[3dem] Precipitation observed after making freeze substitution cocktail containing 5% water

[Christopher Peddie]

Hi Qiaohui,

Mix the osmium, water and acetone and cool to -20oC. Then add the uranyl acetate from a stock e.g. 20%. Cooling the mixture in my experience stops the uranyl acetate from precipitating out.

Best,
Chris


From: 3dem [mailto:3dem-bounces at ncmir.ucsd.edu] On Behalf Of Qiaohui Yang
Sent: 19 December 2019 08:39
To:
Subject: [3dem] Precipitation observed after making freeze substitution cocktail containing 5% water


Hi everyone!
We recently tried to make freeze substitution cocktail consisting of 1% osmium tetroxide, 0.1% uranyl acetate and 5% water but observed that the mixture turned slightly cloudy within 1-2 minutes. We tried to see if the precipitation would occur in the absence of osmium tetroxide, and we observed some cloudiness too after mixing uranyl acetate solution in water with pure acetone.

Just wondering if anyone has encountered similar problem and if so, would appreciate some tips on how to overcome this problem.

Thank you!



Best regards,

Qiaohui


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