yellow isopropanol

Alan Smith alansmith at
Sat Jan 26 17:41:47 EST 2002

It could also be pigments present in your sample.  I have performed many
extraction using TRIZOL and have never encountered yellow IPA (isopropyl
alcohol) under normal circumstances. I have noticed yellow-brown
pigmentation of IPA in tissue from senescing plant leaves most likely do to
various plant pigments. When isolating RNA from tissue high in anthocyanins
i notice a red color most likely associated with the pigment dissolving in
the IPA.  So tissue pigments may be one possibility and the other may be the
breakdown of guanidine thiocyanate.  If your TRIZOL is well over a year old
or has been stored incorrectly this may be a problem.  But i am not sure if

Alan Smith

-----Original Message-----
From: owner-methods at
[mailto:owner-methods at]On Behalf Of "Wolfgang Schechinger"
Sent: Saturday, January 26, 2002 8:22 AM
To: methods at
Subject: Re: yellow isopropanol

Probably some reaction product of thiocyanate.


> ...when precipitating RNA using isopropanol (Trizol method) the
> turns light yellow after about 20 minutes at room temp, and becomes dark
> (along with the RNA pellet) after a few hours at -20 deg.
> Why is this?
> Ty

Dr. Wolfgang Schechinger
Institute of Biomedical Sciences
Academia Sinica, Taipei, Taiwan R.o.C.



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