Presentation on theme: "Detection of Leaching Organic Migrants from Polyethylene Terephthalate (PETE #1) and Polycarbonate (PC #7) water bottles. Paul Dornath Paul Dornath School."— Presentation transcript:
Detection of Leaching Organic Migrants from Polyethylene Terephthalate (PETE #1) and Polycarbonate (PC #7) water bottles. Paul Dornath 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 Bottles placed on the roof of Kelley Engineering Center for up to 3 months Record temperatures three times per day (morning, noon, evening) 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 Bisphenol A A Phosgene Nalgene BottleCamelback Bottle 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. 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) 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) –Disposable plastic water bottles –Measure effect of UV and sunlight over an extended time period (rooftop exposure)PC –Camelback and Nalgene bottles –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? 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 You get 50 times more BPA from eating canned food than you do drinking from water autoclaved in PC
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
Howard Hughes Medical Institute 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 Special Thanks