Re: aliquoting 4% formaldehyde

Posted by Michal Opas on
URL: http://confocal-microscopy-list.275.s1.nabble.com/aliquoting-4-formaldehyde-tp7585663p7585674.html

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Now:
Formaldehyde: did he wonder why people routinely report 3.7% concentration as a fixative? 
"People" have been buying formaldehyde solution from a NNN company, which is 37-37% in water and dilute it 10x. Commercial product has methanol added to prevent polymerization. Store at room temperature.
People who wanted to invest work in having clean fix (formaldehyde soln has contaminants) did not freeze fix but invested work in preparing a fresh fixative (usually 4%) from parafomaldehyde powder for immediate use. No freezing again.
I hope this helps.
Michal

On 20/09/2016 10:34, Cromey, Douglas W - (dcromey) wrote:

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I was talking with a student yesterday about their cells which did not look particularly good under the microscope. The discussion eventually came around to fixation. The student told me that he made up some 4% formaldehyde fixative and then froze back (20 deg C) aliquots for later use. This was something he had seem on an online research forum. In my fairly lengthy experience I have never heard of this being done and I am suspicious that this is NOT a good idea. Thoughts?

 

Doug

 

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