Calcon adsorption and its use in the polarographic determination of iron(III)

Calcon exhibits polarographic activity and gives two waves, one of which is much higher than the other. The irreversible reduction of Calcon is due to its adsorption on a dropping mercury electrode. The parameters of adsorption were calculated. Studying the effects of the medium pH, the composition of the supporting electrolyte, and some metal ions suggested that the tautomeric equilibrium of Calcon shifts in the presence of iron(III). A procedure for the polarographic determination of iron based on this effect was proposed, The calibration graph was linear over the range 4 x 10(-7) to 4 x 10(-6) M iron(III) under the conditions of alternating-current polarography with 4 x 10(-5) M Calcon present.