Formaldehyde RNA gels.

Steven Sullivan sullivan at
Mon Mar 27 00:11:02 EST 1995

Karl Fischer (kfischer at wrote:
: In article <saleem.18.000F274A at>, saleem at (Dr Saleem
: Mohammed) wrote:

: > From a paper from biotechniques (1993, can't remember the exact details), it 
: > was suggested that 0.22M formaldehyde could be used.  The authors recommend 
: > using 0.22M formaldehyde in the sample buffer and in the gel running buffer.  
: > This helps prevent diffuse ribosomal RNA bands so giving a cleaner picture of 
: > the quality of the RNA.

: Or, as has been posted a while back, you can cast the gel with
: formaldehyde at a final concentration of 0.66M and leave it out of the
: running buffer (Basic Methods in Molecular Biology by Davis, Dibner and
: Battey, Elsevier, 1986). I do recommend using formaldehyde in freshly
: prep'd loading buffer (approx 6.4% final concentration).

The resolutin is much better when you have formaldehyde in the running 
buffer too; that's why the 0.22M method is more appealing.  I'v 
eused both and now use the second exclusively.  

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