Thymolphthalein Solution

A 0.1% w/v solution of thymolphthalein in ethanol (96%).

Complies with the following tests.

Sensitivity A mixture of 0.2 mL and 100 mL of carbon dioxide-free water is colourless. Not more than 0.05 mL of 0.1m sodium hydroxide VS is required to change the colour of the solution to blue.

Colour change pH 9.3 (colourless) to pH 10.5 (blue).