Phenol extraction problem/phases not separating

[Pete]

On Fri, 29 Nov 1996, MARLENE SNYDER wrote:

> I am extracting DNA from frog toes collected in lysis buffer 
> :SDS/Tris/EDTA/Sucrose - nothing out of the ordinary.
> 
> I am using a standard phenol-chloroform extraction.
> 
> Most of my extractions work as expected but about 1 in 8 refuses to separate; 
> the lysis buffer and phenol mix.  The buffer is the same in each sample and I 
> don't understand why this is happening.  So if anyone knows why and 
> (more importantly) what I can do to make the phases separate so I can continue 
> the extraction, I would appreciate hearing from you.
> 
> Ian Paterson
> 
In my experience, this may happen when your DNA concentration is very 
high and thus your DNA solution is rather viscous. I would dissolve the 
DNA in a larger volume and make the extraction then.

Pete