Iodine analysis

Repeated attempts to obtain the band at 1030 cm 1 in spectra of the respective solids of various compositions did not furnish the desired result. Nevertheless, the band was observed in IR transmission spectra of gaseous components that separated from molten K2NbF7 and were collected in a standard gas phase cell with Csl windows appropriate for IR measurements. Fig. 85 presents the structure of the band and exact wave numbers of its components. Storage of the gas in the cell for several days resulted in a yellow deposit on the windows due to oxidation and subsequent separation of iodine. Analysis of available reported data [364 - 367] enables to assign the band observed at -1030 cm 1 to vibrations of OF radicals. It should be emphasized that a single mode was observed for OF in the argon matrix while in the case of nitrogen, two modes were indicated [367]. 

Elemental composition P 19.13%, I 78.38%, H 2.49%. The compound may be decomposed cautiously in water and the iodide ion measured by ion chromatography or electrode method (see Iodine, Analysis). Liberated phosphine may be diluted with helium and analyzed by GC/MS (see Phosphine, Analysis). 

Chlorine, bromine and iodine analysis is best accomplished by a conventional silver(I) nitrate titration after decomposing the sample in an C)2 flask. There is no interference from hydrogen fluoride. 

The product formed along with the monomercuric methylene iodide w as a white body insoluble in all the usual solvents, but yielding iodoform with iodine. Analysis points to mercury iodoform or methine tri-mercuric iodide, GH(HgI)g, and the same compound was obtained by Hofmann when an ethereal solution of iodoform was allow ed to stand in contact with mercurous chloride for a long time. 

The method of amperometric detection, after chromatographic separation of ions, provides a fast (with a run time less than 3 min) and sensitive way (with a method detection limit of 0.6pg/l comparable to O.lpg/1 by ICP-MS for total iodine analysis) to determine iodide concentration. Minimal memory effect was observed, as evidenced by a measured apparent iodide concentration of only 0.005% for the first noniodide-containing sample injected immediately after a high-concentration (lOOmg/1) iodide standard. 

Norwegian milk and dairy products also contain relatively high amounts of iodine. Analysis of the iodine concentration in milk (i.e., low-fat milk, 1.5% fat) showed seasonal variation. The average iodine content of low-fat... 

In 1996 a convenience sample of 100 eight-year-old schoolchildren participating in a study of blood pressure and bone density (Dwyer et al., 1999 Jones et al., 2000) were selected to provide a timed overnight urine sample for iodine analysis. The median urinary iodine concentrations (UIC) was 42 tg/l (range 0-200 tg/l). The majority (92%) of the children had concentrations less than 100 tg/ 1 and 55% had levels less than 50 ig/l (Hynes, 2001). Based on the WHO categories for assessing the severity of IDD the sample of children was considered to have moderate iodine deficiency (World Health Organization,... 

There are also studies that comp)are sp>ectrophotometric and RP-HPLC determinations of iodine concentrations in urine (Bier et al., 1998). In the first one ammonium persulfate was used as an oxidant in the modified ceiic arsenite method. With the use of this sensitive method iodine concentrations can be determined in very small sp>ecitnens (50 pL). A Technicon Autoanalyzer II and a paired-ion-RP HPLC were the basic analytical equipment. The authors found that the precision of this optimized ammonium j ersulfate method yielded inter assay CVs of <10% for urinary iodine concentrations >10 pg/dL The detection limit was 0.0029 pg iodine. There was a high correlation between all three methods (r > 0.94 in any case) and the interpretation of the results was consistent. The authors suggested that the manual ammonium persulfate method could be performed in any routine clinical laboratory for urinary iodine analysis. Another benefit of the described methods is a p>ossibility to process a large number of samples with high accuracy and ininimal technician s time. 

Reduction of iodate to iodide before total iodine analysis was necessary because the species had different sensitivities by ICP-MS. Gradient elution with 5 mM KNO3... 

Elzie, J. L. Neutron Activation of Silver, Cadmium, Indium, Tin, Antimony, Tellurium, and Iodine Analysis of Meteoritic, Terrestrial, and Lunar Materials. Thesis. University of California, Los Angeles (1972). 135 p. 26 52906... 

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