Bernard Murray, PhD spam at
Tue Nov 16 16:49:25 EST 1999

In article <38317392.A5C5D0C2 at>,
Frank.Fackelmayer at wrote:

> "Bernard Murray, PhD" wrote:
> > In article <3830525A.A98B327C at>, james stevenson
> > <pcxjs at> wrote:
> >
> > > If its gone yellow, then its decomposed.
> >
> > This is nonsense.  Clear straw-yellow MOPS solutions are just fine
> > (I consider it a helpful indication that it has been autoclaved
> > - although MOPS buffer will turn yellow spontaneously on exposure
> > to air).
> I don´t think it is nonsense to say that the yellow color of MOPS results from
> its decomposition.

Sorry, the original context was that the "decomposed" buffer was unusable
and that was the point I was disputing.  I agree that something must have
changed if the colour is different.  It still acts as a buffer and has
no detrimental effect upon RNA.

> That said, I have to admit that I once used autoclaved MOPS after 2 years on
> the shelf at RT (dark yellow!), and had no problems at all. Apparently
> decomposition only affects a small proportion of the stuff and there is enough
> intact MOPS left....

That was exactly my point.  You can buy commercial MOPS solutions
and all the suppliers I have seen autoclave their offerings so
the solutions are yellow.  I've used solutions several years old
without any problems (stored room temperature out of direct sunlight).


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

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