[3dem] Quality of ethane for freezing

[Ariane Briegel]

Dear Esther, 
we had similar issues a few years back. If I remember correctly,the "pure CP Ethane" label of the ethane changed to  99%  purity, whereas older "pure CP Ethane" was specified  99.5%.
After we ordered a higher grade ethane, there contamination issues disappeared.

We also use an ethane/propane mix in the lab- this mixture doesn't freeze at all and we have great success using it:
An improved cryogen for plunge freezing. Microscopy and Microanalysis : the Official Journal of Microscopy Society of America, Microbeam Analysis Society, Microscopical Society of Canada, 14(5), 375–379. 
Good luck!


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Ariane Briegel, Ph.D.
California Institute of Technology
Broad Center, MC 114-96
1200 E. California Blvd.
Pasadena, CA 91125

Tel: 626-395-8848
Fax: 626-395-5730
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On Feb 1, 2013, at 8:22 AM, Bullitt Esther wrote:

> Hi,
> 
> We have always bought technical grade ethane rather than the high purity.  By the bottom of the tank, the grids have contamination, and so we switch it out.
> 
> This last time, the tank cost half the price, and has been showing contamination pretty soon after we started using it.  Perhaps it is now a lower grade.
> 
> Do people recommend buying the high purity ethane?  My understanding is that it then freezes very rapidly, so one must contend with thawing it often.
> 
> thanks,
> Esther
> 
> ---
> Esther Bullitt, Ph.D.
> Dept. of Physiology & Biophysics
> Boston University School of Medicine
> 700 Albany Street, Room W302
> Boston, MA  02118-2526
> 
> Email:      bullitt at bu.edu
> Telephone:  617-638-5037
> Facsimile:  617-638-4041
> http://www.bumc.bu.edu/phys-biophys/faculty/bullitt
> 
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