A New Micellar Mediated Cloud-Point Extraction Procedure for Sensitive and Selective Determination of Trace Amounts of Total Iodine in Milk-Based Nutritional Products by Means of Indirect Spectrophotometry

Abstract

A new micellar mediated cloud-point extraction procedure (CPE) has been developed for sensitive and selective determination of trace amounts of total iodine by means of indirect spectrophotometry. The method is based on selective charge transfer complex formation of I3, which is produced by the reaction of iodate in presence of 25-fold excess periodate with excess iodide and with acridine orange (AOH+) being a selective fluorescent cationic dye at pH 3.0 phthalate buffer, and then the CPE of charge transfer complex formed from aqueous solution at phthalate buffer using nonionic surfactant, Triton X-114. The calibration graphs were rectilinear in the ranges of 1.5–20 and 20–160 μg L−1 for IO3 −, with r 2 higher than 0.9996 in two linear regions with changing sensitivity. Under optimal conditions obtained, the limits of detection and quantification were 0.4 and 1.5 μg L−1 and the precision (as RSD) for determination of 10, 50, and 100 μg L−1 of iodate was in the range of 2.4–4.7 % (n 5). The method was successfully applied to selective and reliable determination of total iodine in milk-based nutritional products. The accuracy of the method was controlled by analyzing two standard reference materials (SRMs) at suitable matrix to milk samples.