The method describes how to determine the iron content of water photometrically with a cuvette test.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Iron can usually be found in water in the form of hydrogen carbonate, often only in a low concentration (< 0.1 mg/l). Larger quantities (> 0.5 mg/l) require that the water be subjected to deferrization in order to prevent the formation of deposits on piping (particularly in the presence of iron bacteria). When exposed to air, iron partially precipitates out in the form of iron(III) hydroxide as rust-colored flakes or as turbidity in water.
Iron(II) ions form a rust-colored complex with 1,10-phenanthroline. Iron(III) ions are reduced to iron(II) ions.