Problems with silver staining

[Dima Klenchin]

In article <DL8v5x.IsL at freenet.carleton.ca>,
   at332 at FreeNet.Carleton.CA (Matt Parker) wrote:
-->
-->	Hi! We use the BioRad Silver Stain Plus kit, and lately we've been
-->having some problems with it. When we add the sodium carbonate to the
-->staining solution, it forms a white precipitate, which eventually goes
-->away with stirring. That isn't the real problem, however: the staining is
-->taking at least 2 or 3 times longer than it used to. 

Never happened to me with Bio-Rads kit. However, we stopped buying it cause
exactly the same stuff could be prepared in the lab at a 1/10th of the price
(Bio-Rad give a ref. to the method described in Anal. Biochem, 1987, 165:33-37). 
If you wish I can send you a protocol. One thing that IS different from 
Bio-Rad's:

when using home-made kit the way Bio-Rad does, I ALWAYS get white 
precipitate. The "problem" is solved easily: SLOWLY add 50 ml of 
silver/ammonium/nitrate/tunstosilicate mixture TO the 50 ml of carbonateic (not 
carbonate to silver). No precipitate, no decrease of staining time. Even if you 
will never prepare the kit yourself, similarly to home-made kit I predict that 
your problem with Bio-Rad's stuff will go away if you just swap the addition of 
the reagents. 

Hope it helps. 

- Dima