Determination of total iodine in samples with an organic matrix by solid-phase spectrophotometry

A solid-phase spectrophotometry method is proposed for determining total iodine in samples with an organic matrix. The method involves the sorption of I 2 formed in oxidation of iodide with oxone (active ingredient potassium peroxomonosulfate) by polyurethane foams, followed by the registration of the adsorbent absorbance at 360 nm. Sample preparation includes treatment with an aqueous methanolic solution of tetramethylammonium hydroxide followed by thermostation at 90 ± 2°C for 3 h. The detection limit for iodine calculated using the 3 s -test is 0.03 μg in a sample aliquot portion of ≤8 cm 3 . The relative standard deviation is 8–12% for iodine concentration in the range 0.3–5.0 μg/g.