[Histonet] gomori methenamin silver

[Fred Underwood]

I do get a sediment that forms in the stock solution after several
months.  I have used it and still get good results.  However, I have
started replacing the stock solution after 6 if it hasn't been used up
by then.

Fred

>>> "Gudrun Lang" <gudrun.lang <@t> aon.at> 12/17/03 09:16AM >>>
Dear histonetters,
I need help of those, who are familiar to Gomori Methenamin Silver
staining.
I have troubles to convince my colleages about the advantages of using
a stock meth-silver-solution. (instead of fresh making each time)
stock:    1:40 10%Silvernitrate : 3% Hexamethenamin (stable for few
months); 
working:  1:10 Borax : stock
My colleages think, that the stock solution soon becomes instable. And
that there is a kind of sediment at the bottom of the bottle (more
concentration of silver).

Can anyone tell me about bad experience with older stock solutions?
What happens, when the stock solution is older than two (or three,..)
months? Is the result of the stain weaker or darker?

Question 2:
What is the the function of Hexamethenamin? I know it causes the high
pH, but does it make any compound with the silvernitrate?

Any help is welcome
Best wishes from Austria

Gudrun Lang
Akh Linz, Austria