用于检测铁离子的PVC膜的初步研究

A PRELIMINARY STUDY ON PLASTICIZED PVC MEMBRANE FOR IRON(Ⅱ) ION'S DETECTION

目的 :研究固定在PVC膜上的络合显色剂与水中Fe2 +的反应特性。方法 :以 4 ,7-二苯基 - 1,10 -二氮杂菲为显色络合剂 ,PVC膜为固相介质 ,初步研究了应用PVC膜检测水中Fe2 +离子的固相萃取分光光度分析法 ;从反应动力学的角度 ,讨论了影响有色配合物在PVC膜上形成的膜成分因素。结果 :脂溶性的阴离子添加剂和增塑剂是影响有色配合物在PVC膜上形成的重要因素 ,加入阴离子添加剂有利于Fe2 +与 4 ,7-二苯基 - 1,10 -二氮杂菲在PVC膜上形成有色配合物的速度在一段时间内保持稳定 ,显色试剂在增塑剂中的溶解度、显色试剂及配合物在增塑剂中的扩散速率 ,对显色反应完全后PVC膜的吸光度大小及反应过程中吸光度随时间增加的速率有影响 ;与Fe2 +反应后 ,PVC膜的光密度值与Fe2 +浓度成正比。结论 :本研究为PVC膜最终应用于Fe2

Objective: To study the specialities of reaction being taken place between chelate reagent in PVC membrane and Fe 2+ in water.Methods:By using bathophenanthroline as a chelate reagent,PVC membrane as an extraction medium, a solid-extraction spectrophotometric method for detection of Fe 2+ in water was developed.From the reaction kinetic point of view,the components of membrane which influenced the colored chelate complex formation in membrane have been discussed. Results: The lipophilic anion additive and plasticizer were important factors influenced the colored chelate complex formation .Lipophilic anion additive helped Fe 2+ and bathophenanthroline to form the colored chelate complex in a relative constant rate in PVC membrane; the chelate reagent's solubility and its diffusion rate in plasticizer may influence the absolute value of absorbance in PVC membrane after reaction and the increasing rate of absorbance with time during the reaction. After reacting with Fe 2+ solution ,the optical density of PVC membrane was proportional to the concentration of Fe 2+ . Conclusion: This study laid the base for determination of Fe 2+ in water using PVC membrane containing bathophenanthroline.