Oligo stability in water at -20 C

Richard J. Dudley rjdudley at YAHOO.COM
Wed Aug 12 10:17:46 EST 1998


> Pure water is pH 7.0 by definition.   (Equal concentration of H+ and
> OH-).  If your pH meter reads 6, then it is the pH meter that is
failing,
> not necessarily the water.  And I will add that most pH meters
cannot give
> a precise reading in such weakly buffered conditions, so do not feel
that
> you have an inferior product!

The definition is true; however, Milli-Q is not "pure by definition"
water.  There are dissolved gasses (e.g., CO2, N2, O2).  CO2 is of
special importance, since it does play a role in buffering water (and
your blood) with the carbonate-bicarbonate buffering system.  The mere
act of retrieving water from the Milli-Q tap intorduces CO2. 
Adidtionally, I don't think that Milli-Q (or other deionization
systems) scrub protons; they are more geared for nitrates, sulfates,
etc.

rich
==
--- --- --- -- -- -- --- --- ---
Richard J. Dudley (rdudley at iname.com)
Research Specialist V
Dept. of Cell Biology and Physiology
The University of Pittsburgh
->biosci archives can be searched at www.bio.net <-

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