A rapid and simple fluorimetric determination of iodide in iodized table salts

Abstract

A new, simple and rapid fluorimetric method is proposed for the determination of iodide in iodized table salts based on the fluorescence exhibited by the ionic complex formed between AgI2- and the brilliant green cation (eexc = 256 nm, eem = 521 nm) at pH 3.0 and Ag+ concentration of 0.8 mg/L. The relationship between fluorescent response expressed as Fluorescence Intensity Units (FIU) and KI concentration of standards in 20 g NaCl/L was linear in the range of 0.15 to 1.2 mg KI/L. The sensitivity of the method was 300 FIU for 1 mg KI/L with a detection limit of 0.15 mg KI/L. The proposed method was applied in commercial iodized table salts and the results obtained were correlated closely to those obtained by the official method of the AOAC.