2′(2呋喃亚甲基)水杨酰腙Schiff碱铜(Ⅱ)配合物为中性载体的高选择性硫氰酸根离子选择电极的研究

Study on Highly Selective Thiocyanate Electrode Based on Copper(Ⅱ) Complex with 2′-(2-Thienylidence)- Hydroxybenzoylhydrazide as Neutral Carriers

首次研究了以2＇-（2-呋喃亚甲基）水杨酰腙Schiff碱铜（Ⅱ）配合物[Cu（Ⅱ）-THBH]为中性载体的PVC膜电极，该电极对硫氰酸根离子（SCN^-）具有优良的电位响应特性并呈现出反Hofmeister选择性行为，其选择性次序从大到小为：SCN^-，Sal^-，CLO4^-，I^-，Br^-，NO3^-，Cl^-，NO2^-，SO3^2-，SO4^2-，H2PO4^-．电极在pH5．0的磷酸盐缓冲体系中，对SCN^-在1．0×10^-1～5．0×10^-6mol／L浓度范围内呈近能斯特响应，斜率为-53．4mV／dec（25℃），检测下限为1．2×10^-6mol／L．利用交流阻抗和紫外可见光谱初步研究了阴离子与载体的作用机理．结果表明配合物中心金属原子的结构以及载体本身的结构与电极的响应行为之间有非常密切的构效关系．该电极具有响应快、重现性好、检测限低、制备简单等优点．将电极初步应用于实际样品废水分析，结果与HPLC法一致．

A new highly selective thiocyanate electrode based on Copper（Ⅱ ） Complex with 2＇-（2-Thienylidence）-Hydroxybenzoylhydrazide [Cu（ Ⅱ ）-HTBH] as neutral carrier is developed, which displays an antiHofmeister selectivity sequence： SCN^- ,Sal^- ,ClO4^- ,I^- ,Br^- ,NO3^- ,Cl^- ,NO2^- ,SO3^2- ,SO4^2- , H2PO4^-. The electrode exhibits Nernstian potential linear range to thiocyanate from 1.0× 10^-1 to 5.0× 10^-6 mol/L with a detection limit 1.2 × 10^-6 mol/L and a slope of 53. 4 mV/dec in pH 5.0 of phosphorate buffer solution at 25 ℃. The response mechanism is discussed in view of the a. c. impedance technique and the UV spectroscopy technique. These deviations result from the direct interaction between the central metal and the analyte ion and steric effect associated with the structure of the carrier. The electrode has the advantages of simplicity, fast response, fair stability and reproducibility and low detection limit. The electrode can be applied to waste water analyis and the result obtained is fair agreement with the result given by HPLC methods.