基于UV光固化聚合膜硫氰酸根离子选择性电极的研究

Thiocyanat Selective Electrodes Based on UV Photopolymerizable Membrane

以二丙烯酸脂肪族尿烷酯低聚物为基本原料 ,碘化十二烷基三庚基铵为电活性物质 ,采用 UV光固化聚合成膜研制硫氰酸根离子电位敏感电极。对膜的成分进行了优化 ,优化后的膜与 PVC膜比较具有较高的机械强度和较强的附着力。电极对硫氰酸根离子响应的线性范围为 4.7× 1 0 - 6 ～ 1 .0× 1 0 - 1mol/L,检测下限为 1 .2×1 0 - 6 mol/L ,电极斜率 5 7.5± 1 .5 m V/decade,对常见阴离子电位选择性系数进行了测试 ,电极具有良好的选择性。将电极用于人体尿样中硫氰酸盐的测定 。

A photocurable polymer membrane for thiocyanate sensitive electrode was developed based on aliphatic urethane diacrylate as raw material and dodecyltrioctyl ammonium iodide as ionophore. A homogeneous and transparent membrane can be obtained by high power UV directly irradiating prepolymer of electrodes for several seconds, but not in a nitrogen atmosphere. Dodecyltrioc tylammonium iodide was directly used as the ionophore of thiocyanate electrodes, which was activated using thiocyanate solution. Procedure of preparation electrodes has been obviously simplified. The membrane composition has been optimized in order to attain good mechanical properties and optimal electrode response by adjusting ratio of monomer, reactive diluent, ionophore and plasticizer in the experiment. Optimal membrane exhibited better mechanical properties such as adhesion compared to PVC membranes. Proposed electrode responded to thiocyanate ion in a linear response range between 4.7 ×10 -6 ~1.0×10 -1 mol/L with detection limit of 1.2×10 -6 mol/L and slope 57.5±1.5 mV/decade. The selectivity coefficients of electrode for common existing anions had been tested and the electrode showed fair selectivity. The electrode was preliminarily applied to the determination of thiocyanate in human urine with satisfactory results.