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武汉大学化学系近几年来合成了多种不对称双偶氮变色酸类试剂,其中之一是2-(2-胂酸基苯偶氮)-7-(2,6-二溴-4-磺酸苯偶氮)-1,8-二羟基萘-3,6-二磺酸,简称DBS-儡氮胂。它与轻稀土的显色反应研究尚少,文献介绍是在盐酸介质中进行,因而不适用于银合金分析。本文研究了在pH 3的硝酸-邻苯二甲酸氢钾缓冲介质中,铈与DBS-偶氮胂反应条件。方法的选择性高,镍、锰、钴、锌及大量的银不干扰铈的测定。方法操作简便,可用于直接测定10~(-1)～10~(-3)%铈。在测定银中10~(-2)%的铈时,其变动系数为1.28%。
In recent years, the Department of Chemistry, Wuhan University has synthesized a variety of asymmetric disazo chromotropic acid reagents, one of which is 2- (2-arsanoylphenylazo) -7- (2,6-dibromo- Sulfonated phenylazo) -1,8-dihydroxynaphthalene-3,6-disulfonic acid, referred to as DBS-arsenazo. It has little research on the color reaction of light rare earths. The literature introduction is carried out in hydrochloric acid medium, so it is not suitable for silver alloy analysis. In this paper, the reaction conditions of cerium with DBS-arsenazo in pH 3 nitric acid-potassium hydrogen phthalate buffer medium were studied. High selectivity of the method, nickel, manganese, cobalt, zinc and a large amount of silver does not interfere with the determination of cerium. The method is simple and can be used for the direct determination of 10 ~ (-1) ~ 10 ~ (-3)% cerium. In the determination of silver 10 ~ (-2)% of the cerium, the coefficient of variation of 1.28%.