溴酸钾甲基橙钛铁试剂钒体系催化光度法测定痕量钒英文.doc

溴酸钾2甲基橙2钛铁试剂2钒( Ⅴ) 体系催化光度法测定痕量钒杨武 , 溴酸钾2甲基橙2钛铁试剂2钒( Ⅴ) 体系 催化光度法测定痕量钒 杨 武 , 张 煊 , 管 飞 (西北师范大学 化学化工学院 , 甘肃 兰州 730070) 摘 要 : 讨论了在钛铁试剂活化下钒催化溴酸钾氧化甲基橙的最佳反应条件 , 建立了测定钒的新方 法 . 在 011 mol·L - 1 H2 SO4 溶液中 , 506 nm 处监测反应 , 可测定 011～10010 ng·mL - 1 范围的钒 . 方法检 测下限可达 30 pg·mL - 1 , 比文献方法提高了 30 余倍. 用于铝合金及食品样中钒的测定 , 结果满意 . 关键词 : 钒 ; 催化光度法 ; 甲基橙 中图分类号 : O 65713 ; O 614151 + 1 文献标识码 : A 文章编号 : Ⅹ(2000) 0120075206 A modified spectrophotometric determination of vanadium by catalysis of the methyl orange2tiron2bromate reaction YANG Wu , ZHANG Xuan , GUAN Fei ( Chemistry Chemical Engineering College , Northwest Normal University , Lanzhou 730070 , China) Abstract : Conditions are described for improving the speed and sensitivity of a catalytic determination of vanadium. The reaction of methyl orange with potassium bromate using tiron as an activator at 011 mol·L - 1 sulfuric acid and spectrophotometric measurement at 506 nm are recommended. Reagent concentration , reaction temperature and p H were studied in detail . The calibration curves are obtained over the range 011～10010 ng·mL - 1 of vanadium by fixed2time method and the detection limit was down to 30 pg·mL - 1 , which was about 30 times better than the previous methods. The improved method was applied to determination of vanadium in aluminum alloy and food samples with satisfactory results. Key words : vanadium ; catalytic spectrophotometry ; methyl orange 1 Introduction Vanadium plays an important role in physiological systems including normalization of sugar levels , participation in various enzyme systems as an inhibitor and a cofactor and catalysis at the oxidation of 收稿日期 : 1999211224 基金项目 : 甘肃省教委科研资助课题 (961223) 第一作者简介 : 杨武 (1966 —) , 男 , 甘肃西和人 , 西北师范大学教授 , 博士. 主要研究方向为稀土配位化 学和光度分析中的超高灵敏反应. various various amines〔1 〕as well as acts as an essential element for cell growth atμg·L - 1 levels. However it can be toxic at higher concentration〔2 ,3〕. Recen