Preparation of amine salts of thymolphthalein monophosphate and their use for measuring phosphatase activity.

Preparation of 2-Amino-2-Methyl-1 ,3Propandiol-Thymolphthalein Monophosphate (AMPD-TMP) Place 5 g (4.27 mmol) of magnesium thymolphthalein monophosphate (Eastman Kodak, Rochester, N. Y. 14650) in a 500-ml Erlenmeyer flask and add 100 ml of 2 mol/ liter HC1. Stir vigorously until the magnesium salt is well dispersed, add 100 ml of diethyl ether and continue stirring until a uniform suspension is obtained. Transfer the mixture to a separatory funnel and separate the phases. Extract the aqueous phase with an additional 75 ml of diethyl ether and equilibrate the combined ether extracts with 20 ml of saturated aqueous sodium chloride solution.