Re microwave processing

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From:a i d a n s c h u r r <>
To:Clarke Ian <>,
Content-Type:text/plain; charset=US-ASCII

Hi Ian,

The microwave energy should dramatically speed up the fixation 
process for formalin.  In aqueous solution formaldehyde exists 
mostly as methylene glycol, in equilibrium with monomeric 
formaldehyde.  The microwave energy actually forces the 
equilibrium back to the left, creating dramatically more free 
formaldehyde (the bit that actually does the fixation).  The net 
effect is that you should be able to fix a bit of tissue as you 
describe in about five minutes... the trick is to be patient enough to 
allow the formalin to penetrate the tissue - this you cannot speed 
up with the microwave!

Hope this is some help.


>                   Could anyone tell  us what the microwave processor is
> actually contributing to the finished block.We think that all we are using
> the microwaves for is as a means to quickly heat up the dehydrating
> solutions and wax as we have not seen any effect on fixation .We are in the
> process of just heating the solutions and adding the block to them for the
> same time they where in the processor to see if this would give us the same
> results.
>               I would appreciate any thoughts people may have on these
> findings and any recent papers on the subject.
> Ian Clarke
> Histopathology/Cytopathology department
> Craigavon Area Hospital
> 66 Lurgan Road
> BT66 5QQ
> Northern Ireland.

shin: device for finding furniture in the dark...
a i d a n   c   s c h u r r 
     mlso,  histology department
      hutt valley health
       lower hutt, new zealand

     ph.  ++64 4 5709173
     fax  ++64 4 5709214

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