[tyro89]

Hello,

Like the subject of this post suggests I’m a researcher conducting microbiology research. At one moment today I tried to create a solution to use as a base for Petri dishes. This mix was hot liquid agar with water and ethinylestradiol dissolved in methanol.

The expected reaction of this mix was, well, nothing. What happened was quiet the opposite. When the methanol/ethinylestradiol solution entered the liquid hot agar 1/2 to 3/4 of the agar was solidified and turned milky white. This is very confusing to me. I repeated the mix and obtained the same results.

It might be important to note the volumes; the mix is consisting of 2g of ethinylestradiol/L of agar with water.

I know it is not the methanol that reacts since I made a mix of methanol and liquid agar with water successfully.

If anyone have any idea or know what is going on I would be very grateful to learn what is going on in my mix and most important, if the estrogen is consumed and hence the mix useless.

Thanks a lot for your time 

[agrobert]

What  I think is happening is that your agar solution is saturated and the concentrated ethinylestradiol is crashing out as an oil/solid when poured.  Nothing should be discarded as I do not see any possibility of ethinylestradiol being "consumed" or degraded but you need to figure out a system with better solubility.

[tyro89]

What  I think is happening is that your agar solution is saturated and the concentrated ethinylestradiol is crashing out as an oil/solid when poured.  Nothing should be discarded as I do not see any possibility of ethinylestradiol being "consumed" or degraded but you need to figure out a system with better solubility.

This could be a possibility but is unlikely since a solution using the same agar was made but with the same amout of glucose instead of ethinylestradiol. If the solution with ethinylestradiol is crashing out as an oil/solid wouldnt the solution with glucose do the same?

Sorry that i forgot to mention that I had also done a test mix with glucose.

[Yggdrasil]

Glucose is very hydrophilic (polar) whereas ethinylestradiol is very hydrophobic (non-polar).  They will have completely different solubility properties.

[tyro89]

Glucose is very hydrophilic (polar) whereas ethinylestradiol is very hydrophobic (non-polar).  They will have completely different solubility properties.

But shouldnt this problem be overcome by the fact that the ethinylestradiol was mixed with methanol prior to entering the agar/water solution?

[Yggdrasil]

No, that just makes it so that you can add the ethinylestradiol as a solution instead of a solid.  My suggestion would be to add the ethinylestradiol slowly while mixing.  Also, if you still see solidification, try putting it into a 60 C water bath to see if you can remelt the agar.

[tyro89]

No, that just makes it so that you can add the ethinylestradiol as a solution instead of a solid.  My suggestion would be to add the ethinylestradiol slowly while mixing.  Also, if you still see solidification, try putting it into a 60 C water bath to see if you can remelt the agar.

All mixes were made in a 60C water bath but the rate that the two solutions were put togheter was not slow. I will try to add slower to see if there is a change in results. As a final question to this: how come 1/2-3/4 of the solution turns solid when the amount of ethinylestradiol in methanol is about 1:60?? (1mL of methanol with ethinylestradiol added into 60mL of agar and water)

Thanks everyone for helping me out it is really appreciated!

[agrobert]

1/2 to 3/4 is qualitative not quantitative.  At this point something is crashing out whether it be ethinylestradiol or agar solution you don't know.  Their solubilities are different and dependent on concentration.  I would suggest trying ethanol instead of methanol or figuring out another bicompatible system.