Bathophenanthrolinedisulphonic acid and bathocuproinedisulphonic acid, water soluble reagents for iron and copper

Abstract

Bathophenanthrolinedisulphonic acid and bathocuproinedisulphonic acid have been isolated in solid form as sodium salts and characterised. Both materials retain the high sensitivity of the parent materials as spectrophotometric reagents, for iron and copper respectively. They are water soluble and unlike the parent reagents may be used in aqueous perchlorate solutions. Interferences are about the same as with the parent reagents, but the pH range for maximum colour formation extends two pH units further into the alkaline region. Iron II tribathophenanthrolinedi-sulphonic acid is an excellent oxidation-reduction indicator, changing sharply from red to green in the cerate titration of iron II; it may be used in solutions containing perchloric acid.