Catalytic kinetic determination of trace amounts of iron(III) with polarographic detection

This method is based on the catalytic effect of Fe3+ on the oxidation reaction between Acid Chrome Blue K and potassium bromate in sulfuric acid medium at 100 degrees C, and in 0.08 mol/L NH4OH - 0.01 mol/L (NH4)(2) SO4 supporting electrolyte, Acid Chrome Blue K exhibits a sensitive polarographic wave at 0.55 V vs. SCE, and change of concentration is traced by a polarographic detection technique. The linear range of Fe3+ is 10-100 ng/mL. This new catalytic method has been applied to the determination of iron in natural water and food with satisfactory results.