Potassium iodate

About: Potassium iodate is a(n) research topic. Over the lifetime, 611 publication(s) have been published within this topic receiving 5940 citation(s). The topic is also known as: KIO3.

Determination of Hydrolyzable Tannins (Gallotannins and Ellagitannins) after Reaction with Potassium Iodate

Abstract: A widely used method for analyzing hydrolyzable tannins afer reaction with KIO3 has been modified to include a methanolysis step followed by oxidation with KIO3. In the new method, hydrolyzable tannins (gallotannins and ellagitannins) are reacted at 85 °C for 20 h in methanol/sulfuric acid to quantitatively release methyl gallate. Dried plant samples can be methanolyzed under the same conditions to convert hydrolyzable tannins to methyl gallate. Oxidation of the methyl gallate by KIO3 at pH 5.5, 30 °C, forms a chromophore with λmax 525 nm, which is determined spectrophotometrically. The detection limit of the method is 1.5 μg of methyl gallate, and with plant samples, relative standard deviations of less than 3% were obtained. Keywords: Tannin; polyphenolic compound; hydrolyzable tannin; methyl gallate; galloyl glucose; gallotannin; potassium iodate

Determination of dissolved oxygen in seawater by direct spectrophotometry of total iodine

Abstract: A modified procedure has been proposed for the colorimetric determination of dissolved oxygen in seawater to improve its precision and accuracy. When a pickled sample is acidified, iodine liberated in the iodometric reaction is measured by direct spectrophotometry at 456 nm. Loss of molecular iodine by volatilization is eliminated by transferring the sample to a flow cuvette without contact with air. The method was calibrated for oxygen by spiking known amounts of potassium iodate. Precision was found at better than 0.2% r.s.d. (full scale). Evaluation of accuracy was made by comparison with calculated oxygen solubilities, which shows a relative bias of no more than 0.5% for oxic waters. The analytical throughput was much faster than that of the standard titration procedure.

Stability of iodine in iodized salt used for correction of iodine-deficiency disorders. II.

Abstract: The purpose of this study was to assess the effect of humidity and packaging materials on the stability of iodine in typical salt samples from countries with tropical and subtropical climates under controlled climatic conditions. Initially we examined eight samples. In the second phase we expanded the study to salts from 18 sources and attempted to correlate the observed stability with salt impurities naturally present in these samples. High humidity resulted in rapid loss of iodine from salt iodized with potassium iodate ranging from 30% to 98% of the original iodine content. Solid low-density polyethylene packaging protected the iodine to a great extent. High losses were observed from woven high-density polyethylene bags which are often the packaging material of choice in tropical countries. Impurities that provided moisture at the salt surface had the most deleterious effect. Although clear correlations were not obtained the presence of reducing agents hygroscopic compounds of magnesium and so forth seemed to have the most adverse effects on the stability of iodine. Surprisingly carbonates had little effect on stability over the range present in the samples. Packaging salt in low-density polyethylene bags which provided a good moisture barrier significantly reduced iodine losses and in most cases the iodine content remained relatively stable for six months to a year. The findings from this study indicate that iodine can be highly unstable and in order to ensure the effectiveness of local salt-iodization programmes countries should determine iodine losses from local iodized salt under local conditions of production climate packaging and storage. (authors)

The vapour pressures of saturated aqueous solutions of sodium chloride, sodium bromide, sodium nitrate, sodium nitrite, potassium iodate, and rubidium chloride at temperatures from 227 K to 323 K

Abstract: The vapour pressures of saturated aqueous solutions of NaCl, NaBr, NaNO3, NaNO2, KIO3, and RbCl were determined in the temperature rangeT=(278 to 323) K using an electronic hygrometer with an electrolyte sensor and compared with the literature data, which are available only for the first four salts. These vapour pressures serve to evaluate the water activities, osmotic coefficients, and molar enthalpies of vaporization and solution at saturation.

Iodination of irrigation water as a method of supplying iodine to a severely iodine-deficient population in Xinjiang, China.

Abstract: Severe iodine deficiency still occurs in many countries, and causes cretinism and mental impairment. In southern Xinjiang province, China, after usual methods of iodine supplementation had failed, we iodinated irrigation water to increase iodine in soil, crops, animals, and human beings. 5% potassium iodate solution, dripped into an irrigation canal for 12 or 24 days, increased soil iodine 3-fold, and crop and animal iodine 2-fold. Median urinary iodine excretion in children increased from 18 to 49 micrograms/L (two groups of similar age). The cost for iodine was US $0.05 per person per year. Soil iodine remained stable over one winter, and dripping of iodine during the second year (US $0.12 per person per year) resulted in a further 4-fold increase in soil iodine and a 1.8-fold increase in iodine in crops. We conclude that iodination of irrigation water is an advantageous and cost-effective method of supplying iodine in southern Xinjiang, and may be useful in other areas dependent on irrigation.