钒金试剂作指示剂容量法测定痕量铀  

Vanadate Titration of Trace Uranium in Natural Water by Using a New Vanadate-Gold Indicator

作　　者：李玉成 

机构地区：[1]广东省韶关市六十三号信箱 512026

出　　处：《岩矿测试》1990年第2期152-154,共3页Rock and Mineral Analysis

摘　　要：铀是放射性物质,又是变价元素。它易被水溶解和迁移,故广泛存在于天然水之中。地质、环保、卫生防疫等工作都需要准确快速测定天然水中铀含量。目前普遍采用活性炭富集分离固体荧光光度法、TOPO萃取富集分离固体荧光光度法和激光荧光光度法。前两种方法富集分离手续冗长,而激光荧光光度法的仪器应用尚不广泛。本文在Ti(Ⅲ)还原,NH_4VO_3滴定法测定矿石中U的基础上,采用高灵敏的钒金试剂作指示剂,在22—27％的H_3PO_4介质中直接测定天然水中痕量U。A new vanadate-gold indicator was applied successfully to the vanadate titration of trace uranium in natural water. Uranium in the water sample (1 ml) is reduced to U (Ⅳ) by TiCl3 in phosphoric acid. NaNO2 is added to oxidize the excess Ti (Ⅲ) and other reducing elements while the U (Ⅳ) in phosphate complex remains untouched. The , excess nitrite is destroyed with urea and the U(Ⅳ) titrated against standard ammonium vanadate (T=0.5-50000ng U/ml) in a 22-27% H3PO4 medium, with the addition of one drop of the new indicator. The end point is judged by a violet-red color. The range of determination is 1 f1 10^(-8)-1 f1 10^(-2)g/L for uranium.

关 键 词：钒金 试剂 指示剂 容量法 铀 水 

分 类 号：P578.41[天文地球—矿物学]