Use of some new chelating agents for the colorimetric determination of iron: Ethylenediamine-bis-sulphosalicylaldehyde

Ethylenediamine-bis-sulphosalicylaldehyde, which gives strong violet-red coloration with. ferric salts owing to the formation of a stable metal chelate complex, Fe(C₈H₉O₄NS)Cl.H₂O, has been utilized for the colorimetric determination of ferric iron, using a Hilger-Spekker photoelectric absorptiomcter. The maximum intensity of absorption occurs at pH 2.8–5.5 in the green region (510–520 mμ) of the visible spectrum.The colour complex has been found to obey Beer's law between 0.25 and 10 p.p.m. The influences of several foreign, ions on the reaction have been carefully studied. The metal chelate complex has been isolated and its properties studied.