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Alcohol, Alcohol, Alcohol, Alcohol

I was working at my lab bench last night and thought it was interesting how many alcohols I use regularly. The alcohols are all small (4 carbons or less), but each plays its own unique role.

The 50% methanol and 5% methanol are used for fixing protein gels.

The 1-butanol is used to even out the top of (and remove bubbles from) hand-poured acrylamide gels. It gets added in small amounts directly to the top of the gel. I have taped a small transfer pipet to the side to facilitate this.

The isopropanol is used to precipitate DNA. A 40% solution of isopropanol added to a mix of salt and DNA will bring the DNA out of solution (but leave the salt in solution, thus purifying DNA away from the salt).

The 70% ethanol is used to wash the precipitated DNA in order to remove the isopropanol. This is done because ethanol evaporates faster than isopropanol, allowing a quicker purification of the DNA. The 70% ethanol is also used to disinfect external surfaces of possible bacterial contamination.

The 40% ethanol solution, on the other hand, is recommended for disinfecting internal surfaces. I prefer my solutions of 40% ethanol on the rocks.

The 100% ethanol (also called absolute ethanol) is used for making the other stock solutions of ethanol. It can also (like isopropanol) be used to precipitate DNA. And finally, in extreme circumstances, it can be used to "supplement" the 40% ethanol solution for days that would just be too hard otherwise.

If you are from OSHA or from the University Radiation Protection office, please note: I would never consume beverages of any sort in the lab. In fact, the photos above are all simply clever photoshopped collages. I beg of you: don't take away my funding!

Comments

  1. Ana10:54 AM

    My goodness.

    ReplyDelete
  2. jackflak11:03 AM

    Do you ever have occasion to use Kessler's?

    ReplyDelete
  3. J. Michael Andresen1:33 PM

    I have not yet had the occasion to use Kessler's. I shall have to give it a try the next time I'm in a laboratory supply store.

    ReplyDelete

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