RE: [Histonet] gomori methenamin silver

From:"Bartlett, Jeanine"

We use the Grocott's Method.
Stock Solution A: 0.21%  Silver nitrate (2.1 grams silver nitrate with 1000 ml distilled water): make in chemically clean glassware and refrigerate
Stock Solution B: Methenamine-borax (27.0 grams methenamine, 3.8 grams borax, 1000 ml distilled water): make in chemically clean glassware and refrigerate
Both stock solutions are stable for up to at least 4 months.  We use equal portions of each for our working solution.  We do not have a problem with sediment and the staining is just as good at 4 months as it is earlier.  We haven't tried it beyond that time period because we always have it used up by then.  I think the methenamine gives the silver the alkaline properties needed for a proper reaction.
Jeanine Bartlett, HT(ASCP)
Centers for Disease Control
Infectious Disease Pathology Activity
1600 Clifton Road, MS/G-32
Atlanta, GA 30333
-----Original Message-----
From: [] On Behalf Of Gudrun Lang
Sent: Wednesday, December 17, 2003 9:17 AM
To: Histonetliste
Subject: [Histonet] gomori methenamin silver

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

<< Previous Message | Next Message >>