Catalytic Kinetic Determination of Trace Amounts of Iodide by The Spectrophotometric Method with Spadns in Micellar Medium

Abstract

A new, simple, sensitive and selective catalytic spectrophotometric method was developed for the determination of trace amounts of iodide. The method is based on the catalytic effect of iodide on the oxidation of Spadns by bromate in micellar medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of Spadns at 507 nm with a fixed-time method. The decrease in the absorbance of Spadns is proportional to the concentration of iodide in concentration range 60.0-300.0 ng/mL, with a fixed time of 0.5-3.0 min from initiation of the reaction.The limit of detection is 20 ng/mL iodide.The relative standard deviation of 0.08 and 0.10 μg/mL iodide was 1.7 and 2.4 %, respectively. The method was applied to the determination of iodide in water.