Chromatogram - 15-5-2012 at 20:47
I know, I still have to finish my first project but I'm already conceiving of another. A DIY lyophilizer. This seems quite conceivable. A vacuum pump,
a dry ice box with condenser, hoses, flask, and stopper/cork. It seems to easy to be true? Is it really that easy?
sargent1015 - 15-5-2012 at 20:59
You are going to keep it cold with dry ice?
Chromatogram - 15-5-2012 at 21:26
I was thinking of cooling the condenser, to keep solvent off the pump, with dry ice. Not cold enough? I'm not sure what temps I could reach with dry
ice but I know we store it in an Ultra-Low. Liquid nitrogen instead?
ziqquratu - 16-5-2012 at 01:02
We made one that I think worked OK. All a lyophiliser requires is, as you suggest, a sealed container, a high vacuum source, and a condenser. We used
real lyophiliser jars (although any vacuum safe jar would do!), connected by vacuum tubing to a well-greased trap immersed in liquid nitrogen, which
in turn was connected directly to a high vac pump.
We froze the samples in liquid nitrogen (we were using water/acetonitrile mixtures - our biochemists were drying protein samples), placed them in the
jars, put them under vacuum... The only thing to be conscious of is making sure you look after the pump - change the oil regularly, make sure the trap
is always filled with nitrogen, etc - otherwise the pressure will be higher and the thing won't work (which is true of real lyophilisers, too!).
Just to answer your final point - dry ice goes down to around -78 °C (most commonly used as a bath with acetone). I've never done it, but I believe
it's cold enough to use for a trap (we always use liquid nitrogen on ours, though).
sargent1015 - 16-5-2012 at 07:22
-78 is good to any degree, but if you are freeze drying stuff you will have to constantly be filling the condenser with dry ice for the reason
ziqquratu mentions. Not necessarily a fun endeavor.