RE: [Histonet] isopropanol as dehydrating agent in microwave processing

From:"Charles W. Scouten, Ph.D."

Are you familiar with the Pelco Neurowave?  It is a quite different product than the kind of microwave written about in Kok & Boon.   A circulating coolant keeps the contents from getting warm, and absorbs microwaves before a standing wave develops.  Sounds like it does nothing (a microwave oven that doesn't heat) but I have seen really sharp results out of it.  When an IHC sample is split, and run through a protocol that is 10% as long as standard, but half in and half out of the microwave, the difference is dramatic.  The microwave sample is better than conventional, the non microwave sample is not noticeably stained.

Charles W.  Scouten, Ph.D. 
5918 Evergreen Blvd. 
St. Louis, MO 63134 
Ph: 314 522 0300  
FAX  314 522 0377 

-----Original Message-----
From: John Kiernan [] 
Sent: Tuesday, September 23, 2003 12:06 AM
To: pooja chopra
Subject: Re: [Histonet] isopropanol as dehydrating agent in microwave processing

For almost all applications in practical 
histotechnology you can use isopropanol
instead of ethanol. Both these alcohols
mix similarly with water and with clearing
agents such as xylene or chloroform.
Neither ethanol nor isopropanol will mix with
solid or melted paraffin wax. 

In some microwave processing techniques, 
specimens are moved from isopropanol into wax.
The microwave heat is said to evaporate the
isopropanol and allow infiltration with wax,
without the need for an intermediate solvent.
This method is recommended in Kok & Boon (1992)
Microwave for Microscopists, 3rd ed. There was
some heated Histonet discussion about all this
in the late 1990s. Some of it may still be in
the archives:

For a thesis on microwave processing you will 
need a copy of Kok & Boon's book as a starting
point, and you will need to follow up their
references. If your library subscribes to
Web of Science you will be able to find recent
papers that cite earlier papers and books.
Without access to Web of Science it is impossible
to find out if someone else has recently done
and published your intended research.

Hope this helps,
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
pooja chopra wrote:
> Dear Histonetter,
> I am a new user of this email group. I am a resident doctor doing my thesis
> research on microwave fixation and processing in a moderately funded
> government laboratory in India. I am using a domestic microwave oven, as a
> lab oven is not affordable.
> I have been able to use only isopropanol (IPA) in the microwave processing
> schedule as it is very difficult to get license for ethanol in India. I have
> read lots of discouraging things that IPA should not be used as dehydrator,
> even in microwave method. I would like to hear from someone, regarding
> whether there is any way of making use of IPA both as dehydrator and
> clearing agent.
> Thanks,
> Pooja Chopra

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