萨文[1]提出的铀试剂Ⅲ已广泛地为许多元素的光度测定所采用。该试剂的主要优点是,它与钍、锆、铪及四价铀生成的络合物具有很高的稳定性。因此,能够在存在大量磷酸盐、草酸盐、酒石酸盐、柠檬酸盐的情况下测定这些元素。此外,用铀试剂Ⅲ光度测定上述元素的灵敏度也很高。铀试剂Ⅲ作为测定六价铀的试剂也同样具有很高的灵敏度(克分子消光系数为75500[2]), The uranium reagent III proposed by Savan [1] has been used extensively for the photometry of many elements. The main advantage of this reagent is its high stability to complexes with thorium, zirconium, hafnium and uranium. Therefore, these elements can be assayed in the presence of large amounts of phosphate, oxalate, tartrate, citrate. In addition, the uranium reagent Ⅲ photometric determination of the above elements is also very high sensitivity. Uranium reagent III also has high sensitivity as a reagent for the determination of hexavalent uranium (extinction coefficient of 75,500 [2]),