Autoclave Guanidinium Isothiocyanate?

David J. Meyer meyerdj at
Fri Jan 20 15:36:54 EST 1995

In article <3fm4ma$5n9 at>, "M. Frank" <mr-frank at>

> 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


David J. Meyer
Department of Biological Chemistry
University of California-Los Angeles
meyerdj at

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