Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai Shandong, 264003, PR China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, 26620, PR China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, Shandong, 266071, PR China.
Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Environmental Processes, YICCAS, Yantai Shandong, 264003, PR China; School of Chemistry and Materials Science, Ludong University, Yantai, 264025, Shandong, China.
Talanta. 2021 Sep 1;232:122489. doi: 10.1016/j.talanta.2021.122489. Epub 2021 May 1.
The developments of alternative signal readout strategies for the ion-selective electrodes (ISEs) are necessary in order to break through the limitation of the Nernst equation. In this work, a simple, convenient and easily operated strategy based on the non-enzymatic amperometric measurement of HO is proposed to read out the potentiometric responses for the ISEs. The proposed amperometric signal readout based on HO is carried out in a two compartment electrochemical cell configuration containing a detection cell and a sample cell, physically connected by a salt bridge. A glassy carbon (GC) electrode is placed in the detection cell to monitor the oxidation current of HO, and an ISE is placed in the sample cell to act as both the reference electrode and the potentiometric sensor for obtaining the ion activities. The oxidation of HO is induced by a constant potential applied between the GC electrode and the ISE, and subsequently modulated by the potential change of the ISE in the presence of the primary ion. The proposed amperometric signal readout based on HO shows the satisfied slope sensitivity and detection limit, which are better than or compared to those for the potentiometric responses for the ISEs. This work provides a general strategy for transforming the potential response of the ISEs into the amperometric readout, and is promising for detection of cations (eg., Ca) and anions (eg., NO) with high sensitivity and excellent selectivity.
为了突破能斯特方程的限制，有必要开发替代的离子选择性电极（ISE）信号读出策略。在这项工作中，提出了一种简单、方便且易于操作的策略，基于 HO 的非酶电流测定来读出 ISE 的电位响应。基于 HO 的提出的电流信号读出是在包含检测池和样品池的两室电化学池配置中进行的，通过盐桥物理连接。将玻碳（GC）电极置于检测池中以监测 HO 的氧化电流，将 ISE 置于样品池中作为参考电极和电位传感器，以获得离子活性。通过在 GC 电极和 ISE 之间施加恒定电位来诱导 HO 的氧化，随后通过在主要离子存在下 ISE 的电位变化来调制。基于 HO 的提出的电流信号读出表现出令人满意的斜率灵敏度和检测限，优于或与 ISE 的电位响应相当。这项工作为将 ISE 的电位响应转化为电流读出提供了一种通用策略，有望用于高灵敏度和优异选择性地检测阳离子（例如 Ca）和阴离子（例如 NO）。
