Science Buddies: "Ask an Expert"

Hello,

I am doing a science fair project on how temperature effects BPA (bisphenol A) release and how the chemical effects micro-organisms such as brine shrimp. I have done some research and have found out that I need to conduct a HPLC (high pressure liquid chromatography) test. I have found a place that does this test and they wanted to know what solvent is needed to identify the presence of BPA. Any help or suggestions would be beneficial to me and I greatly appreciate your help. Thanks a lot for your time!

Hi banyen,

As solvents, I found alcohol and acetonitrile.

Alcohol is mentioned at http://www.bisphenol-a.org/pdf/M5.pdf
Acetonitrile is mentioned at http://dmd.aspetjournals.org/cgi/conten ... 33/11/1748

As background, you may want to read the wikipedia entries for
BPA at: http://en.wikipedia.org/wiki/Bisphenol_A
Acetonitrile at http://en.wikipedia.org/wiki/Acetonitrile

Note particularly the safety section in the acetonitrile write-up. It may be best to use the 10% alcohol.

Per your question of how to do a great project, please consult:
https://www.sciencebuddies.org/science- ... ?From=body

Hi!!

Thanks for your help. Would purified water work as well???

Hi Banyen,

Wikipedia (http://en.wikipedia.org/wiki/Bisphenol_A) and some other sources report that BPA has a solubility of 120-300 ppm (approx 120-300 mg/L) in water around room temperature. Other resources report the solubility as "none" or "zero":

http://apps.kemi.se/flodessok/floden/ke ... _a_eng.htm
http://www.inchem.org/documents/icsc/icsc/eics0634.htm

so it seems like that solubility is generally considered pretty low. However, solubility almost always increases with temperature, and you are planning to heat the water -- so you might want to look for info on solubility at higher temps and maybe even do some tests at home to see how hot the water gets with the microwave times you were planning to use, or perhaps how hot a particular food gets Some things you might want to consider when deciding whether it's appropriate: What solvents are present in food (e.g. is BPA soluble in oils?)? What concentrations need to be present in food to pose a health risk? What volume of solvent will you place in the container? What is the lowest concentration that can be detected with your chosen method of analysis? How does the water solubility compare to solubility in other solvents you were considering (at the appropriate temp)?

Something a bit more complicated to think about: I think someone mentioned, for example, a 10% solution of alcohol -- this means 10% alcohol, 90% purified (distilled or maybe deionized) water. Alcohols (not sure what was intended -- isopropyl, ethyl, methanol, etc) evaporate faster than water, so especially since the mixture would be heated, I'd be worried that you'd end up with something like 1 % alcohol, 99% water at the end, and that could make your data hard to interpret. Also, most usual laboratory solvents aren't present in foods that are microwaved (one would hope). So, assuming that the amount of BPA that dissolves in water is solidly in the measurable range, using just water probably creates the situation most relevant to the problem you're interested in. You could always do some trials with other solvents just to see what happens, though.

Best wishes,
Amanda

Hello,

I am also starting to work on BPA and of course dissolution matter comes...

I wanna get rid of BPA in water via ozone at room temperature (for water treatment concern).
And the analysis method I picked up is HPLC-UV to follow degradation and to do kinetic studies.
I was thinking to use 10% methanol / 90% water to prepare 1000ppm of BPA.
But I am wondering whether the methanol could be influence by ozone or not?
Does anyone have an idea about that?

(difficult to find info about!)

Thanks a lot.

But I am wondering whether the methanol could be influence by ozone or not? Does anyone have an idea about that?

Please note that it has been a VERY long time since I had chemisty so don't count on my answer being definitive!

Ozone is a strong oxidizing agent; however, CH3-OH doesn't have any carbon-carbon bonds that can be oxidized directly, the OH ion is a negative ion which doesn't want an oxygen, so unless there is some metalic catalyst and a strong acid (proton donor) that will cause a carboxyl / carbonyl reaction, I don't see any viable prediction of a reaction involving the methanol. HPLC columns are metalic so if you are concerned about a breakdown of the methanol, you need to avoid low pH situations. But you already need to avoid low pH situations or you will break down BPA chemically via an acid-base reaction and invalidate your experiment. You probably want to insure that the pH of your test solution is near normal especially if you want to extrapolate your results to what might happen in animals.

Thank you Craig for your fast response.

After several talks, it seems that ozone may not have an influence on methanol.
And your detailed response confirmed that as well.
I will also care a lot about the pH during experiments.

Another question is, I am trying to prepare 100ppm of BPA (purity>99%) in DDI water(because 1000ppm in pure water is impossible to prepare)
After one night magnetic stirring, almost all the solid is not visible anymore...
BUT:
- it is because it is fully dissolve in DDI water?
- or just because the tiny particles (non visible through eyes) are dispersed in aqueous medium?
The second option could be a problem for HPLC analysis...
Some people advise me to dissolve BPA in MeOH first and dilute with water then to avoid this situation...

Some people advise me to dissolve BPA in MeOH first and dilute with water then to avoid this situation...

Based on what I read on BPA solubility to answer your previous question, BPA is far more soluble in an acqueous methanol solution than in water, particularly cold water. Count me as one who would advise disolving the BPA in a methanol solution instead of water as long as a methanol solution will work for the rest of your experimental proceedure. Since you have already mixed BPA and water and you are cocerned about the possibility of a partial suspension, just add methanol and mix for half a minute. Any suspended BPA will quickly disolve. Note: By using methanol as your solvent, it won't take very long to disolve your BPA the next time you mix up a solution.

Heyyy!

My project is regarding how temperature affects the chemical Bisphenol A release. I know that you can use a HPLC to detect the prescence of BPA, but can you use a thin layer chromatography test as well????

Thanks

Hi,

Yes, Thin Layer Chromatography has been used to analyze Bisphenol A. Here is a paper abstract on it:

http://cat.inist.fr/?aModele=afficheN&cpsidt=15867127

Best wishes,

Barrett Tomlinson

Hi banyen,
I merged your old topic with your new one so that the experts can follow the progress of your project. To ask new questions related to this project, please post in this topic using the "add reply" button.
Good luck!
Chris

Do you know of any common brand bottles that for sure contain BPA, and are still available to buy?
By the way, can you tell me HOW to do the TLC at home?


thanks

Do you know of any common brand bottles that for sure contain BPA, and are still available to buy?

No. The fundamental problem is that once some country has a problem with a material that requires labeling or discontinuation, manufacturers will usually eliminate the use of that material rather than deal with making sure they don't accidentally ship the wrong thing to the wrong place. Additionally, the regulatory requirements become a legal basis for any potential legal actions in other jurisdictions. Once people stop using a given plastic, then the plastic manufacturers will quickly drop the production of it so even containers for non-food items will quickly change to something else as well.

I did a quick web search for "detecting Bisphenol A" and found several very interesting methods, all of which are beyond what could be done outside of a college or industrial research lab with the exception of HPLC / GC spetrographic approaches that can be done with expensive but still more general purpose scientific equipment.

If you were a graduate student or post doctorial interested in this specific area, you would probably have to move to a lab that was interested in funding this kind of research in order to conduct it.

As a junior high student, you don't have those kinds of options unless there just happens to be a local college or university that is doing work in this area and has people who are willing to help out young scientists unless you live in a community where there is a specialized advanced science program highschool that happens to have HPLC / GC spectrographic equipment. Short of that, your best option is to find something that can be done with what you have available to you.

Thank you!

I have already checked at many of the colleges around and they don't want me to use their machine because they are afraid that their machine might "jam up". Can you tell me how I could do a thin layer chromatography at home to detect BPA. Someone had said that it would work, but I don't know how.

Thin layer chromatography http://orgchem.colorado.edu/hndbksupport/TLC/TLC.htmlis primarily a way to get a clue as to how many components are in a mixture. By calculating the Rf of an unknown and comparing it to the Rf's of known compounds, you can get a guess at what it might be, but more specifically, you can rule out what it isn't. If a known has a relative Rf value that is nowhere near any of the constituents, then that known is NOT present in the mixture. The converse is NOT true. Unfortunately, this method doesn't work for constituents in the less than 5,000 PPM range which is what I think you are trying to look for. Simply stated, there won't be enough BPA around to show up via TLC.

I realize that you really want to do a project that tests for BPA, but I don't think you have the means of doing so. Maybe it is time to look for a project that you have the resources to do. If you are interested in TLC or paper chromatography, they can be used to do a lot of neat things as long as you pick something that has high enough concentrations to be seen.

HEY!!

I am finally able to use a HPLC!!! However, I need to know the concentrations of BPA. I looked this up, and on the Bisphenol A website, it says that it is generally less than 5 parts per billion. You had said that it is less than 5000 ppm. Which is more accurate? Thanks!

What I said was

Unfortunately, this method [TLC] doesn't work for constituents in the less than 5,000 PPM range which is what I think you are trying to look for.

I looked this up, and on the Bisphenol A website, it says that it is generally less than 5 parts per billion. ... Which is more accurate?

They are both "accurate". My statement that the expected concentration of Bisphenol A is less than 5,000 PPM is accurate per your website which indicates it is generally less than 5 PPB. 5 PPB is less than 5,000 PPM. The more "precise" statement is less than 5 PPB because it narrows the range significantly.

If somebody guessed you weighed less than 500,000 pounds on earth, they would be "accurate" (correct). If somebody else guessed that you weighed less than 500 pounds on earth, I suspect they would also be "accurate" (correct). Whose guess was more "precise", the one that guessed "less than 500 pounds".

My use of 5,000 PPM was directed at telling you more about the boundaries of what TLC methods might be capable if pushed to extreme limits and said very little about Bisphenol A concentrations. In other words, TLC method limitations and expected Bisphenol A concentrations weren't even in the same ball park.

Hello,
I just made a huge mistake!! I had our granite countertops removed and there was an epoxy strip joining two pieces which the person who removed it heated for about 30 minutes (my kids were in the basement the whole time) and even scraped away which did create dust (why did I do that!!!). I am 99% sure it had bpa. I cleaned my cabinets with vinager and tried to forget about it. Then I realized that my glass cooktop was getting a film! I just cleaned it yesterday and it was the same color as the epoxy !!!! I imagine, in my super safety concerned mind, that I have been exposing my kids to these fumes for two weeks, cooking on the stovetop. I imagine it is on everything from being in the dishwasher with my pots and pans that were on the cooktop: from my glasses to plates and silverware from the inside of my dishwasher.

Is there any way to clean bpa or do I now need a new cooktop and cookware and plates. I will buy new things if there is no way to remove it. Have I done irrepriable damage to my kids can this stuff be flushed out? Can I have their urine tested, I have read that blood, yeast tests are being developed. I have no idea how to turn this mistake around!

If you can help or know someone who can, I would greatly appreciate any help.

Hi Ochopeces,

These forums are for K-12 students, parents, and teachers working on school science projects. Although I can tell that you have genuine concerns and want expert advice, your questions don't fall within the scope of these forums. However, you may find assistance on a different set of online forums.