聚乙烯醇存在下高铼酸根与乙基紫光度法测定钼样中痕量铼

Spectrophotometric determination of trace rhenium in molybdenum samples using the system of ReO-4-ethyl violet-polyvinyl alcohol

提出用高铼酸根-乙基紫-聚乙烯醇体系直接光度法测定铼的方法。在表面活性剂存在下,乙基紫与高铼酸根形成的离子缔合物分散在水相中而进行的显色反应,不但解决了乙基紫与高铼酸根缔合物水溶性差的问题,而且提高了显色反应的灵敏度。显色反应的最大吸收波长为647nm,采用摩尔比、等摩尔连续变化和平衡移动法测定了该离子缔合物中乙基紫与高铼酸根的组成比为1∶1。在10mL溶液中铼的线性范围为0～10.0μg,ε647=1.36×105L.mol-1.cm-1,检出限为1.4×10-3μg/mL。适量的柠檬酸或酒石酸存在下,钼、钨不干扰。用于烟道灰、氧化钼、钼砂样品中痕量铼的测定,样品加标回收率为97.0%～100.6%。

A direct spectrophotometry for the determination of rhenium using ReO4^- ethyl violet- polyvinyl alcohol system is reported. The ethyl violet reacts with ReO4^- to form an ion association complex, which is easy to solve a dissolve in aqueous phase inthe presence of polyvinyl alcohol. This not only solve a difficulty of in-soluble in water, but also increase in reaction sensitivity. The reaction product has maximum absorption at 647 nm. By using the method of molar ratio, continuous variation and equilibrium shift, the composition ratio of ethyl violet and ReO4^- in the ion association complex is found to be 1 ： 1. Beer＇s law is obeyed in the range of 0 - 10.0μg/10 mL. An apparent molar absorptivity is ε647 = 1.36 × 10^5 L·mol^-1 ·cm^-1. The detection limit is 1.4 ×10^-3μg/mL. In the presence of right amounts of citric acid or tartaric acid, molybdenum and tungsten do not interfere. The method has been applied to the determination of trace rhenium in molybdenum trioxide, flue dust and molybdenum ore samples with recovery of 97.0 % - 100.6 %.