Bromophenol Blue
Bromophenol Blue (CAS: 115-39-9) is a sulfonphthalein dye widely used as a pH indicator and tracking dye in laboratories. It changes from yellow at about pH 3.0 to blue-violet at about pH 4.6.
Because it is stable, strongly coloured and easy to dissolve in dilute alkali or ethanol, it is a routine choice for titration, analytical testing and quality-control work.
It is also a standard tracking dye in agarose and polyacrylamide gel electrophoresis, where it lets users follow sample migration visually. Buyers value consistent dye content and reliable colour response from batch to batch.
Supplied as a fine powder, it should be stored tightly closed away from light and moisture. Buyers usually check dye content, loss on drying and the clarity of the working solution, since these decide how sharp the end point or band appears in routine testing.
• Acid-base indicator: gives a sharp yellow-to-blue colour change in the pH 3.0-4.6 range, suited to titrations and analytical methods. It is a popular choice for weak-acid titrations and for checking acidity in non-aqueous systems.
• Electrophoresis tracking dye: added to loading buffers for DNA, RNA and protein gels to monitor run progress without interfering with separation. Its low molecular weight migration relative to DNA fragments makes it easy to interpret run progress.
• Biological and chemical staining: used in protein assays, chromatography spot detection and as a colour component in laboratory reagents. Staining is quick and reproducible, so it fits teaching, QC and research laboratories alike.
• Indicator solutions and test kits: used to prepare ready-to-use indicator solutions, test papers and diagnostic reagent components where a clear colour signal is needed.
Product Name: Bromophenol Blue
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