三价铬镀铬液中三价铬的碘量法分析

改进了三价铬镀铬液中三价铬的分析方法。在弱酸性条件下,用过硫酸铵作氧化剂将三价铬氧化成六价铬,用碘量法测定六价铬,得到三价铬的质量浓度。实验表明,在弱酸性条件下,不加硝酸银作催化剂,用过硫酸铵能将三价铬完全氧化成六价铬。分析结果的相对平均偏差为0.13%。本法简单而准确,分析成本低,标准溶液稳定,优于传统方法。

Determination of Trivalent Chromium in Trivalent Chromium Plating Bath by Iodimetry

An analytical method of trivalent chromium in trivalent chromium plating bath was improved.The trivalent chromium is oxidized to form hexavalent chromium by using ammonium persulfate as oxidant under weak acidic conditions and without silver nitrate as activator.The hexavalent chromium is determined by iodimetry,and then the mass concentration of trivalent chromium is obtained.The tests show that the trivalent chromium can be oxidized completely by ammonium persulfate under under weak acidic condition without activator.The relative average deviation of the determination result was 0.13%.The method is simple,exact,lower anlaysing cost,and has a stable standard solution.So it is superior to the conventional method.