darel
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DMSO shelf life
I purchased a lot of DMSO bottles. Look really old. Owner said they were brand new just sitting around, didn't know how long. It doesn't smell at all.
Don't want to taste test. I did find this article
http://www.arkema-inc.com/literature/pdf/360.pdf
Looks like the stuff will last a long time without much degration. But other forums and papers say it will only last a few months. Howlong does it
really last. What kind of test is there for measuring purity besides specific gravity?
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JohnWW
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I have a 500 ml amber-glass bottle of the stuff that I purchased several years ago, thinking that, diluted with water and applied on a cloth, it might
cure arthritic pain, as has been reported. I still have it, practically unused.
I also have a phial containing, as a yellow powder, the complex formed by acidified FeCl3 solution with DMSO, which I made in an university lab class
over 40 years ago, and in which half the Fe(III) is present as FeCl4- and half is present as a DMSO complex cation. I held onto it because the two
types of Fe(III) present in the compound would make it a very interesting subject for Mössbauer spectroscopy; there would be two distinct sets of
gamma-ray recoil peaks.
[Edited on 16-8-09 by JohnWW]
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unionised
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DMSO is fairly stable. If the reaction described on that web page had happened to any meaningful extent you would be able to smell the mercaptan.
You can measure the freezing point to get an idea of the purity (and also, if you remove the stuff that doesn't freeze, you can purify it that way).
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entropy51
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My DMSO is over twenty years old and it works in several preps just like the journal articles say it should. Mine is stored in a cool dark place, as
should all chemicals be.
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Formatik
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about 2 years
Good shelf life is 2 years according to Sigma Aldrich. Injectable DMSO also has a label on it saying not to use after 2 years. The German wiki states
after prolonged storage DMSO possess a foul odor (like that of dimethyl sulfide). I have stuff it's like over 5 years old and it indeed has such a
malodor to it (unlike the light-oyster type smell of the pure stuff). General storage directions state to store it in tightly-closed glass containers
around room temperature to protect from moisture (it's strongly hygroscopic), and store it out of light. Light probably decomposes it.
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hodges
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I have some DMSO that is around 4 years old. It was stored in a dark location inside, so not much temperature variation. It has only a weak odor,
probably just DMSO itself. Just tried putting some in the refrigerator and I did find a small portion of it did not freeze - likely this is water
absorbed from the air. So it seems to me at 4 years under good storage conditions it is still in pretty good shape (other than some water
contamination).
Hodges
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Formatik
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In my years old sample, there is definite dimethyl sulfide odor. The cabbage-like stench of sulfide compared to several month old DMSO with mild smell
is like comparing apples and oranges.
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