Phenol Red

RT

354, 38

Bright red to dark red powder

Phenol red is used as a pH indicator. A solution of phenol red will have a yellow color at a pH of 6.4 or below and a red color at a pH of 8.2 and above. The sodium salt of phenol red is used widely in culture media to identify changes from neutral to acidic pH values. It is typically used in cell culture media at 11mg/L. Acid end products from carbohydrate fermentation lower the pH causing the pH indicator phenol red to turn from red (alkaline) to yellow (acid).

Synonyms:
Phenolsulfonephthalein; 3, 3-Bis(p-hydroxyphenyl)-2, 1-3H-benzoxathiole

CAS Number:
143-74-8

Molecular Formula:
C19H14O5S

Molecular Weight:
354.38

Appearance:
Bright red to dark red powder

Visual Transition Interval:
pH 1.2 (orange)
pH 3.0 (yellow)
pH 6.5 (brownish)
pH 8.0 (red violet)

Loss on Drying:
≤5%

Storage and Stability:
May be stored at RT. Stable for 12 months after receipt at RT.

Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

Toxicity and Hazards: 
All products should be handled by qualified personnel only, trained in laboratory procedures.