Estimation of iron with salicylaldehyde hydrazone

Iron is determined by precipitation as the reddish orange ferrous complex of salicylaldehyde hydrazone (SH) in the pH range 10.0-11.0. With ferric iron an unstable complex is formed which changes readily to the stable ferrous complex. The iron complex has a metal-ligand ratio of 1:2, contradicting the 1:3 ratio reported earlier. The reagent can be used for separation of iron from several ions.