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精硒中硫的测定,多半采用燃烧比色法和燃烧碘量法,此法不仅工作条件差,而且不适于大批试样分析.我们参考文献,将硒中硫全部氧化为SO_4~(2-),在高温下硒呈SeO_2或溴化物挥发除去,残存的硒用HBr处理.SO_4~(2-)在过量BaCrO_4存在下,进行置换反应(BaCrO_4+SO_4~(2-)(?)BaSO_4+CrO_4~(2-)),继利用Cr(Ⅵ)与二苯偕肼的显色反应,间接光度法测定精硒中痕量硫.
The determination of sulfur in refined selenium, mostly using combustion colorimetry and combustion of iodine method, this method not only poor working conditions, and not suitable for a large number of sample analysis.We refer to the literature, the sulfur in the selenium is fully oxidized to SO_4 ~ (2- ), SeO_2 or bromide was volatilized and removed at high temperature, and the remaining selenium was treated with HBr.SO_4 ~ (2-) was replaced by BaCrO_4 + SO_4 ~ (2 -) BaSO_4 + in the presence of excess BaCrO_4, CrO_4 ~ (2-)). The colorimetric reaction of Cr (Ⅵ) with dibenzyl hydrazine followed by indirect spectrophotometry was used to determine trace sulfur in refined selenium.