還元蒸留メチレン青(溶媒抽出)吸光光度法による鉄鋼中の微量硫黄の定量

概要

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A sensitive spectrophotometric method has been developed for the determination of microamounts of sulfur in iron and steel. The sample is dissolved in hydrochloric and nitric acids thus converting sulfur to sulfate. After removing nitric acid by heating with perchloric acid the sulfate is reduced with a mixture of hydriodic and hypophosphorus acids, and the hydrogen sulfide evolved is determined spectrophotometrically as methylene blue. For trace amounts of sulfur below 5 ppm, in order to increase the sensitivity of the method the methylene blue is furthermore extracted into dichloroethane as the ion pair with perchlorate. The proposed method is applicable to a wide variety of iron and steel samples although a slight modification is required when the sample contains selenium, titanium, niobium and tantalum. The range of determination is 0.5 to 100 ppm using 0.5 g sample ; the standard deviations at the 50 and 2 ppm levels are 0.7 and 0.1 ppm, respectively.
社団法人日本鉄鋼協会の論文
1981-12-01