钛铁试剂光度法快速测定镀铬溶液中的铁

Quick Speetrophotometrie Determination of Iron in Cr Plating Solution with Tiron

本文用钛铁试剂作试剂,利用它和三价铁在弱酸性溶液中生成稳定的蓝色络合物,用光度法测定镀铬溶液中铁杂质的含量。采用72型分光光度计,3cm比色皿,以水作参比液,在波长680nm处比色测定。试验表明,钛铁试剂-Fe(Ⅲ)络合物的吸光度在pH3-7的范围内不随酸度而变化,还表明,当CrO_3高至500g/l,CR_2O_310g/l,Cu^(+2)5g/l,F-10g/l,SiF_6^(2-)10g/l时,对测定铁没有干扰。本文方法简练,快速而准确,优于其它各种方法。

The iron content in Cr plating solution is determined with spectrophotometric method by using Tiron(catechol sodium disulfonate)as reagent, which can react with Fe^(3+) ions in weak acidic solution and form blue complex. The spectrophotometric determination is carried out at 680nm by usidg Model 172 spectrophotometer and 3cm cell with water as reference solution. The extinction value is stable at the range of pH 3-7 and the relationship between extinction value and Fe^(3+) content strictly obey the Law of Beer. Tests show that when CrO_3 reaches 500 g/L, Cr_2O_3 10 g/L, Cu^(2+) 5 g/L, F^- 10 g/L. and SiF_4^- 10 g/L, no interference would occur. The method is simple, rapid, accurate and superior to others.