Alkaline silver staining (SDS, IEF, 2D)
Adjusting the amount of sodium thiosulfate in the developer:
Prepare the silver solution, and bath gel in it.
During the silver step of the gel, prepare the developer, but without sodium thiosulfate. Pipet 50 uL of the silver solution in a weighing tray.
Pipet 50 uL of the developer into the silver solution droplet and count to 3. Within these 3 seconds the color of the droplet should turn into brown-black.
This is an important check, whether all substances are present in the solutions: AgNO3,
Na2CO3, and formaldehyde, all three substances must be present, otherwise no success!).
If this test takes longer than 10 seconds, check quality of chemicals and cleanness of the equipment (staining trays).
Important: from the silvering step on, no plastic trays should be used, but only glass or stainless steel (some plastic trays contain softeners, which interfere with the silver staining procedure!)