SDS equilibration buffer

6.7-ml 4X resolving gel buffer

72.07 g urea

69-ml 87% (v/v) glycerol

4.0 g SDS

A few grains bromophenol blue

Adjust the buffer to a final volume of 200 ml with H₂O. The resulting buffer will contain 50 mM Tris-Cl, 6 M urea, 30% (v/v) glycerol, and 2% SDS. Store in 40-ml aliquots at -20ºC.