OPTIMIZATION OF KINETIC DETERMINATION OF IODATE BY METHYL ORANGE OXIDATION IN THE PRESENCE OF HYDRAZINE

Abstract

Instead of the fixed time method the difference in induction periods of decolorization of a blank solution and a sample solution has been suggested as analytical signal for iodate ion determination by Landolt reaction of methyl orange with potassium bromate in the presence of hydrazine. Optimal conditions are: 0.024 M H₂SO₄, 2∙10^–6 M methyl orange, (5–6)∙10^–5 M KBrO₃, 1∙10^–5 N₂H₄. Calibration curve is linear in (0.06–2.4) μg/mL range, reproducibility error is less than 2.7%, relative error of determination is less than 3.3 %, for aqueous solution analysis.