Since my crystallization condition contains PEG, I am trying to use PEG as one of my cryo for testing. For example, one crystallization condition is 0.2M Na2PO4, 20%PEG3350. I want to make 0.2M Na2PO4 and 40% PEG3350 as cryoprotectant. When I added 200ul salt from 1M stock, and 800ul PEG from 50% stock, mixed them, seems they stayed as emulsion (confirmed by microscope), no matter how I pipette or vortex them. I tried to incubate it at 40degree, seems it got worse.

I am now trying to re-make the cryo from solid reagent, not solution stock. Will this be helpful? Or is there any other trick?

I will really appreciate!

Best,

Xiao