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Purity problems in DNA extracted from stool samples - (Oct/18/2012 )

Dear all,

I would like to ask whether nobody has had the similar problem I´ve had with the DNA I extracted from rats stool samples.
The problem is that these animals have been supplemented with phenolic compounds and when the DNA is extracted from their stool samples even if the ratio 260/280 is admissible (aprox. 1.8-1.9) the 260/230 is too low (0.7-0.9) (I suppose it could be because of the phenolic contamination), when compared to the ratios that I obtain from the samples which have not been supplemented.

In addition, when I performed the PCR with these samples, the results are worst than the results I get with the samples obtained from rats that have not been supplemented.

For the DNA extraction I use QIAamp DNA Stool Mini Kit, so my question is whether you could advice me about any possible alternative/solution, or if someone has had the same problem, the way he/she solved it....

Thank you very much in advance for your help,


Try some butanol cleanup protocols designed originally for samples from Trizol.
For example his one is used for RNA, maybe there won't be differences.


and could be used for DNA? I will have a look at it.
Thank you very much


Seems so.