3, 6-pyridazinediol as a specific spectrophotometric reagent for the determination of iron

Iron(III) reacts with 3,6-pyridazinediol in presence of nitric acid to give pink color having maxima at 480 mμ. The color reaction which is specific for iron(III), has 1 μg/ml as visual limit of identification and provides the basis of a new spectrophotometric method for the determination of iron. The quantitative assessment of the tolerable amount of different ions which do not interfere with the determination are reported. The mechanism of the color reaction is not clear.