|Molar mass||698.01 g·mol−1|
|Appearance||beige to brown powder|
|Melting point||225 °C (437 °F; 498 K) decomposes|
|UV-vis (λmax)||423 nm|
|S-phrases||S24/25, S28, S37, S45|
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
|Bromocresol green (pH indicator)|
|below pH 3.8||above pH 5.4|
In aqueous solution, Bromocresol green will ionize to give the monoanionic form (yellow), that further deprotonates at higher pH to give the dianionic form (blue), which is stabilized by resonance:
An ethanol solution (0.04 wt.%) of bromocresol green has been proposed for TLC staining and is suitable for visualisation of the compounds with functional groups whose pKa is below 5.0 (carboxylic acids, sulfonic acids, etc.). These appear as yellow spots on a light or dark blue background; no heating is necessary. Bromophenol blue solution can be used for the same purpose.
The compound is synthesized by bromination of cresol purple (m-cresolsulfonphthalein).
It is used as a pH indicator and as a tracking dye for DNA agarose gel electrophoresis. It can be used in its free acid form (light brown solid), or as a sodium salt (dark green solid). It is also an inhibitor of the prostaglandin E2 transport protein.
Bromocresol green may cause irritation. Avoid skin and eye contact.
- Kolthoff, I.M. Treatise on Analytical Chemistry, New York, Interscience Encyclopedia, Inc., 1959.
- "Bromocresol Green". Sigma Aldrich.
- Fred Senese. "Acid-Base Indicators". Frostburg State University Dept. of Chemistry.
- Diamond, D.; Lau, K. T.; Brady, S.; Cleary, J. (2008). "Integration of analytical measurements and wireless communications—Current issues and future strategies". Talanta 75 (3): 606. doi:10.1016/j.talanta.2007.11.022.