以2─（2′，4＇，6＇─三羟苯基偶氮）苯胂酸光度法测定铁（Ⅲ）  

Spectropkotometric determination of iron(Ⅲ)using a novel reagent 2-(2′,4',6'-trihydroxyphenylazo)-benzenearsonic acid

作　　者：马会民[1] 黄月仙[1] 梁树权[1] 

机构地区：[1]中国科学院化学研究所

出　　处：《化学试剂》1995年第3期129-131,188,共4页Chemical Reagents

基　　金：国家自然科学基金;化学所所长基金

摘　　要：研究了新试剂２－（２＇，４＇，６＇－三羟苯基偶氮）苯胂酸（ＴＰＢＡ）与铁（Ⅲ）的显色反应。结果表明，铁（Ⅲ）与试剂在ｐＨ４．４的ＨＣｌ－ＮａＡｃ介质中发生专一显色反应，生成１：２棕红色配合物，其最大吸收位于５３５ｎｍ，摩尔吸光系数为４．２２×１０３Ｌ·ｍｏｌ－１·ｃｍ－１，线性范围为０～３μｇ／ｍＬ。拟定的方法选择性很高，可直接用于较复杂样品如土壤中总铁的测定。又由于５倍量Ｆｅ（Ⅱ）的共存不干扰，方法尚适用于Ｆｅ（Ⅲ）－Ｆｅ（Ⅱ）体系中Ｆｅ（Ⅲ）的选择性价态分析。分析结果均令人满意。Color reaction of a new reagent 2-(2',4', 6'-trihydroxyphenylazo)benzenearsonic acid(TPBA)with iron(Ⅲ),which is of specificity,has been investigated. It was found that a 1:2(Fe:TPBA)reddish brown complex was formed with a maximum absorption at 535nm in pH4.4 media of HCl-NaAc.The molar absorptivity is 4.22×103L·mol-1·cm-1 and the linear range 0～3μg/mL.The proposed method can be used to determine iron(Ⅲ)in complex samples such as soils.In addition, up to 5-fold Fe(Ⅱ)does not interfere with the determination of Fe(Ⅲ),thus the method is suitable for speciation analysis of Fe(Ⅲ)in the presence of Fe(Ⅱ)with satisfactory results.

关 键 词：三羟苯基偶氮 苯肿酸 分光光度法 铁 TPBA 

分 类 号：O614.811[理学—无机化学] O657.32[理学—化学]