4.REAGENTSU.K.
All reagents shall be of recognized analytical grade:
4.1. water, complying with the requirements of ISO 3696, Grade 3.U.K.
4.2. potassium iodide, 100 g/l solution, not containing iodate or free iodine.U.K.
4.3. starch, solution.U.K.
Mix 5 g of soluble starch in 30 ml of water, add this mixture to 1 000 ml of boiling water, boil for three minutes and allow to cool.