Department of Applied Chemistry, Tokyo University of Science, Shinjuku, Tokyo 162-8601, Japan.
Analyst. 2017 Oct 9;142(20):3857-3866. doi: 10.1039/c7an01068k.
All-solid-state ion-selective electrodes as potentiometric ion sensors for lithium, sodium, and potassium have been demonstrated by installing a composite layer containing a powder of alkali insertion materials, LiFePO, NaMnO, and KMnO·nHO, respectively, as an inner solid-contact layer between the electrode substrate and plasticized poly(vinyl chloride) (PVC)-based ion-sensitive membrane containing the corresponding ionophores for Li, Na, and K ions. These double-layer ion-selective electrodes, consisting of the composite and PVC layers prepared by a simple drop cast method, exhibit a quick potential response (less than 5 s) to each alkali-metal ion with sufficient Nernstian slopes of calibration curves, ca. 59 mV per decade. The installation of the insertion materials as the inner solid-contact layers is highly efficient for the stabilization of membrane potential, resulting in a prompt response to the alkali ion activity in the analyte, compared to those of the electrodes without the alkali insertion materials. From alternating current impedance measurements for the electrodes, the inner layer of the installed alkali insertion materials drastically reduces the impedance of the membrane/electrode interface, leading to an improvement in their ion-sensing performance.
全固态离子选择性电极作为电位型离子传感器，用于锂、钠和钾，通过安装包含碱插入材料的粉末的复合层来实现，分别为 LiFePO、NaMnO 和 KMnO·nHO，作为电极基底和含有相应离子载体的增塑聚（氯乙烯）（PVC）基离子敏感膜之间的内固相接触层，用于 Li、Na 和 K 离子。这些双层离子选择性电极由通过简单的滴铸方法制备的复合层和 PVC 层组成，对每个碱金属离子具有快速的电位响应（小于 5 s），校准曲线的斜率约为 59 mV/decade。将插入材料作为内固相接触层安装对于稳定膜电位非常有效，与没有碱插入材料的电极相比，这导致对分析物中碱离子活性的快速响应。通过对电极进行交流阻抗测量，安装的碱插入材料的内层大大降低了膜/电极界面的阻抗，从而提高了它们的离子传感性能。
