碘化钾-亚甲基蓝浮选光度法测定痕量Pb(Ⅱ)的研究  

Flotation spectrophotometry determination of trace Pb(Ⅱ) by potassium iodide-methylene blue

作　　者：陈婷玉[1] 李春香[1] 闫永胜[1] 

机构地区：[1]江苏大学化学与化工学院,江苏镇江212013

出　　处：《化学试剂》2006年第8期485-486,504,共3页Chemical Reagents

基　　金：科技部创新基金项目(03C26213200932);江苏大学高级人才基金项目(04JDG017)资助

摘　　要：利用Pb^2＋-I^--[MB]^＋三元体系，研究了溶剂浮选光度法测定铅的方法，考察了pH、配合剂用量、浮选时间及浮选剂等因素对浮选和测定的影响，优化出最佳浮选及测定条件。在水溶液中，Pb（Ⅱ）与碘化钾、亚甲基蓝生成稳定的三元离子配合物[Pbl4]^2-·[MB]2^＋，该配合物在水相与有机相间形成第3相，并溶于丙酮，于λmax=657nm处测定吸光度，进而可确定Pb^2＋的含量。本法操作简便，快速，灵敏度高（e657=5．05×10^5L·mol^-1·cm^-1），精密度理想（在25mL溶液中，平行测定5．0μg Pb（Ⅱ）11次，RSD=2．76％），Pb（Ⅱ）的浓度在3．0—18．0μg／25mL范围内服从比尔定律，方法检出限为5．18×10^-5μg／mL。该方法适用于各种环境水样中铅的分析检测。The determination of Pb（ Ⅱ ） with solvent flotation system of Pb^2＋-I^--[MB]^＋ was studied in this paper. Several parameters, including the pH value, the volume of complex reagent, the flotation time, and the organic solvent used were studied. The optimal conditions of determination were selected. The results show that ternary ion-association precipitates[ PHI4]^2-·[ MB]2^＋ were formed. The flotation[ PhI4 ]^2- ·[ MB]2^＋ in acetone was dissolved and the absorbance of the solution at 657nm was measured. This method has the advantage of convenience, rapidity and high sensitivity （e657=5.05×10^5L·mol^-1·cm^-1）. It has been proved to have satisfactory precision （5.0μg Pb（ Ⅱ ） n = 11, RSD = 2.76 % ）. The calibration curve was linear over the range of 3.0 - 18.0μg/25mL. Detection limit of this method was found to be 5.18 × 10^-3μg/mL.The method can be satisfactorily applied to determining lead in waste water,and the average recoveries of Pb（ Ⅱ ） was about 97.4% - 103.6%.

关 键 词：浮选光度法 离子配合物 铅 

分 类 号：O614.43[理学—无机化学]