Starch Substrate

Determine the water content of starch EPBRP by heating at 120° for 4 hours. Stir a quantity of starch EPBRP equivalent to 2.0 g of the dried substance with 10 mL of water and add, stirring continuously, to 160 mL of boiling water. Rinse the container with several 10-mL quantities of water, add the washings to the hot starch solution and heat to boiling, stirring continuously. Cool to 20° and add sufficient water to produce 200 mL.

Use on the day of preparation.