This 30 mL (one ounce) bottle of bromophenol blue (also known as bromphenol blue) is a 0.4% solution in water. Used as a pH indicator, it changes color over a pH range from 3.0 (yellow) to 4.6 (blue).

Uses of bromophenol blue indicator include testing for soap in unwashed biodiesel and glycerol.

Comes packed in convenient squeeze bottle for dispensing by the drop.