Detection of Leaching Organic Migrants from
Polyethylene Terephthalate (PETE #1) and
Polycarbonate (PC #7) water bottles.
Paul Dornath
School of Chemical, Biological and Environmental
Engineering (CBEE)
Mentor: Dr. Skip Rochefort
Partners: Brian Maloney (SBI) and Moey Handloser
(ASE)
Chemical Leaching
Chemicals from inside
plastic
i.e., small molecules
moving through the
solid polymer matrix
Degraded surface
particles
Polyethylene Terephthalate (PETE)
Plastic
Known to consumers as
#1 PETE in recycling
codes
Most common uses:
water and 2 L. soda
bottles
Ester of ethylene glycol
and terephthalic acid
What May Cause PETE to
Leach?
UV radiation
– Photo-Fries
rearrangement
– 310 nm wavelength
Unreacted polymer and
plasticizers from inside
the plastic can diffuse at
40 C.
Why We Are Concerned
Cause
Placement of PETE
merchandise
Unknown storage
conditions
Solar sterilization
Effect
Bad taste (acetaldehyde)
Organic molecules
entering into our body
Hypothesis and Objectives
Hypothesis
– Sunlight causes PETE to degrade into organic
fragments via Photo-Fries rearrangement and
elevated heat. Compounds of interest are
acetaldehyde, phthalate plasticizers and aromatic
organic fragments.
Objectives
– Determine if organic compounds leach from PETE
bottles when exposed to sunlight using SPE and
GC/MS
– Determine types of molecules using GC/MS
– Quantify extent of leaching as a function of exposure
time using GC/MS
Method of Exposure
Bottles placed on the roof of
Kelley Engineering Center for up
to 3 months
Record temperatures three
times per day (morning, noon,
evening)
– Air temperature
– Inside middle and end bottles
– Underneath bottles
Polycarbonate (PC) Plastic
Ester of Bisphenol A
(BPA) and phosgene
Commonly sold as
Nalgene water bottles
(#7 PC) and as baby
bottles.
Reports of BPA
leaching have made
them less popular and
led to their removal
from some markets
Camelback Bottle
Bisphenol A
A
Nalgene Bottle
Phosgene
Polycarbonate
Bisphenol A Toxicology
First toxicology tests at WSU in
1997 indicated that lab rats
eating polycarbonate cages
that had been autoclaved were
getting sick
BPA acts like estrogen and
can disrupt the endocrine cycle
in high doses
High temperatures , scrubbing
(surface abrasion), strong
detergents increase leaching .
Hypothesis and Objectives
Hypothesis
– BPA will leach out of heated polycarbonate water
bottles in very small amounts (less than 10 ppb)
Objectives
– Develop a technique to determine the concentration of
BPA in water contained in autoclaved bottles
– Develop a standard GC/MS curve for BPA in water.
– Determine the level of BPA leaching (if any) as a
function of hot water washing cycles.
Method of exposure
Autoclave PC water
bottles containing water.
Run GC/MS tests on the
water (after solid phase
extraction SPE)
Multiple passes of bottles
through autoclave
Autoclave
T = 121 C. P = 2 bar
Let’s review
PETE (#1)
PC
– Disposable plastic
water bottles
– Camelback and Nalgene
bottles
– Measure effect of UV
and sunlight over an
extended time period
(rooftop exposure)
– Determine how much
Bisphenol A (BPA) is
leaching when PC
bottles are autoclaved
Solid Phase Extraction
Gas Chromatograph and Mass
Spectroscopy (GC/MS)
Gas chromatograph
– Ionizes molecules
– Separates molecules by mass
– Feeds MS a stream of molecules one a time
from lightest to heaviest
Mass spectrometer
– Measures mass of individual molecules
– Compounds identified by specific spectrum
– Can only measure one mass at a time
Flow Chart of Process
GC/MS Results for PETE
MS: Identified DEHP to 91% confidence
(Water sample with 2 month exposure)
GC: DEHP of unknown concentration
(in red)
GC/MS Results for PC
Top (GC):
First autoclave shows
BPA is about 10 ppb
Bottom (MS):
Identified BPA to 93 %
confidence
How Much BPA Comes Out?
You get 50 times more BPA from eating
canned food than you do drinking
from water autoclaved in PC
EPA says the maximum dose
per day is 50
micrograms/kg/day
We found BPA leaching at an
average concentration of 4 ppb
after autoclaving
A 70 kg human would have to
consume 1,000,000 liters of
this autoclaved water per day
in order to achieve the
minimum toxic dosage of BPA
Conclusions
Polycarbonate (PC) Studies
Preliminary results show no concentration of BPA going
over 10 ppb from autoclaved PC bottles
We were successful in designing an extraction and
concentration system for BPA
We are currently waiting to run a series of test that will
make our data statistically accurate
PETE Studies
Very few harmful chemicals were identified (only low
levels of DEHP)
Acetaldehyde will be the next molecule of interest to test
Special Thanks
Howard Hughes Medical Institute
University Honors College
Dr. Kevin Ahern, HHMI Coordinator
CBEE
– Dr. Skip Rochefort
– Dr. Mohammad Azizian
– Brian Maloney (SBI)
– Moey Handloser (ASE)
Chemistry Department
– Dr. Christine Pastorek
– Dr. Emile Firpo
– Kristi Edwards
– Greg Jones