Phenol red

Phenol red

0Phenol red is a pH indicator frequently used in cell biology laboratories. It is a weak acid, which can lose hydrogen ions in solution, so it can be either in the acid form or the conjugate base form, depending on the pH of the solution.

Chemical Properties

Phenol red exists as a red crystal that is stable in air. Its solutions are orange if the pH is 6.8. In this circumstance, phenol red is not ionized. Between pH 6.8 and 8.2, phenol red changes from yellow to red. It is bright pink in strong alkali solutions.

Uses

Phenol red is used as a pH indicator, as a dye, and as a tracking dye for DNA agarose gel electrophoresis. It is also used in cell biology for monitoring cell culture growth.

pH Indicator

Phenol red is a popular pH indicator due to its clear and distinct color variance at different pH values. Phenol red solution can range from a yellow color at a pH of 6.0 to a bright pink color at a pH of 8.1.

Cell Biology

In cell biology, phenol red is used to monitor cell cultures. As the pH decreases in cell culture media, phenol red changes from red to yellow. This color change is used to monitor changes in the pH of the medium caused by the cellular production of lactic acid.

Safety

Phenol red is considered safe for laboratory use, but it can be harmful if ingested or inhaled, and it can cause irritation to the skin and eyes.

See Also

• pH indicator
• Cell culture
• Acid-base titration

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