water in experiments

Bernard Murray spam at
Wed Sep 22 02:09:20 EST 1999

In article <7s9haj$l75$1 at winter.news.rcn.net>, "Marc Andelman"
<drgonfly at ultranet.com> wrote:

> Hi folks. I would very much like to know what researchers think of the
> currently available labortory water purification systems.
> Is there anything that needs improving?
> Can stuff carry over into a still and would cleaner feed water into
> the still be desireable?  How many people use other technology
> rather than stills? Why?

The last few labs I've been in have all used a cartridge system
to purify nominally ("house") deionised water.  If the
resulting resistance is >18 Mohm it is considered pure
(unless we suspect contamination by organics).  From brief tests
the water is also RNase and DNase free.
   On one occasion I found that it was impossible to perform
a particular assay (sensitive assay for reduced glutathione)
using still-purified water as contaminants caused too much
spontaneous oxidation (EDTA could not cure it) whereas using
cartridge-purified water the assay ran beautifully.
   The only improvement I could think of would be in price
(but that would improve just about any product :-)  ).


Bernard P. Murray, PhD
Department of Cellular & Molecular Pharmacology, UCSF

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