using costly equipment– AMS ($3,000,000)
• Or low tech– LSC (low precision)
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Measuring ‘Green-ness’
• What is the plant content of these bottles and bags?
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Stable Isotopes: Answer These Questions
• Stable isotope data can give simple, unambiguous answers to all these questions and more
• Unique signature from a permanent record of history/source
• Huge potential applications• Can provide simple analysis/screening information• Completely under-exploited to date• New instrumentation is changing that
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Sparkling Water δ13C Analyses
-40.00
-35.00
-30.00
-25.00
-20.00
-15.00
-10.00
-5.00
0.00
• Simple, yet high precision, high reproducibility
δ13C
/per
mil
Fossil fuel based CO2 (Crystal Geyser)
Geothermal based CO2 (Perrier, left and
San Pellegrino)
Artesian well (Fiji)
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Honey Analysis, AOAC 998.12
Sample
Protein ( ‰ ) Honey ( ‰ ) C4 Sugars ( %)
Sample 1 -26.57 -27.35 -4.6
Sample 2 -26.79 -27.57 -4.6
Sample 3 -26.27 -25.45 5.0
Sample 4 -26.21 -27.84 -9.8
Sample 5 -26.55 -26.19 2.1
Sample 6 -27.80 -27.45 1.9
Data shows that all of the samples tested here are unadulterated using AOAC 998.12 criteria.
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Sample Delta (‰) S.D. (‰) IRMS(‰) Difference (‰)
Honey A -22.22 0.165 -22.2 -0.02
Honey B -21.85 0.120 -22.0 0.15
Honey C -25.22 0.184 -25.6 0.38
Honey D -25.08 0.047 -25.1 0.02
Honey E -27.20 0.082 -26.8 -0.40
Honey F -24.47 0.089 -24.4 -0.07
Honey G -23.77 0.032 -23.9 0.13
Honey H -23.65 0.065 -23.9 0.15
Honey I -23.66 0.046 -23.8 0.14
Honey J -23.74 0.107 -24.2 0.46
Honey Analysis Compared with IRMS
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Food Fraud Detection
Honey adulteration with corn syrup: 5%, 10% & 15%
Exceptional correlation of calculated & measured δ13C values
Δδ values are < 0.1 ‰, even at the 5% adulteration level
R2 = 0.9999
-27-26-25-24-23-22-21-20-19-18-17-16-15-14-13-12-11-10
-27 -26 -25 -24 -23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10
Predicted δ13C value (‰)
Mea
sure
d δ
13C
val
ue
(‰)
100% HFCS
100% Honey
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Orange Juice Origin
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Commercial Apples
• A quick screening method of using stable isotopes to distinguish the true origin and/or composition of natural food and beverage products
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Olive Oil Sample Sources (6 Countries)
Australia
Lebanon
TurkeyGreece
Italy
Spain
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Olive Oil δ13C Analysis: CRDS vs. IRMS
2ul Inj. Vol. CRDS
δ13C (‰)
S.D. (n=3) (‰)
IRMS
δ13C (‰)
Italy -28.98 0.05 -29.27
Australia -31.23 0.01 -31.19
Spain -28.95 0.18 -28.94
Turkey -30.34 0.11 -30.32
Greece -29.29 0.02 -29.21
Lebanon -29.11 0.23 -28.87
(California -30.03 0.19 N/A)
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Conclusion
• Fast, easy tests for food authenticity• Supply chain screening for adulteration• Push button, simple methods for routine lab use
