[3dem] Contamination problem on cryo grids

[rg2502 at columbia.edu]

Hi Bill,
The type of contamination that the images show is  definitely not  
ethane contamination.  While what you suggest is sometimes an issue,  
Ethane contamination looks much different.  It appears as very high  
contrast and much smaller blobs.  This is more along the lines of  
something that is being deposited with the buffer not after the fact  
as is the case with ethane.
Bob

Quoting Bill Tivol <tivol at caltech.edu>:

>
> On Sep 19, 2008, at 4:41 AM, Anselm Kusser wrote:
>
>>
>>> We are repeatedly experiencing problems with significant amount of  
>>>  contamination on our grids (follow the links to have a look at   
>>> some example images).
>
>> What you are seeing is not contamination, it is what we term   
>> "splotchy ice" which occurs if there are contaminants on the carbon  
>>  causing the carbon to be hydrophobis not hydrophyllic.
>
>
> Dear Anselm,
> 	Another possibility is that there is a contaminant in the ethane.  We
> sometimes see this when the ethane tank is nearly empty.
> Yours,
> Bill Tivol, PhD
> EM Scientist
> Ultrafast EM Facility
> Noyes Laboratory, MC 127-72
> California Institute of Technology
> Pasadena CA 91125
> (626) 395-8833
> tivol at caltech.edu
>
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