The meting point of PEG 1000 is around 38C. Obviously, if Sigma has
heated the batch to fill the bottles in the first place this is a futile
exercise... I'd ask them first.
Flip
Vellieux Frederic wrote:
R.Srinivasan wrote:
Dear All,
I have got initial crystals in a condition with PEG 1000. The
PEG 1000 stock we had in our lab was rock solid and when i heated it
to about 50 degrees for 15 to 20 minutes it became a solution. We
thought the compound has got out dated or something like that and
bought a brand new bottle from Sigma and this is rock solid too.
Is this something characteristic of PEG1000? The hit condition
says its 12.5% w/v PEG 1000 but it apparently seems i could never get
a powder of it.
So my question is, Can i go ahead using this melted solution
form of PEG1000 for setting up optimizations?
Thank you all in anticiaption,
Vasan
All higher molecular weight PEG's are solid. Some are stored as flakes,
but as you mention some are rock solid. And it's very difficult to get
them out of the container (breaking the bottle is sometimes necessary).
What I would go for personally would be mechanical grinding because I do
not know what happens to the PEG when it's heated to 50 deg or higher.
But perhaps you could take your bottle, cut the content in half, make a
powder out of the one half and use the other one with this heating
method and see if there are any differences. Or else if you happen to
have an analytical chemistry service at hand, provide them with a small
sample of each of the 2 and ask them to check if there is any difference.
Fred.
