age of silver staining reagents

[BabcockHall]

Hello Everyone,

 

Does anyone know how quickly the reagents for silver staining SDS PAGE gels for proteins go bad? We have a kit that is 3-4 years old. The kits are pricey, most likely due to the silver itself, so we would prefer not to replace it unless it is necessary. If one reagent is likely to go bad, can we just replace that one? We have experience in our lab with ordinary SDS PAGE, but silver staining is new to us.

[CharonY]

It depends quite a bit on the protocol (and kit components). I always made the stains myself and use the MS-compatible staind. One of the first things to go tends to be the sensitizer. If made yourself or the bottle has been opened (but stored appropriatelyI would think that within a few months the components would degrade significantly. Fully closed kits tend to have shelf lives of 1-2 years (though I would check the manual and lot information). 3-4 years may be pushing it (especially if they have been around a while before purchase), but I would simply run a test gel with a dilution series of a reference sample and look how sensitive it still is and whether it is sufficient for applications.