Biomaterialist
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Registered: 25-4-2011
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DIY: Freeze drying?
Hi!
I am wondering if anybody has some suggestions on how to do a DIY freeze drying process. I have a strong pump which I use to vacuum dry reagents and
products and I also have access to nitrogen, but have no clue how to do some lyophilization shenanigans.
Any comments are highly appreciated!
Other info: I want to freeze dry around 50 mL total of water from some peptides and cellulose like materials that are sensitive to high heat (in case
any wonders why i do not use rotatory evaporation).
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The WiZard is In
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Id The Analogue Guy shelves —
Rolland O Hower
Freeze-Drying Biological Specimens: A Laboratory Manual
Smithsonian Institution Press
1979
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Saerynide
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Hook up the vacuum pump to a cold trap (LN2 or some kind of freezer) to the thing you want to freeze dry. If using LN2, be sure no air gets in, or O2
will condense in your trap  To be extra careful, no freeze drying of organic
solvents!!!
We were about to do this in our lab when our freeze drier broke down, but I kind of chickened out (I don't want to see any pretty blue liquid  )
I think in theory, you should be able to freeze dry without the trap, provided you have a powerful enough pump and dont mind all the water vapor going
through the pump... but I didn't manage to get it to work - I guess I couldnt pull a hard enough vacuum fast enough?
Make sure you freeze the living crap out of your sample (-80 is ok, -196 is better  ). If it melts and the vacuum breaks, you're screwed and your sample will be all over the place  happened to me too many times....
[Edited on 6/28/2011 by Saerynide]
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franklyn
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If time is not important such that you don't need the processed item yesterday
a normal frost free refrigerator freezer will dry out an item over a period of a
month or so. I did this with a pealed potato and when I removed it from the
ice box it had been lightened significantly and resembled high density foam.
I still have it outside on top of the refrigerator after 3 years and it has not
changed at all in appearance.
.
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Saerynide
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WOW.... now putting food in the freeze drier is something I've never tried (my lab would freak if they found vegetables in there lol) Did you taste
it? Freeze dried icecream, pizza, and strawberries all taste like styrofoam to me
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satisfy any applicable law, regulation or legal process"
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chemoleo
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Peptides, proteins, biomaterials and such things are usually freeze dried by first freezing the aqueous sample (i.e. <50% volatile solvent, such as
acetonitrile) in N2(l). Then it is placed into a vacuum flask, and attached through a manifold to the electric cold trap (which cools to -110C when it
contains common solvents, or -50C if only H2O). A high vacuum is applied (0.1 hPa), and two days later a 20 mL sample will be freeze dried to a
powdery residue.... surface area of course matters here.
You can buy cold traps, but they are worth $8 k or so. Depending on the make.
Good luck!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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