在我们实验室中曾研究过用碘酸盐-络合滴定法测定钍,该法在于以碘酸盐形式从伴生元素中分离出钍,用定量的氨羧络合剂Ⅲ标准溶液溶解滤出的沉淀,然后以1-(2-吡啶偶氮)-2-萘酚作指示剂用硫酸铜标准溶液反滴定过量的氨羧络合剂Ⅲ溶液。当滴定到终点时,浅绿色的溶液可被一滴过量的硫酸铜溶液明显地变为红紫色。 In our laboratory has been studied using iodate - complexometric titration thorium, which is based on the form of iodate from the accompanying elements isolated thorium, with a quantitative ammonia carboxylamine complex Ⅲ standard solution dissolved filter The precipitate was then back-titrated with an excess of copper carboxylate III solution using 1- (2-pyridylazo) -2-naphthol as an indicator. When titrating to the end point, the light green solution can clearly turn magenta with a drop of excess copper sulphate solution.