Analytical Sciences

Kinetic-Photometric Determination of Iodide Based on Its Inhibitory Effect on the Bromate Oxidation of Victoria Blue 4-R

V. D. MITIC,* S. D. NIKOLIC,** and V. P. STANKOV-JOVANOVIC*

*Faculty of Natural Science and Mathematics, Department of Chemistry, University of Nis, Visegradska 33, Serbia & Montenegro
**Faculty of Chemistry, University of Belgrade, P. O. Box 550 11001 Belgrade, Studentski trg 12-16, Serbia & Montenegro

A new sensitive kinetic method has been developed for the determination of trace amounts of I^- over the range of 50 - 300 ng cm^-3. The method was based on the inhibitory effect of iodide on the oxidation of Victoria Blue 4-R by KBrO₃. The reaction is monitored spectrophotometrically at 596.3 nm. Method development includes optimization of reagent concentration and temperature. The kinetic parameters of the reaction were reported and a rate equation was suggested. The effects of certain foreign ions upon the reaction rate were determined for the assessment of the selectivity of the method. The proposed method was successfully applied to the determination of iodide in real samples. The new developed method was found to have fairly good selectivity, sensitivity, simplicity and rapidity.

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