generally the aqueous extracts cannot be dried easily, only way is to keep in lyophilizer. So can anyone tell me shall I process my extract with liquid N2 and keep in lyophilizer?
What we typically do with the liquid when we need it to be lyophilized, is that we freeze them first in a vessel. Make sure the vessel can sustain your liquid turning to ice. Some of ours did not... Anyway once it is a block of ice lyophilize it such as you do with the solid samples...
I think you could use the way with liquid N2 if you do not want to wait for the extract to freeze in the common freezer...
Leelavanthy, I think you just answered your own question. Freeze-drying (Lyophilization) is the best way to dry a liquid material, especialyl if it contains heat sensitive materials.
I have used 100 µBar (10 Pa) at room temperature before, and condenser surface temperature -40°C. The low pressure is sufficient vacuum to cause sublimation and the room temperature will cause the needed heat transfer (energy) to support moisture evaporation needed in the drying process.