SDS PAGE Sample Buffer

Janet Smith | Boston Biomedical Research Institute

Both 2X and 4X SDS PAGE Sample Buffer (SB) are good to have around, and can be stored at room temperature. The 2X stock is nicer to work with (it is less viscous), but sometimes 4X SB is necessary. Once β-mercaptoethanol (BME) has been added to an aliquot, we store it at room temperature and use it for a week or so.

1X SDS PAGE Sample Buffer is

10% (by volume) glycerol
62.5 mM Tris-HCL, pH 6.8
2% SDS
0.01 mg/ml bromophenol blue
5% β-mercaptoethanol (BME)

Recipe for 4X SB

4 ml glycerol (5.04 g)
0.8 g SDS
2.5 ml 1M Tris-HCl
80 μl bromophenol blue slurry (5 mg/ml in water; vortex well before using.)
H₂O to 8 ml
Add BME to 20% (for example 0.2 ml bME to 0.8 ml 4X SB) before using.

Recipe for 2X SB

2 ml glycerol (2.52 g)
2.5 ml 20% SDS
1.25 ml 1M Tris-HCl
40 μl bromophenol blue slurry (5 mg/ml in water; vortex well before using.)
H₂O to 9 ml
Add BME to 10% (for example 0.1 ml BME to 0.9 ml 2X SB) before using.

Reference Recipe for 100 ml 2X SB from "The Red Book"

25 ml buffer A (0.5 M Tris-HCl, pH 6.8 and 0.4% SDS)
20 ml glycerol (25.2 g)
4 g SDS
2 ml BME (2%, which is different from the 10% we usually use.)
1 mg bromophenol blue
H₂O to 100 ml