It is probably possible, you should check DMSO's phase diagram. However, do you want to stay friend with your colleagues? DMOS stinks (and it will condensate on the cold trap, how will you remove that without contaminating the lab?) plus I would be very worried about effects on the pump (an extra cold trap before the pump?). What about using a speedvac instead, at least it is built with aggressive solvents in mind.

I think

D.H. Rasmussen, A.D. MacKenzie Phase diagram for the system water-dimethylsulfoxideNature (London), 220 (1968), pp. 1315–1317

might have relevant information (at least a phase diagram, no idea about the sublimation efficiency) .

Catherine

Thank you Catherine. Not sure if we have a speedvac but sounds like the freeze dryer might not be sensible... Given it's only 200uL, I was thinking I might get away without too much effect on the equipment itself, but maybe best not to chance it! I'll see if my cells can tolerate the DMSO by itself.

Thanks

Ben

Dear Ben, 

You can freeze dry your sample as long as you get rid of the DMSO. As Catherine says it will contaminate the pump (unless you have a cold trap before the pump). Do you have access to more sample? If so, then just go ahead (don't waste time or risk endangering the work environment because of your accident). If your sample is precious and unique, and have access to speedvac then try that option. If not, try eliminating the DMSO by a number of other strategies, for instance dialysis, gel chromatography, before concentrating your sample by freeze-drying. Hope this helps,

Ana

You may be able to use C18, like in a Waters Sep-pak cartridge, to remove the DMSO.

If you have a large amount of sample, a small column  might work too. I once had to submit a sample in DMSO-D6 for NMR and wanted to remove the DMSO for other work, so I wrote the app note linked below.

http://www.isco.com/WebProductFiles/Applications/101/Application_Notes/AN97_Removal%20of%20Non%20volatile%20Solvents.pdf

Be careful with the speedvac. Back when I was a grad student, we destroyed the lid to a speedvac by drying out of DMSO. I don't know if they've changed the materials to be more stable to organics since.

freeze drying is the way to go. But my suggestion is you have little amount of DMSO (200 uL) so I will advice you to add water (disltilled) to it and use evaporator dry (use this method only if addition of water can not affect your samples). 

The boiling-point of DMSO is 189°Celsius. So, lyophilization may take a longer time than with water. Do simply try small DMSO "blanks" in your lyophilizer. If they disappear, you can lyophilize your samples.

Would it be possible to aliquot into a small volume and then let it air dry

 DMSO can definitely be evaporated in a freezedrying, its freezing / melting point is as high as 19 degrees C, if the condenser is good it should  not contaminate the oil 

Ben - you can, but ... take care!

If you have one sample at 200ul then you're more than likely to get away with it.  If you have a whole lot, so more than 200ul then you need to take a good deal of care for the freeze dryer.

The freezing point of DMSO is high, as previously mentioned.  But deliquesence means that DMSO is rarely every pure, although some water in there can help the freezing it may not help your sample.  The key in freeze drying, is the vapour pressure of DMSO, which is really low, you need to get way below 100mTor to get DMSO to boil below it's freezing point.  You also really need to have a frozen shelf in your dryer to keep the sample frozen, else ambient heat (DMSO only has 1/3 the heat of vapourisation of water) will melt your DMSO.  You need to make the parts of your system HOT so that the DMSO only condenses in the condenser, and not all over the door, gaskets, drum, etc.  Then there is the material compatibility of all the dryer components with DMSO - which is generally poor for polymer rubbers.

As I say, one or two small samples, you should get away with it, if you are doing this routinely with more samples then you need dedicated equipment else the hardware owner will becomre cross with you quite quickly!   BioPharma Process Systems in Winchester can help in UK, they also have a freeze drying research arm too.

Best

Rob