Starch Iodide Paper

Immerse strips of filter paper in 100 mL of starch solution containing 0.5 g of potassium iodide. Drain and allow to dry protected from light.

Test for sensitivity Mix 0.05 mL of 0.1 M sodium nitrite with 4 mL of hydrochloric acid and dilute to 100 mL with water. Apply one drop of the solution to starch iodide paper; a blue spot appears.