Bio-Rad GS-900™ Calibrated Densitometer - Manual (Page 2)

Bio-Rad Laboratories, Inc. 10032602 Rev A
2000 Alfred Nobel Drive, Hercules, CA 94547
510-741-1000
• Fix gel for 15 min with gentle agitation
• Discard the fixing solution
o Dispose of fixing solution properly
• Alternatively, the gel can be fixed with 50% methanol and 10% acetic acid with no loss in sensitivity.
Fixing can be replaced with three 5 min water washes or no wash at all, but sensitivity will be reduced.
Gel Staining
• Rinse the gel in a shallow staining tray with deionized water
• Add QC colloidal Coomassie stain to the gel and incubate with gentle agitation at room temperature
for 1–20 hr
o Maximum sensitivity is obtained after staining for 10–20 hr. Staining for 16 hr allows detection
of amounts <10 ng of BSA
o If rapid staining is desired, gels may be stained for only 1 hr with a slight reduction in sensitivity
o Cover the staining container to reduce evaporation of the staining solution
Gel Destaining
• Discard the staining solution
o QC colloidal Coomassie stain is formulated without methanol or acetic acid, which need to be
disposed of as hazardous waste
• Destain the gel in deionized water. Destain for 1–3 hr with gentle agitation. Change the water at least
three times
o Highest signal-to-background levels are obtained with 3 hr of destaining
o If rapid destaining is desired, destain 1 hr with 3 changes of water; signal-to-background
decreases slightly
• Destained gels are now ready for imaging and analysis
o Gels can be stored in water for up to 3 days without a significant decrease in sensitivity