RNA preps - looking for suggestions

[Bernard Murray]

In article <357C8CAB.292C at science.uottawa.ca>, mbeyers at science.uottawa.ca wrote:

> Theo Thijs wrote:
> > 
> > If you don't care about the RNA yield why don't you try TriZol buffer?
> > 
> 
> Well, actually, I do care about the yield and I've tried Trizol and such
> in the past.  Recalling that a perfect RNA sample should have an
> A260/A280 ratio of about 2.0, I've done no better than achieve 1.4 with
> Trizol.  However, the prep I'm using ALWAYS gives me 2.0 +/- 0.02.
> 
> So my conclusion is that, to save two extra pipetting steps, people are
> paying huge amounts of money for the convenience of Trizol.

I don't think home-made Trizol is that expensive (you're just paying
for the guanidinium and phenol mainly).  I agree that the ratios can
be suspiciously low at times but the RNA looks good on a gel and
probed bands are generally nice and sharp and this is what counts.
     I also agree that one method does not necessarily fit all (although
Trizol comes close) so by all means stick to what works.
     For high speed spins (eg. up to 20 k rpm) in Sorvall or Beckman rotors
I use plastic (polythene?) tubes from Sarstedt and these are nuclease
free and phenol resistant.
     Bernard
-- 
Bernard Murray, PhD
Dept. Cell. Mol. Pharmacol., UCSF, San Francisco, USA