Ponceau S (sodium salt)

Ponceau S is a stain that permits the rapid, reversible detection of proteins immobilized on various matrices, including nitrocellulose and polyvinylidene fluoride membranes.1 It can be used to locate proteins or evaluate efficiency of transfer. Reversible staining with ponceau S has also been validated as an alternative to actin probing as a loading control.2 This stain can also be used as a fiducial marker in mass spectrometric imaging.3