Abstract: An inhibitory kinetic spectrophotometric method was proposed for the determination of trace iodine. The method is based on the inhibition effect of iodine on the nitrite-catalyzed oxidation of menthylene blue by potassium bromate in dilute sulphuric acid medium. The linear range of the determination is 0 to 480 g/L,and the detection limit is 3.7×10-7 g/L. This method is simple,rapid and highly sensitive. It has been used for determination of trace iodine in salt with satisfactory results.

Key words: iodine, kinetic spectrophotometry, inhibition reaction, methylene blue, potassium bromate benzyl tri-ethyl ammonium chloride