阻抑溴酸钾氧化乙基橙褪色动力学极谱法测定痕量铁  

Determination of trace iron by kinetic polarography based on inhibitory fading of ethyl orange oxidized by potassium bromate

作　　者：李艳霞[1] 贾华丽[1] 李玖零[1] 

机构地区：[1]周口师范学院化学系,河南周口466000

出　　处：《冶金分析》2012年第1期56-59,共4页Metallurgical Analysis

基　　金：河南省高等学校青年骨干教师资助计划项目(2010GGJS-154);周口师范学院实验室开放项目(201110)

摘　　要：在稀硫酸介质中,痕量铁(Ⅲ)对溴酸钾氧化乙基橙褪色反应有很强的抑制作用。基于乙基橙能在氨性介质中在电极上于-0.60V处产生灵敏的极谱吸附波,利用极谱法监测阻抑反应过程中乙基橙浓度的变化,建立了铁(Ⅲ)-溴酸钾-乙基橙体系阻抑动力学极谱法测定痕量铁(Ⅲ)的新方法。详细讨论了硫酸用量、溴酸钾用量、乙基橙用量及反应温度和时间等条件对铁(Ⅲ)测定的影响。在选定最佳条件下,方法的线性范围为0.004 8～0.4μg/mL,检出限为0.002 1μg/mL。用于水样中铁的测定,结果与火焰原子吸收光谱法测定值一致,相对标准偏差(RSD)为1.2%～2.9%。In dilute sulfuric acid medium,trace Fe（Ⅲ） had strong inhibitory effect on the fading reaction of ethyl orange oxidized by potassium bromate.The ethyl orange showed a sensitive polarographic adsorptive wave at-0.60 V on electrode in ammonia medium.Based on this,the change of ethyl orange concentration in inhibitory reaction was monitored by polarography.Consequently,a new determination method of trace Fe（Ⅲ） by inhibitory kinetics polarography in Fe（Ⅲ）-potassium bromate-ethyl orange system was established.The effect of sulfuric acid dosage,potassium bromate dosage,ethyl orange dosage,reaction temperature and time on the determination of Fe（Ⅲ） was investigated.Under the optimal conditions,the linear range of method was 0.004 8-0.4 μg/mL.The detection limit was 0.002 1 μg/mL.The proposed method was applied to the determination of iron in water.The results were consistent with those obtained by flame atomic absorption spectrometry.The relative standard deviation（RSD） was 1.2 %-2.9 %.

关 键 词：铁(Ⅲ) 乙基橙 阻抑反应 动力学极谱法 

分 类 号：O657.3[理学—分析化学]