2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺与钌(Ⅱ)的显色反应及其应用

来源期刊：冶金分析2010年第5期

论文作者：韩权 霍燕燕 陈虹 杨晓慧

文章页码：54 - 57

关键词：钌； 分光光度法； 2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺

Key words：ruthenium； spectrophotometry； 2-(5-iodine-2-pyridylazo)-5-dimethylamino-aniline

摘    要：研究了2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺(5-I-PADMA)与Ru(Ⅱ)的显色反应并以5-I-PADMA作为显色剂分光光度法测定钌的方法。在pH4.0～6.2 HAc-NaAc缓冲溶液中,盐酸羟胺存在并加热条件下,Ru(Ⅱ)可与5-I-PADMA形成稳定的1∶2络合物。该络合物形成后,可稳定存在于无机酸(HCl,H₂SO₄,HClO₄,H₃PO₄)中,适宜的酸浓度范围分别为0～2.0 mol/L HCl,0～1.8 mol/L H₂SO₄,0～1.7 mol/L HCl O4和0～3.0 mol/L H₃PO₄,其最大吸收峰位于618 nm,表观摩尔吸光系数达5.22×10⁴ L·mol^-1·cm^-1。钌(Ⅱ)浓度在0～1.0 mg/L范围内符合比尔定律。利用EDTA作掩蔽剂,可允许较大量的常见金属离子存在。所拟方法用于钌炭催化剂和钌分子筛中微量钌的测定,相对标准偏差分别为1.2%和0.41%(n=6)。

Abstract: The coloring reaction of 2-(5-iodine-2-pyridylazo)-5-dimethylaminoaniline (5-I-PADMA) with ruthenium(Ⅱ) was studied,and a new spectrophotometric determination method of ruthenium(Ⅱ) was established using 5-I-PADMA as coloring reagent.In HAc-NaAc buffer solution at pH 4.0-6.2,ruthenium(Ⅱ) could react with 5-I-PADMA to form a 1∶2 complex under heating in the presence of NH₂OH·HCl.The complex was stable in inorganic acid.The appropriate concentration for HCl,H₂SO₄,HClO₄ and H3PO4 was 0-2.0 mol/L,0-1.8 mol/L,0-1.7 mol/L and 0-3.0 mol/L,respectively.The maximum Absorption wavelength was at 618 nm,and the apparent molar Absorptivity was 5.22 ×10⁴ L·mol^-1·cm^-1.Beer’s law was obeyed for ruthenium(Ⅱ) in the range of 0-1.0 mg/L.Most of the common ions could exist using EDTA as masking reagent.The proposed method has been successfully applied to the determination of trace ruthenium in ruthenium-carbon catalyst and ruthenium-molecular sieve,with relative standard deviations(RSD) of 1.2 % and 0.41 %(n=6),respectively.