Ponceau S

[Na+].[Na+].[Na+].[Na+].OC1=C (C=C2C=C (C=CC2=C1N=NC3=C (C=C (C=C3) N=NC4=CC=C (C=C4) [S] ([O-]) (=O) =O) [S] ([O-]) (=O) =O) [S] ([O-]) (=O) =O) [S] ([O-]) (=O) =O

Ponceau S (Acid Red 112) is the most commonly used stain for immunoblotting protocols. Ponceau S dye is applied as an acidic aqueous solution, and the proteins on the membrane are stained with red color.