光度法测定微量铁(Ⅲ)——基于其对溴甲酚绿与溴酸钾氧化褪色反应的催化作用  

Photometric Determination of Microamounts of Fe(Ⅲ) Based on Its Catalytic Effect on the Color-fading Oxidation Reaction of Bromocresol Green with Potassium Bromate

作　　者：孙雪花[1] 柴红梅[1] 马红燕[1] 刘珍叶[1] 惠会青[1] 

机构地区：[1]延安大学化学与化工学院,延安716000

出　　处：《理化检验（化学分册）》2009年第3期343-345,共3页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：陕西省延安大学校内专项基金(YDK2006-25)

摘　　要：在0．2mol·L-1磷酸介质中，铁（Ⅲ）对溴酸钾氧化溴甲酚绿指示剂褪色具有强的催化作用，从而建立了一种催化动力学光度法测定铁的方法。试验结果表明：在440nm最大吸收波长处，沸水浴条件下，时间控制在12rain时，△A（△A=A0-A）趋于稳定且最大。铁（Ⅲ）的线性范围在7．2～1800弘g·L叫内吸光度△A与铁（Ⅲ）浓度呈线性关系，检出限为6．8μg·L-1。用于测定几种不同水样中微量铁（UI），所得结果与火焰原子吸收光谱法的结果一致。方法的回收率在95．5％～100．1％之间，测定值的相对标准偏差（n=6）在2．8％～4．0％之间。It was found that in 0. 2 mol · L-1 H3PO4 medium, the redox reaction between bromocresol green and potassium bromate was strongly catalyzed by the presence of microamounts of ferric ion, leading to an enhancement of color-fading of the bromocresol green, the absorption maximum of which was found at 440 nm. The reaction attained to equilibrium by heating in a water bath at 100 ℃ for 12 min. Linear relationship between values of △A（△A=A0--A） and concentration of Fe（ Ⅲ ） ion was obtained in the range of 7. 2--1 800 μg per L of solution. Detection limit （3S/b） of the method was found to be 6. 8μg. L-1. In analyzing samples of water of different sources by the proposed method, results obtained were in consistency with the results found by FAAS method. Values of recovery and RSD＇s （n= 6） obtained were in the ranges of 95. 5- 100. 1% and 2. 8%- 4. 0% respectively. Keywords： Photometry; Catalytic color-fading; Ferric iron; Bromocresol green

关 键 词：光度法 催化褪色 铁 溴甲酚绿 

分 类 号：O657.31[理学—分析化学]