Destaining, silver stains

The first photographic reducer used to destain silver-stained polyacrylamide gels employed ammonium hydroxide, copper sulfate and sodium thiosulfate (1 ). It is also a subproportional reducer. The diamine stains are most resistant, while the photodevelopment stains are most sensitive to destaining. 

Detection and analysis Once the electrophoretic separation is completed, the gel is treated with a stain, most popularly Coomassie Brilliant Blue, to reveal protein bands. In the case of Coomassie Brilliant Blue, this process involves a stain-destain cycle, and as proteins can differ in their affinity to take up this dye the detection is really only considered qualitative. There are various other alternative stains which include Amido black. Ponceau red and silver nitrate. Of these, silver staining is widely considered to be one of the most sensitive staining... 

Silver destaining solution (for silver-stained gels only) dissolve potassium ferricyanide (2 mg/mL) in sodium thiosulphate solution (0.2 mg/mL). Make fresh immediately before use. 

The Heukeshoven and Dernick (1988) method was optimized by Pharmacia for the Phast system, which runs at varying temperatures. At low sensitivity, the experimenter can also perform all steps at RT (staining time of approximately 75 minutes). In some protocols, the proteins develop specific colors (e.g., sialoglycoproteins turn yellow, BSA blue). The basis for these color reactions remains unknown, and their experimental utility was low until recently (Dzandu et al. 1984 Nielsen and Brown 1984). If your silver gel turns out too dark, you can destain the gel again as follows. 

---