溴酚藍(lán)在酸性水溶液中以磺化羥基醌的形式存在，又稱四溴酚磺酞。溴酚藍(lán)是一種pH指示劑，并且是一種強(qiáng)藍(lán)色染料。它具有輕微的負(fù)電荷并且可沿與DNA相同的方向遷移，允許用戶對(duì)分子在凝膠中移動(dòng)的進(jìn)程進(jìn)行監(jiān)測(cè)。不同的凝膠組成具有不同的遷移速率。 

應(yīng)用：

在 DNA、RNA（瓊脂糖）和蛋白質(zhì)（聚丙烯酰胺）凝膠電泳中，溴酚藍(lán)用作示蹤染料。它已用于為蛋白質(zhì)印跡分析制備蛋白質(zhì)樣品。溴酚藍(lán)在瓊脂糖凝膠中以與300-500 bp DNA大致相同的速率遷移，在蛋白聚丙烯酰胺凝膠中位于緩沖前沿。此外，它還是為人熟知的重要血腦屏障檢測(cè)染色劑。

Bromophenol blue is useful as a tracking dye in electrophoresis, an industrial dye, a laboratory acid-base indicator and a biological stain. In gel electrophoresis it can be used as a color marker and as as a biological stain it can be used to stain proteins and nucleic acids. Bromophenol blue is an intermediate and is used as an acid-based indicator in the pH range of 3-4.6 where the color changes from yellow to blue.
An electrophoresis tracking dye also used as an acid-base indicator