Iodine speciation analysis

NAA provides a possibility of nondestructive performance of reliable determination of total iodine in foodstuffs and diets at very low levels. The lowest detection limit of all analytical techniques can be achieved if RNAA or PS-NAA is used. PS-NAA is also suitable for iodine speciation analysis. 

L. Fernandez Sanchez, J. Szpunar, Speciation analysis for iodine in milk by size-exclusion chromatography with inductively coupled plasma mass spectrometric detection (SEC-ICP MS), J. Anal. Atom. Spectrom., 14 (1999), 1697D1703. 

In addition, chromatographic separation combined with detection methods, such as neutron activation analysis (NAA) and ICP-MS, was also reported for chemical speciation analysis of iodine in water (Hou et at, 1999b Reifenhauser and Heumann, 1990 Schwehr and Santschi, 2003). In... 

Speciation analysis of iodine in hydrolyzed solution of tissues, urine and serum... 

Michalke and Schramel (1999) reported a method of CE coupled to ICP-MS for the speciation analysis of iodine. A buffer comprising phosphate (pH 2.3), NaOH, sodium dodecyl sulfate (SDS) and borate (pH 8.3) for stacking was employed for the separation of iodide, iodate, T4 and T3. The separated four iodine species were subsequently detected during a pressure-driven detection step (basehne-separated) at 19.5, 29.1, 36.6 and 42.2 s. The detection fimits were determined at 0.08 p,g I/l (iodide), 0.3 p.g I/l (iodate), 3.5 p.g I/l (T4) and 2.5 p,g I/l (T3). This method has been appfied for iodine speciation in human serum and urine. The serum from a healthy person contained iodide (13p.g I/l), T4 (6lp,g I/l) and T3 (7.5p.g I/l), whereas the serum from a thyroid-operated person lacked T3. 

Speciation analysis of iodine in human urine samples has also been carried out by ion chromatography (IC) combined with ICP-MS (Stark etai, 1997). Because of the possible interconversion of the iodine species, depending on the pH value, different eluent—column combinations were used for acidic or alkaline sample solutions. Iodide, iodate and several unidentified, presumably organo-iodine species could be separated and detected. 

The most commonly used methods for speciation analysis of iodine in tissues and food are chromatographic techniques, such as anion exchange, size exclusion and reverse-phase chromatography, coupled with ICP-MS detection. 

In environmental waters, the most important oxidation states are iodide ( — 1) and iodate ( + 5). Most published methods for the analysis of radioiodine aim only to convert all species to one chemical form in order to determine a total concentration value for the particular nuclide of interest. However, some specialist methods designed for the analysis of the stable element such as that recently described by Woittiez et al. (1991) for the determination of iodide, iodate, total inorganic iodine and charcoal-absorbable (organic) iodine in seawater could presumably be adapted to provide information about the speciation of radioiodine as well. More difficult to adapt would be techniques such as polarography which have been useful in the measurement of the iodide/iodate system (e.g. Liss et al., 1973). 

GC combined with ICP-MS or ECD is quite often used for the determination of volatile organic iodine. A system similar to that used for seawater was used for the analysis of air samples (Schwarz and Heumann, 2002). WeviU and Carpenter (2004) reported a similar system for the speciation... 

Iodate (lOi") may be determined by DPP with detection limits down to 2 x 10 moll . Oxidation of the 1 in the sample to lOT followed by polarographic analysis will allow the determination of the chemical speciation of iodine. 

Surface and bottom seawater samples from three locations in the Kattegat and Baltic Sea were analyzed for and in both iodide and iodate species, and total inorganic iodine by neutron activation analysis using nuclear reactions of l(n,y) I and I(n,y) I (Hou et al. 2001). Levels of 2.3 x 10 mol/1 for and 7 x 10 mol/1 for are obtained. Therefore, these isotopes of iodine are promising tracers of physical and biochemical process in the ocean, and research about the chemical speciation of and in ocean will be developed. ... 

In 1980s, Rack and colleagues at University of Nebraska carried out a series study on speciation of iodine, chlorinated pesticides, and seleium in urine using liquid chromatography and molecular neutron activation analysis. They developed procedures for trace level determination of iodoamino acids and... 

In species-unspecific isotope dilution techniques, an isotopically enriched standard solution is added post-column, and the data evaluation is performed as described in Section 7.3.4 for CE coupling. Species-unspecific isotope dilution for HPLC coupling has been described for the determination of Cd, Cu and Zn in metallothioneins extracted from eel liver, while Fe, Cu and Zn were determined in proteins separated from human serum. This technique has also been applied to iodine determination in humic substances,as well as selenium speciation in human serum. Species-specific isotope dilution using HPLC-ICP-MS has been described for selenium analysis, the analysis of organotin species in sediments, methylmercury in fish tissue, trimethyllead in water, and chromium speciation. Overviews to this topic have been published, e.g. by Heumann and Hill. ... 

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