When I use freeze-dryer, after freeze at -80C for 5 or 7h, drying it but there are always sample loss after drying, some of the dried sample get out of the glass tube. How to avoid the loss?
Dear Yuan,
If you see loss because the sample sticks to the sides of the vessel - and it will not easily be taken out with a sample spoon- then this means that it is not fully dry if it is sticking - longer secondary drying time will be needed.
If you see sample loss during the cycle because of mass flow out of your vial / flask or bumping - then you need to revisit the cycle design. There are many tools or people to do that.
Kind regards,
Rob
Cover the tube with Parafilm, and poke several small holes in the film. This will help to keep the sample in the tube. Some of it may be stuck to the film.
Dear Xiaofang Yuan,
I completely agree with Adam B Shapiro. I used to use it regularly.
Dear Adam, I have tried parafilm, but the sample is attached to parafilm, then it is hard to sepearte sample from parafilm.
Dear Yuan,
It sounds like you have an agressive cycle which is blowing the dried powder about, and / or, there is a build up of resistance in the dry layer, and the drying layer underneath is blowing the dry powder on top - out of the tube. "Blow out". There is a good introduction to freeze drying to be found here:
http://www.spscientific.com/ArticlesAndTechnicalPapers/
Look for the "Basic Principals of Freeze Drying" paper by John Barley.
Kind regards,
Rob
hi, Cover the tube with filter paper
You can also use aluminum foil and poke several small holes in the foil.
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