摘要
研究了新试剂2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺(5-I-PADMA)与铱(Ⅲ)的高灵敏显色反应。结果表明,在pH 5.6～7.3的HAc-NaAc缓冲溶液中,铱(Ⅲ)与5-I-PADMA可形成稳定的1:2配合物,其最大吸收峰位于475 nm;铱配合物形成后,当以适量的无机酸(HC l,H2SO4,HC lO4,H3PO4)酸化,可转变为另一种具有较高吸收特性的质子化形体,其吸收峰红移至616 nm,适宜的酸浓度范围分别为0.6～6.0 mol/L HC l、0.24～3.9 mol/L H2SO4、0.6～3.9 mol/L HC lO4和0.6～7.2 mol/L H3PO4,表观摩尔吸光系数达1.01×105L·mol-1.cm-1,是目前测定铱的高灵敏二元显色体系之一。铱(Ⅲ)含量在0～0.7μg/mL范围内符合比尔定律。本法应用于催化剂中微量铱的测定,结果满意。
The highly sensitive color reaction of 2-（5-iodine-2-pyridylazo）-5-dimethylaminoaniline（5-I-PADMA） with iridium（III） has been studied.The experimental results show that iridium（III） reacts with 5-I-PADMA in a buffer solution of HAc-NaAc at pH 5.6 ~ 7.3 to form a stable 1：2 complex,and it shows a maximum absorption peak at 475 nm.The complex can be changed into another stable proton species possessing a higher absorption characteristic by acidification with a mineral acid（e.g.HCl,H2SO4,HClO4,H3PO4）.The optimal concentrations of HCl,H2SO4,HClO4 or H3PO4 are found to be 0.6 ~ 6.0 mol/L HCl,0.24 ~ 3.9 mol/L H2SO4,0.6 ~ 3.9 mol/L HClO4 and 0.6 ~ 7.2 mol/L H3PO4 respectively.The apparent molar absorptivity is 1.01×105 L · mol-1 · cm-1 at the maximun absorption of 616 nm.Beer＇s law is obeyed in the range of 0 ~ 0.7 μg/mL for iridium.The method is convenient,fast and highly sensitive.It has been successfully applied to the determination of trace iridium（III） in catalyst with satisfactory results.
出处
《分析试验室》
CAS
CSCD
北大核心
2011年第7期50-53,共4页
Chinese Journal of Analysis Laboratory
基金
陕西省自然科学基础研究计划项目(2010JM2018)资助
