RNA isolation / purity

fabio fabio at fabius.it
Sun Dec 19 16:17:29 EST 2004

seg ha scritto:
> Hello!
> IŽve a question concerning the purity of isolated RNA:
> What about the ratios A260/A280 and A260/A230?
> Should they be as high as possible or do values for A260/280 of above 2.1 
> and/or values of above 2.4 for A260/A230 indicate contamination, too?
> What ranges are the best for each ratio?
> best regards
> Jo 
A260/280 ratio display less variability at pH8 than 7, so it might be 
useful to evalute nucleic acid molar extintion coefficients at the 
higher pH.
Instead to use TE it's better 1-3 mM Na2HPO4 buffer at pH 8,0-8,5 
becouse you can treated it with DEPC.
Good ratios are from 1,7-1,8 to 2,2 (I have never seen more than 2,2).

Fabio Di Benedetto
Laboratory Technician

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