Autoclave Guanidinium Isothiocyanate?

M. Frank mr-frank at
Tue Jan 24 12:25:25 EST 1995

meyerdj at (David J. Meyer) wrote:
> In article <3fm4ma$5n9 at>, "M. Frank" <mr-frank at>
> wrote:
> > Another person in our group here swears that guanidinium isothiocyanate
> > needs to be autoclaved before use in RNA extractions. None of the 
> > procedures I have seen (maniatis, chrigwin, chomczynski, etc) mention
> > this, and usually recommend filtering the buffer instead. What's more,
> >  I've heard that autoclaving GuISCN will decrease its activity as a
> > chaotropic agent. Is this in fact true? If it is, is there any way to 
> > "regenerate" the GuISCN buffer or does Dave need to trash this batch,
> > and make another?
> > 
> > Thanks
> > Michael R. Frank
> > Plant Biology
> > Univ. of Illinois, UC
> > 
> > 
> > "Things fall apart, it's scientific!"
> You probably have more RNase activity in your tissue sample than you have
> introduced from your (freshly distilled, or autoclaved, or DEPC'd) H2O,
> stirbar, beaker, etc. The whole procedure is only as clean as the dirtiest
> part, so I don't worry too much about it. I've even seen people grab
> glassware from the cabinet to make their sol'ns, and they never had
> problems.
> -- 
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> David J. Meyer
> Department of Biological Chemistry
> University of California-Los Angeles
> meyerdj at

Thanks, Dave, but that wasn't the original question. The question was simply: 
Does autoclaving guanidinium isothiocyante-based buffers harm them
in any way? If anyone really knows, we are still waiting for a 
definitive answer. We realize that autoclaving the buffer is redundant, 
but already having done so, CAN THE BUFFER STILL BE USED? Several 
people have said yes, several have said no, but no one has been able to 
offer data, references, or even a good chemical explanation to back up
their position.

Michael R. Frank

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