Moriuchi-Kawakami Takayo, Kanaya Yuki, Urahama Yoshiaki
Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, 5-16-1 Omiya, Asahi, Osaka 535-8585, Japan.
Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology, 5-16-1 Omiya, Asahi, Osaka 535-8585, Japan.
Talanta. 2014 Sep;127:146-51. doi: 10.1016/j.talanta.2014.04.006. Epub 2014 Apr 15.
The potentiometric polymeric membranes for ion-selective electrodes were evaluated by analyses of the proton spin-spin relaxation times T2 with pulsed NMR. The T2 measurements were performed using the Hahn-Echo, Solid-Echo and CPMG pulse sequences. The T2 values and fractions F of each component were obtained by analyses of the FID signals measured with the Hahn-Echo pulse sequence. The softer potentiometric polymeric membrane possessed the main fraction F(L), providing a relatively longer T(2L) value. A linear relationship existed between the weight ratio of the membrane solvent and ln T(2L) (or ln total T2×F). This analysis method could quantify the degree of hardness or softness of the potentiometric polymeric membranes with the differences in the membrane solvent weight. The normalized derivative spectra were acquired from the transverse magnetization M(t) data measured by using the Solid-Echo and CPMG pulse sequences. In the normalized derivative spectra of the potentiometric polymeric membranes, most PVC peaks in the short time region shifted to a larger area of long time regions by plasticization, and the softer potentiometric polymeric membrane incorporating more membrane solvent exhibited a relaxation peak in the relatively longer time region. Thus, the normalized derivative spectra were effective in elucidating the compatibility of the PVC with the membrane solvent.
通过使用脉冲核磁共振分析质子自旋 - 自旋弛豫时间T2来评估用于离子选择性电极的电位聚合物膜。使用哈恩回波、固体回波和CPMG脉冲序列进行T2测量。通过分析用哈恩回波脉冲序列测量的自由感应衰减信号获得各组分的T2值和分数F。较软的电位聚合物膜具有主要分数F(L)，提供相对较长的T(2L)值。膜溶剂的重量比与ln T(2L)（或ln总T2×F）之间存在线性关系。这种分析方法可以根据膜溶剂重量的差异来量化电位聚合物膜的硬度或软度程度。从使用固体回波和CPMG脉冲序列测量的横向磁化强度M(t)数据中获取归一化导数谱。在电位聚合物膜的归一化导数谱中，短时间区域内的大多数PVC峰通过增塑转移到长时间区域的较大面积，并且含有更多膜溶剂的较软电位聚合物膜在相对较长的时间区域表现出一个弛豫峰。因此，归一化导数谱对于阐明PVC与膜溶剂的相容性是有效的。
