Since water boils at less than 100oC, you may have problems with 
antigen retrieval (try recording the temperature when the water is 
boiling- it can be as low as 96oC!). If you replace the water in the 
water bath with oil or PEG (Can't remember the exact solution), you 
can obtain a temperature higher than 100oC. This should give you a 
chance of consistent antigen retrieval.

This was a trick we used when we used to do the protein binding 
radioassay for B12 and folate many years ago (in my biochem days)

Regards,   Tony

.
Tony Henwood
Senior Scientist
Anatomical Pathology
Royal Prince Alfred Hospital
Sydney, AUSTRALIA

http://www2.one.net.au/~henwood
http://www.pathsearch.com/homepages/TonyHenwood/default.html