三元离子配合物浮选光度法测定痕量镉(Ⅱ)的研究  

Study on the flotation spectrophotometric determination of trace Cd(Ⅱ) by ion-pair complexes

作　　者：李春香[1] 陈婷玉[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9期527-528,546,共3页Chemical Reagents

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

摘　　要：利用Cd2^2＋-I^- MB^＋三元体系，研究了溶剂浮选光度法测定镉的方法。考察了pH、配合剂用量、浮选时间、及浮选剂种类等因素对浮选和测定的影响，优化出最佳浮选及测定条件。实验结果表明，在水溶液中Cd（Ⅱ）与碘化钾、亚甲基蓝生成稳定的三元离子配合物[CdI4^2-]·[MB^＋]2。该配合物在水相与有机相问形成第3相，并溶于丙酮，通过测定λmax=657nm处吸光度，可求得Cd^2＋含量。本法操作简便、快速、灵敏度高（ε657=3．21×10^5L·mol^-1·cm^-1），精密度理想（在25mL溶液中，测定2．0μg Cd（Ⅱ）9次，RSD=4．6％），Cd（Ⅱ）的浓度在1．0～5．0μg／25 mL范围内服从比尔定律，方法检出限为7．7×10^-8mog/L。实测了工业污水和生活污水中的镉，加标回收率为98．4％～99．0％，结果令人满意。This paper studies on the determination of Cd （Ⅱ） with solvent flotation system of Cd^2＋-I^--MB^＋ . Several parame-ters including pH value, volume of complex reagent, flotation time, and selection of organic solvent were studied. The testing conditions of Cd （Ⅱ） were optimized. The results showed that ternary ion-association precipitate[ CdI4^2- ]·[MS^＋]2 was formed. It was soluble in acetone and the maximum absorption of the solution was at 657 nm. This method had many advantages such as convenience, rapidity, high sensitivity （ε657=3.21×10^5L·mol^-1·cm^-1） and satisfactory precision （2.0 gg Cd（ Ⅱ ）n = 9, RSD = 4.6 % ） as well. The calibration curve was linear in the range of 1.0～5.0 μg/25 mL. The detection limit of this method was found to be 7.7 ×10^-8mol/L. The method has been applied to the determination of Cd（Ⅱ） in waste water with satisfactory resuits,and the recoveries of Cd（Ⅱ） were about 98.4% ～ 99.0%.

关 键 词：浮选光度法 离子配合物 镉 

分 类 号：O614.242[理学—无机化学]