The method describes how to determine the iron content of water using a phenanthroline solution.
Iron(II) ions react with 1,10-phenanthroline, forming a rust-colored complex; ferric iron is reduced to ferrous iron prior to complex formation by hydroxyl ammonium chloride. The color of the solution is visually compared to a color disk using a comparator.
The method describes how to determine the manganese content of water through oxidation to permanganate.
Manganese ions are catalytically oxidized into purple-colored permanganate ions. The purple color of the solution is determined using a comparator (or photometrically):
Mn2+ + 12 H2O → MnO4- + 8 H3O+ + 5 e-