Bromophenol Blue (CAS 115-39-9)

Bromophenol Blue, with the chemical formula C19H10Br4O5S and CAS number 115-39-9, is a synthetic dye belonging to the family of pH indicators and halogenated phenolsulfonphthaleins. This compound is characterized by its intense blue color, which has proven invaluable in various biochemical and chemical research applications, particularly in molecular biology and analytical chemistry. Bromophenol Blue operates primarily through its ability to shift color in response to pH changes; it transitions from yellow at pH 3.0 to blue at pH 4.6, making it highly useful for tracking pH changes in different experimental settings. In gel electrophoresis, for example, Bromophenol Blue is routinely used as a tracking dye; it migrates at a predictable rate within polyacrylamide or agarose gels, allowing researchers to monitor the progress of molecular separation processes. This characteristic is crucial for estimating the migration of nucleic acids or proteins during electrophoresis, providing a visual marker that helps in determining when to halt the process to achieve optimal separation results. Its vivid color and clear transition between pH values make Bromophenol Blue an essential tool in laboratories for experiments requiring precise pH indication and process tracking without involving its integration into the sample′s chemical structure.