Phthalein Purple

Metalphthalein; C₃₂H₃₂N₂O₁₂ + aq (2411-89-4)

Indicator grade of commerce.

A creamy white to brown powder complying with the following test.

Sensitivity Dissolve 10 mg in 1 mL of 13.5m ammonia and dilute to 100 mL with water. To 5 mL of the solution add 95 mL of water, 4 mL of 13.5m ammonia, 50 mL of ethanol (96%) and 0.1 mL of 0.1m barium chloride VS; the solution is bluish violet. Add 0.15 mL of 0.1m disodium edetate VS; the solution becomes colourless.