离子交换树脂分离富集催化动力学电位法测定痕量钒  

Catalytic-Kinetic Potentiometric Determination of Trace Amount of Vanadium After Anion Exchange Separation

作　　者：李慧芝[1] 范荣[1] 翟殿棠[1] 杜旭[1] 

机构地区：[1]济南大学化学化工学院,济南250022

出　　处：《理化检验（化学分册）》2008年第2期131-133,共3页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：山东省博士基金(NO.2002BS0501)

摘　　要：研究了在稀硫酸介质中,以痕量钒（Ⅴ）催化溴酸钾氧化碘化钾的反应为指示反应,用碘离子选择电极跟踪I^-,建立了催化动力学电位法测定钒的方法。在一定的条件下,该指示反应为一级反应,反应速度可用电位的变化ΔE表示。当时间固定,ΔE与钒（Ⅴ）浓度在0.015-0.1 mg·L^-1范围内呈线性关系。方法的检出限为3.2×10-7g·L^-1。该法可用于钢铁样品中钒的测定,试样溶液中钒（VO4^3-）预先从弱碱性溶液中（pH 7.0-8.2）用强碱性阴离子交换树脂分离。用1.0 mol·L^-1硫酸从树脂上将钒（Ⅴ）洗脱后按所述方法测定。测定结果与标准值相符,相对标准偏差小于5%。In a dil. H2SO4 medium, the oxidation of I^- ion by KBrO3 was catalyzed by trace amount of vanadium（Ⅴ）, and the potentiol change of I2/I3^- was detected by iodide ion selective electrode. It was found that the difference of potentials between the non-catalyzed reaction and catalyzed reaction （ΔE= E0-E1） was kept in linear relationship with the concentration of vanadium（Ⅴ） in the range from 0. 015-0.10 nag of V（Ⅴ ） per L, with a detection limit of 3.2×10-Tg·L^-1. It was also shown that the catalytic reaction was a lst-order reaction, and its rate of reaction was expressed by △E. In its application to the determination of vanadium in steel samples, a preliminary anion ion-exchange separation of vanadium as VO4^3- on 717 strong-basic anion exchange resin from a slightly basic solution of pH 7. 0-8. 2. The vanadium （VO4^3-） was eluted from the resin with 1. 0 mol·L^-1 H2 SO4, and determined by the proposed method. The results obtained were checked quite well with the standard values, and values of RSD＇s （n=9） were less than 5%.

关 键 词：催化动力学电位法 钒(Ⅴ) 碘离子选择电极 阴离子交换分离 

分 类 号：O657.31[理学—分析化学]