how to make nuclease free water ?

Bernard Murray, PhD spam at
Tue Jul 11 16:08:02 EST 2000

In article <8kfetl$sgc at>, "Kunal Mukhopadhyay"
<kunalm at> wrote:

> MilliQ system works pretty well to make sure your water is pure.
> Also, make sure your glassware/eppendorfs/all material in contact , is
> autoclaved and clean.

Ummmm... no.  All plasticware straight out of the bag is essentially
nuclease free so keep a bag specifically for nucleic acid work and
only go into it with gloves on.  Don't autoclave glassware or spatulae
or whatever as this does not kill RNase and can actually contaminate
your material from that brown residue on the inside (usually a nice
source of lysed bacteria).  Instead, *bake* it as long and as hard
as you can.  Some colleagues favour proprietary decontaminating solutions.
For cleaning gel boxes, trays and combs I've used hydrogen peroxide
as per Sambrook et al.

One (obvious) comment about "pure" water systems is to make sure they
are clean.  If the exit pipe is turning green (I've seen that)
then take it off when collecting clean water.  Also make sure the
resistance is about 18 M-ohm as when the purity starts to die off
it can be due to things growing in the cartridges (I've seen that
as well) - bleach the outer containers when you change them and
flush the system well.


Bernard P. Murray, PhD
bpmurray at cgl . ucsf . edu
Department of Cellular & Molecular Pharmacology, UCSF

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