Bromophenol Blue Solution

Dissolve 0.1 g of bromophenol blue in 1.5 mL of 0.1m sodium hydroxide and 20 mL of ethanol (96%) and add sufficient water to produce 100 mL.

Complies with the following tests.

Sensitivity A mixture of 0.05 mL of the solution and 20 mL of carbon dioxide-free water to which 0.05 mL of 0.1m hydrochloric acid VS has been added is yellow. Not more than 0.1 mL of 0.1m sodium hydroxide VS is required to change the colour to bluish violet.

Colour change pH 2.8 (yellow) to pH 4.4 (bluish-violet).