Keeping water out during freeze precip

[CultiV8]

Hey guys, I've had a really hard time getting crystals as of late. No matter the steps I go through to make the pyrex dish airtight, ice crystals form and then melt, leaving a mix of water and goo instead of nice dry crystals. I've tried covering the dish with multiple layers of plastic wrap secured by a rubber band, plastic wrap with ziplock bags, putting the dish inside a larger plastic dish with an airtight seal, and most recently three ziplock bags with a dessicant packet in one of them. Ice crystals every time.

How do you avoid condensation and ice crystals forming in the freezer? Or what am I doing horribly wrong? Thanks everyone!

 

[Transform]

mgs04 talk to me more about this please

MgSO4 Anhydrous magnesium sulfate. Made by heating Epsom salts in an oven at 180°C for an hour or more. It will melt into a hard lump, so you have to be prepared to smash it up somehow, and you'll need to line your oven-proof dish with aluminium foil. Once dried like this, it will act as a dehydrating agent for a wide variety of solvents, with a number of caveats and exceptions.

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Post in thread 'Keeping water out during freeze precip'

Oct 21, 2016

magnesium sulfate (heptahydrate) is epsom salt, and doesn't alter the pH to any significant extent in a nonpolar solvent with residual water. microwave it for 5-10 mins on high to dehydrate, same for baking soda (microwaving or baking decarboxylates it to sodium carbonate). sodium carb is typically used as a 5% solution (5g in 95mL water) to wash the nonpolar phase in the sep funnel, prior to separating and freeze precipitating.

for drying the nonpolar, I always go with epsom salt. calcium sulfate is another effective one

• benzyme