[3dem] contamination in cryo samples

[Morgan Beeby]

Nadav,

We have recently had similar contamination problems.

Although it sounds as if you've already tried alternative holders, hor 
us, we (after a lot of troubleshooting!) found that switching from our 
Gatan 914 holder to a Gatan 626 holder solved the problem. We don't yet 
have a rationale for why this worked, yet, unfortunately. Gatan suggest 
that the spring clamp on the 914 may need replacing and we hope to do 
this ASAP.

best,

Morgan



On 01/09/2016 10:00, Nadav Elad wrote:
>
> Dear all
>
> We are having a serious contamination problem in our cryo preparations 
> and would be grateful for any suggestion. Although this issue has been 
> discussed in the past in this forum, the solutions raised do not seem 
> to work. The attached image shows the contamination on a bad day. I am 
> referring mainly to the lighter, smaller particles (10-20 nm) which 
> are the most persistent. They seem to be above or below the ice layer 
> and are the first to evaporate under the electron beam. The 
> concentration of contaminants is variable.
>
> We are using a Leica EM GP plunger for freezing, and Tecnai T12 and 
> F20 microscopes with Gatan side entry holders. We have tried to 
> replace the ethane cylinder and are in the process of ordering a third 
> one, cleaning the glow discharger machines, different cryo holders, 
> different cryo-transferring units and grids of varying sources. There 
> seems to be no leaks in the compustages of the microscopes.
>
> Thank you for your help
>
> Nadav
>
> --
>
> Nadav Elad, Ph.D.
> Electron Microscopy Unit
> Weizmann Institute of Science
>
> Rehovot, Israel
> Tel: +972 (0) 8 934 2115
>
> Mobile:  +972 (0) 52 3909 420
>
> Email: nadav.elad at weizmann.ac.il <mailto:nadav.elad at weizmann.ac.il>
>
>
>
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-- 
*Morgan Beeby* | Lecturer in Structural Biology
Department of Life Sciences
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Imperial College London
South Kensington Campus
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