pH for RNA work

H. Yim hyim at u.washington.edu
Wed Feb 5 12:40:24 EST 1997


And yet another method:  Buy Trizma  base and Trizma-HCl and keep them
seperate from general lab stock.  On page 1052 of the 1997 Sigma catalog,
there is a table that tells you how much to weigh  out of each to get a
particular pH at a particular temperature.  This way you avoid pH meters,
pH paper etc. Good Luck,  

Harry Yim Ph.D.
Mailstop:CH-32
Dept of Infectious Diseases
Children's Hospital and Medical Center
Seattle WA 98105

hyim at chmc.org  
hyim at u.washington.edu
(206) 528-2767
fax (206) 527-3890


On 4 Feb 1997, George Rutherford wrote:

> In article <5d6fh0$c1k at light.nih.gov>, bernard at elsie.nci.nih.gov (Bernard
> Murray) wrote:
> 
> > In article <v01530501af1be322547d@[130.212.39.77]>, jmorlan at SFSU.EDU says...
> > >
> > >Banwari,
> > >
> > >We rinse our electrode in DEPC-treated water.  Strictly speaking, this does
> > >not make the electrode RNAse free, but we seldom have any problems doing it
> > >this way.
> > >
> > >-John
> > >SFSU
> > 
> > >>Hi!
> > >>While making RNAse free Tris, does the pH electrode have to be
> > >>RNase free for adjusting the pH? If yes, then how do you make an
> > >>electrode RNase free?
> > >>Thanks in advance
> > 
> > I'm a little more paranoid and go through the following cycle;
> > 
> > a) carefully remove a small aliquot from the main solution
> > b) check the pH
> > c) try and adjust the pH of the main solution
> > 
> > until the pH of the solution is correct.  You can start out with
> > testing single drops on pH paper until you are within 1 pH unit.
> > I fully admit this may be a little over the top but the pH meter
> > is shared with a lot of people (and I don't trust any of them).
> > ...at least I have yet to start DEPC treating my NaOH and HCl stocks ;-)
> > 
> >         Bernard
> 
> 
> I'm a bit more paranoid still, and wouldn't bother with the meter;I'd
> stick with pH sticks, especially because meters (even using 'Tris
> electrodes') have never seemed all that accurate to me for pH'ing Tris.
> 
> George
> 
> 




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