Transcript PFOA in Teflon Coated Cookware

PFOA in
Teflon Coated
Cookware
Megan Hartmann
CHEM 4101
December 9th, 2011
PFOA and Teflon
• Perfluorooctanoic Acid
– A carcinogen and toxicant
– Synthetic compound
– Molar Mass
• 414.07 g/mol
– Typical amount found in cookware
• 4.3 ppb
• Teflon
– Chemically known as
polytetrafluoroethylene (PTFE)
– Synthetic fluorocarbon polymer
– Degrades around 260°C
Background
• PFOA is a surfactant used to attach
PTFE into cookware making it non-stick.
• PFOA is removed when cookware is
cured, but residual amounts can remain
• If the cookware is scratched or heated
to high temperatures during cooking,
the residual levels can be released into
the air or the food being prepared.
Hypothesis
By using proper analytical
techniques the residual PFOA
that is released when Teflon
coated cookware is heated to
high temperatures can be
measured.
Techniques Considered
Techniques
Advantages
Disadvantages
IR
• PFC’s are easily
differentiated between
• Fast
• Matrix and Solvents
must be essentially nonexistent
Reverse Phase HPLC
• Good Selectivity
• Easily reproducible
• PFC’s all have different
retention times
• Costly
• Time consuming
• Requires large amounts
of solvents
•
•
•
•
• Newer technique
without much data
available
• Must use HPLC and not
GC
Suppressed Conductivity
Detection
Good Selectivity
Good Sensitivity
Fast
Inexpensive
Method of Choice: GC-MS
Standards: PFOA from Sigma-Aldrich
Order Number:171468
PFTE from Sigma-Aldrich
Order Number:430935
Figure 1: Retrieved from http://www.chromacademy.com/resolver-november2010_Understanding_GCMS_part_1.asp
Agilent 7000 GC/MS
• High Selectivity
• Fast Analysis (500
transitions per second)
• Fluorinated
compounds have
different retention
times
Figure 2: Retrieved from Agilent Technologies. (2009). Agilent 7000B Triple Quadrupole GC/MS. [Brochure].
Agilent 7000 ESI-Triple Quadrupole
Mass Spectrometer
• Signal to Noise Ratio of 500:1 for 100
femtograms
• LOD- femtogram level
• Operates at temperatures as high as 200°C
• High selectivity
Figure 3: Retrieved from Agilent
Technologies. (2009). Agilent 7000B Triple
Quadrupole GC/MS. [Brochure].
Sample Prep
1. Empty Teflon coated cookware is
heated up to varying temperatures
– Specifically around 200-300°C
• Smoke point of oils and where Teflon
degrades
2. PFTE (Teflon) must be scraped off of
cookware and made into a powder
3. Internal standards of PFOA and PFTE
are added
Expected Results
Potentially harmful levels of PFOA will be
found in Teflon coated cookware upon
heating to high temperature
Figure 4: Typical Quadrupole Mass Spectrum for PFOA
Retrieved from Begley, T. "Perfluorochemicals: Potential sources of and migration from food packaging.”
Conclusion
To determine the safety of Teflon
coated cookware GC/MS analysis
can be used to measure the levels
of residual perfluorooctanoic acid
which are harmful to humans.
References
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Begley, T. "Perfluorochemicals: Potential sources of and migration from food
packaging." Food additives and contaminants 22.10 (2005):1023.Guo, Zhishi, and X.
Liu, and K. Krebs, “Perfluorocarboxylic Acid Content in 116 Articles of Commerce.”
National Risk Management Research Laboratory, Environmental Protection Agency,
2009.
Huang, Ke, and KHuang. "Determination of trace PFOA in textiles with HPLC-UV
spectrometry." 印染 37.9 (2011):37.
Kadar, H. "Comparative study of low- versus high-resolution liquid chromatographymass spectrometric strategies for measuring perfluorinated contaminants in fish."
Food additives & contaminants. Part A. Chemistry, analysis, control, exposure & risk
assessment 28.9 (2011):1261.
King, Anthony. "Sticking point", Chemistry and Industry. 2007, 17, 24-25
Lindstrom, Andrew, and A B BLindstrom. "Polyfluorinated Compounds: Past, Present,
and Future." Environmental science & technology 45.19 (2011):7954.
Lv, Gang, GLV, andLv. "Determination of perfluorinated compounds in packaging
materials and textiles using pressurized liquid extraction with gas chromatographymass spectrometry." Analytical Sciences 25.3 (2009):425.
Skoog, Douglas A., F. James. Holler, and Stanley R. Crouch. Principles of Instrumental
Analysis. 6th ed. Belmont, CA: Thomson Brooks/Cole, 2007.
Tracy, M., Liu, X., and Pohl, C. “Analysis of Perfluorooctane Sulfonate and
Perfluorooctanoate in Water Samples Using Reversed-Phase Liquid Chromatography
with Suppressed Coonductivity Detection.” Dionex Corporation. 2009.
Agilent Technologies. (2009). Agilent 7000B Triple Quadrupole GC/MS. [Brochure].