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铅的络合滴定较早应用的指示剂以铬黑T为最多,近几年不少人改用二甲酚橙、PAN和Gu-PAN在酸性溶液中(pH5)进行铅的测定。对于铟镓铅锑合金中铅的测定我们采用了以硫酸铅沉淀形式将铅与铟、镓、锑分离后,分别以铬黑T、二甲酚橙、PAN和Gu-PAN作指示剂进行了比较,发觉用铬黑T和二甲酚橙时,二者终点变化均不明显,且前者常使终点延缓。比较了PAN与Cu-PAN两指示剂,发觉用Gu-PAN在碱性溶液(pH9～10)及在酒石酸的存在下,能得到相当明显突变的终点,溶液
Lead complexometric titration of the indicator used earlier to chrome black T is the most in recent years, many people use xylenol orange, PAN and Gu-PAN in acid solution (pH5) lead determination. For the determination of lead in indium gallium lead-antimony alloy we used lead sulfate precipitation form of lead, indium, gallium, antimony separation, respectively, with chrome black T, xylenol orange, PAN and Gu-PAN as an indicator Comparison, found that with black chrome black T and xylenol orange, the end point of the two changes are not obvious, and the former often make the end of delay. Comparing the two indicators of PAN and Cu-PAN, found that Gu-PAN in alkaline solution (pH9 ~ 10) and in the presence of tartaric acid, can get quite obvious end point of the mutation, the solution