Selenous acid bromide

A sensitive gas-chromatographic determination of selenium is possible as 5-chlor-or 5-nitro-piazselenol. These compounds are extractable into benzene or toluene for direct injection into a gas-chromatograph with BCD or TCD After treatment of steel samples with diluted mixtures of equal volumes of hydrochloric and nitric acids in the presence of perchloric acid, the selenium is completely converted into the quadrivalent state. Large amounts of Fe(III) are masked with phosphoric acid. In pure sulfuric acid ultramicro amounts of selenium are converted into seleneous acid with a bromine-bromide redox buffer solution For high-purity... 

Selenic acid reacts on warming with bromides in acid solution to produce elemental bromine. 

Shimoishi and Toei determined ultramicroamounts of selenium in pure sulphuric acid by oxidizing it to selenous acid with bromine-bromide redox buffer solution followed by quantitative conversion to 5-nitropiaselenol, by reaction with 4.nitro-o-phenyldiamine, and extraction into toluene and estimation of the 5-nitropiaselenol under the same conditions as described above. 

Zinc Hydrosulfite Zinc Nitrate Fluorine Graphite Oxygen Chlorine Nitrous Acid Sulfurous Acid Hydrogen Sulfide Selenic Acid Ammonium Hyposulfite Ammonium Thiosulfate Ammonium Sulfate Ammonium Phosphate Dibasic Diammonium Phosphate Hexafluorouranium Uranium Hexafluoride Silver Chloride Aluminum Fluoride Aluminum Trifluoride Aluminum Ammonium Sulfate Ammonium Alum Silver Bromide Magnesium Chloride Magnogene Barium Sulfite Bismuth Trichloride Cesium Bromide... 

Shimoishi and Toei [766] have described a gas chromatographic determination of selenium in non saline waters based on l,2-diamino-3,5-dibromobenzene with an extraction procedure that is specific for selenium (IV). Total selenium is determined by treatment of non saline water with titanium trichloride and with a bromine-bromide redox buffer to convert selenide, elemental selenium and selenate to selenious acid. After reaction, the 4,6-dibromopiazselenol formed from as little as lng of selenium can be extracted quantitatively into 1 ml of toluene from 500ml of natural water up to 2ng L 1 of selenium(IV) and total selenium can be determined. The percentage of selenium(IV) in the total selenium in river water varies from 35 to 70%. 

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