Cresol Red

Cresol Red (full name: o-Cresolsulfonephthalein) is a triarylmethane dye frequently used for monitoring the pH in aquaria.

Cresol Red can be used in many molecular reactions instead of water. For example restriction digestion or PCR.

Cresol Red can also be used as a color marker to monitor the process of agarose gel electrophoresis and polyacrylamide gel electrophoresis. In a 1% agarose gel it runs approximately at the size of a 125 base pair (bp) DNA molecule (it depends on the concentration of buffer and other component). Bromophenol blue and xylene cyanol can also be used for this purpose.