Speciation of iodide, iodine, and iodate in environmental matrixes by inductively coupled plasma atomic emission spectrometry using in situ chemical manipulation

Dissolved iodine, iodide, and iodate are determined in environmental matrix es by in situ chemical manipulation and inductively coupled plasma atomic e mission spectrometry (ICPAES), The method uses equipment commonly available to most laboratories involved in environmental inorganic analysis, Total d issolved iodine, iodide, and iodate are determined by ICPAES using iodine v apor generation, Total iodine is determined directly by ICPAES after filtra tion, Total dissolved iodide (I-) is oxidized in situ to iodine by the addi tion of sodium nitrite in sulfuric acid in a simplified continuous flow man ifold, Iodate is determined by prereduction at the instrument before analys is by the in situ oxidation ICPAES procedure, A standard nebulizer produces the gas-liquid separation of the total iodine, which is then quantified by ICPAES at 206.16 nm, The instrument detection limit for the iodine analysi s was 0.04 mu g/mL. Recoveries from seawater, saltwater, and freshwater sta ndard reference materials ranged from 85 to 118% and averaged 98%, For samp les containing both iodine and iodide, the total is determined with in situ oxidation, iodine is determined without the oxidizing reagents, and iodide is calculated from the difference, For samples containing ail 3 species, p re-reduction is used and the iodine and iodide concentrations are subtracte d for quantitation of iodate. The analysis is selective for these 3 species (I-, I-2, and IO3-), A group of 20-30 samples may be analyzed and quantita ted for all 3 individual, commonly occurring iodide species in less than 1 h, The procedure is considerably faster than any other reported techniques, This method is especially well-suited to the analysis of small environment al samples.