Merck, 1072410005, Phenol red

General description
Phenol red (phenolsulfonphthalein, PH R) belongs to the class of triphenylmethane dyes. It is a waterͰsoluble anionic dye, mostly used as a pH indicator in cell biology laboratories. Also, in different protocols, it is used to detect H2O2(Hydrogen peroxide).
Application
Phenol red can be used as a:
Dye in the preparation of phenol red/n-Si photodiode [phenol red/n-type silicon wafer] by spin coating technique. The device is appropriate for photo-detection applications.
Color-changing dye in the design of fiber optic pH sensor because as the acidity increases, the dye′s absorption properties shift from the green to the blue section of the spectrum.
Indicator in the determination of freshwater pH.

Features and Benefits
Phenol red is used to detect pH changes in cell culture,
pH is 6.4 or below yellow color
pH is 8.2 or above red color.

Analysis Note
Appearance of solution: passes test
1st transition range: pH 1.2 - pH 3.0brownish orange - yellow
2nd transition range: pH 6.5 - pH 8.0brownish yellow - red violet
Loss on drying (110 °C): ≤ 1
Transition range (according to ACS): passes test
ACS conforms