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PH10.3～10.5的HClO_4—Na_2SO_3—NH_4Cl—NH_4OH—EDTA-动物胶-KIO_4体系中,硒于-0.8伏左右产生一个非常灵敏的催化波,方法的基本条件及其机理已有报导.本文将此法应用于钢铁中微量硒的测定.拟定在盐酸:高氯酸:水=3:2:1的介质中,以抗坏血酸还原重铬酸根等氧化剂,用三氯甲烷萃取硒的溴化物,使硒有效地与铁及其它元素分离.本法适用于MnNiCrB钢、10PNbVTiZr钢、硅钢及其生铁中10~(-6)%硒的测定.方法的相对标准偏
Selenium has a very sensitive catalytic wave in the range of pH10.3 ~ 10.5 HClO_4-Na_2SO_3-NH_4Cl-NH_4OH-EDTA-animal glue-KIO_4 system. The basic conditions and mechanism of this method have been reported in this paper. This method is applied to the determination of trace selenium in steel.It is proposed that the oxidant such as dichromate is reduced with ascorbic acid in the medium of hydrochloric acid: perchloric acid: water = 3: 2: 1, the bromide of selenium is extracted with trichloromethane Selenium is effectively separated from iron and other elements.The present method is suitable for the determination of 10 ~ (-6)% selenium in MnNiCrB steel, 10PNbVTiZr steel, silicon steel and pig iron, and the relative standard deviation