[Histonet] Grocott's Methenamine Silver Stain

Kathleen Roberts kgrobert <@t> rci.rutgers.edu
Wed May 5 15:47:12 CDT 2004

OK, so I guess I'll get some solid chromium trioxide and make it up that 
way and see if it makes any difference, though if the samples are 
over-oxidized, I may not be able to get anywhere with them...at least 
I'll be able to work it out with the control slides.

Thanks for the reminder about disposal...you reminded me that, since I 
am the chemical safety officer for the lab, that I need to get a list 
together of all the stuff that Rutgers Env. Health & Safety needs to 
pick up and send it over to them.  My to-do list never ends...  :o)

Thank you very much for your help-

Gayle Callis wrote:

>Dissolve 4 gms chromium trioxide in 100 mls of distilled water, a simple
>chemical solution. Chromic acid is a misnomer from years ago, it is made
>from chromium trioxide. I have used 5% but 4% is the norm.  I do use a
>solution for 1 week if I am still doing the stain the next day. 
>Remember you CANNOT dump chromium solutions down the drain, toxic waste and
>must be collected. 
>By the way, lithium carbonate will only neutralize any residual acid left
>in tissue which damages nuclei by acid hydrolysis of DNA/RNA, and may help
>restore the staining of hematoxyling.  Howeer, LiCO3, a base, does NOT
>reverse the chemical effects of acid IF you have overoxidized the groups
>you want to bind silver to with GMS.  Once protein hydrolysis is done and
>gone beyond the endpoint you need, you are in trouble. 
>This is the reason that hydrochloric acid and even formic acid is not
>advised IF you want to do a Feulgens staining reaction for DNA, the
>hydrolyzation step is basically overdone, and you get weak to no staining.    
>Gayle Callis
>Research Histopathology Supervisor
>Veterinary Molecular Biology 
>Montana State University - Bozeman
>PO Box 173610
>Bozeman MT 59717-3610
>406 994-6367 (lab with voice mail)
>406 994-4303 (FAX)

More information about the Histonet mailing list